Does off-grid solar confuse you? Check out my DIY friendly website for solar system packages and product recommendations, and so much more! www.mobile-solarpower.com Join our DIY solar community! #1 largest solar forum on the internet for beginners and professionals alike: www.diysolarforum.com Check out my best-selling, beginner-friendly 12V off-grid solar book (affiliate link): amzn.to/2Aj4dX4 If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Solar. Low prices and great warranty, and they can take your entire house offgrid with their new Powerwalls: ts.la/william57509 ~~~~~~~~~~~~~~~~~~~~~~~~~ My solar equipment recommendations (Constantly updated! Check here first): 12V/48V Lithium Batteries: www.mobile-solarpower.com/solar-batteries.html Solar System Component Directory: www.mobile-solarpower.com/solarcomponents.html Plug-N-Play Systems: www.mobile-solarpower.com/full-size-systems.html Complete 48V System Kits: www.mobile-solarpower.com/complete-48v-solar-kits.html DIY Friendly Air Conditioner/ Heat Pumps: www.mobile-solarpower.com/solar-friendly-air-conditioners.html Complete 48V System Blueprint: www.mobile-solarpower.com/48v-complete-system-blueprint.html ~~~~~~~~~~~~~~~~~~~~~~~~~~ My Favorite Online Stores for DIY Solar and Coupon Codes: -Current Connected: SOK, Victron and High Quality Components. Best prices and warranty around: currentconnected.com/?ref=wp -Signature Solar: Cheap Server Rack Batteries and Large Solar Panels: www.signaturesolar.com/?ref=h-cvbzfahsek -Ecoflow Delta Official Site: My favorite plug-n-play solar generator: us.ecoflow.com/?aff=7 -AmpereTime: Cheapest 12V batteries around: amperetime.com/products/ampere-time-12v-100ah-lithium-lifepo4-battery?ref=h-cvbzfahsek -Rich Solar: Mega site and cheaper prices than renogy! Check them out: richsolar.com/?ref=h-cvbzfahsek -Shop Solar Kits: Huge site with every solar kit you can imagine! Check it out: shopsolarkits.com/?ref=will-p -Battery Hookup: Cheap cell deals bit.ly/2mIxSqt 10% off code: diysolar -Watts 24/7: Best deals on all-in-one solar power systems, with customer support and distribution here in the USA: watts247.com/?wpam_id=3 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contact Information: I am NOT available for personal solar system consult! If you wish to contact me, this is my direct email: williamprowsediysolar@gmail.com Join the forum at diysolarforum.com/ if you wish to hang out with myself and others and talk about solar FTC Disclosure Statement and Disclaimers: Every video includes some form of paid promotion or sponsorship. Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these. My videos are for educational purposes only. Information is subject to change/update at any time. Electricity is DANGEROUS and can kill. Be smart and use common sense :) DIY Solar Power with Will Prowse is a participant in the Amazon Services LLC Associates Program, An affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com
Hi Let me make this clear and I hope you respond I have just bought 2 x 2000 w KRIEGER INVERTERS Plugged them onto 6 x 1000 ah connected in series at home and one blew up the other does not even work as it should WHY ? What size Inverter should you have if say the Voltage I tested says 64 VOLTS From the Solar to the Battery readings ? get back t o me please ASAP Troy
I sparked the contact between a 3000w psw inverter and 12v/100ah LifeP04 battery bank. The result was an unrecoverable BMS in the first battery in the bank! Good thing BattleBorn has a 10-year warranty. I wish I had seen this video first! Another FANTASTIC video, Will. Thanks for all you do.
Im glad you mentioned this as its something not a lot of people are aware of. For me, I use a lightbulb in a holder to charge as its a resistor and the bulb will dim once the capacitors are charged.
Never saw your idea implemented before. It was good that you proved what damage can happen. Usually, you hear a laugh when the batteries spark and never hear how it can hurt your system! 👍
Lots of "light bulb" comments. Remember that any simple electrical heating device (incandescent light bulb, hair dryer, soldering iron, heat gun, glue gun, etal) is essentially a resistor and will do the same thing as long as you don't exceed it's power-handling capability. Great job as always Will, I'm SO glad I found your YT channel!
Been connecting my 24v 3000w inverter the hard sparky way countless times without dying or going blind... But for the safety of your LifePo batteries it is best to use a resistor to avoid this.
Almost forgot about this, had to come back to find this video and order some more resistors before I put together a new system in 24v. You're the man Will! 💪🏾💪🏾💪🏾💯
All I could look at was the wrenches on the magnets above the batteries. Seriously though, love the content, it's refreshingly simply delivered and any unintentional humor only adds to the charm. Keep it up!
Every one of those wrenches are shorter than the distance between the battery terminals. The odds of two wrenches falling and resting across each other while also touching both terminals are much higher than winning the powerball jackpot, though I am sure the guys at Dudeperfect could do it, film it, and make you believe they nailed it on the first take.
By far one of your most important, accurate and useful video that I have seen since subbing. Way better than you loosing time on overpriced underperforming fraudulantly called solar generators.
Great public service / safety announcement! I frequently see people doing this wrong, and it's so simple not to. Now with a short video that I can point to, if I forward it on people will actually watch it! Thanks Will! Keep doing what you love.
I used to use a incandescent test light to charge the capacitors in high power car audio systems. The benefit is the light glows dimmer and dimmer as the caps charge. The light across the inverter input will discharge too. Nice videos. Thanks.
