Hi EEVblog. Just ran across this post and I realize I'm commenting three years after the fact. Just want to say that those of us flying RC multicopters, sUAV's, etc., would NEVER run a LiPo cell down to 3.0V. For most of us, the very minimum would be around 3.4 or 3.5V. Put another way, we generally never discharge our LiPo's past about 80% of their rated capacity. I guarantee you that discharging a LiPo down to 3.0V cell voltage will ruin the battery in no time whatsoever. Just sayin. Thanks for all the GREAT videos, David. I've learned so much from your channel!
Hi Dave, great video! Most of those 4 button chargers have a USB socket on one side, it's possible to do up to 0.5A discharge tests/graphs and even charge graphs with them using some freeware software (got it on the other laptop will post name later) Some ppl reckon the voltage monitoring and balancing on that charger isn't so accurate due to low tolerance components - looks like yours was nailed though!
Dave, I've noticed in the Battery Discharge Wizard window while you ranted on the constant current and not power mode ability of the thing, there's a scroll bar at the bottom, maybe if you scroll it to the right, it will reveal more modes? It certainly looks like it would to me. Cheers!
Power tool companies have pretty widely available and standardized high capacity battery packs, so if you want to ship a power supply without battery and have it be easy for people to get their own battery with it, maybe consider making it for something like the Ryobi battery pack?
For these sort of applications I always use a small Li-Ion battery protection circuit. I sometimes harvest them from old cell phone batteries and it provides me a bit of insurance in case I leave a load connected to a battery or such.
27:00 -- you set it to 'sample save time 1000ms' and unchecked the box = no database at the end. Very cool software though. I've wanted to make an arduino version before, just haven't had the need.
I was also gonna get one of those 5000 mAh batteries from hobbyking a while back but they were out of stock at the time. But they certainly look like nice batteries for some cool projects.
The Turnigy Accucell 6 has a combination temperature/"USB" port on the left side that you can connect to a computer and gather a metric buttload of information during charge and discharge. USB in quotes because it's actually TTL RS-232 signalling, and you need an adapter (available cheaply on ebay, I got one for $2.49 shipped).
800milliohms ESR, which I would assume most of is in the contact resistance of the croc clips, the wire and the bodgy binding posts. You need to take 2 copper strips, drill a hole in them to fit the posts and drill and tap another set to handle the 4mm sockets. Then you can plug the cords in easily with minimal extra resistance, and with a very low loss on the connection.
Dave, great videos, I have loved watching them ever since finding eevblog. Have you considered using Panasonic NCR18650 series batteries? They come in 2900 mAh, 3100mAh, and 3400mAh capacities with a mass of 45g per cell. The cost is approx. $6-7 per cell when you buy 180 at a time. One downside of these cells is that to get the full capacity you must discharge to approx. 2.5V which may not work for your application.
@ about 23:31 did you say "Due to the internal ESR", meaning that the displayed voltage is lowered by the load's equivalent series resistance? thanks, cool vid
It's lowered by the batteries internal resistance, the voltage (E) drop across any resistance is equal to current (I) times resistance (R), E=I*R
12 ปีที่แล้ว
Hi Dave, great work, keep it up. Just a random thought: maybe "*" will look better than "s" for set current/voltage (more symmetrical and stuff, and you have to know what that character on the left means anyway)
Indeed it does. I've noticed some other errors to,perhaps it's time for Dave to make another video like the one he did on the pickit 3,that was hilarious and the response from microchip was even more hilarious. :-D
dont absolutely get too close to 3 v with lipos, they build internal resistance that way, then they can puff and potentially catch fire while recharging next time
Good video! Does the BK load have sense wires? If so, you should've sensed the voltage right the cell tabs. Otherwise your BK load reads a lower voltage due to IR drop in the banana cables.
Might want to check your supplier catalogue, Dave - they make spade connector to 4mm banana jack adapters. Usually come in test lead kits for a few quid (which I guess would be a few AUD down your way) or you can probably get better quality ones (e.g. Pomona) from the likes of Farnell. Might work a bit better than jamming the 4mm plugs side-on into the binding post...
Hi , will those batteries work in a quadcopter?, i remember in a past video when you where setting up your new lab you mention you where going to build a quad copter, did you ever manage to do so?
