LVC, temps and runtime.

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Batman

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Arrma RC's
  1. Kraton 8S
Took my Kraton 8s out for it's second run last night. LVC kicked in but to my surprise one of the batteries voltage was around 3.3v and the other 3.6v. This was the first time I used these batteries, I balanced charged them also, thoughts?

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On my first run with this truck I used gensacearespammers 4s 5000mAh 50c packs and the LVC kicked in at 3.6v for those and both packs had similar voltage range and I got a longer run time also (16-20mins).

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These were the temps using the Turnigys, thoughts?

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All ESC settings are stock.
 
Looks like they're not matched, bad luck I guess. One pack probably has a significantly higher internal resistance than the other.
 
Are you 100% confident that's the issue? Only reason I'm using them is so I don't void the warranty on the batteries.
I can’t imagine they would void the warranty just because you swapped connectors. If the cells are well balanced today, they are good packs. I cut mine off after a quick cells check. Put XT150’s on before my first run.
 
Several possibilities

You said this was the first run on these batteries?
Typically you need ~ 5 cycles before a battery is at it's peak performance.

I agree, ditch the adapters. Most likely the one that is attached to the 'higher' battery has a higher resistance.
Do a temp check on them as well, that will tell you.

I guarantee you that the lower pack tripped the LVC, I bet it went below 3V under load and you are damaging your cells doing it. They usually recover to what you see unless you keep driving, which LVC prevented.

Learn to stop before LVC kicks in. It's meant as a last emergency stop and not something to rely on. Yo are trading 1 min of run time for breaking packs and by end of season they will have less capacity due to mistreatment.

I can’t imagine they would void the warranty just because you swapped connectors. If the cells are well balanced today, they are good packs. I cut mine off after a quick cells check. Put XT150’s on before my first run.
I'm almost certain they would but check with the manufacturer.

In general, people don't know how to do it properly, short leads by cutting both at the same time etc.
Same is true with Arrma, you cut off the leads you void the warranty.
 
I can't recommend the smc precision lipo alarm enough for cases like this.

The very first time I ran my kraton 6s with dual 3s in series I ran it to a point where I felt it should have hit lvc. Sure enough when I brought it in my cells were at 3.5v across both packs cells.

I don't trust the lvc settings on the esc. Even my hobbywing lvcs are turned off and I use the lipo alarm set to 3.7v.

On top of that, I put the pack with the "lowest cell reading" on the negative side of the series and attach the lipo alarm to that pack.

Haven't had any issues so far. To add though, from my drone experience I have a habit of doing extra balancing beyond my charger. My fpv racing/freestyle drones can kill a battery and we don't always have space for a lipo alarm so have to do extra battery care.
 
Several possibilities

You said this was the first run on these batteries?
Typically you need ~ 5 cycles before a battery is at it's peak performance.

I agree, ditch the adapters. Most likely the one that is attached to the 'higher' battery has a higher resistance.
Do a temp check on them as well, that will tell you.

I guarantee you that the lower pack tripped the LVC, I bet it went below 3V under load and you are damaging your cells doing it. They usually recover to what you see unless you keep driving, which LVC prevented.

Learn to stop before LVC kicks in. It's meant as a last emergency stop and not something to rely on. Yo are trading 1 min of run time for breaking packs and by end of season they will have less capacity due to mistreatment.


I'm almost certain they would but check with the manufacturer.

In general, people don't know how to do it properly, short leads by cutting both at the same time etc.
Same is true with Arrma, you cut off the leads you void the warranty.

Attached EC5's to the batteries now and storage charged them again, hopefully it makes a difference. I need to learn to get used to noticing the difference in performance out put once the batteries get low and stop immediately.

Is around 13mins of runtime with these batteries normal?

20200521_183243.jpg
 
Not familiar with 8S Kraton or how you drive but 13 min could be normal with a lot of WOT on grass.
I'm almost certain it will improve slightly with these packs as they are new.
 
Not familiar with 8S Kraton or how you drive but 13 min could be normal with a lot of WOT on grass.
I'm almost certain it will improve slightly with these packs as they are new.

To be fair it was entirely on grass and going full throttle a decent amount since there were no jumps.
 
Yes, that would be normal, it is for my 6S bashing style. Add jumping or anything else and obviously the time will improve.
Again, time will probably improve due to lipo's being new. Bash on and get them cycled! (y)
 
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