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LiPo battery voltage too low

LiPo battery voltage too low

Old 04-05-2012, 04:29 PM
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Unhappy LiPo battery voltage too low

I have a 2 cell 20C 5000 lipo battery (nominally 7.4V, but when idle is actually more like 8.4V), and accidentally left it connected to my rc car for a while while the car was off. The battery was then at 2.45V. I plugged it into my charger, with the balance cable, and it gave me "Error 7" (this is an Onyx 245 charger btw) - the voltage is too high or too low. I tried again without the balance cable, and hit 4V after a minute or so, and then said it was done (I guess it thought this was a 1-cell battery). When I tried again, with the balance cable this time, it again beeped at me and gave me error 7, not continuing. By the way, the voltage is now 3.7V, about 10 minutes later.

Any thoughts on how to fix this? I've heard I should charge it as an NiMH battery, but am worried I'll permanently damage it or blow it up (note that I can do this outside, not in the sun, if necessary for safety reasons) and have one of those lipo charging bags that I always use.
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Old 04-05-2012, 08:06 PM
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Bin it. And call it lesson learnt.
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Old 04-05-2012, 08:17 PM
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Originally Posted by somerandomguy
I have a 2 cell 20C 5000 lipo battery (nominally 7.4V, but when idle is actually more like 8.4V), and accidentally left it connected to my rc car for a while while the car was off. The battery was then at 2.45V. I plugged it into my charger, with the balance cable, and it gave me "Error 7" (this is an Onyx 245 charger btw) - the voltage is too high or too low. I tried again without the balance cable, and hit 4V after a minute or so, and then said it was done (I guess it thought this was a 1-cell battery). When I tried again, with the balance cable this time, it again beeped at me and gave me error 7, not continuing. By the way, the voltage is now 3.7V, about 10 minutes later.

Any thoughts on how to fix this? I've heard I should charge it as an NiMH battery, but am worried I'll permanently damage it or blow it up (note that I can do this outside, not in the sun, if necessary for safety reasons) and have one of those lipo charging bags that I always use.
for one dont ever charge a lipo as anything other then specifically for lipo otherwise it will swell up and possibly burst or catch on fire (which nobody wants that) try discharging it if you havent already and you might have made it worse when you charged it without the balance plug but idk for sure so just try to discharge first then try to recharge if this doesnt work i would recomend calling or emailing the company who makes it because they will know best about it and see what they have to say. if all else fails yes throw it away but do the proper procedure like your suppost to before throwing it away
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Old 04-05-2012, 08:49 PM
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The right thing to do is trash it and call it a lesson, but many packs have been safely and successfully recovered. It could end in catastrophic failure, or you could have a good pack for many more cycles. If you are comfortable with the consequences then why not give it a try? A lipo will not instantly explode without warning, but it can be dangerous without the proper precations to ensure it cannot cause damage to anything else. If you are not comfortable with a possible fire then do not attempt this.

Set your charger for Nimh mode. if you have to pick a cell count go with 5 cells. Set the charge rate to 0.5A or less. No balance connection. Do not leave the pack, stay close and monitor it constantly. If you see any abnormal behaviour, any rapid temperature change or any swelling, discontinue the process immediately, but honestly I bet you will be just fine. Wait for the voltage to get a little over 6.0V, somewhere around 6.1-6.2V should be fine. This should happen rather quickly within 5-10 minutes, if it goes for 20 minutes and is still not up to 6V I would discontinue the process. Once the pack is over 6V stop the charger and set it for lipo mode.

Charge like normal on lipo mode with the balance connector. Everything should be back to normal now but it would be wise to keep a close eye on the pack for the first few cycles until you are comfortable knowing it is working well. It would also be wise not to use high charge rates the first few cycles.
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Old 04-06-2012, 06:06 AM
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Originally Posted by burnineyes
The right thing to do is trash it and call it a lesson, but many packs have been safely and successfully recovered. It could end in catastrophic failure, or you could have a good pack for many more cycles. If you are comfortable with the consequences then why not give it a try? A lipo will not instantly explode without warning, but it can be dangerous without the proper precations to ensure it cannot cause damage to anything else. If you are not comfortable with a possible fire then do not attempt this.

Set your charger for Nimh mode. if you have to pick a cell count go with 5 cells. Set the charge rate to 0.5A or less. No balance connection. Do not leave the pack, stay close and monitor it constantly. If you see any abnormal behaviour, any rapid temperature change or any swelling, discontinue the process immediately, but honestly I bet you will be just fine. Wait for the voltage to get a little over 6.0V, somewhere around 6.1-6.2V should be fine. This should happen rather quickly within 5-10 minutes, if it goes for 20 minutes and is still not up to 6V I would discontinue the process. Once the pack is over 6V stop the charger and set it for lipo mode.

