30/45/80/120A LiPo Discharger Build

[WickedFog]

Dude! Just watched your vid. That Deans was far from melting. I was sitting here yelling at my phone - check the battery! Lol.

Great job on this build man. Seriously impressive!

 

[Greywolf74]

Thanks guys!

For those of you that havent seen it...heres the video of my DIY 100A 2S LiPo Discharger

 

[STONER RC]

Well there goes the amp rating on the deans connectors. awesome build "WOLF".. much respect tou definitely know your .. about lipos and electric power... WELL DONE BUD
Your going to fill the rc lipo world upside down..and also blow the connectors ratings out the window.. I got XT60 and XT90 if you want some for testing...

 

[Greywolf74]

Well there goes the amp rating on the deans connectors. awesome build "WOLF".. much respect tou definitely know your .. about lipos and electric power... WELL DONE BUD
Your going to fill the rc lipo world upside down..and also blow the connectors ratings out the window.. I got XT60 and XT90 if you want some for testing...

Not sure if I'm gonna set the world on fire but its definitely gonna be fun

 

[Doom!]

This is going to be interesting, can't wait to see if there are any unexpected results.

 

[Greywolf74]

Ok, So after the test yesterday where I accidently let the lipo discharge momentarily dip down to around 2.4v/c we did get some more puffing as you guys saw. So I let the battery cool down completely and then charged it back to full and then 2 complete cycles on it. Here are the before and after numbers.

These measurements were taken with my Progressive RC ESR meter.
Before:
125A continuous max | true C rating = 16C | cell 1 = 2.31mohm | cell 2 = 3.07mohm

After:
121.9A continuous max | True C Rating =15C | cell 1 = 2.79mohm | cell 2 = 3.23mohm

So we can tell we did a little bit of damage to the cells by the increased IR however most of the puffing (both the slight puffing it had originally and the extra puffing we ended up with) is just due to electrolyte degradation which is a byproduct of either age or number of cycles. The electrolyte in a battery is the chemical(s) that allow energy to flow between the cathode and the electrode. The cathode and electrode are the positive and negative terminals inside the battery. Eventually as a lipo gets old, gets a lot of use on it, or is abused in some fashion (think over charging, over discharging, or some sort of shock to the battery) the electrolyte material begins to break down and give off a mixture of gases. The main gas is oxygen but also carbon dioxide and carbon monoxide too. At any rate once the gasses separate from the electrolyte material it may be able to reabsorb a little of it but it will not be able to reabsorb all of it. This is why lipos become puffy and its also why if you get a lipo that becomes a little puffy and you cycle it once or twice on your charger a little of the puffiness may go down but once its puffed theres no unpuffing it I'm afraid.

So in conclusion the raise in IR is an indicator that we did damage the cells a bit from over discharging but the puffiness if probably more to do with the age or the amount of cycles on the lipo already. If this had been a brand new battery we may not have had any puffing at all or it could have been very minimal. For example my SMC lipo that accidently got discharged down to 2.6v/c in my K8 has no puffiness at all and the IRs are still under 2mohm on all cells. Given the still relatively low IR of the cells in spite of the fact that this battery is old and/or worn out actually suggests that this Pro-Match Racing company probably produces so good quality lipos. I had not heard of this company previously.

I'm still learning about electronics and lipos but based on what I do know this is the hypothesis I've come to regarding what happened to this particular battery.

 

[WickedFog]

Ok, So after the test yesterday where I accidently let the lipo discharge momentarily dip down to around 2.4v/c we did get some more puffing as you guys saw. So I let the battery cool down completely and then charged it back to full and then 2 complete cycles on it. Here are the before and after numbers.

