Really, a quality video, with nice humor. I like that you give instructions for a safer and cleaner result. Plus you give explanations of what you are doing and why. Regardless of building or buying such a mini UPS, the learning process and understanding of the details are valuable for other projects plus as a general knowledge too. Thanks.
It's not working for me. Before connecting to boost converter, bms output voltage is 11.68 v but as soon as I connect it to boost converter, voltage drops to 0.67 V. And so can't step up the output for 12v. But when I connect boost converter directly to battery output, it works, which is not advisable !!! Please help with this
@@viralindia8951 if your bms output is 11.6v then you can easily use it as 12v. There's no need to use a boost converter. Also, there is a limit to the input voltage for the boost converter. You should check the specification.
Hi Sorin. Transforming 12 V -> 220 V in a UPS and back 220 V -> 12 V in a router's power supply was always not a good idea to me. I always wanted to get (build) a pure 12 V device. This your video inspired me to do that. Thank you so much for this! Please let me share some of my observations with other people working on such devices like me. 1) You can remove the step up converter from your schematic for most cases. The most of routers, network switches and others have buck converters inside. Usually they reduce voltage to 3.3 V to power the controller. This means you can power devices by even 5 V. Just try. You will be surprised. It looks like manufacturers choose power supplies having just economical reasons while devices can eat from 5 V to even 18 V. 2) Do not worry about back current into the power supply. It is usually less than 2 mA for most power supplies and is safe for them. Thank you again for your videos.
I like this design because you take extra care by A. putting the fuses directly on the battery as the BMS can fail and B. adding a capacitor on the output to smooth out the flow. Very nice. I'm going to make this, but with 3S.
this is a very practical project and anyone who suffers from random power outages should do this. Very simple and straight forward! Great video as always :D
You must add a diode to the laptop plug from where the adapter is connected to prevent the electricity from going back towards the charger. Not only would the backup of UPS will increase but it would be safer this way.
@@jithinramesh3022 The two main places that people source parts for electronics projects are AliExpress and Banggood. They're both Chinese websites which allow you to essentially get the parts for the cheapest price and they usually have global free shipping. I would personally recommend Banggood because I usually get my items within a week and a half when ordering from there vs AliExpress which can take weeks but usually not over a month. I live in New Zealand which means components ordered from these sites get here a bit faster then other parts of the world. As for your question regarding the components that Aji used I might recommend trying a premade board that essentially does everything the BMS in the video does in a single package. Something like this: www.banggood.com/18650-Lithium-Battery-Boost-Module-12V-Charging-UPS-Uninterrupted-Protection-Integrated-Board-With-C-p-1280431.html?rmmds=search&cur_warehouse=CN
@@ChillarPunter with 3S battery and 12V router no step up or step down converters are needed. Router will still work, even when supplied with 9V (3S battery at 1% charge)
Very nice, I was designing exactly such a thing for my rooter today and there pops up your video in my recommendations! In my design, I also added a constant current, constant voltage buck converter and set the current limit recommended on the data sheet of the 18650.
hi. if you used a buck converter, then it means you have a bigger battery pack. but the current limit of the buck converter is for the converter output, not the converter input (the battery pack). the input current and output current of the converter differs, depending on the load, converter efficiency and battery pack. there is nothing wrong with it, just don't set a lower output current than your router needs.
I have the battery pack charging FROM the buck converter output, that way when the battery is flat, it charges at constant current (1.65A for my cells... they're 3500mAh so ~0.5C charge) up until the preset voltage is reached for full charge, then it switches to constant voltage mode and then the current drops quickly down. I still use a boost converter on the battery pack to the UPS output to keep the voltage constant as the battery voltage drops. I then use a much higher voltage power supply (24V, ~1A, 25W) because its slightly cheaper and also I get better efficiency stepping down from higher voltages with the buck (>90%). The buck isn't strictly necessary and your design is elegant.
Brilliant.. I've lost a lot of work due power outages of few seconds, but that's enough for the router to restart and I have to wait until the router reconnects. I definitely try to do something similar as your mini ups. Thanks for the good idea.
Very nice and useful build. You explained everything very clearly and also put a list of the required components in your video description. Very well done.
If you want better efficiency, remove the step up converter and add one more battery in series. The router should be able to operate from about 9V up to 14V. Li-ion batteries work 3.5V - 4.2V, which gives you 10.5V - 12.6V power supply.
No, my router works 11v-18v. Although rated at 12v. It doesn't work anything less than 11v. So step up is mandatory. Schottky diodes are also required.
I like the precision temp sensor, also the cumbersome looking soldering iron... nice project to keep us occupied ... I think your cat looks as if it's been electrified, judging from the spiky fur... :)
Hello Sorin, Thank you for this video and it was helpful for me to provide a solution to the unexpected power outage of my wifi router. All the best and appreciate you.!!
8:00 you should also make a knot with the power cord inside the case, that way if you pull on the power cord, it wont pull the electronics out and damage the soldering points
That or one of those crimping type strain reliefs that just snaps into the hole a lot of appliances use. If space is the issue as in that small case one of those snap in might take less room.
Thank you Sorin for sharing this video, really informative , I have some notes regarding :1-You can use a battery holder for the 18650 you using in case you need to replace the batteries it will more easy rather than doing the soldering job again.2-You can use a protection schottky diode on the input side link SS54 so that the voltage can flow in one direction & not back to the charger in case of utility power outage 3-you can add a switch yo turn of the built in voltage meter to preserve some energy in case of long term power outages.4-what about low battery , should we get any indication when the battery is going low , it the UPS turn it self off in that case ?5-also what about short circuit protection on the output side ? Thank you.
hi. 1- yes you can use a battery holder, but I prefer to solder the cells. I test all the cells before I use them, so very rarely I had problems and need to replace cells. I prefer soldering the cells, because with battery holders there may be an imperfect contact in time between the cell and the holder, also the plastic enclosure needs to be bigger. 2- a diode will block the current from one direction, but it also has a small voltage drop. so the charging voltage will drop below 8V, which is not enough to charge the cells. the charger LED is using only a few mA, it doesn't make any difference in the 6 hours working time of the UPS. it remains like this for now. 3- the voltmeter display is using 17-20 mA, depending on how many LEDs are lit. so yes you can save a little energy by disconnecting it. you can add a capacitor and a microswitch to the voltmeter. when you press the microswitch for 1-2 sec, the capacitor is charged and the voltmeter will remain on for a few sec, enough to read the value. 4- the BMS has over discharge protection at around 2.9V per cell. you can check the UPS voltmeter, when the voltage decreases to under 6V, the cells are almost discharged and it will shortly turn off. I did this test in the video. 5- this step up converter doesn't have short circuit protection, so you can add another fuse on the positive output terminal. or you can use another (bigger) type of step up converter, with short circuit protection included.