Some of these lipo cells have insane C ratings but I've always been dubious about using them that high. It almost seems too high for such a small cell... Had a couple Chinese cells off ebay supposedly rated at some reasonably high discharge. I think I got it quite close to that in one of my RC cars but no way over. Over about 3 months of use, they started puffing up.
thanks for the vid Dave! i was looking at these for my LED lightboxes and was wondering if the higher discharge units equal greater than rated capacity when run at lower discharge rates given their size increase... guess i was wrong :)
Hobbyking will really discount their LiPO (turnigy) cells if you buy them in any kind of quantity. Also, Why not use 2 smaller cells in a 1S2P to get the higher capacity? With that low of a draw, balancing really won't be an issue and I'm sure you can get them to make you up a custom pack w/connector.
Amazing mate, not very often you get the advertised capacity, normally exaggerated. I'm drooling over the electronic load! Didn't you untick the box to log the sampling to database pal?
Anybody else noticed the typo in the battery discharge wizard? In the discharge current list the time unit says "secnod" instead of "second". Look for youself at 19:29
If you use a soldered flex cable for your LCD you could locate it off board rather than stack it and keep the design as thin as possible. I'd use an extruded aluminum enclosure with a groove for the board to slide into and the battery could sit underneath. Then you could mill out a rectangle in the top for a cheap four button membrane button pad also connected with a flex cable. Thing would look like a chunky remote control with 5 way binding posts on the bottom, or better yet Anderson power pole quick disconnects.
Dave I would be compelled to take apart that BK Precision Load and put proper binding posts on it that accept banana plugs. Otherwise it would drive me BANANAS!
I have a question Dave I have been looking at the load test equipment you use to test power supplies ect. I like to build one for testing solar equipment. I have looked at ones for up to 3Kw the wattage I like to test. I like to test with voltages up to 60 volts ect but the one you have is quite pricey. Do know of a way to build your own test equipment. and I like to beable to program it for different loads and voltages. Any ideas would be great thanks.
Hello sir! I watch your videos and I love them I just want to know where do you buy components from. Power Supply,oscillo... And if they ship Worldwide. Thanks
i ve built a custom capacity meter and test any cells i can get my hands on. What i ve concluded is that the cutoff voltage of consumer electronics li ion cells is way too high @3,5v most of the times. If its discharged @3.1v you can get considerably more capacity even though you may be affecting the battery life, but then again who keeps their smartphone for more than a year and a half. The added capacity could make up for the reduced number of charge cycles.I think you can get 400-500 charges like this that would take you almost to a year and 4-5 months before your battery needs replacement...
is there any support for this type of battery? Lipo battery holder ? I have to make a PCB with battery Lipo but I don't know how to attach them on my PCB. Thank you!
Nice review. Now I'm still wondering why this unit or most others seem to lack voltage sense wires? When discharging at high currents, you want to measure the batteries voltage, not the battery voltage after vdrop from the test leads. Also, is there any Internal Resistance tester? Would be a nice feature...
remember the 20c is DisCharge And Charge Rate. the Later is the Time X Amps I believe they perform best if pushed both ways... And Like to Be about 100 -120 Degris F Nice and stable! also, the Low Volt Cut off needs a time below to avoid the spike drawls from Big motor controller
Same question was asked on the EEVblog forums. firewalker: Are those batteries bundled with a protection circuit of some kind (temperature e.t.c.). Can someone access the the data? Psi: na, RC batteries have no protection. It's almost impossible to have protection when you have legitimate loads of up to 200A.
This is problem because.. price ? The packs of LiPo & LiFe for RCs are mostly very simple to dissemble. Cells are just stacked up & between them is often cheap double side tape, and the leads are on one side soldered on small PCB(no electronic). In RC we often disassemble the packs (LoPo&LiFe) to remove the bad single cells and merge the good ones to one god pack. (To save money :) )
Take a spare set of bananna leads and get a good set of 10 AWG panduit open hook eyelets and silver solder them onto the bananna leads then you can leave them permanently hooked onto the terminals.
No it isn't. Nearly all Li-Po cells can safely be discharged to 2.75v as per the manufacturer's own spec sheet with no danger, damage or long-term loss of capacity.