These measurements were taken with my Progressive RC ESR meter.
Before:
125A continuous max | true C rating = 16C | cell 1 = 2.31mohm | cell 2 = 3.07mohm

After:
121.9A continuous max | True C Rating =15C | cell 1 = 2.79mohm | cell 2 = 3.23mohm

So we can tell we did a little bit of damage to the cells by the increased IR however most of the puffing (both the slight puffing it had originally and the extra puffing we ended up with) is just due to electrolyte degradation which is a byproduct of either age or number of cycles. The electrolyte in a battery is the chemical(s) that allow energy to flow between the cathode and the electrode. The cathode and electrode are the positive and negative terminals inside the battery. Eventually as a lipo gets old, gets a lot of use on it, or is abused in some fashion (think over charging, over discharging, or some sort of shock to the battery) the electrolyte material begins to break down and give off a mixture of gases. The main gas is oxygen but also carbon dioxide and carbon monoxide too. At any rate once the gasses separate from the electrolyte material it may be able to reabsorb a little of it but it will not be able to reabsorb all of it. This is why lipos become puffy and its also why if you get a lipo that becomes a little puffy and you cycle it once or twice on your charger a little of the puffiness may go down but once its puffed theres no unpuffing it I'm afraid.

So in conclusion the raise in IR is an indicator that we did damage the cells a bit from over discharging but the puffiness if probably more to do with the age or the amount of cycles on the lipo already. If this had been a brand new battery we may not have had any puffing at all or it could have been very minimal. For example my SMC lipo that accidently got discharged down to 2.6v/c in my K8 has no puffiness at all and the IRs are still under 2mohm on all cells. Given the still relatively low IR of the cells in spite of the fact that this battery is old and/or worn out actually suggests that this Pro-Match Racing company probably produces so good quality lipos. I had not heard of this company previously.

I'm still learning about electronics and lipos but based on what I do know this is the hypothesis I've come to regarding what happened to this particular battery.

I had never heard of them either. Is it a banggood special?

 

[STONER RC]

Ok, So after the test yesterday where I accidently let the lipo discharge momentarily dip down to around 2.4v/c we did get some more puffing as you guys saw. So I let the battery cool down completely and then charged it back to full and then 2 complete cycles on it. Here are the before and after numbers.

These measurements were taken with my Progressive RC ESR meter.
Before:
125A continuous max | true C rating = 16C | cell 1 = 2.31mohm | cell 2 = 3.07mohm

After:
121.9A continuous max | True C Rating =15C | cell 1 = 2.79mohm | cell 2 = 3.23mohm

So we can tell we did a little bit of damage to the cells by the increased IR however most of the puffing (both the slight puffing it had originally and the extra puffing we ended up with) is just due to electrolyte degradation which is a byproduct of either age or number of cycles. The electrolyte in a battery is the chemical(s) that allow energy to flow between the cathode and the electrode. The cathode and electrode are the positive and negative terminals inside the battery. Eventually as a lipo gets old, gets a lot of use on it, or is abused in some fashion (think over charging, over discharging, or some sort of shock to the battery) the electrolyte material begins to break down and give off a mixture of gases. The main gas is oxygen but also carbon dioxide and carbon monoxide too. At any rate once the gasses separate from the electrolyte material it may be able to reabsorb a little of it but it will not be able to reabsorb all of it. This is why lipos become puffy and its also why if you get a lipo that becomes a little puffy and you cycle it once or twice on your charger a little of the puffiness may go down but once its puffed theres no unpuffing it I'm afraid.

So in conclusion the raise in IR is an indicator that we did damage the cells a bit from over discharging but the puffiness if probably more to do with the age or the amount of cycles on the lipo already. If this had been a brand new battery we may not have had any puffing at all or it could have been very minimal. For example my SMC lipo that accidently got discharged down to 2.6v/c in my K8 has no puffiness at all and the IRs are still under 2mohm on all cells. Given the still relatively low IR of the cells in spite of the fact that this battery is old and/or worn out actually suggests that this Pro-Match Racing company probably produces so good quality lipos. I had not heard of this company previously.

I'm still learning about electronics and lipos but based on what I do know this is the hypothesis I've come to regarding what happened to this particular battery.