Nice vid. I recently started using TP4056 Chrg/Prot boards with a long 22 gauge silicone electrical wire to help charge solar lights with 18650's when sunlight isnt good enough. With how well it works it doesn't make sense why big solar lights aren't designed with this feature built in
You have always inspired me to step out and try some of your projects. Thanks for the content. For the power flowing back to the adaptor, you could have a diode to prevent that, learnt that from a solar installation...
Those plastic bit in the case are called "stand offs". They "stand off" a pcb from the case. Normally used on pic's so the motherboard doesn't short against the case
with exactly same build you need one more step down DC to DC board to lower 12V from power supply to 8.5-8.4V to charge the whole mini UPS, all the rest stays the same.
Great explanation! Thank you, very easy to understand the operation of 18650 cells on smaller scale. I'm trying something similar before going larger, these things actually are alittle scary and should be treated with caution. One thing I don't understand, does the bms monitor each individual cell ? Thanks great job and that was an important tip selecting good vs bad batteries from the start. 👍👍
Friend, Sorin, thanks for an excellent tutorial. (I have subscribed) I like that your presentation was well photographed. Everything you showed was easy to understand. (even a dummy such as myself) One suggestion, perhaps go a bit slower. Thanks so much, looking forward to more of your presentations.
I built a small ups with a 9v battery and boosted it upto 12v using the converter, I used it to power my stereo speaker but after a few minutes it resetted itself and when it came back up it worked perfectly. But it killed my device's original speakers, now I'm stuck in headphone mode. I didn't have 2 18650 cells so that's why I used a 9v battery. But I have another recharge ups. Thanks for the tutorial friend.
Why not make it out of 3S for 12.6v fully charged and 9v fully discharged? Then you would not need the boost converter. Your fiber router would probably cut off around 10v or less than that.
I wanted to have a very stable 12V output. other people will probably make it for some other devices that may need a stable voltage. this is possible only with a dc converter. it will last longer with a step up converter, because it's using the entire battery capacity. and I wanted it to be small, with 3 cells it needs a bigger plastic enclosure.
yes a diode will block the current in the reverse direction, but it also has a forward voltage drop of around 0.9V so the charging voltage will drop under 8V, which is not enough to charge the cells. the charger LED is using only a few mA, it doesn't make any difference in the 6 hours working time of the UPS.
I've modded this good original design, my fibre router was affected by the high frequency of the boost output. Instead of 2x 18650+boost I found it simpler to use a 3S 20A Li-ion Lithium Battery 18650 Charger PCB BMS. and a standard 3s battery holder. Mod the standard router power lead to tee in the BMS via a 5.5 power jack and fix to the back of a standard 3s 185650 holder (if you need more double up and use 2 cells in parallel x3). 3 cells just about makes a good enough 12v and not having to boost makes life much less complicated, you can use the router's standard psu with bee sting connector to feed the BMS. Because the BMS is teed across the feed and doesn't intercept it - switchover is still instant and bonus is the batteries smooth the PSU output without a capacitor - it means you can disconnect (borrow) the UPS to act as a powerbank without powering down the Router so with the BS on the back of a standard 3 cell 18650 carrier I think it's actually a smaller footprint with a more convenient switchless "always on" connection. Because you tee the UPS to the power feed there is no chance of an accidental break in service win win.
+1 for ur humour and the smug face 😂 (1:10) Why you did not use your previous DIY charger to test the batteries?? maybe because it do not have a screen showing capacity of batteries? So time to make a v.2.0!! , DIY Charger and Tester Capacity for 18650 bats. Look ZB2L3 Battery Capacity Tester, not a bad module 😉 And look for us a DIY spot welding machine please, most uses microWave transformer, but a bit hard for simple hobbist... maybe with capacitor?? you will figure something it out 😊
just a tip, if you change the setting on the opus charger to "charge test" it will charge the cells up to 4.2, discharge them, giving you the discharge capacity, then charge them back up. making it easier and quicker to test them multiple times
Appreciate the compact circuit, I am also trying to make the same. But one query arises in my mind. That why we did not consider, reverse discharge protection diod in the supply side.
you can buy a cheap USB cable with barrel jack at the end, just make sure you buy the cable that can do a QC 3.0 handshake since you will be taking advantage of QC 3.0 12volt output. After that just buy a powerbank that supports QC 3.0 with 12v output, pretty much every QC3.0 compatible powerbank support it, after that daisy chain it with QC 3.0 usb charger and your good to go, a UPS for your ISP router, not to mention everything I told cost around 35-40USD for all of it.
Bro does it work normally by the 12V adapter and when the AC power is cut off it works from batteries. Or is it continuesely working from the battery power?
hi. the BMS board stops the charging of the cells when they are full. but if the charging voltage suddenly drops (main power is off) the BMS lets current from the cells to power the step up converter. if you want to build this UPS I suggest you use this BMS board, it's better: www.aliexpress.com/item/32863604994.html?spm=a2g0o.productlist.0.0.78a81a17yfgf8N&algo_pvid=7a7a9384-1f05-43f8-af1c-2152aba8627a&algo_expid=7a7a9384-1f05-43f8-af1c-2152aba8627a-1&btsid=0ab6d69f15918369686154295e5c92&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
Tocmai ce am trecut si eu la fibra optica si am si o gramada de celule si bms-uri, deci am ce face in weeknd! Multam de idee si cum ar spune americanu' : keep up the good work !
hi. buck/boost converters get very hot, because they work with a lower efficiency than buck or boost converters, so they use more current. also it depends on the load, if your router needs more current than mine, the converter will get even hotter.
