Did i destroy my LiPos?

[goldphive]

Hello everyone,

Im new to this whole LiPo battery scene and think that i may have destroyed my batteries. i checked the charge of both my 5S batteries before going out for a spin on my electric skateboard and they both were balanced and charged, now coming back from the ride (the board died after about 15 minutes) i went to charge the batteries again and theyre both showing up as only 4S. the charger i am using is an IMAX B6AC. please help

 

[flat tire]

RC chargers typically warn you like that when your pack is at low voltage since there is crossover between your pack at low voltage and the next lowest series configuration at high voltage. It's a safety feature to prevent you from overcharging which can cause a fire. If none of your cells went below ~3.55v they should be perfectly healthy.

 

[goldphive]

how can i get it back to normal?

 

[JackFlorey]

how can i get it back to normal?

Charge them at 4S for a short time, then disconnect, power cycle, and try again to see if it will recognize 5S.

If that doesn't work you may need to befriend someone with a 5S charger or a bench power supply to get them back into 5S range.

 

[flat tire]

You should be able to charge like normal. It's probably just a warning. Say "OK" and it should do the 5s charge routine selected. JackFlorey has clearly never used a RC charger that does this so his post isn't relevant to you.

 

[goldphive]

You should be able to charge like normal. It's probably just a warning. Say "OK" and it should do the 5s charge routine selected. JackFlorey has clearly never used a RC charger that does this so his post isn't relevant to you.

lol thanks, i was going to say... the imaxb6ac is a 5S charger...

i will give that a shot and hopefully it works. this was my second run on the board but first time running 36v in series. im wondering if there is something wrong with my settings on my VESC that caused it to run 1 cell lower than the rest.. should i be using a BMS?

 

[flat tire]

How do you know you ran one cell low? I think you may have misunderstood my first post. Go back and read it again because that's not what I said. Anyway your balance charger should have a monitor function where you can check the individual voltages. Do that. Also, if you discharge lipo too far it will always go out of balance. It has nothing to do with your controller just how much juice you used. Although, many controllers will allow you to set an auto-shutoff at a certain voltage to avoid inadvertent over-discharge. And you don't want to take lipo below around 3.6 resting voltage / cell or it will get damaged.

If you have a RC balance charger and can figure out how to use it you don't need a BMS.

 

[goldphive]

i just checked the balance and all cells were sitting at around 3.0v its been charging for a few minutes and is at about 3.48 currently. still only showing during the check. but when i look at each cell it shows all 5.

 

[goldphive]

How do you know you ran one cell low? I think you may have misunderstood my first post. Go back and read it again because that's not what I said. Anyway your balance charger should have a monitor function where you can check the individual voltages. Do that. Also, if you discharge lipo too far it will always go out of balance. It has nothing to do with your controller just how much juice you used. Although, many controllers will allow you to set an auto-shutoff at a certain voltage to avoid inadvertent over-discharge. And you don't want to take lipo below around 3.6 resting voltage / cell or it will get damaged.

If you have a RC balance charger and can figure out how to use it you don't need a BMS.

i just thought that 1 cell had ran low because the charger only showed 4cells instead of 5cells. my mistake, im new to all this.

 

[goldphive]

Thanks for the help flat tire. my battery is showing 5S again.

 

[dogman dan]

Do try not to discharge so deep anymore. 3v is very bad, but not quite ruined in one ride. Stop at 3.65v per cell ideally. This reduces stress on the cells, vs discharging to 3.5v. You can get warning buzzers to put on the packs, or at least one of them, to help keep from doing it again. Don't leave the buzzer on the pack overnight though, just while you ride.

You did damage those cells discharging to 3v, but if they did not puff up like a blown up rubber glove, they are still usable. You did a lot of wear on them in one ride though.

 

[goldphive]

Do try not to discharge so deep anymore. 3v is very bad, but not quite ruined in one ride. Stop at 3.65v per cell ideally. This reduces stress on the cells, vs discharging to 3.5v. You can get warning buzzers to put on the packs, or at least one of them, to help keep from doing it again. Don't leave the buzzer on the pack overnight though, just while you ride.

You did damage those cells discharging to 3v, but if they did not puff up like a blown up rubber glove, they are still usable. You did a lot of wear on them in one ride though.

ive done a lot more research since this happened yesterday and have ordered warning buzzers. now just trying to find how to get the controller to shut off at 3.6v and maybe limit how much current it is putting out

 

[flat tire]

Careful with the buzzers, they can be inaccurate and may by default trigger at too low a voltage. Also can be annoying if you want to use them for a safe cutoff because you will sag under that point loading the battery for some amount at the end of the pack, varying on how much power in c-rate you pull.

You'll figure out what kind of riding uses what energy. Worse case, stop and measure voltage periodically. Performance will also decrease as the pack winds down so you can learn to use that as an indicator too. You could also install a power meter which you can find on all kinds of sites including amazon by searching that term and then use it to precisely calibrate total capacity and then gauge the capacity of the pack down to a fraction of a watt hour. You could check it periodically.

 

[goldphive]

Careful with the buzzers, they can be inaccurate and may by default trigger at too low a voltage. Also can be annoying if you want to use them for a safe cutoff because you will sag under that point loading the battery for some amount at the end of the pack, varying on how much power in c-rate you pull.

You'll figure out what kind of riding uses what energy. Worse case, stop and measure voltage periodically. Performance will also decrease as the pack winds down so you can learn to use that as an indicator too. You could also install a power meter which you can find on all kinds of sites including amazon by searching that term and then use it to precisely calibrate total capacity and then gauge the capacity of the pack down to a fraction of a watt hour. You could check it periodically.

Thanks for the tip, the buzzers came in today. i am going to compare them to the readings on my lipo charger to see if any of them are inaccurate. il will pick the 2 best buzzers out of the 5 that i bought. i took the board out for another spin yesterday and kept an eye on how the board operated. i lost power after about 15 minutes of riding, no power meaning no brakes either but when i checked my batteries they were sitting at 3.82v per cell, i have the VESC programmed to shut down at 3.6v. I think my settings on the Vesc are wrong somewhere, or im overheating