This video has been incredibly helpful. I blew the fuses in the exact same inverter you have used in your video by not pre-charging the capacitors and hope this fixes the issues
Thanks again Will for keeping things simple and easy to understand. Really appreciate your useful examples…..I’d be burning alot of money if not for folks like you….learning important stuff here.
Good to know. Inverter companies should include this information and a resistor in the packaging with their inverters. It wouldn't cost them Jack Diddly Squat and it might keep someone from damaging their eyes, batteries, or other equipment.
Used to drive a 48V EV in the 90' and the solution was to keep a 60W incandescent bulb in the battery compartment, so whenever I had disconnected the battery pack, but didn't want the bang and sparks when re-connecting, it was simply a matter of placing the center prong of the bulb on the battery terminal and the cable on the threaded part of the bulb, and when the bulb extinguished, the caps were charged so I could simply slide the cable onto the battery terminal with no fireworks. But yes, the authorised way of doing that is with a precharge resistor and a push button, and a small bulb to have an indication of when current is no longer flowing and the pre charge is complete.
Is there a specific voltage and watt requirements for the light bulb method? I found a light bulb with cable and crocodile clips which is rated 12V 25W, is this enough for precharging capacitor in UPS that uses two pair of 12V SLA batteries?
@@marcusn7854 The bulb is simply Used as a power resistor, with a visual indication of when the pre charge has finished. That means, any bulb Will do as Long as its voltage rating is equal og higher than your battery pack. So your 12V bulb is going to burn out if you connect IT to 24V. If you get a second 12V bulb and connect Them in series, IT Will Work too. I Used a Common 220V AC household bulb, and IT glowed only dimly on 48V, but IT was easy to see when IT turned off. If you are American, Use a 110V bulb. IT should light just the same on 24V as my 220v bulb did on 48v.
That is good to know, I would have assumed big inverters would have some circuitry to prevent this but guess it's bad to assume! For a permanent setup you could probably have a resistor as part of the circuit by default and a separate switch to bypass it. I guess ideally two switches so you can still isolate the entire thing.
Thanks Will. Pretty much found everything I need to know to build my van solar system and feel confident its safe and will perform from your videos alone. Saved me endless trawling through questionable advice on forums.
Dude, you are perfecting the perfect off grid system that can power a house out of a shed, including transportation! Wow! Using solar panels that can be downgraded to charge anything less powerful than and including a house! Shit, if you pakcage that like you have done with generators and sell it undercutting the market to get it out there would change everything! You do this and that's revolutionary. ✊🏽
Thanks Will, another informative episode. I am surprised to learn that large wattage inverters don't have a high value leakage resistor soldered across the input terminals to allow them to discharge over a few seconds once power is removed.
I'm in the process of researching setting up a solar system on a small narrow boat over here in England. All the videos I've looked at and read up online I've not come across this information. Thank you very much.
Many people install a switch or circuit breaker between the battery and inverter. Whenever the switch is flipped on, it will also generate a spark. I suppose we could manually pre-charge manually or install a push-button switch with resistor before flipping the switch but is there some kind of contactor, delay, relay, and/or device available off the shelf that can be installed across the breaker/switch to AUTOMATE the pre-charging? I doubt such an accessory cost much to make.
I discovered a method of precharging capacitors using no extra parts. Just the battery and the inverter. However, this method can only be used if you built your own battery from 3.2v cells. Simply attach the positive inverter cable to the positive side of the battery, then touch the negative cable to the negative post of the first cell in the series. Then touch it to the second negative post, then the third, etc. This allows you to use the battery itself to slowly ramp up the voltage, 3.2v at a time.
WOW, it's amazing to me that the inverter manufacturers allow the terminals to stay hot for days. A 1k ohm (ish)resistor inside would discharge them fast enough and not waste too much power.
Precharge resistors are good. You can use anything from 1Ω to 100Ω depending on how much current you want to flow, and how long you have to wait until charged. If you put a scope on it and record the voltage over time with different resistors, then you'll be able to show properly what resistance to use is best, and why.
Easiest way to pre charge is with any INCANDESCENT light bulb. A 100W 120v bulb will do it instantly on a 12v system. On 48V setups the bulb will get lightly lit and go dark in a second or two. Should be across inverter supplying circuit breaker. If mounted on a light bulb socket, it can be unscrewed and turned in before breaker is reset. Not pre charging is a crime against inverter input capacitors.
i usually use a 12v 55watts halogen automotive headlight bulb. easy to find and you can see if pre-charging completed. innitialy bulb will lit ip and slowly dims while charging in progress
Does anyone know what resistor should be used with a 12v, 3000w inverter with a 12v LiFePO battery? A link to Amazon would be great, but I can't seem to find it in the description. Secondly, does anyone know the formula for calculating resistor? Thanks advance. Great content, Will!
I’m trying to develop a system to put a parallel system of 12 Volts in series with another parallel system of 12 Volts and then create a total voltage of 24 volts going towards a resistor bank.. if we get two large wattage resistors and of equal values such as 500 ohms each and tap wiring to the inverter off of the center and one side we once again have 12 Volts.. a perfect voltage divider.. but, I want to make it not quite equal so I’m thinking make one 550 ohms and one 450ohms and that should give me about 14.4 volts and 9.6 on other side.. so I would use the 14.4 side to give extra volts across the larger resistor.. enough to keep my inverter from beeping so frequently.. can it be done?? Not sure yet what resistor values to go with for sure, but …. voltage 1 * R1 + voltage 2 * R2 over the total voltage * ( R1 + R2) is formula for the output.. voltage on one section then is Divided to create the individual voltages.. i.e. using 550 ohms and 450 ohms and the 24 volt total system would yield 14.4volts and 9.6 volts.. use the 14.4 volt side.. then if total voltage drops a bit, no big deal at output..
dude your videos are ALWAYS on point, to the point and incredibly clear and helpful - thanks a metric TON bro!! My new litto batts are ALMOST here and I just so HAPPENED to see someone popping a small switch and searched out what it was, i have a 10000w 24v split phase inverter!! You just saved me ruining alot of expensive stuff thanks thanks thanks!