Well sir I must say THANK YOU!!! I'm impressed with the device and the testing.. You've done a fantastic job. And the results are surprising as you did say the battery was a 75c rating when you first plug it in correct? and the amps are crazy. 123 average continues.. WOW.. that's alkt of power being pulled from that battery. And I my self have not heard of or seen one of those lipos either. Interesting

 

[Greywolf74]

I had never heard of them either. Is it a banggood special?

nah, they have their own website. I found THIS review of the company on big squid. They basically said theyre mediocre budget batteries or at least the 30C 5200mah pack they tested was.

Well sir I must say THANK YOU!!! I'm impressed with the device and the testing.. You've done a fantastic job. And the results are surprising as you did say the battery was a 75c rating when you first plug it in correct? and the amps are crazy. 123 average continues.. WOW.. that's alkt of power being pulled from that battery. And I my self have not heard of or seen one of those lipos either. Interesting

It was supposedly a 150C pack originally. The internal temp of the discharger reached about 120F.

 

[Greywolf74]

I just bought a couple new Pro-Match Racing LiPos for testing. I got a 5200mah 50C and a 5000mah 150C. The second one was a shorty pack but I can't see where that would matter for testing purposes. Its still a 5000mah 150C lipo. I'm thinking next payday I might pick up one of there graphine packs for testing but their graphine packs are HV LiPos so I'm not sure about that

 

[STONER RC]

nah, they have their own website. I found THIS review of the company on big squid. They basically said theyre mediocre budget batteries or at least the 30C 5200mah pack they tested was.

It was supposedly a 150C pack originally. The internal temp of the discharger reached about 120F.

Wow 150c that's crazy . And only produced 16c max.. WOW and 120° on the discharger and that was a pure dump of power . That's not bad for temps but the C rating is interesting.

 

[Greywolf74]

Wow 150c that's crazy . And only produced 16c max.. WOW and 120° on the discharger and that was a pure dump of power . That's not bad for temps but the C rating is interesting.

I bought another of their 150C packs. I'll see what the ESR meter says the true C rating is on a brand new pack.

 

[STONER RC]

I bought another of their 150C packs. I'll see what the ESR meter says the true C rating is on a brand new pack.

Oh man. This should be good

 

[olds97_lss]

I'm dying to see numbers! LOL!

I need to ditch a few of my 3S and 4S packs that I've built out of old ones. They are just taking too long to charge, the IR is high on a cell in each of them and they don't discharge evenly. Not worth the headache... I'm contemplating getting more liperior's, just wish I had more time on the ones I have. Isn't like I'm spending a lot, probably $120 for 4 packs, but would still like to see some real data on them when you get that far.

 

[Greywolf74]

I'm dying to see numbers! LOL!

I need to ditch a few of my 3S and 4S packs that I've built out of old ones. They are just taking too long to charge, the IR is high on a cell in each of them and they don't discharge evenly. Not worth the headache... I'm contemplating getting more liperior's, just wish I had more time on the ones I have. Isn't like I'm spending a lot, probably $120 for 4 packs, but would still like to see some real data on them when you get that far.

Yeah,I've not been making much progress. I need to spend less time on the forums and more time at the work bench. I'm gonna get the last of the adapters I need soldered up over the weekend and get connectors soldered on the Hyperion datalogger this weekend and figure out how to use it. Once I get that done Ill be ready to start testing. Well except I need to figure out an exact testing methodology.

I'm thinking I'm gonna run each pack through the same gauntlet which will look something like this:

1) Take IR and True C Rating (TCR) measurements right out of the box.
2) Run each lipo through 5x 1C cycles on the charger
3) Take IR and TCR rating measurements again.
4) Run each lipo through a 1C discharge on the capacity tester down to 3V/C to measure true capacity.
5) Run each lipo through 5 cycles being charged at 1C but discharged at 35A while graphing the 35A discharges.
6) Measure IR & TCR
7) Test capacity at 1C again down to 3V/C
8) Run each lipo through 5 cycles being charged at 1C but discharged at 70A while graphing the 70A discharges.
9) Measure IR & TCR
10) Test capacity at 1C again down to 3V/C
11) Run each lipo through 5 cycles being charged at 1C but discharged at 100A while graphing the 100A discharges.
12) Measure IR & TCR
13) Test capacity at 1C again down to 3V/C

These will be resistive load discharges so the Amperage will drop as the voltage drops but it will be the same across the board so as long as the baseline is the same for all the tests then the comparative data should still be valid.

