Need Assistance on Checking Battery Health

[jamesbea]

On my 6S rigs I usually run one single 6S battery. Last week I decided to run 2x3S batteries (the two batteries are identical brand/mah/C rating). Not long after I started the run my truck started kicking in and out. From my experience, this is due to one of the batteries having issues causing a voltage drop & the esc acting erratic.

When I look on my charger at the individual cells they are all within range of each other, but I am aware there is a way to read ohms that will give you more information on the battery's overall health. Honestly, I am ignorant to this component and would appreciate any insight, or if there is a better way to find the battery (cell) that is causing the issue. For reference my charger is a HOTA D6+.

Thanks!

 

[jkflow]

Do a normal charge, go to the channel of interest and use the arrow buttons to cycle the bottom display through the modes, one of them is the 'IR value in miliohm.
This only works while doing a charge.

 

[Dales396lt4]

It’s always good to check the Internal Resistance. On each cel, lower the better.

 

[jkflow]

all the values should be comparable and below ~ 8mOhm but report out.
There are a lot of other potential failure sources besides a lipo though.

Usually a bullet de solders itself over time when you are WOT a lot.

 

[jamesbea]

Thanks for all the feedback. Below you will see my findings, any insight would be appreciated.

Battery 1:

Battery 2:

Batteries in question:

 

[Eno]

They look puffed. IR values are too high IMO. At least for serious 6S bashing...

 

[Hector_Fisher]

I don't see anything super out of wack with your lipos or the IR. It's not the best IR, but that's pretty run of the mill with low-mid range Zeee batteries, and honestly what you're seeing is what i'd expect from them. The 5200 mah (either 6s or 2x3s) is on the low side for a 6s basher, IMO, and their 60c lipos are generally the weaker of their packs. But you can sometimes sort all that out with lower gearing. Not sure what your 6s lipo is, but it's possible the 2x3s pair is just weaker than the 6s pack and that's the issue you're experiencing. What is your 6s lipo for comparison?

 

[jamesbea]

I don't see anything super out of wack with your lipos or the IR. It's not the best IR, but that's pretty run of the mill with low-mid range Zeee batteries, and honestly what you're seeing is what i'd expect from them. The 5200 mah (either 6s or 2x3s) is on the low side for a 6s basher, IMO, and their 60c lipos are generally the weaker of their packs. But you can sometimes sort all that out with lower gearing. Not sure what your 6s lipo is, but it's possible the 2x3s pair is just weaker than the 6s pack and that's the issue you're experiencing. What is your 6s lipo for comparison?

Thanks for the info, the 6s battery I use is also a Zee battery. It is a 6000mah/100C pack. I never have any issues with that one. Also, running a 17 tooth pinion with a stock spur.

 

[ScaleJunkie]

all the values should be comparable and below ~ 8mOhm but report out.
There are a lot of other potential failure sources besides a lipo though.

Usually a bullet de solders itself over time when you are WOT a lot.

They look puffed. IR values are too high IMO. At least for serious 6S bashing...

Could be worse, this is an SMC 7400 mah that I still run, balances every time.

I keep a very close eye on it while I'm charging it, and will be retiring it soon. This battery is 5 years old. I do not advocate for playing with a battery like this and I know how dangerous it is.

Having drastically different resistance like this causes the cells with lower resistance to charge faster, and can be dangerous. I charge at 1c or less and stop the charge to balance the cells before I start charging it again.

 

[jkflow]

IR values are always hard to compare between different measurement systems. From OP, those are ok with respect to each other.
By all means I had Zeee that were great and when I bought a set ~ 18 month ago they were absolute poop i.e. have similare values as yours but simply break down under load. Not only that, the actual capacity is usually 10-30% under what is stated. Most likely that is your issue i.e. over-advertised capacity.
This assumes that a different pack doesn't show the same symptoms (as in your case), else I'd be looking at wiring etc.

The C rating is about 15-20 in reality, based on testing that others performed. Now combine the low C with the lower than advertised capacity and you get a max current of ~ (4500mAh/1000*20C) 4.5*20 = 90A and you will get serious voltage drops as a result.

This sounds like that is your problem.

Avoid all Amazon brands, they literally only have a different sticker, same source but different distributors. This varies wildly and is only a snapshot in time but for sure you will always get the bottom 30% coming off any production line. They are ok for bashing but up the capacity to ~ 6500mAh minimum. That gets you into real 5800mAh range (or 116A peak)., realistic for bashing.

Note: Those SMC values look tired but 5 years is great!

 

[ScaleJunkie]

IR values are always hard to compare between different measurement systems. From OP, those are ok with respect to each other.
By all means I had Zeee that were great and when I bought a set ~ 18 month ago they were absolute poop i.e. have similare values as yours but simply break down under load. Not only that, the actual capacity is usually 10-30% under what is stated. Most likely that is your issue i.e. over-advertised capacity.
This assumes that a different pack doesn't show the same symptoms (as in your case), else I'd be looking at wiring etc.

The C rating is about 15-20 in reality, based on testing that others performed. Now combine the low C with the lower than advertised capacity and you get a max current of ~ (4500mAh/1000*20C) 4.5*20 = 90A and you will get serious voltage drops as a result.

This sounds like that is your problem.

Avoid all Amazon brands, they literally only have a different sticker, same source but different distributors. This varies wildly and is only a snapshot in time but for sure you will always get the bottom 30% coming off any production line. They are ok for bashing but up the capacity to ~ 6500mAh minimum. That gets you into real 5800mAh range (or 116A peak)., realistic for bashing.

Note: Those SMC values look tired but 5 years is great!

I have been rather pleased with it and will be buying again. This is after charge.

 

[jkflow]

I run exclusively SMC in my boats and love them. Not really expensive when you consider that they last 4-5 years while my Zeee etc all kick the bucket after 1 - 2 seasons.
CNHL, mixed opinions and experience.