In 2020 I put together a system with two 280Ah LiFePO4 batteries with JBD BMS and a Victron Multiplus 12/3000. No problem with inverter pre-charge. The BMS didn't care and I didn't blow the 225 amp Class T fuse. Fast forward to 2024 and my new system is a 48 volt 280 Ah LiFePO4 battery with JK BMS and Victron Quattro 48/3000 inverter. Blew the dang $50 Class T fuse as soon as I connected the inverter! I couldn't find the right resistor so I implemented the 48 volt fork lift light bulb solution. It worked great and didn't blow the Class T fuse.
I always wondered why I would only get one spark and wondered why the spark was so big! Thanks! I've done 3500 watt magnum inverter chargers with 600ah busses and never could get around the massive spark! Unless I used the battery disconnect lol
For my backup power system i built for my computer room. After i burnt up the contacts in a pair of high current relays i added a pre charger. Just using a resistor and a car horn relay. From memory the resistor im using is one of those ones designed for if you use LED replacement lights on your car to load the circuit more. The arduino i use to control it all just turns the precharger on for 5seconds before closing the main relay to the inverter.
Thx for this info. I built a 3 battery bank about 4 years ago with a 2000 watt inverter and nobody ever mention this to me. Yes, i got some nice sparks when connecting the terminals to the inverter, but i figured it must just be a mild normal thing (not dangerous). Your $1 resister is about $10 with shipping.
Yes several other youtube channels claim the sparking is of no worry and normal... I do not know if that is true or not that the sparking do not damage anything, it can for sure lead to things welding stuck...
Do you have an Amazon affiliate link for that little capacitor you have there I’m getting ready to build a small home solar set up I will be using a REDODO Battery and a Victron energy smart controller 100 V/50 charge controller I may go with a Victron phoenix 12 V inverter unless you have a better recommendation for a 12 volt inverter? I don’t wanna ruin my batteries so I would like to buy one of these little capacitors I’m not sure where to find one? OK so I just found a 25 watts one ohms resistor on Amazon will that work for a 12 V system to pre-charge my 12 V inverter or should I get a different size ?
Thanks. Great advice. I just don't understand why some people give you a "dislike" (thumbs down). I found nothing inaccurate or not useful in your presentation. I suspect they're just jealous. My advice: "Damn the torpedoes, full speed ahead".
Wow, good video. So, what happens when you turn your system off using a battery disconnect switch? Does this surge / spark happen within the disconnect switch when you power things back on?
Hi, I dont see alot of people pre-charging inverters with 12v batterie battery banks AND 2000/3000 inverters. I found your video interesting and Im wondering if this applies to 12v or is more a concern with 24v batterie system and up? Cheers!
I had seen this video, but forgot about the caps after blowing out a 30A fuse during some load testing. Putting in the new fuse was a little scary! The lesson is now welded in, so to speak. I didn't have a 10W low resistance resistor handy, so I put some clips on a 120vac 40w light blub. Works fine.
It such a good point that it is very disappointing that no practical solutions are offered when for when fitting an inverter in situ - particulary as they will be turned off and back on on a regular basis - even pointing the way to some off the shelf solutions (well anything really) would have been really helpful
I always used an incandescent light bulb, when the bulb goes out, you know it's charged. It also works the same way to discharge. With a 12 or 24v system a regular automotive test light works great. Any voltage higher might be a little difficult to find a bulb for though?
Great video. I have done exactly what you are doing using a value of 200 ohm or larger and leave it connected for a minute or so. Another thing I have done is use a tail light bulb from a car in series with the inverter and the battery. (12 volt system) I just leave it connected unitl the bulb goes out and give it a few seconds more for good luck. The bulb will be bright and slowly dim. If the bulb suddenly goes out it may have burnt out so be careful if using the bulb method.
Thanks, you are the only one on you-tube that has said to do this, I guess all those experts need to learn a little more. You would think that at least Battle Born would tell their customers that in a video??
It can also damage the inverter!.. I use a 60-100 watt light bulb, the incandescent bulb can glow for a few seconds, but when its charged , it will stop glowing,
Is this (resistor) required if you don't disconnect the hot or ground ? Is this (resistor) only required during initial hook up of Hot and Ground to terminals ?
Thanks for the great advice and safety tips. I hope all your viewers heed your advice. Like your channel for the great information about solar products and your honest reviews of the products.
@@robertrocheville7769 what would that circuit consist of? Looking to have it be automated so that when the battery drops low enough to cut off power to the inverter, and the battery charger kicks on it doesn't fry the BMS, or load protections in the battery when the inverter comes back online.
@@dotNSF Not based on the batteries total potential, but the difference in potential. Basically one battery(or capacitor) is at 46V and the other is at 52. The circuit holds them apart until the voltage is low enough to be safe.