Cute!!! I like this little ups! you earned a sub. I need to put a meter on my router and see how much it draws, and build a mini ups to suit (I have 4 18650 Samsung cells here waiting for a project!)
hey nice build i was searching for this kind of project as there is lots of power outage and generator takes time to start . can i leave the whole thing plugged in all the time will it over heat . and is the capacitor and the LCD necessary my router is rated for 12v 2amp
if you need a UPS with 12V and 2A you need something better. a 16.8V & 2-3A charger, a 4S BMS protection board with balance and overcharge release voltage features, a 4S battery pack and a 5A step down converter. 5A so it will not heat up at 2A.
Good video. Just a question, shouldn't you supply the BMS with a constant current to make sure that the batteries are not been charged with too much current. For example if you using 2000mah batteries, then you should limit the charging current to 1A. I have read the datasheet of the chipset on the BMS and there is nothing about current limiting onboard.
hi. the BMS board has an overcharge protection of 4.25-4.35V ± 0.05V. this voltage is a bit high and can stress the cells. you can add a diode in series with the charger and decrease the voltage to around 8V. this way the charging current will not be a problem. the current will also self limit, because a part of the charging current is used by the step up converter to increase the voltage to 12V, so a little over 1A will remain to charge the cells.
I have couple of questions: 1. Why capicitors and how do you determine the specification? 2. How are you handling the heat disscipitation from buck boost converter as with xl6009, and 8v to 12v with current 0.5 A, it generated good amount of heat.? 3. What is the total capacity and how long this product will support ie. 1 or 2 hours... Very well documented and good video.
hi. capacitors hold a small electrical charge. they are useful, for example, when you connect a big load, the supply voltage may decrease for a second. the capacitor charge will help to keep the voltage stable in that second. the bigger the capacitance, the higher the charge is. so for a bigger load you need a bigger capacitance. for voltage smoothing usually I use capacitors between 1000 - 6300uF, depending on the project. in this project, the step up converter IC only warms up a bit. it can handle up to 85 degrees C and I also added a small heatsink. but for higher current you need a bigger heatsink or a ventilated enclosure. more than that, my ONT is using maximum 270mA, so no problem with the heat. in these conditions it has an autonomy of around 6 hours.
I''ve seen other similar builds use a diode reverse bias on the negative terminal of the power input from power supply - you mention in the video that the charger light remains on because it is taking power from the UPS. Is that what would be prevented with the diode in place?
hi. the li-ion cells are not continuously charging. when the cells are fully charged, the charging process is stopped. but the cells will slowly self discharge and when the cell voltage is starting to decrease, the charging process starts again. the step up converter is powered by the charger, so the cells are not charging and discharging in the same time. the problem is that the cells will have a lot of charging cycles, this will decrease their lifespan. this cheap BMS board is not the best for this project, you need a BMS with overcharge release voltage.
Very nice tutorial, and a good basis for other mini ups projects like an emergency cell phone charger. Sure you got those mini power banks they sell, but those are way overpriced. Thank you.
Okay, so after checking again and again the problem was with the fuses. Without the fuses everything is fine. Interesting even though the fuses are meant for protection. Thank you for your help you are the best 😉
@@Sorin_DIY I'm thinking more batteries in parallel and probably a better BMS. Anything else? Is it possible to also create a relay path that totally cuts off the DC output for the AC charger if the AC charger is not energized?
If you are always charging the batteries and using the batteries to supply energy to the router, consider lower the charging voltage of the batteries. The batteries can be damaged if always working on maximum voltage. Lowering the voltage can increase the life time of the batteries
Hello Sorin, I am finding it difficult to understand the purpose of the switch. If the switch is in the off position, the UPS is not going to allow current to flow from the battery to the router, so the router will not work anyway. The whole point of the UPS is to keep the router working incase of a power outage. Your thoughts please.
Hi. The switch is installed between the battery (more exactly the BMS output) and the DC converter. there must always be a way to completely cut off the battery from the load.
Interesting. Here in the UK our ONTs come with battery backup units, but all that’s inside them is four NiMH AA batteries and a charger. Although it’s only really needed so that any phone service provided over fibre keeps working if there’s a power cut.
You need a charger, not a power supply. Charger: CCCV Power supply: CV only CCCV = constant current / constant voltage. Charger: puts out either a constant current or a constant voltage, depending on the state of charge of the battery Power supply: puts out a given voltage no matter what, cannot be connected to a battery Even if you start from a power supply, you still need a charger between the power supply and the battery, to drop the voltage and limit the current. So, you might as well keep it simple and just use a charger. Note: a "Lab supply" is a CCCV type of power supply, and can be used as a charger.
hi. you need a charging controller or at least a DC-DC converter for the battery pack. and a solar panel with an output power much higher than what your load needs, so it will be able to power your load and charge the battery pack in the same time. I plan to make such a project, but it will take some time.
Great vid! I do have a question though, as the input to the battery does not have a current limiting circuit, would it not lead to a surge current inrush when the battery gets fully depleted and the mains supply gets back online? Best case, it would trip the protections in the bms and not charge the battery and worst case it could kill the battery. Thoughts?
hi. in this video I use a small battery pack, made with only 2 recovered lithium cells with a small capacity connected in series. it doesn't put too much pressure on the charger. the charger can deliver a maximum constant current of 2A. so the charging current is limited by the charger, which is 2A minus a few hundred mA, which are used by the DC-DC step up converter, to power the ONT with 12V. so the charging current is limited to around 1.5A, which is a bit high for a small battery pack, but there is no problem. and this happens only if there is a long power outage to completely discharge the battery. if the power outage lasts only 1-2 hours, the battery will not discharge too much and it will draw only few hundred mA from the charger. the problem you mentioned occurs when you make a bigger battery pack and use a more powerful charger, then you need a CV-CC converter to limit the charging current, as I did in the 12V&19V UPS.