Teth47 LiPo and LiFePO4 are very very different beasts altogether. I think its LiPo he talked about - very high current drain, but low longevity. BTW commercial LiPo is actually Li-Ion in flexible polymer casing, commercial polymer electrolyte lithium battery doesn't exist yet.
Where WOULD we be without turnigy! I use their batteries for everything, LARGE rc planes and helis.. Cordless drills.. my profesional location audio mixer, powering 12 lcd's and it goes on and on and on!! thanks for the info!!
Hi Dave. Do you think that this radio controlled watermelon is using a LiPo battery? The TH-cam Video is: 7X5wdwlVpK0 (Just put youtu.be forward slash in front of that, can't post a link here)
We use 360 of those 5000 mAh cells for our electric motorcycle arranged as 12 cells in parallel, 30 in series. We pull upwards of 700 amps peak and 100-400 amps continuous.
That is jaw dropping. I am totally amazed by these cells! Pls, can you tell me if the capacity suffers a lot when you use your pack with around 1.5c to 7c continuous and around 12c peak (which I just roughly calculated that you draw with 700 amps on 111V) ? Cheers :)
Miguel Bodega Unfortunately, we've never actually fully discharged the battery pack. We're a collegiate group and don't have many opportunities to take the bike out for a track day. When we have taken it out, we've had problems keeping a solid connection between each set of cells in series. The high current likes to arc if anything shakes loose while on the track. We're redesigning the pack (which honestly used way too many little bolts and nuts and luck) to avoid this problem (probably gonna spot weld the tabs like they do with 18650's). We're also designing a load test that should let us cycle the batteries several times a day and record stats on things like the capacity, temperature, voltage drops, etc.
Watswat5 Judging by personal use for hobby RC and these batteries, I'd say you can expect in the neighborhood of 3-500 cell cycles before you get a significant drop in performance and capacity with proper battery management and cell balancing. Have you matched the cells in terms of internal resistance?
I just love this channel for 30 min "just a quick video" alone already.
The previous version had rotary encoders. It didn't fit this form factor case. Vertical ones on the new layout are also quite tall.
Will check that when back at the lab, thanks.
Hi EEVblog. Just ran across this post and I realize I'm commenting three years after the fact. Just want to say that those of us flying RC multicopters, sUAV's, etc., would NEVER run a LiPo cell down to 3.0V. For most of us, the very minimum would be around 3.4 or 3.5V. Put another way, we generally never discharge our LiPo's past about 80% of their rated capacity.
I guarantee you that discharging a LiPo down to 3.0V cell voltage will ruin the battery in no time whatsoever. Just sayin.
Thanks for all the GREAT videos, David. I've learned so much from your channel!
Im running mine down to 3.65 under normal load. That are about 10% left in my case, just enough for a safe landing.
Ditto. I never, ever run LiPos down to less than 3.5V per cell.
Yes, most likely through my existing distributors in the US, Singapore and Germany.
Hi Dave, great video! Most of those 4 button chargers have a USB socket on one side, it's possible to do up to 0.5A discharge tests/graphs and even charge graphs with them using some freeware software (got it on the other laptop will post name later)
Some ppl reckon the voltage monitoring and balancing on that charger isn't so accurate due to low tolerance components - looks like yours was nailed though!
I look forward to the finished product.
Video is on my other youtube account.
Yes your PCB lay out videos are great. Great pointers, I love em.
Great video Dave! I am always interested in practical battery related material. It is a great supplement to the stuff I learn in school. Thanks!
Dave, I've noticed in the Battery Discharge Wizard window while you ranted on the constant current and not power mode ability of the thing, there's a scroll bar at the bottom, maybe if you scroll it to the right, it will reveal more modes? It certainly looks like it would to me. Cheers!
There is also online some info on changine some resistors inside to ones with a better acuracy for giving a more acurate balance/charge.
In the "Append Battery Sampling Data To Database" box, it also has the units as milli Siemens (mS), rather than milli seconds (ms)
Power tool companies have pretty widely available and standardized high capacity battery packs, so if you want to ship a power supply without battery and have it be easy for people to get their own battery with it, maybe consider making it for something like the Ryobi battery pack?
Yes, this was just a free proto from CircuitLabs.
Welcome back PSU. Nice. Thanks Dave.
I'd be happy to use low-C cells, if a similar capacity is available.