⚠️ Question! What about the internal inverter switch.? Does the pre+charging of inverters apply to every scenario? Our communications engineer watched this video and mentioned “If inverter is OFF when connecting, where’s the load?” And “Does the inverter’s internal switch or relay, etc.. suffer from contact arcing and burning damage?” We are using 2000 and 3000 Watt Giandel and Renogy pure sine-wave inverters with our emergency vehicles (ambulances & light rescue) at 12v. Some are permanently mounted and powered from the vehicle batteries (2x 12v deep cycle marine type) Some are mounted in Pelican wheeled cases with 100ah LifePO4 batteries for portability. After showing Though this doesn’t apply to our fire apparatus as we have onboard diesel generators, if installing inverters in the vehicles that are all 24vdc, any particular advice? Thanks for a great channel with a truly outstanding comment section!
Good quality super-caps can hold a serious level of charge for several days. Dashcams using them can hold their time settings for as long as ten days (though usually more like a week). Never trust a capacitor to be discharged until you do that yourself ;)
Love your videos. I've learned so much and I understand it. You have a way of explaining these ideas in easy to understand language. Thank you! Also...will you be evaluating the new Ecoflow Delta 1300 solar generator? That one looks promising but I would love to see what you find out about it.
Any inverter that I could do this to, I would, regardless of wattage. Potentially extend the life of your capacitors. That surge is hard on the caps too.
Just another tip when it comes to capacitors, it is really easy to calculate the resistor needed. But this only work IF you a aware of the capacitance of the bank. What you calculate is the time constant or RC R=resistor C=capacitors. t=R*C so if you got a 30ohm resistor and a bank of 100'000uF (0,1F), just put those values in the formula and BAM! 30Ohm * 0,1F = 3s to about 60% charge if they're completelly drained. The second advice is, why bother with dischargin when you easily can just permanatly mount a resistor beetween the power "poles/skrews" and as soon as you disconnect the battery bank it starts to drain the capacitors. Same formula just the opposit result. But I'd use a larger on, let's say 1K (1000Ohm) which will drain the capacitors within 2min. A 1000 ohm resistor will draw about 0,012A or 0,144W so you'll ned atleast a 1/4W or 1/2W resistor. No disessambly required at all for any of this tips.
The Epever Ipower plus (5000W) has current limit to prevent sparkles/Arc when connecting the 48V batteries bank, this is nice, I did not have to use a resistor (LifePO4)
This is great, but I do have a question... I was under the understanding you were supposed to attached the positive lead to inverter last. Can you do this same thing between the positive lead and the positive terminal on the multiplus inverter, or should i do this only between the negative busbar from batteries and the negative lead of the inverter?
Does off-grid solar confuse you? Check out my DIY friendly website for solar system packages and product recommendations, and so much more! www.mobile-solarpower.com
Join our DIY solar community! #1 largest solar forum on the internet for beginners and professionals alike: www.diysolarforum.com
Check out my best-selling, beginner-friendly 12V off-grid solar book (affiliate link):
amzn.to/2Aj4dX4
If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Solar. Low prices and great warranty, and they can take your entire house offgrid with their new Powerwalls: ts.la/william57509
~~~~~~~~~~~~~~~~~~~~~~~~~
My solar equipment recommendations (Constantly updated! Check here first):
12V/48V Lithium Batteries: www.mobile-solarpower.com/solar-batteries.html
Solar System Component Directory: www.mobile-solarpower.com/solarcomponents.html
Plug-N-Play Systems: www.mobile-solarpower.com/full-size-systems.html
Complete 48V System Kits: www.mobile-solarpower.com/complete-48v-solar-kits.html
DIY Friendly Air Conditioner/ Heat Pumps: www.mobile-solarpower.com/solar-friendly-air-conditioners.html
Complete 48V System Blueprint: www.mobile-solarpower.com/48v-complete-system-blueprint.html
~~~~~~~~~~~~~~~~~~~~~~~~~~
My Favorite Online Stores for DIY Solar and Coupon Codes:
-Current Connected: SOK, Victron and High Quality Components. Best prices and warranty around: currentconnected.com/?ref=wp
-Signature Solar: Cheap Server Rack Batteries and Large Solar Panels:
www.signaturesolar.com/?ref=h-cvbzfahsek
-Ecoflow Delta Official Site: My favorite plug-n-play solar generator:
us.ecoflow.com/?aff=7
-AmpereTime: Cheapest 12V batteries around:
amperetime.com/products/ampere-time-12v-100ah-lithium-lifepo4-battery?ref=h-cvbzfahsek
-Rich Solar: Mega site and cheaper prices than renogy! Check them out:
richsolar.com/?ref=h-cvbzfahsek
-Shop Solar Kits: Huge site with every solar kit you can imagine! Check it out:
shopsolarkits.com/?ref=will-p
-Battery Hookup: Cheap cell deals
bit.ly/2mIxSqt
10% off code: diysolar
-Watts 24/7: Best deals on all-in-one solar power systems, with customer support and distribution here in the USA:
watts247.com/?wpam_id=3
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Contact Information:
I am NOT available for personal solar system consult! If you wish to contact me, this is my direct email: williamprowsediysolar@gmail.com
Join the forum at diysolarforum.com/ if you wish to hang out with myself and others and talk about solar
FTC Disclosure Statement and Disclaimers:
Every video includes some form of paid promotion or sponsorship. Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these. My videos are for educational purposes only. Information is subject to change/update at any time. Electricity is DANGEROUS and can kill. Be smart and use common sense :)
DIY Solar Power with Will Prowse is a participant in the Amazon Services LLC Associates Program,
An affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com
Hi Let me make this clear and I hope you respond I have just bought 2 x 2000 w KRIEGER INVERTERS Plugged them onto 6 x 1000 ah connected in series at home and one blew up the other does not even work as it should WHY ?