@@Sorin_DIY But the 2A adapter doesn't really limit the current does it? The charger should just burn off trying to instantaneously bring up the battery voltage to its own output voltage bringing a surge in current more than it can safely supply (2A). Theoretically a 2s battery discharged to around 7 volts should draw somewhere around 20-40 amps from a 9v considering the internal resistance of the battery to be around 40-80 milli ohms. So the bms should have triggered the overcurrent or the charger should have THEORETICALLY burnt out trying to supply that 20-40 amps (if the bms didn't exist) But ofcourse none of that happens in your video and your setup functions as it should. Could you explain a bit more about why the battery doesn't draw the theoretical amount of current and in doing so trip the bms or kill the charger (if the bms is ignored)? Appreciate your input!
a good charger acts like a CC-CV power supply. the charging current is limited to 2A and the voltage drops when you connect it to the BMS/battery. then the voltage increases slowly, while the battery is charged. it doesn't force more amps into the battery, because it can't deliver more than 2A, so the voltage drops. you can see this exact charging method in my fast charging powerbank video with a 25.2V (25.4V max) and 2A charger. but if you have a low quality charger it can damage the battery if it doesn't stabilize the voltage and current.
@@Sorin_DIY As long as the charger self limits the output current and not blow up trying to match the current demand it all makes sense. I did not know a charger could behave in a current limiting manner when connected to a battery (which is not a standard load in the sense that potential difference accross it doesn't immediately match the charger's once connected) Thanks!
the battery pack is charged with a charger and a BMS board. the charger can deliver 2A at 8.4V (max 8.6V) using a CC/CV method. the BMS board has all the needed protection features including balance charging. so together they charge the battery pack using CC/CV method, they balance and protect the cells. the step up converter is used only to increase the voltage to 12V.
First of all thank you so much for the wonderful tutorial. There are two things i wanted to ask you sir. 1. What if we connect volt meter after the converter 12volt side? 2. My 8.7v charger don't have auto cutoff circuit when it's full charged. So if i connect power continuously will it damage my Router or Circuit? Thanks Sir.
hi. if you connect the voltmeter after the step up converter it will always show 12V. I suggest you use the 2S BMS from the link below, it stops the charging automatically when the cells are fully charged. the 8.7V charger will still power the step up converter: www.aliexpress.com/item/32863604994.html?spm=a2g0o.productlist.0.0.78a81a17yfgf8N&algo_pvid=7a7a9384-1f05-43f8-af1c-2152aba8627a&algo_expid=7a7a9384-1f05-43f8-af1c-2152aba8627a-1&btsid=0ab6d69f15918369686154295e5c92&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
@@Sorin_DIY Sir, You have really inspired me and i have made it with the help of your video. But there is one problem. It took 5 Diodes in series to convert 12V to around 8.6V and Diodes are getting really really very heat up while charging. For now i have unplugged for safe side. Can you please help in diode heat problem i am so close :)
is there a way to get the BMS to reduce the target voltage for the batteries? I would think that limiting the voltage to, say, 4.0V, on the li-ion cells would extend the life of the cells significantly.
hi. you can't make the BMS charge the cells with less voltage. but you can add a diode in series with the charger. it will stop the current going back to the charger LED and, because diodes have a small forward voltage drop, it will decrease the voltage to around 8V. this will probably extend the lifespan of the li-ion cells, but it will decrease the UPS autonomy.
Really, a quality video, with nice humor.
I like that you give instructions for a safer and cleaner result.
Plus you give explanations of what you are doing and why. Regardless of building or buying such a mini UPS, the learning process and understanding of the details are valuable for other projects plus as a general knowledge too. Thanks.
It's not working for me. Before connecting to boost converter, bms output voltage is 11.68 v but as soon as I connect it to boost converter, voltage drops to 0.67 V. And so can't step up the output for 12v. But when I connect boost converter directly to battery output, it works, which is not advisable !!!
Please help with this
@@viralindia8951 if your bms output is 11.6v then you can easily use it as 12v. There's no need to use a boost converter. Also, there is a limit to the input voltage for the boost converter. You should check the specification.
Hi Sorin. Transforming 12 V -> 220 V in a UPS and back 220 V -> 12 V in a router's power supply was always not a good idea to me. I always wanted to get (build) a pure 12 V device. This your video inspired me to do that. Thank you so much for this!
Please let me share some of my observations with other people working on such devices like me.
1) You can remove the step up converter from your schematic for most cases. The most of routers, network switches and others have buck converters inside. Usually they reduce voltage to 3.3 V to power the controller. This means you can power devices by even 5 V. Just try. You will be surprised. It looks like manufacturers choose power supplies having just economical reasons while devices can eat from 5 V to even 18 V.
2) Do not worry about back current into the power supply. It is usually less than 2 mA for most power supplies and is safe for them.
Thank you again for your videos.
Tested and approved as correct!
I like this design because you take extra care by A. putting the fuses directly on the battery as the BMS can fail and B. adding a capacitor on the output to smooth out the flow. Very nice. I'm going to make this, but with 3S.
this is a very practical project and anyone who suffers from random power outages should do this.
Very simple and straight forward! Great video as always :D
You must add a diode to the laptop plug from where the adapter is connected to prevent the electricity from going back towards the charger. Not only would the backup of UPS will increase but it would be safer this way.
my thoughts EXACTLY
What should the diode rating be?
@@AtlantaTerry anything would do a 1n4007 has a rating of about 700v.
While your at it could add an inline fuse that would blow before the ones on the battery did as those are harder to get to.
Sorry where would the diode be connected?
Nice build! Best part is it will protect the router in those short power blips that usually reset everything. Great job!
Yes. I need a small UPS for my Raspberry Pi system.
Those would likely sell well on amazon many people would love them.
I also made one for my router but with 3S config. It'll be more practical to do so because you don't have to change the 12V adapter.
Good video sir!
What step up transformer did you use?
Can you please help by giving a list of the components you use? I am looking into building one but don't know where to get the components online.
@@jithinramesh3022 The two main places that people source parts for electronics projects are AliExpress and Banggood. They're both Chinese websites which allow you to essentially get the parts for the cheapest price and they usually have global free shipping. I would personally recommend Banggood because I usually get my items within a week and a half when ordering from there vs AliExpress which can take weeks but usually not over a month. I live in New Zealand which means components ordered from these sites get here a bit faster then other parts of the world. As for your question regarding the components that Aji used I might recommend trying a premade board that essentially does everything the BMS in the video does in a single package. Something like this: www.banggood.com/18650-Lithium-Battery-Boost-Module-12V-Charging-UPS-Uninterrupted-Protection-Integrated-Board-With-C-p-1280431.html?rmmds=search&cur_warehouse=CN
@@ChillarPunter with 3S battery and 12V router no step up or step down converters are needed. Router will still work, even when supplied with 9V (3S battery at 1% charge)
For 3s, the Charging voltage should be greater than 12.6. How did you get this voltage with 12V adapter without using step up convertor?