Charge like normal on lipo mode with the balance connector. Everything should be back to normal now but it would be wise to keep a close eye on the pack for the first few cycles until you are comfortable knowing it is working well. It would also be wise not to use high charge rates the first few cycles.
^ Do this. Keep an eye on the pack with your multimeter at the Balance tap to watch the cells. When all cells get above ~3v, cut the charge and then charge it in LiPo/Balance mode.
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Old 04-06-2012, 07:05 AM
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Burnin': Nice post.
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Old 04-19-2014, 10:41 AM
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Default Worked like a charm

I just had this very issue and the problem was corrected by those directions the nmih way
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Old 04-19-2014, 10:47 AM
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Originally Posted by RCSLIM
I just had this very issue and the problem was corrected by those directions the nmih way
In these years of RC i can say i already made that mistake some times...

What you need to know and to do is this...

Since the batery is discharged... even 0.0v all you need to do is charge in nihm mode... and when she reachs the desired voltage, switch off and charge in normal mode for a minute or 2... then switch off and charge balance.

Since she's charged balanced use it for 3 to 6 times(discharge/charge) in balance charge mode and she's good as new... as long it did not pass more then 3 to 4 days... if a week pass when 0.0v on a lipo she will be dead soon... otherwise it's just a lapse and all fine...

Believe me, i have done that several times! and still using them after 2 years!

If you try to charge in normal mode or balance mode a lipo below 2.5v the charger does not charge! Gives error!

Remember to storage charge if more then 3 to 4 days of not use... never let them full charged more then those days... that's the same of leaving them below 2.5v or less!

Peace!
Check if she swalled... if not she's good if you not leave her more then 3 to 4 days below that voltage even if it was 0.0v!
The secret is not letting those days pass with 0 voltage!
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Old 04-19-2014, 11:14 AM
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Do yourselves a favor and do this outside away from flammable materials and always in a lipo sack!
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Old 04-20-2014, 05:48 PM
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Originally Posted by targetingxmod
In these years of RC i can say i already made that mistake some times...

What you need to know and to do is this...

Since the batery is discharged... even 0.0v all you need to do is charge in nihm mode... and when she reachs the desired voltage, switch off and charge in normal mode for a minute or 2... then switch off and charge balance.

Since she's charged balanced use it for 3 to 6 times(discharge/charge) in balance charge mode and she's good as new... as long it did not pass more then 3 to 4 days... if a week pass when 0.0v on a lipo she will be dead soon... otherwise it's just a lapse and all fine...

Believe me, i have done that several times! and still using them after 2 years!

If you try to charge in normal mode or balance mode a lipo below 2.5v the charger does not charge! Gives error!

Remember to storage charge if more then 3 to 4 days of not use... never let them full charged more then those days... that's the same of leaving them below 2.5v or less!

Peace!
Check if she swalled... if not she's good if you not leave her more then 3 to 4 days below that voltage even if it was 0.0v!
The secret is not letting those days pass with 0 voltage!

I approve this method, I had the same issue you have and that's how I corrected it.
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Old 04-21-2014, 06:18 AM
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I did this with a 1s lipo. It was 2.7 volts. about a minute on a nimh charger brout it up to3+ so I could use a lipo charger.
I would not consider dong this unless you watch it 100% on the nimh charger and 100% the 1st 20 minutes on the lipo charger Don
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Old 11-25-2016, 11:55 AM
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Default FLIKING LEGEND WAIT FOR IT DARY...

AWESOME IDEA! mine jumped into the 6 v range in no time i guess it was just off by that much and tripping the unit... ill invest in a better one for sure... BUMPPPPPPPPP... i made an account just to say thank you sir!

Originally Posted by burnineyes
The right thing to do is trash it and call it a lesson, but many packs have been safely and successfully recovered. It could end in catastrophic failure, or you could have a good pack for many more cycles. If you are comfortable with the consequences then why not give it a try? A lipo will not instantly explode without warning, but it can be dangerous without the proper precations to ensure it cannot cause damage to anything else. If you are not comfortable with a possible fire then do not attempt this.

Set your charger for Nimh mode. if you have to pick a cell count go with 5 cells. Set the charge rate to 0.5A or less. No balance connection. Do not leave the pack, stay close and monitor it constantly. If you see any abnormal behaviour, any rapid temperature change or any swelling, discontinue the process immediately, but honestly I bet you will be just fine. Wait for the voltage to get a little over 6.0V, somewhere around 6.1-6.2V should be fine. This should happen rather quickly within 5-10 minutes, if it goes for 20 minutes and is still not up to 6V I would discontinue the process. Once the pack is over 6V stop the charger and set it for lipo mode.

Charge like normal on lipo mode with the balance connector. Everything should be back to normal now but it would be wise to keep a close eye on the pack for the first few cycles until you are comfortable knowing it is working well. It would also be wise not to use high charge rates the first few cycles.
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Old 12-18-2017, 08:12 AM
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I'm having issues with my lipo battery. But because my car uses 2 batteries.im going to see if by having one fully charged battery that it will somehow put power back into the other battery without needing to charge it
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