What size Inverter should you have if say the Voltage I tested says 64 VOLTS From the Solar to the Battery readings ? get back t o me please ASAP Troy
I sparked the contact between a 3000w psw inverter and 12v/100ah LifeP04 battery bank. The result was an unrecoverable BMS in the first battery in the bank! Good thing BattleBorn has a 10-year warranty. I wish I had seen this video first! Another FANTASTIC video, Will. Thanks for all you do.
I've watched countless videos related to this type of equipment but this is the first time I heard of this. Thanks!
The first time in all my years of doing solar that this has been mentioned. Thank you sir!
I thought your the dude who heated up a miniature sausage everytime they work ALSO
@@fojrsepta4959 huh?
Im glad you mentioned this as its something not a lot of people are aware of. For me, I use a lightbulb in a holder to charge as its a resistor and the bulb will dim once the capacitors are charged.
Never saw your idea implemented before. It was good that you proved what damage can happen. Usually, you hear a laugh when the batteries spark and never hear how it can hurt your system! 👍
I listen to Wills videos just so i can hear him say “TITAN”! My favorite part every time!
And butt-ON
“TiTAN” makes me smile every time he says it.
GAF
Lots of "light bulb" comments. Remember that any simple electrical heating device (incandescent light bulb, hair dryer, soldering iron, heat gun, glue gun, etal) is essentially a resistor and will do the same thing as long as you don't exceed it's power-handling capability.
Great job as always Will, I'm SO glad I found your YT channel!
Hi, having trouble finding a resistor.. but do have a glue gun...how would I go about using it? Thanks!
No kidding, you probably just saved my eyes and my life. Great video. Short to the point and extremely valuable information!
Been connecting my 24v 3000w inverter the hard sparky way countless times without dying or going blind... But for the safety of your LifePo batteries it is best to use a resistor to avoid this.
Almost forgot about this, had to come back to find this video and order some more resistors before I put together a new system in 24v. You're the man Will! 💪🏾💪🏾💪🏾💯
All I could look at was the wrenches on the magnets above the batteries. Seriously though, love the content, it's refreshingly simply delivered and any unintentional humor only adds to the charm. Keep it up!
Every one of those wrenches are shorter than the distance between the battery terminals. The odds of two wrenches falling and resting across each other while also touching both terminals are much higher than winning the powerball jackpot, though I am sure the guys at Dudeperfect could do it, film it, and make you believe they nailed it on the first take.
By far one of your most important, accurate and useful video that I have seen since subbing. Way better than you loosing time on overpriced underperforming fraudulantly called solar generators.
Thank God I saw this video before connecting my first inverter and battery together today. Thank you!
Will, thank you for sharing this safety tip! I've seen others that have a DIY build for a 24 volt system and they never talked about this!
This worked for me. Thank you. I damaged an inverter years ago not knowing this. You do a great service with your fine programs.
Great public service / safety announcement! I frequently see people doing this wrong, and it's so simple not to. Now with a short video that I can point to, if I forward it on people will actually watch it!
Thanks Will! Keep doing what you love.
I used to use a incandescent test light to charge the capacitors in high power car audio systems. The benefit is the light glows dimmer and dimmer as the caps charge. The light across the inverter input will discharge too. Nice videos. Thanks.
I had no idea! My problem is now solved. I was about to return this brand new inverter 4000 watt. Thanks Will!!!!
This video has been incredibly helpful. I blew the fuses in the exact same inverter you have used in your video by not pre-charging the capacitors and hope this fixes the issues
Did it fix your issue
Thanks again Will for keeping things simple and easy to understand. Really appreciate your useful examples…..I’d be burning alot of money if not for folks like you….learning important stuff here.
Good to know. Inverter companies should include this information and a resistor in the packaging with their inverters. It wouldn't cost them Jack Diddly Squat and it might keep someone from damaging their eyes, batteries, or other equipment.
Used to drive a 48V EV in the 90' and the solution was to keep a 60W incandescent bulb in the battery compartment, so whenever I had disconnected the battery pack, but didn't want the bang and sparks when re-connecting, it was simply a matter of placing the center prong of the bulb on the battery terminal and the cable on the threaded part of the bulb, and when the bulb extinguished, the caps were charged so I could simply slide the cable onto the battery terminal with no fireworks. But yes, the authorised way of doing that is with a precharge resistor and a push button, and a small bulb to have an indication of when current is no longer flowing and the pre charge is complete.
Is there a specific voltage and watt requirements for the light bulb method? I found a light bulb with cable and crocodile clips which is rated 12V 25W, is this enough for precharging capacitor in UPS that uses two pair of 12V SLA batteries?
@@marcusn7854 The bulb is simply Used as a power resistor, with a visual indication of when the pre charge has finished. That means, any bulb Will do as Long as its voltage rating is equal og higher than your battery pack. So your 12V bulb is going to burn out if you connect IT to 24V. If you get a second 12V bulb and connect Them in series, IT Will Work too. I Used a Common 220V AC household bulb, and IT glowed only dimly on 48V, but IT was easy to see when IT turned off. If you are American, Use a 110V bulb. IT should light just the same on 24V as my 220v bulb did on 48v.
That is good to know, I would have assumed big inverters would have some circuitry to prevent this but guess it's bad to assume! For a permanent setup you could probably have a resistor as part of the circuit by default and a separate switch to bypass it. I guess ideally two switches so you can still isolate the entire thing.