Luv your projects and your humour.
Sure he has a sense of humour , I like it too.
The precision sensor, "between hot/cold."
Very nice, I was designing exactly such a thing for my rooter today and there pops up your video in my recommendations! In my design, I also added a constant current, constant voltage buck converter and set the current limit recommended on the data sheet of the 18650.
hi. if you used a buck converter, then it means you have a bigger battery pack. but the current limit of the buck converter is for the converter output, not the converter input (the battery pack). the input current and output current of the converter differs, depending on the load, converter efficiency and battery pack. there is nothing wrong with it, just don't set a lower output current than your router needs.
I have the battery pack charging FROM the buck converter output, that way when the battery is flat, it charges at constant current (1.65A for my cells... they're 3500mAh so ~0.5C charge) up until the preset voltage is reached for full charge, then it switches to constant voltage mode and then the current drops quickly down. I still use a boost converter on the battery pack to the UPS output to keep the voltage constant as the battery voltage drops. I then use a much higher voltage power supply (24V, ~1A, 25W) because its slightly cheaper and also I get better efficiency stepping down from higher voltages with the buck (>90%). The buck isn't strictly necessary and your design is elegant.
Always informative, I learn something everytime I watch your videos...
Brilliant.. I've lost a lot of work due power outages of few seconds, but that's enough for the router to restart and I have to wait until the router reconnects. I definitely try to do something similar as your mini ups. Thanks for the good idea.
Very nice video, congratulations ! ("Precision Sensor" for temperature was perfect ! )
I like this build. There are many applications you can use this for, like emergency lighting when the power goes out
Very nice and useful build. You explained everything very clearly and also put a list of the required components in your video description. Very well done.
It is shame that TH-cam algorithm does not recommend such good content
I love the "wearing protective goggles with smug face" part.. Funny
If you want better efficiency, remove the step up converter and add one more battery in series. The router should be able to operate from about 9V up to 14V. Li-ion batteries work 3.5V - 4.2V, which gives you 10.5V - 12.6V power supply.
No, my router works 11v-18v. Although rated at 12v. It doesn't work anything less than 11v. So step up is mandatory. Schottky diodes are also required.
I like the precision temp sensor, also the cumbersome looking soldering iron... nice project to keep us occupied ... I think your cat looks as if it's been electrified, judging from the spiky fur... :)
Hello Sorin, Thank you for this video and it was helpful for me to provide a solution to the unexpected power outage of my wifi router. All the best and appreciate you.!!
NIce! I just ordered a bunch of 18650's for another project, so that was great timing for me. Thanks!
Bravo omule! E ceva de munca si la ceea ce ai realizat cat si la clip, felicitari!
8:00 you should also make a knot with the power cord inside the case, that way if you pull on the power cord, it wont pull the electronics out and damage the soldering points
ok
That or one of those crimping type strain reliefs that just snaps into the hole a lot of appliances use. If space is the issue as in that small case one of those snap in might take less room.
I was actually looking for something like this, a portable or mini UPS for use with the Raspberry Pi. Thanks for making this tutorial, Sorin. :)
Video: How much safety you need?
Sorin: YES
Too much protection than any oth product which is made officially 🤣😅😆
This is the first ever channel that I have intentionally subscribed. Liked it and much helpful.
Interested in your temperature measurement instrument.
Very clean and nice looking project.
Thank you Sorin for sharing this video, really informative , I have some notes regarding :1-You can use a battery holder for the 18650 you using in case you need to replace the batteries it will more easy rather than doing the soldering job again.2-You can use a protection schottky diode on the input side link SS54 so that the voltage can flow in one direction & not back to the charger in case of utility power outage
3-you can add a switch yo turn of the built in voltage meter to preserve some energy in case of long term power outages.4-what about low battery , should we get any indication when the battery is going low , it the UPS turn it self off in that case ?5-also what about short circuit protection on the output side ?
Thank you.
hi. 1- yes you can use a battery holder, but I prefer to solder the cells. I test all the cells before I use them, so very rarely I had problems and need to replace cells. I prefer soldering the cells, because with battery holders there may be an imperfect contact in time between the cell and the holder, also the plastic enclosure needs to be bigger. 2- a diode will block the current from one direction, but it also has a small voltage drop. so the charging voltage will drop below 8V, which is not enough to charge the cells. the charger LED is using only a few mA, it doesn't make any difference in the 6 hours working time of the UPS. it remains like this for now. 3- the voltmeter display is using 17-20 mA, depending on how many LEDs are lit. so yes you can save a little energy by disconnecting it. you can add a capacitor and a microswitch to the voltmeter. when you press the microswitch for 1-2 sec, the capacitor is charged and the voltmeter will remain on for a few sec, enough to read the value. 4- the BMS has over discharge protection at around 2.9V per cell. you can check the UPS voltmeter, when the voltage decreases to under 6V, the cells are almost discharged and it will shortly turn off. I did this test in the video. 5- this step up converter doesn't have short circuit protection, so you can add another fuse on the positive output terminal. or you can use another (bigger) type of step up converter, with short circuit protection included.
Nice vid.
I recently started using TP4056 Chrg/Prot boards with a long 22 gauge silicone electrical wire to help charge solar lights with 18650's when sunlight isnt good enough. With how well it works it doesn't make sense why big solar lights aren't designed with this feature built in
Today is a good day because sorin uploaded another informative diy video
You have always inspired me to step out and try some of your projects. Thanks for the content. For the power flowing back to the adaptor, you could have a diode to prevent that, learnt that from a solar installation...
I learned a lot with this YT video.. esp the BMS system and how it works. Great job. Thanks
Sorin you're the best
i think i can make this because i just ordered some parts thanks sorin
Just build mine... I thought I burn out my BMS when I saw Sparks while soldering but it works thanks for your video.
Oh. Thank God i found this on my feed.