Thanks for the update Dave!
For these sort of applications I always use a small Li-Ion battery protection circuit. I sometimes harvest them from old cell phone batteries and it provides me a bit of insurance in case I leave a load connected to a battery or such.
16:00 , Loving that time unit; «Secnod»
27:00 -- you set it to 'sample save time 1000ms' and unchecked the box = no database at the end.
Very cool software though. I've wanted to make an arduino version before, just haven't had the need.
I was also gonna get one of those 5000 mAh batteries from hobbyking a while back but they were out of stock at the time. But they certainly look like nice batteries for some cool projects.
The Turnigy Accucell 6 has a combination temperature/"USB" port on the left side that you can connect to a computer and gather a metric buttload of information during charge and discharge. USB in quotes because it's actually TTL RS-232 signalling, and you need an adapter (available cheaply on ebay, I got one for $2.49 shipped).
LOL Dave wants a LONG Package.
Very nice. I've always wanted to make one of these. Will have to check out the forum for ideas :)
I've never seen a single cell one. Or one in a nice usable form factor.
It's always been an emergency backup teardown idea!
Oh, and without the battery, because shipping Lithium batteries now is a nightmare.
Great video! Turnigy should pay you for the advertising you gave them!
800milliohms ESR, which I would assume most of is in the contact resistance of the croc clips, the wire and the bodgy binding posts. You need to take 2 copper strips, drill a hole in them to fit the posts and drill and tap another set to handle the 4mm sockets. Then you can plug the cords in easily with minimal extra resistance, and with a very low loss on the connection.
I was hoping the same thing. Nothing spectacular, but I expected a bit more.
Dave, great videos, I have loved watching them ever since finding eevblog.
Have you considered using Panasonic NCR18650 series batteries? They come in 2900 mAh, 3100mAh, and 3400mAh capacities with a mass of 45g per cell. The cost is approx. $6-7 per cell when you buy 180 at a time. One downside of these cells is that to get the full capacity you must discharge to approx. 2.5V which may not work for your application.
Secnod is a time unit used in Australia, where - as we know - everything is upside down.
no wonder we get no rain... oh wait, what about california?
I need to install the capture software on that laptop, and move my USB studio mic over to the bench. PITA.
3.2 is the min voltage of a lipo, most stop at 3.4
@ about 23:31 did you say "Due to the internal ESR", meaning that the displayed voltage is lowered by the load's equivalent series resistance? thanks, cool vid
It's lowered by the batteries internal resistance, the voltage (E) drop across any resistance is equal to current (I) times resistance (R), E=I*R
Hi Dave, great work, keep it up. Just a random thought: maybe "*" will look better than "s" for set current/voltage (more symmetrical and stuff, and you have to know what that character on the left means anyway)
This is cool Dave keep up the good work mate
Dave why not use rotatory encoders insted of buttons?
They don't have any in large capacity single cell.
Why didn't you capture the screen on the computer rather than pointing the camera at the LCD?
You should put a quick connect on the batteries so you can slade them in and out like a cartrage for easy switching batteries.
Have you made a lipo cutoff to stop the battery getting damaged on low voltage?
how about a review and tear down of that Turnigy charger?
Indeed it does.
I've noticed some other errors to,perhaps it's time for Dave to make another video like the one he did on the pickit 3,that was hilarious and the response from microchip was even more hilarious. :-D
dont absolutely get too close to 3 v with lipos, they build internal resistance that way, then they can puff and potentially catch fire while recharging next time
Safety cutout is usually 2.5V. have you considered using 18650's?
Good video! Does the BK load have sense wires? If so, you should've sensed the voltage right the cell tabs. Otherwise your BK load reads a lower voltage due to IR drop in the banana cables.
19:30 Secnod? you mean SECOND
Might want to check your supplier catalogue, Dave - they make spade connector to 4mm banana jack adapters. Usually come in test lead kits for a few quid (which I guess would be a few AUD down your way) or you can probably get better quality ones (e.g. Pomona) from the likes of Farnell.
Might work a bit better than jamming the 4mm plugs side-on into the binding post...
Any RaspberryPi vids in your future?
Yeah, will have to look for those. To ebay I go...
Hi , will those batteries work in a quadcopter?, i remember in a past video when you where setting up your new lab you mention you where going to build a quad copter, did you ever manage to do so?