If anyone has any ideas or suggestions on my testing methodology now would be the time to speak up. I hope to start testing by at least early next week if not sooner.

 

[STONER RC]

Yeah,I've not been making much progress. I need to spend less time on the forums and more time at the work bench. I'm gonna get the last of the adapters I need soldered up over the weekend and get connectors soldered on the Hyperion datalogger this weekend and figure out how to use it. Once I get that done Ill be ready to start testing. Well except I need to figure out an exact testing methodology.

I'm thinking I'm gonna run each pack through the same gauntlet which will look something like this:

1) Take IR and True C Rating (TCR) measurements right out of the box.
2) Run each lipo through 5x 1C cycles on the charger
3) Take IR and TCR rating measurements again.
4) Run each lipo through a 1C discharge on the capacity tester down to 3V/C to measure true capacity.
5) Run each lipo through 5 cycles being charged at 1C but discharged at 35A while graphing the 35A discharges.
6) Measure IR & TCR
7) Test capacity at 1C again down to 3V/C
8) Run each lipo through 5 cycles being charged at 1C but discharged at 70A while graphing the 70A discharges.
9) Measure IR & TCR
10) Test capacity at 1C again down to 3V/C
11) Run each lipo through 5 cycles being charged at 1C but discharged at 100A while graphing the 100A discharges.
12) Measure IR & TCR
13) Test capacity at 1C again down to 3V/C

These will be resistive load discharges so the Amperage will drop as the voltage drops but it will be the same across the board so as long as the baseline is the same for all the tests then the comparative data should still be valid.

If anyone has any ideas or suggestions on my testing methodology now would be the time to speak up. I hope to start testing by at least early next week if not sooner.

OH BOY.... wish I lived closer to you I would give you a hand. Bring over the quad so can charge more batteries at the same time. But sure you have multiple chargers as well. In your WolfRC store.

 

[Greywolf74]

OH BOY.... wish I lived closer to you I would give you a hand. Bring over the quad so can charge more batteries at the same time. But sure you have multiple chargers as well. In your WolfRC store.

LOL, yeah I can charge up to 9 lipos at a time if I drug out my old and/or Chinesium chargers I dont really use anymore but I've only got 4 that I really use. I only have 2 chargers that cycle LiPos though

 

[Greywolf74]

Well I finished making all the adapters I need, now I have about 14 or so batteries to solders connectors on and then I just have to figure out how the datalogger works. Slowly getting there...

 

[Greywolf74]

I've was having some issues with the discharger. Come to find out it was the smaller breakers that were periodically malfunctioning. I dont know if it was because they were smaller amperage ratings or just wore out from use. I replaced all of the breakers with 300A breakers! So far its working perfectly again! Now I can get back to testing

 

[STONER RC]

I've was having some issues with the discharger. Come to find out it was the smaller breakers that were periodically malfunctioning. I dont know if it was because they were smaller amperage ratings or just wore out from use. I replaced all of the breakers with 300A breakers! So far its working perfectly again! Now I can get back to testing

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Hell yeah buddy!!! The new breakers look awesome. So happy/glad to see you getting back to testing lipos. And running RC's again. We all need to take a break time to time. Or we just get burnt out. Which then it's no fun, nicely done bud....

Thank you very much. For all the testing and research you do. For all of the guys here on the best RC forum out there. And the RC community as a whole.

Really appreciated bud you rock. I'm sure your results and research really helps people to make a good decision on what lipo to purchase for their RC. The lipos aren't cheap so to have good quality test results from a RC user them selves. Really helps to make a good informative decision on which lipo to pick up..