Very nicely presented. Thank you for explaining so well. 😊👍
Those plastic bit in the case are called "stand offs". They "stand off" a pcb from the case. Normally used on pic's so the motherboard doesn't short against the case
thanks for clarifying this. I know what they are for, just didn't know how to call them in English.
best spoken english lecture
Thanks for the video. Can you please advise what changes I would need to make if I want to use 12V power supply? Thanks for your answer.
with exactly same build you need one more step down DC to DC board to lower 12V from power supply to 8.5-8.4V to charge the whole mini UPS, all the rest stays the same.
@@baniakrulez Thanks. Will do.
really great project
Great explanation! Thank you, very easy to understand the operation of 18650 cells on smaller scale. I'm trying something similar before going larger, these things actually are alittle scary and should be treated with caution. One thing I don't understand, does the bms monitor each individual cell ? Thanks great job and that was an important tip selecting good vs bad batteries from the start. 👍👍
hi. yes the BMS monitors the voltage of each cell, that's why it has a lead between the cells. it's the yellow wire in my schematic.
I love videos that give good instruction. That's the reason I've subscribed to you keep up the good work.
Friend, Sorin, thanks for an excellent tutorial. (I have subscribed) I like that your presentation was well photographed. Everything you showed was easy to understand. (even a dummy such as myself) One suggestion, perhaps go a bit slower. Thanks so much, looking forward to more of your presentations.
I built a small ups with a 9v battery and boosted it upto 12v using the converter, I used it to power my stereo speaker but after a few minutes it resetted itself and when it came back up it worked perfectly. But it killed my device's original speakers, now I'm stuck in headphone mode. I didn't have 2 18650 cells so that's why I used a 9v battery. But I have another recharge ups. Thanks for the tutorial friend.
Try for the next project a spot welding device solution for nickel strip .
Very good and respect to your Li Ion Information. Very good also for safety! You should use a metal case for absolutely safety
Why not make it out of 3S for 12.6v fully charged and 9v fully discharged? Then you would not need the boost converter. Your fiber router would probably cut off around 10v or less than that.
I wanted to have a very stable 12V output. other people will probably make it for some other devices that may need a stable voltage. this is possible only with a dc converter. it will last longer with a step up converter, because it's using the entire battery capacity. and I wanted it to be small, with 3 cells it needs a bigger plastic enclosure.
High quality content right there it's rare to see those
Hey , you forgotten 1 diode at input of BMS, that will help to reduce extra current drawn by charger LED during power fails
yes a diode will block the current in the reverse direction, but it also has a forward voltage drop of around 0.9V so the charging voltage will drop under 8V, which is not enough to charge the cells. the charger LED is using only a few mA, it doesn't make any difference in the 6 hours working time of the UPS.
"LED": Light Emitting DIODE.
So why would you need a second diode?
@@AtlantaTerry simp
Nice compact solution and great explanations with a bit of humour thrown in :)
I really love this channel..
verry imformative,and funny...
ohhh,,,,!!
it has ads now,,,,thats it sorin,,, 🙌
I've modded this good original design, my fibre router was affected by the high frequency of the boost output.
Instead of 2x 18650+boost I found it simpler to use a 3S 20A Li-ion Lithium Battery 18650 Charger PCB BMS. and a standard 3s battery holder. Mod the standard router power lead to tee in the BMS via a 5.5 power jack and fix to the back of a standard 3s 185650 holder (if you need more double up and use 2 cells in parallel x3). 3 cells just about makes a good enough 12v and not having to boost makes life much less complicated, you can use the router's standard psu with bee sting connector to feed the BMS. Because the BMS is teed across the feed and doesn't intercept it - switchover is still instant and bonus is the batteries smooth the PSU output without a capacitor - it means you can disconnect (borrow) the UPS to act as a powerbank without powering down the Router so with the BS on the back of a standard 3 cell 18650 carrier I think it's actually a smaller footprint with a more convenient switchless "always on" connection.
Because you tee the UPS to the power feed there is no chance of an accidental break in service win win.
Te rog fa un video in care arati cum ai facut ampermetrul!!
Este doar un volt/ampermetru pus intr-o carcasa. :)
Nice one Sorin! Keep up this small useful projects and great content!
+1 for ur humour and the smug face 😂 (1:10)
Why you did not use your previous DIY charger to test the batteries?? maybe because it do not have a screen showing capacity of batteries? So time to make a v.2.0!! , DIY Charger and Tester Capacity for 18650 bats.
Look ZB2L3 Battery Capacity Tester, not a bad module 😉
And look for us a DIY spot welding machine please, most uses microWave transformer, but a bit hard for simple hobbist... maybe with capacitor?? you will figure something it out 😊
Cool video dude. Wish more people would make videos like these.
Sorin, bro, are you russian? Its nice that this video of your's is in english. Congrats bro!!!
No, he's Romanian.
@@George-sp1sr
Aaahhh i see...
just a tip, if you change the setting on the opus charger to "charge test" it will charge the cells up to 4.2, discharge them, giving you the discharge capacity, then charge them back up. making it easier and quicker to test them multiple times
I know. I forgot to film it.
Oi! ... Who are you calling elderly?
:)
Appreciate the compact circuit, I am also trying to make the same. But one query arises in my mind. That why we did not consider, reverse discharge protection diod in the supply side.
it will work, but you need a 9V charger to compensate for the diode forward voltage drop.
@@Sorin_DIY Is it okay to use a 12V 0.5A charger and a 3S 10A BMS?
my router has a built-in batery kkkk
that's nice
You are the best diy guy in the world 🌎
Truthfully the first video i liked, subscribed and shared
When I see you fit things the together as if made for each other I'm sure you could break the world record on "points scored on Tetris in 60s😂" ✌️
Sorin, love your videos. Love your choice of juice. Love your awesome accent 😂👍🇨🇦
Subscribed for the quality of humour and of course the quality of content 😎
Cool, might have to build one of these. I usually use a 10000mah powerbank, which can last around 7 hours running an adsl modem router with wireless.
you can buy a cheap USB cable with barrel jack at the end, just make sure you buy the cable that can do a QC 3.0 handshake since you will be taking advantage of QC 3.0 12volt output. After that just buy a powerbank that supports QC 3.0 with 12v output, pretty much every QC3.0 compatible powerbank support it, after that daisy chain it with QC 3.0 usb charger and your good to go, a UPS for your ISP router, not to mention everything I told cost around 35-40USD for all of it.