Will this thing be available in Canada? Or possibly distributed through Adafruit?
Ha, I was taking the piss. :-P Thanks for the update on the PSU, been waiting for a long time...
Can you solder a wire to those battery terminals?
I can not do it in cellphone batteries. That thing is made only for spot welding.
Some of these lipo cells have insane C ratings but I've always been dubious about using them that high. It almost seems too high for such a small cell... Had a couple Chinese cells off ebay supposedly rated at some reasonably high discharge. I think I got it quite close to that in one of my RC cars but no way over. Over about 3 months of use, they started puffing up.
thanks for the vid Dave! i was looking at these for my LED lightboxes and was wondering if the higher discharge units equal greater than rated capacity when run at lower discharge rates given their size increase... guess i was wrong :)
Hobbyking will really discount their LiPO (turnigy) cells if you buy them in any kind of quantity. Also, Why not use 2 smaller cells in a 1S2P to get the higher capacity? With that low of a draw, balancing really won't be an issue and I'm sure you can get them to make you up a custom pack w/connector.
You could try cable ties and appropriate mounting holes ...
Almost anywhere, just search for 8x2 LCD.
Amazing mate, not very often you get the advertised capacity, normally exaggerated. I'm drooling over the electronic load! Didn't you untick the box to log the sampling to database pal?
Of course you'd need a BMS. And there are actually commercially available products that do exactly what you suggest! :)
Dave, if you revise the board is there any way to add an output on/off switch?
Anybody else noticed the typo in the battery discharge wizard?
In the discharge current list the time unit says "secnod" instead of "second".
Look for youself at 19:29
If you use a soldered flex cable for your LCD you could locate it off board rather than stack it and keep the design as thin as possible. I'd use an extruded aluminum enclosure with a groove for the board to slide into and the battery could sit underneath. Then you could mill out a rectangle in the top for a cheap four button membrane button pad also connected with a flex cable. Thing would look like a chunky remote control with 5 way binding posts on the bottom, or better yet Anderson power pole quick disconnects.
Ooh, Do a teardown of that charger! I have that same model for my airplane and heli batteries!
It's 16x2's I have heaps of!
Dave I would be compelled to take apart that BK Precision Load and put proper binding posts on it that accept banana plugs. Otherwise it would drive me BANANAS!
Do those cells have the protection circuitry built in?
Hi, just a quick video...
Checks time - 29:32 - Feels good : )
I have a question Dave I have been looking at the load test equipment you use to test power supplies ect. I like to build one for testing solar equipment. I have looked at ones for up to 3Kw the wattage I like to test. I like to test with voltages up to 60 volts ect but the one you have is quite pricey. Do know of a way to build your own test equipment. and I like to beable to program it for different loads and voltages. Any ideas would be great thanks.
i didnt know you was into RC eevblog!
Hello sir!
I watch your videos and I love them
I just want to know where do you buy components from. Power Supply,oscillo...
And if they ship Worldwide.
Thanks
I could realy use the usb battery charger! Dave How can I get one are you satisfied with the end product or are you still updateing it?
Dear Dave
Where can i buy your tester?
i ve built a custom capacity meter and test any cells i can get my hands on. What i ve concluded is that the cutoff voltage of consumer electronics li ion cells is way too high @3,5v most of the times.
If its discharged @3.1v you can get considerably more capacity even though you may be affecting the battery life, but then again who keeps their smartphone for more than a year and a half. The added capacity could make up for the reduced number of charge cycles.I think you can get 400-500 charges like this that would take you almost to a year and 4-5 months before your battery needs replacement...
Great post, Mate! Love the way you tell it like it is :-)
is there any support for this type of battery? Lipo battery holder ?
I have to make a PCB with battery Lipo but I don't know how to attach them on my PCB.
Thank you!
"I'd rather stay with the same LCD" or rather "I'd rather stay with the same LCD because I've got a box of 500 I pre-purchased." :)
I think discharging it at 95% capacity still damages the battery/ shortens the life cycle. A safe capacity threshold would be 80%, 85% at max.
