3s Lipo battery problem

[Rookie1980]

Just brought my first brushless buggy corally radix 6s which came with x2 core rc 3s battery’s which are supposed to be more or less brand new can’t charge till tomorrow waiting for a xt90 connector for charger but have received voltage checker
One off the batteries seems to have a problem 2 cells are reading 3.7 and one 2.6 will it balance itself out when charged help would be much appreciated thankyou

 

[nino]

Probably, but that one cell will also probably always lag behind the others. If you can return the packs, do so.

 

[Rookie1980]

Thanks for reply mate appreciate it the batteries came withe the car second hand the car was brand new so can't send back I’ll give the balance charge ago and hopefully won’t blow up before hand

 

[bill_delong]

so long as none of the cells have dropped below 1.5V for longer than a week, then you can boost the battery in NiMh mode for about a minute, then connect the balance harness and complete the charge in LiPo mode, more info here:

https://batteryuniversity.com/article/bu-808a-how-to-awaken-a-sleeping-li-ion

 

[Rookie1980]

Thanks for the advice bill I’ll try and find a video on how to boost battery in Nmh mode

 

[bill_delong]

no video necessary....

1) disconnect balance harness from battery to charger
2) connect battery to charger with main 3S lead
3) place charger in NiMh mode and charge battery for no more than 1 minute, then manually stop charger, this will boost voltage of low cell above 3.0V
4) place charger in LiPo mode and connect balance harness, resume charge as normal

Most chargers have a safety feature that will not charge a battery if any cell is below 3.0V which is why it may be necessary to boost in NiMh mode.

*** DO NOT WALK AWAY WHEN CHARGING IN NIMH MODE ***

limit to no more than 1 minute in NiMh mode, I have seen a handful of LiPo fires at the track in my area when folks boost their packs in NiMh mode and forget to switch back to LiPo mode!

 

[Rookie1980]

Thankyou bill I’ll let u know how I get on will I have to change any of settings in nimh mode or just plug in and start sorry about all the questions

 

[tntpoof]

when in nimh mode you only charge to low cell. try to get it close to 3.7 as possible.. not sure your charger can handle down around 3 as stated above. your going to have to make a custom lead to charge that low cell. get a male 5 cell balance plug only use center plugs as to put power back in battery
https://www.amazon.com/Keszoox-Balance-Extension-Charging-Silicone/dp/B09N1P48BB/ref=sr_1_17?crid=1IHNIIWF328ZV&keywords=5+cell+balance+plug&qid=1683143492&sprefix=5+cell+ballance+plug,aps,473&sr=8-17
id just get one of these cut the wires off so you can solder your connector of choice .best to make wire and plug so you dont have a pop
charge at 1 amp in nimh mode

 

[bill_delong]

Thankyou bill I’ll let u know how I get on will I have to change any of settings in nimh mode or just plug in and start sorry about all the questions

all depends on the charger, chances are it will keep the same charge rate which is fine, anything above 2A will work

when in nimh mode you only charge to low cell. try to get it close to 3.7 as possible.. not sure your charger can handle down around 3 as stated above. your going to have to make a custom lead to charge that low cell. get a male 5 cell balance plug only use center plugs as to put power back in battery
https://www.amazon.com/Keszoox-Balance-Extension-Charging-Silicone/dp/B09N1P48BB/ref=sr_1_17?crid=1IHNIIWF328ZV&keywords=5+cell+balance+plug&qid=1683143492&sprefix=5+cell+ballance+plug,aps,473&sr=8-17
id just get one of these cut the wires off so you can solder your connector of choice .best to make wire and plug so you dont have a pop
charge at 1 amp in nimh mode

this is overkill, never had to go through this much trouble, once you set the charger back to LiPo mode the balance leads will take care of this for you

 

[Rookie1980]

 

[tntpoof]

OooooooooooooooooooK

 

[Rookie1980]

no video necessary....

1) disconnect balance harness from battery to charger
2) connect battery to charger with main 3S lead
3) place charger in NiMh mode and charge battery for no more than 1 minute, then manually stop charger, this will boost voltage of low cell above 3.0V
4) place charger in LiPo mode and connect balance harness, resume charge as normal

Most chargers have a safety feature that will not charge a battery if any cell is below 3.0V which is why it may be necessary to boost in NiMh mode.

*** DO NOT WALK AWAY WHEN CHARGING IN NIMH MODE ***

limit to no more than 1 minute in NiMh mode, I have seen a handful of LiPo fires at the track in my area when folks boost their packs in NiMh mode and forget to switch back to LiPo mode!

Followed what you said bill all seems good managed to get voltage back up thankyou only thing bit unsure about will the lower voltage cell balance out to 4.2 if I keep charging because the other 2 cells will be complete for a while

 

[nino]

It should, eventually... it could take hours though.
I'd set aside some funds for a new pair of batteries

 

[bill_delong]

It should, eventually... it could take hours though.
I'd set aside some funds for a new pair of batteries

+1

That one cell is "weak" and something to keep an eye on, if your charger can take IR readings of the cells then that will be a good indicator of how bad that cell is. More info on my thoughts about the importance of checking your IR here:

https://www.rcgroups.com/forums/showthread.php?3496127-Which-charger-is-the-best

 

[Rookie1980]

Managed to take my 3s Lipo to wheelspin models today just for them to check it for piece of mind they’ve assured me the battery is fine it’s now in storage mode but the same cell has gone below 3.8v as photo show will that be ok as long as the overall cells is 11.4v

 

[Chipper]

Just brought my first brushless buggy corally radix 6s which came with x2 core rc 3s battery’s which are supposed to be more or less brand new can’t charge till tomorrow waiting for a xt90 connector for charger but have received voltage checker
One off the batteries seems to have a problem 2 cells are reading 3.7 and one 2.6 will it balance itself out when charged help would be much appreciated thankyou

View attachment 164850

I had one similar to that. After you get it to charge in lipo mode. Cycle it several times. Use low amp rates a to fully charge and discharge a few times. This will help bring it back. Your charger should have a discharge mode. if not only discharge to 3.3 volts per cell. Good luck and have fun with the truck.

 

[Rookie1980]

Thanks for the reply mate it does have discharge mode never done that way I’ve only ever done storage mode well once only got it last week so I’ll give that a go

 

[nino]

We know more than the people at the hobby shop.

No need to cycle it on the charger - just use it.

 

[bill_delong]

No need to cycle it on the charger - just use it.

+1

cycling it on the car is just as effective, the more you use the battery the better it will be "conditioned" into balancing out better, however the integrity of the cell is degraded and will never fully recover... it's on "bought time" and would be best to check the IR of the cells to get a better understanding of how far out of range the IR is... if it's more than 2mΩ apart, then I would start shopping for a replacement battery.

Charging without an IR meter is just a guessing game, the first sign of pack swelling is when it would be wise to discard the battery, though I have had packs with slight swelling that I kept for nearly a year with IR readings below 3mΩ which is considered low IR.

final thought... being 0.1v off at balance isn't particularly alarming to me, though knowing the IR is what is more important.