0:15 1) Put a cat next to your adjustable power supply. 2) Say goodbye to your electronics.
Sorin, you are the best!
Bro does it work normally by the 12V adapter and when the AC power is cut off it works from batteries.
Or is it continuesely working from the battery power?
it works on the battery only when the main power is off
@@Sorin_DIY so it is an offline ups. And could you plz tell which part switches the current?
hi. the BMS board stops the charging of the cells when they are full. but if the charging voltage suddenly drops (main power is off) the BMS lets current from the cells to power the step up converter. if you want to build this UPS I suggest you use this BMS board, it's better:
www.aliexpress.com/item/32863604994.html?spm=a2g0o.productlist.0.0.78a81a17yfgf8N&algo_pvid=7a7a9384-1f05-43f8-af1c-2152aba8627a&algo_expid=7a7a9384-1f05-43f8-af1c-2152aba8627a-1&btsid=0ab6d69f15918369686154295e5c92&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
Tocmai ce am trecut si eu la fibra optica si am si o gramada de celule si bms-uri, deci am ce face in weeknd! Multam de idee si cum ar spune americanu' : keep up the good work !
You really make soo amazing videos , like i can use all your projects in my daily life and seriously solved my issues🎉❤😊🙈
Does the voltage booster you use get really hot? I am using a a buck boost converter and it gets hot to the touch and I did add a heat sink as well.
hi. buck/boost converters get very hot, because they work with a lower efficiency than buck or boost converters, so they use more current. also it depends on the load, if your router needs more current than mine, the converter will get even hotter.
Cute!!! I like this little ups! you earned a sub. I need to put a meter on my router and see how much it draws, and build a mini ups to suit (I have 4 18650 Samsung cells here waiting for a project!)
hey nice build i was searching for this kind of project as there is lots of power outage and generator takes time to start . can i leave the whole thing plugged in all the time will it over heat . and is the capacitor and the LCD necessary my router is rated for 12v 2amp
if you need a UPS with 12V and 2A you need something better. a 16.8V & 2-3A charger, a 4S BMS protection board with balance and overcharge release voltage features, a 4S battery pack and a 5A step down converter. 5A so it will not heat up at 2A.
@@Sorin_DIY thanks for th help
@@Sorin_DIY can I use three 4 volt lead acid in series with with a boost converter
Dramatically fantastic. Thanks
Good video. Just a question, shouldn't you supply the BMS with a constant current to make sure that the batteries are not been charged with too much current. For example if you using 2000mah batteries, then you should limit the charging current to 1A. I have read the datasheet of the chipset on the BMS and there is nothing about current limiting onboard.
hi. the BMS board has an overcharge protection of 4.25-4.35V ± 0.05V. this voltage is a bit high and can stress the cells. you can add a diode in series with the charger and decrease the voltage to around 8V. this way the charging current will not be a problem. the current will also self limit, because a part of the charging current is used by the step up converter to increase the voltage to 12V, so a little over 1A will remain to charge the cells.
I have couple of questions:
1. Why capicitors and how do you determine the specification?
2. How are you handling the heat disscipitation from buck boost converter as with xl6009, and 8v to 12v with current 0.5 A, it generated good amount of heat.?
3. What is the total capacity and how long this product will support ie. 1 or 2 hours...
Very well documented and good video.
hi. capacitors hold a small electrical charge. they are useful, for example, when you connect a big load, the supply voltage may decrease for a second. the capacitor charge will help to keep the voltage stable in that second. the bigger the capacitance, the higher the charge is. so for a bigger load you need a bigger capacitance. for voltage smoothing usually I use capacitors between 1000 - 6300uF, depending on the project.
in this project, the step up converter IC only warms up a bit. it can handle up to 85 degrees C and I also added a small heatsink. but for higher current you need a bigger heatsink or a ventilated enclosure. more than that, my ONT is using maximum 270mA, so no problem with the heat. in these conditions it has an autonomy of around 6 hours.
I''ve seen other similar builds use a diode reverse bias on the negative terminal of the power input from power supply - you mention in the video that the charger light remains on because it is taking power from the UPS. Is that what would be prevented with the diode in place?
yes
Another Great Idea from Sorin!!!
The batteries didn't get damaged if they are all the time connected to the power, aren't they continuously charging and discharging? Thanks.
hi. the li-ion cells are not continuously charging. when the cells are fully charged, the charging process is stopped. but the cells will slowly self discharge and when the cell voltage is starting to decrease, the charging process starts again. the step up converter is powered by the charger, so the cells are not charging and discharging in the same time. the problem is that the cells will have a lot of charging cycles, this will decrease their lifespan. this cheap BMS board is not the best for this project, you need a BMS with overcharge release voltage.
Very nice tutorial, and a good basis for other mini ups projects like an emergency cell phone charger. Sure you got those mini power banks they sell, but those are way overpriced. Thank you.
Okay, so after checking again and again the problem was with the fuses. Without the fuses everything is fine. Interesting even though the fuses are meant for protection. Thank you for your help you are the best 😉
I'm thinking of not using the fuses, does it really matter?
@@prakharvj3362 For me it does not matter, it caused me to drop voltage at the output. Without the fuse it works perfectly !!!
Modified a bit, can this be used in DC-driven LED lights as a solar-fed/gridless lighting system?
it will work, but not very efficiently. it needs better components.
@@Sorin_DIY I'm thinking more batteries in parallel and probably a better BMS. Anything else?
Is it possible to also create a relay path that totally cuts off the DC output for the AC charger if the AC charger is not energized?
Very well presented and explained. Thank you for sharing this.
Watched all your Videos. Thanks Sorin. Nice Chanel with interesting DIY electronic projects. Please do more in the future. Love your accent too :)
Thank you. Great work, can't wait for next project.
If you are always charging the batteries and using the batteries to supply energy to the router, consider lower the charging voltage of the batteries. The batteries can be damaged if always working on maximum voltage. Lowering the voltage can increase the life time of the batteries
Hello Sorin, I am finding it difficult to understand the purpose of the switch. If the switch is in the off position, the UPS is not going to allow current to flow from the battery to the router, so the router will not work anyway. The whole point of the UPS is to keep the router working incase of a power outage. Your thoughts please.