Thanks Will. Pretty much found everything I need to know to build my van solar system and feel confident its safe and will perform from your videos alone. Saved me endless trawling through questionable advice on forums.
I prevent sparks in the lithium battery by disabling "discharge" in the BMS. It's a straightforward solution!
Solark 8k comes with 2 resistors just for this reason to topup the capacitors initially.
Awesome video as always saw your interview with Jamie, that was so stoked.
Dude, you are perfecting the perfect off grid system that can power a house out of a shed, including transportation! Wow! Using solar panels that can be downgraded to charge anything less powerful than and including a house! Shit, if you pakcage that like you have done with generators and sell it undercutting the market to get it out there would change everything! You do this and that's revolutionary. ✊🏽
good advice well done I have been in this trade over 50 years now .
Thanks
Thank you!!!
Thanks Will, another informative episode. I am surprised to learn that large wattage inverters don't have a high value leakage resistor soldered across the input terminals to allow them to discharge over a few seconds once power is removed.
They should have a relay to automatically discharge through the normally closed terminals of the relay.
@@ajarivas72 Absolutely, a relay is the ideal solution.
I'm in the process of researching setting up a solar system on a small narrow boat over here in England. All the videos I've looked at and read up online I've not come across this information. Thank you very much.
Many people install a switch or circuit breaker between the battery and inverter. Whenever the switch is flipped on, it will also generate a spark. I suppose we could manually pre-charge manually or install a push-button switch with resistor before flipping the switch but is there some kind of contactor, delay, relay, and/or device available off the shelf that can be installed across the breaker/switch to AUTOMATE the pre-charging? I doubt such an accessory cost much to make.
Excellent video. I fried my inverter during hurricane Fiona (I'm in Prince Edward Island, Canada) and this would have saved me some grief. Thank you
I discovered a method of precharging capacitors using no extra parts. Just the battery and the inverter. However, this method can only be used if you built your own battery from 3.2v cells. Simply attach the positive inverter cable to the positive side of the battery, then touch the negative cable to the negative post of the first cell in the series. Then touch it to the second negative post, then the third, etc. This allows you to use the battery itself to slowly ramp up the voltage, 3.2v at a time.
Make a video bro. I understood nothing
On old submarines the action of switching on those massive battery banks would sometimes release ball lightning .
Thank you for this useful info. I have always wondered how to connect high voltage inverters without a spark, now I know
WOW, it's amazing to me that the inverter manufacturers allow the terminals to stay hot for days. A 1k ohm (ish)resistor inside would discharge them fast enough and not waste too much power.
Precharge resistors are good. You can use anything from 1Ω to 100Ω depending on how much current you want to flow, and how long you have to wait until charged.
If you put a scope on it and record the voltage over time with different resistors, then you'll be able to show properly what resistance to use is best, and why.
Oh very smart! Thank you Andy :D
I would get Sparks with 8 ohm resistors so bumped up the recommendation. I should have tested it. Thank you
Easiest way to pre charge is with any INCANDESCENT light bulb. A 100W 120v bulb will do it instantly on a 12v system. On 48V setups the bulb will get lightly lit and go dark in a second or two. Should be across inverter supplying circuit breaker. If mounted on a light bulb socket, it can be unscrewed and turned in before breaker is reset. Not pre charging is a crime against inverter input capacitors.
@@egilsevalds3920 Good idea, though incandescent bulbs will be as rare as unicorn poop soon.
@@ahaveland stores will still sell appliance bulbs at very least
i usually use a 12v 55watts halogen automotive headlight bulb. easy to find and you can see if pre-charging completed. innitialy bulb will lit ip and slowly dims while charging in progress
Not so good for 48V systems though!
@@ahaveland 48v super halogen, slowly dims and completely blinds you once charged.
I use a standard household filament light bulb.
You put the bulb in line with the ground so even a 48v or 96v it'll dim because the capacitors will charge and no longer pass current.
Does anyone know what resistor should be used with a 12v, 3000w inverter with a 12v LiFePO battery? A link to Amazon would be great, but I can't seem to find it in the description. Secondly, does anyone know the formula for calculating resistor? Thanks advance. Great content, Will!
I’m trying to develop a system to put a parallel system of 12 Volts in series with another parallel system of 12 Volts and then create a total voltage of 24 volts going towards a resistor bank.. if we get two large wattage resistors and of equal values such as 500 ohms each and tap wiring to the inverter off of the center and one side we once again have 12 Volts.. a perfect voltage divider.. but, I want to make it not quite equal so I’m thinking make one 550 ohms and one 450ohms and that should give me about 14.4 volts and 9.6 on other side.. so I would use the 14.4 side to give extra volts across the larger resistor.. enough to keep my inverter from beeping so frequently.. can it be done?? Not sure yet what resistor values to go with for sure, but ….
voltage 1 * R1 + voltage 2 * R2 over the total voltage * ( R1 + R2) is formula for the output.. voltage on one section then is Divided to create the individual voltages.. i.e. using 550 ohms and 450 ohms and the 24 volt total system would yield 14.4volts and 9.6 volts.. use the 14.4 volt side.. then if total voltage drops a bit, no big deal at output..
He’s doing it with a 25 w 30 ohm resistor and it’s a 24 v battery system and a 3000 w inverter
Great video! Higher value resistors at lower wattage will work too. Just takes longer. Large value capacitors do definitely pack a punch.
dude your videos are ALWAYS on point, to the point and incredibly clear and helpful - thanks a metric TON bro!! My new litto batts are ALMOST here and I just so HAPPENED to see someone popping a small switch and searched out what it was, i have a 10000w 24v split phase inverter!! You just saved me ruining alot of expensive stuff thanks thanks thanks!