Nice review. Now I'm still wondering why this unit or most others seem to lack voltage sense wires? When discharging at high currents, you want to measure the batteries voltage, not the battery voltage after vdrop from the test leads. Also, is there any Internal Resistance tester? Would be a nice feature...
remember the 20c is
DisCharge And Charge Rate. the Later is the Time X Amps
I believe they perform best if pushed both ways...
And Like to Be about 100 -120 Degris F Nice and stable!
also, the Low Volt Cut off needs a time below to avoid the spike drawls from Big motor controller
I would love to buy a few of these, or perhaps one with interchangeable batteries, would be excellent for powering my gopro in the field.
could you not have bought a few 1200Mah 1s batteries and put them in parallel?
Dave please change the solder mask color of your board...
Maybe Red to mach the ucurrent...
Same question was asked on the EEVblog forums.
firewalker: Are those batteries bundled with a protection circuit of some kind (temperature e.t.c.). Can someone access the the data?
Psi: na, RC batteries have no protection. It's almost impossible to have protection when you have legitimate loads of up to 200A.
This is problem because.. price ?
The packs of LiPo & LiFe for RCs are mostly very simple to dissemble.
Cells are just stacked up & between them is often cheap double side tape, and the leads are on one side soldered on small PCB(no electronic).
In RC we often disassemble the packs (LoPo&LiFe) to remove the bad single cells and merge the good ones to one god pack. (To save money :) )
Take a spare set of bananna leads and get a good set of 10 AWG panduit open hook eyelets and silver solder them onto the bananna leads then you can leave them permanently hooked onto the terminals.
No it isn't. Nearly all Li-Po cells can safely be discharged to 2.75v as per the manufacturer's own spec sheet with no danger, damage or long-term loss of capacity.
Hey Dave! Why did you pick LiPo rather than Lithium Ion batteries?
Price and current handling. They're LiFePo batteries, amazing current handling and I think that cell is like $12 retail.
Teth47
LiPo and LiFePO4 are very very different beasts altogether. I think its LiPo he talked about - very high current drain, but low longevity.
BTW commercial LiPo is actually Li-Ion in flexible polymer casing, commercial polymer electrolyte lithium battery doesn't exist yet.
Probably a dumb question but is the battery hooked up in reverse polarity?
nml no
Where WOULD we be without turnigy! I use their batteries for everything, LARGE rc planes and helis.. Cordless drills.. my profesional location audio mixer, powering 12 lcd's and it goes on and on and on!! thanks for the info!!
Hi Dave. Do you think that this radio controlled watermelon is using a LiPo battery?
The TH-cam Video is: 7X5wdwlVpK0
(Just put youtu.be forward slash in front of that, can't post a link here)
We use 360 of those 5000 mAh cells for our electric motorcycle arranged as 12 cells in parallel, 30 in series. We pull upwards of 700 amps peak and 100-400 amps continuous.
That is jaw dropping. I am totally amazed by these cells! Pls, can you tell me if the capacity suffers a lot when you use your pack with around 1.5c to 7c continuous and around 12c peak (which I just roughly calculated that you draw with 700 amps on 111V) ? Cheers :)
Miguel Bodega Unfortunately, we've never actually fully discharged the battery pack. We're a collegiate group and don't have many opportunities to take the bike out for a track day. When we have taken it out, we've had problems keeping a solid connection between each set of cells in series. The high current likes to arc if anything shakes loose while on the track. We're redesigning the pack (which honestly used way too many little bolts and nuts and luck) to avoid this problem (probably gonna spot weld the tabs like they do with 18650's). We're also designing a load test that should let us cycle the batteries several times a day and record stats on things like the capacity, temperature, voltage drops, etc.
hey thanks a lot for the info. Keep on the good work and good luck with the new interconnection of the cells!
Watswat5 Judging by personal use for hobby RC and these batteries, I'd say you can expect in the neighborhood of 3-500 cell cycles before you get a significant drop in performance and capacity with proper battery management and cell balancing. Have you matched the cells in terms of internal resistance?
Did this project die I would love one.
Can you find an ARM PC for $25?
That is actually a good idea for a display as I still have a working Nokia 3310 but it is not that easy to use with this kind of project.
Dave is not a "reviewer" but an engineer. And he doesn't do quick videos, despite claims of the contrary.
Please Dave, I would know what you think about ED LEEDSKALNIN and his electromagnets. It seems like a real phenomenon.