Hi. The switch is installed between the battery (more exactly the BMS output) and the DC converter. there must always be a way to completely cut off the battery from the load.
Thanks for making this useful video. Just what I needed.
Interesting. Here in the UK our ONTs come with battery backup units, but all that’s inside them is four NiMH AA batteries and a charger. Although it’s only really needed so that any phone service provided over fibre keeps working if there’s a power cut.
You need a charger, not a power supply.
Charger: CCCV
Power supply: CV only
CCCV = constant current / constant voltage.
Charger: puts out either a constant current or a constant voltage, depending on the state of charge of the battery
Power supply: puts out a given voltage no matter what, cannot be connected to a battery
Even if you start from a power supply, you still need a charger between the power supply and the battery, to drop the voltage and limit the current. So, you might as well keep it simple and just use a charger.
Note: a "Lab supply" is a CCCV type of power supply, and can be used as a charger.
Very good video keep doing this buddy
Nice proyect! Do you think it can be charged with a solar panel ? What should be modificated ?
hi. you need a charging controller or at least a DC-DC converter for the battery pack. and a solar panel with an output power much higher than what your load needs, so it will be able to power your load and charge the battery pack in the same time. I plan to make such a project, but it will take some time.
Just FANTASTIC, great job !
Great vid! I do have a question though, as the input to the battery does not have a current limiting circuit, would it not lead to a surge current inrush when the battery gets fully depleted and the mains supply gets back online? Best case, it would trip the protections in the bms and not charge the battery and worst case it could kill the battery. Thoughts?
hi. in this video I use a small battery pack, made with only 2 recovered lithium cells with a small capacity connected in series. it doesn't put too much pressure on the charger. the charger can deliver a maximum constant current of 2A. so the charging current is limited by the charger, which is 2A minus a few hundred mA, which are used by the DC-DC step up converter, to power the ONT with 12V. so the charging current is limited to around 1.5A, which is a bit high for a small battery pack, but there is no problem. and this happens only if there is a long power outage to completely discharge the battery. if the power outage lasts only 1-2 hours, the battery will not discharge too much and it will draw only few hundred mA from the charger. the problem you mentioned occurs when you make a bigger battery pack and use a more powerful charger, then you need a CV-CC converter to limit the charging current, as I did in the 12V&19V UPS.
@@Sorin_DIY But the 2A adapter doesn't really limit the current does it? The charger should just burn off trying to instantaneously bring up the battery voltage to its own output voltage bringing a surge in current more than it can safely supply (2A).
Theoretically a 2s battery discharged to around 7 volts should draw somewhere around 20-40 amps from a 9v considering the internal resistance of the battery to be around 40-80 milli ohms.
So the bms should have triggered the overcurrent or the charger should have THEORETICALLY burnt out trying to supply that 20-40 amps (if the bms didn't exist)
But ofcourse none of that happens in your video and your setup functions as it should. Could you explain a bit more about why the battery doesn't draw the theoretical amount of current and in doing so trip the bms or kill the charger (if the bms is ignored)?
Appreciate your input!
a good charger acts like a CC-CV power supply. the charging current is limited to 2A and the voltage drops when you connect it to the BMS/battery. then the voltage increases slowly, while the battery is charged. it doesn't force more amps into the battery, because it can't deliver more than 2A, so the voltage drops. you can see this exact charging method in my fast charging powerbank video with a 25.2V (25.4V max) and 2A charger. but if you have a low quality charger it can damage the battery if it doesn't stabilize the voltage and current.
@@Sorin_DIY As long as the charger self limits the output current and not blow up trying to match the current demand it all makes sense.
I did not know a charger could behave in a current limiting manner when connected to a battery (which is not a standard load in the sense that potential difference accross it doesn't immediately match the charger's once connected)
Thanks!
A great video, but my doubt is why isn't a charging module used to charge the battery ? Only a BMS board and a Step up converter are used....
the battery pack is charged with a charger and a BMS board. the charger can deliver 2A at 8.4V (max 8.6V) using a CC/CV method. the BMS board has all the needed protection features including balance charging. so together they charge the battery pack using CC/CV method, they balance and protect the cells. the step up converter is used only to increase the voltage to 12V.
@@Sorin_DIY thanks for the reply, i will build it soon with your video as reference ☺️
First of all thank you so much for the wonderful tutorial. There are two things i wanted to ask you sir. 1. What if we connect volt meter after the converter 12volt side? 2. My 8.7v charger don't have auto cutoff circuit when it's full charged. So if i connect power continuously will it damage my Router or Circuit? Thanks Sir.
hi. if you connect the voltmeter after the step up converter it will always show 12V. I suggest you use the 2S BMS from the link below, it stops the charging automatically when the cells are fully charged. the 8.7V charger will still power the step up converter:
www.aliexpress.com/item/32863604994.html?spm=a2g0o.productlist.0.0.78a81a17yfgf8N&algo_pvid=7a7a9384-1f05-43f8-af1c-2152aba8627a&algo_expid=7a7a9384-1f05-43f8-af1c-2152aba8627a-1&btsid=0ab6d69f15918369686154295e5c92&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
@@Sorin_DIY thank you so much sir, Really really appreciated your kind advise. this is exactly what i wanted. God bless you.
@@Sorin_DIY Sir, You have really inspired me and i have made it with the help of your video. But there is one problem. It took 5 Diodes in series to convert 12V to around 8.6V and Diodes are getting really really very heat up while charging. For now i have unplugged for safe side. Can you please help in diode heat problem i am so close :)
@@Sorin_DIY I have 12V Charger for input
hi. you need more powerful diodes, 5A or more.
is there a way to get the BMS to reduce the target voltage for the batteries? I would think that limiting the voltage to, say, 4.0V, on the li-ion cells would extend the life of the cells significantly.
hi. you can't make the BMS charge the cells with less voltage. but you can add a diode in series with the charger. it will stop the current going back to the charger LED and, because diodes have a small forward voltage drop, it will decrease the voltage to around 8V. this will probably extend the lifespan of the li-ion cells, but it will decrease the UPS autonomy.