In 2020 I put together a system with two 280Ah LiFePO4 batteries with JBD BMS and a Victron Multiplus 12/3000. No problem with inverter pre-charge. The BMS didn't care and I didn't blow the 225 amp Class T fuse. Fast forward to 2024 and my new system is a 48 volt 280 Ah LiFePO4 battery with JK BMS and Victron Quattro 48/3000 inverter. Blew the dang $50 Class T fuse as soon as I connected the inverter! I couldn't find the right resistor so I implemented the 48 volt fork lift light bulb solution. It worked great and didn't blow the Class T fuse.
I always wondered why I would only get one spark and wondered why the spark was so big! Thanks! I've done 3500 watt magnum inverter chargers with 600ah busses and never could get around the massive spark! Unless I used the battery disconnect lol
Does that only need to be done to an inverter once in its lifetime?
Making something as boring as a resistor, interesting! You've done it again. Thanks for the great info!
Is this the same with a deep cycle lead acid battery?
The thought of the spark when I am about to connect these terminals always gives me concern.
Thanks Will.
For my backup power system i built for my computer room. After i burnt up the contacts in a pair of high current relays i added a pre charger. Just using a resistor and a car horn relay. From memory the resistor im using is one of those ones designed for if you use LED replacement lights on your car to load the circuit more. The arduino i use to control it all just turns the precharger on for 5seconds before closing the main relay to the inverter.
super informative and helpful!!
Thanks for saving everyone's eyes and bank accounts !!
Thank you for telling and EXPLAINING about the resistor to charge and to discharge. That was something nobody mention to me lol. Gordon.
Thx for this info. I built a 3 battery bank about 4 years ago with a 2000 watt inverter and nobody ever mention this to me. Yes, i got some nice sparks when connecting the terminals to the inverter, but i figured it must just be a mild normal thing (not dangerous). Your $1 resister is about $10 with shipping.
Yes several other youtube channels claim the sparking is of no worry and normal... I do not know if that is true or not that the sparking do not damage anything, it can for sure lead to things welding stuck...
Do you have an Amazon affiliate link for that little capacitor you have there I’m getting ready to build a small home solar set up I will be using a REDODO Battery and a Victron energy smart controller 100 V/50 charge controller I may go with a Victron phoenix 12 V inverter unless you have a better recommendation for a 12 volt inverter? I don’t wanna ruin my batteries so I would like to buy one of these little capacitors I’m not sure where to find one? OK so I just found a 25 watts one ohms resistor on Amazon will that work for a 12 V system to pre-charge my 12 V inverter or should I get a different size ?
Hi Will,
Thanks for all the videos and detailed explanations. You have helped to make our RV electrical upgrade easier and safer. Thank you!
Tod
Thanks. Great advice. I just don't understand why some people give you a "dislike" (thumbs down). I found nothing inaccurate or not useful in your presentation. I suspect they're just jealous. My advice: "Damn the torpedoes, full speed ahead".
Some people just choose dislike simply because the video is not something that interest them...
Wow, good video. So, what happens when you turn your system off using a battery disconnect switch? Does this surge / spark happen within the disconnect switch when you power things back on?
My question as well. I would think they would add a resistor to the switch, but I doubt they do.
I use a light bulb in a pig-tail socket to tune capacitors. That way, you get feed-back from the light glowing then going dim.
Great video, thanks.
What about if the inverter (connected) is turned off for extended period of time. Do the capacitors remain charged?
Hi, I dont see alot of people pre-charging inverters with 12v batterie battery banks AND 2000/3000 inverters. I found your video interesting and Im wondering if this applies to 12v or is more a concern with 24v batterie system and up? Cheers!
Chunky soft shop pencils work well too! Mine measured about 20ohms.
Lucky to have a Fry's that is still stocked - many are suffering due to business changes. Good idea on using a resistor.
You can use a double sided pencil in a pinch, the graphite is a conductor and has around 20 ohms of resistance.
Great info as always! This channel is amazing.
I feel safe just watching Will's videos.
I had seen this video, but forgot about the caps after blowing out a 30A fuse during some load testing.
Putting in the new fuse was a little scary! The lesson is now welded in, so to speak.
I didn't have a 10W low resistance resistor handy, so I put some clips on a 120vac 40w light blub. Works fine.
It such a good point that it is very disappointing that no practical solutions are offered when for when fitting an inverter in situ - particulary as they will be turned off and back on on a regular basis - even pointing the way to some off the shelf solutions (well anything really) would have been really helpful
I always used an incandescent light bulb, when the bulb goes out, you know it's charged. It also works the same way to discharge. With a 12 or 24v system a regular automotive test light works great. Any voltage higher might be a little difficult to find a bulb for though?
for 48v just chain four 12v bulbs ;) Or maybe use a 220v og 110v bulb?
@@a64738 SMH, my brain didn't even go there. Obvious!
All good info. I was just looking for how to safely discharge my inverter.
Great video. I have done exactly what you are doing using a value of 200 ohm or larger and leave it connected for a minute or so. Another thing I have done is use a tail light bulb from a car in series with the inverter and the battery. (12 volt system) I just leave it connected unitl the bulb goes out and give it a few seconds more for good luck. The bulb will be bright and slowly dim. If the bulb suddenly goes out it may have burnt out so be careful if using the bulb method.
Thanks, you are the only one on you-tube that has said to do this, I guess all those experts need to learn a little more. You would think that at least Battle Born would tell their customers that in a video??
I have a question; how to size the safety disconnect for 100 KWH battery bank ?
"It will create a huge spark that don't have molten metal go right in your eye!"
That's The story of My Life.
It can also damage the inverter!.. I use a 60-100 watt light bulb, the incandescent bulb can glow for a few seconds, but when its charged , it will stop glowing,
Very useful info for DIY enthusiasts, I personally use car/mo-bike tail lamps [filament type not LED] for charge discharge those capacitors. ;)
Is this (resistor) required if you don't disconnect the hot or ground ? Is this (resistor) only required during initial hook up of Hot and Ground to terminals ?
Thanks for the great advice and safety tips. I hope all your viewers heed your advice. Like your channel for the great information about solar products and your honest reviews of the products.
Thanks! Glad I saw this video before putting together a new solar system.
Looking dorky is being safe, thanks for the video, 👍👌❤🇨🇦
I've wondered how hard it would be to make a circuit that would wait for the voltage difference to be small enough before closing a contacter.
@ yep.
Swype-o
@@robertrocheville7769 Just picking on ya, no offense bro. You are totally correct, sir.
That's from another journeyman electrician, sir.
@@robertrocheville7769 what would that circuit consist of? Looking to have it be automated so that when the battery drops low enough to cut off power to the inverter, and the battery charger kicks on it doesn't fry the BMS, or load protections in the battery when the inverter comes back online.
@@dotNSF Not based on the batteries total potential, but the difference in potential.
Basically one battery(or capacitor) is at 46V and the other is at 52.
The circuit holds them apart until the voltage is low enough to be safe.
⚠️ Question! What about the internal inverter switch.?
Does the pre+charging of inverters apply to every scenario?
Our communications engineer watched this video and mentioned “If inverter is OFF when connecting, where’s the load?” And “Does the inverter’s internal switch or relay, etc.. suffer from contact arcing and burning damage?”
We are using 2000 and 3000 Watt Giandel and Renogy pure sine-wave inverters with our emergency vehicles (ambulances & light rescue) at 12v. Some are permanently mounted and powered from the vehicle batteries (2x 12v deep cycle marine type)
Some are mounted in Pelican wheeled cases with 100ah LifePO4 batteries for portability.
After showing
Though this doesn’t apply to our fire apparatus as we have onboard diesel generators, if installing inverters in the vehicles that are all 24vdc, any particular advice?
Thanks for a great channel with a truly outstanding comment section!
A friend of mine actually tested a super cap to see how fast they discharged, they did overnight !, not sure if all capacitors are like that tho.
Good quality super-caps can hold a serious level of charge for several days. Dashcams using them can hold their time settings for as long as ten days (though usually more like a week). Never trust a capacitor to be discharged until you do that yourself ;)
So did I just damage my battle born battery? I had a spark when I tried to connect my inverter to my negative terminal. Is it pooched?
Do you have a video on connecting power from an inverter to a breaker box?
Is the resistor directional? Does it matter what end to use?
Resistor is bi-directional. Does not matter which end you connect.
Thank You for All that you are doing for our Planet Earth.... Peace.. Shalom.. Salam.. Namaste .. 🙏🏻 😊 ✌ ☮ ❤ 🕊
Thanks bro! This video was very helpful...
Excellent video as always Will 👍
What if you discharge capacitors by turning on the inverter?
Yes that works too! :D
Love your videos. I've learned so much and I understand it. You have a way of explaining these ideas in easy to understand language. Thank you! Also...will you be evaluating the new Ecoflow Delta 1300 solar generator? That one looks promising but I would love to see what you find out about it.
Any inverter that I could do this to, I would, regardless of wattage. Potentially extend the life of your capacitors. That surge is hard on the caps too.
Just another tip when it comes to capacitors, it is really easy to calculate the resistor needed. But this only work IF you a aware of the capacitance of the bank.
What you calculate is the time constant or RC R=resistor C=capacitors.
t=R*C so if you got a 30ohm resistor and a bank of 100'000uF (0,1F), just put those values in the formula and BAM!
30Ohm * 0,1F = 3s to about 60% charge if they're completelly drained.
The second advice is, why bother with dischargin when you easily can just permanatly mount a resistor beetween the power "poles/skrews" and as soon as you disconnect the battery bank it starts to drain the capacitors. Same formula just the opposit result. But I'd use a larger on, let's say 1K (1000Ohm) which will drain the capacitors within 2min.
A 1000 ohm resistor will draw about 0,012A or 0,144W so you'll ned atleast a 1/4W or 1/2W resistor.
No disessambly required at all for any of this tips.
Post an Amazon link please for the resistor
I must be thick but cant find the link !!
How big as can't find 25w 30Ohm only 22 or 47 Ohm ... Which one ?
The Epever Ipower plus (5000W) has current limit to prevent sparkles/Arc when connecting the 48V batteries bank, this is nice, I did not have to use a resistor (LifePO4)
Had a buddy loose an eye for not prechargeing , they call him pop- eye😅😂
Wow I had no idea we had to do that great information thank you.
This is great, but I do have a question... I was under the understanding you were supposed to attached the positive lead to inverter last. Can you do this same thing between the positive lead and the positive terminal on the multiplus inverter, or should i do this only between the negative busbar from batteries and the negative lead of the inverter?
Can you tell me if I still need to do this if I'm connecting everything to the bus bar
If you don't want to go buy a resistor, a 1 foot length of .032 stainless safety wire has about 7 ohms. It's what I use to make discharge load banks.