Boss73

HI everyone.


I have a Losi 1/24 scale truck. I have the 3s 11.1V 200Mah 15c Lipo battery. Over the weekend my son was driving the car with his friend. After they were done he brought the car back in, turned off the transmitter, and forgot to turn off the truck. It sat on the table for a couple of hour before I noticed it was still turned on. Battery was dead, nada, nothing.

Tried to charge it with my H1 and it says "warning low voltage" and will not charge it. Did the battery get ruined because it was discharged to much ?
Then I tried to use the cheap wall charger that came with the truck. Plugged it in for a couple of hours, still dead. I even tried the H1 again hoping that the wall charger would have put some life back in to it, nope....

I thought that I read a thread somewhere saying that you could "jump start " a Lipo battery by using the Nicad or Nimh setting on your charger. I believe the thread said to only do this for a couple of minutes only due to fire concerns.

Just wondering if something like this is even possible ?
Has anyone ever heard of doing this to try and save a Lipo ?

Thanks in advance!

mkiiina

iTrader: (71)

Yes it is possible but ymmv. For how cheap those packs are I would just pick up another one. Make him cut the grass, fold laundry, etc to work off the cost.

MarkA

iTrader: (21)

Yes, they almost certainly over discharged it.

Agree with the post above on just replacing. It will be very easy to overcharge those 200mah micro packs in Nimh mode - not worth it to bring back a pack that will likely have diminished performance going forward anyway.

Boss73

Yes and clean the house, I like child labor, especially my own kids ..
Thanks guys ! Thought that it may have less performance even if I could get it to take a charge.

I was a bit discouraged at the price I found on these Losi batteries from Amazon, $46 with a wall charger.. I have been looking around and have not found cheaper stuff.

Where would you guys suggest to look for a battery ?

RENOV8R

I've "bump started" a few lipos, no problem. Like above, change your charger to NiMi setting. But just charge for 15-20 seconds and then try charging it normally. If it still shows "low voltage" then yeah, toss it.

MarkA

iTrader: (21)

I believe this is actually the updated version of the battery for that: http://www.tlracing.com/Products/Def...rodID=DYNB0002

Boss73

Well that would explain why I was having such a hard time find a good price on the "older one" ..

under $26 shipped to my door..

Thanks so much for the link and info..

HockmanRCBoys

iTrader: (8)

if it ever happens again (and it will, with kids and RCs), do like mentioned above, with charging on NIMH setting briefly. Here is one tip that I do, pick up a lipo alarm. Plug the battery into it, and watch the voltage come up slowly while you charge on NIMH. Once all cells are above 3.0v, quickly unhook, and go back to balance charging like you normally would. Keep in mind, if the cells are drained way down (under 2v) it is more dangerous and perhaps a lost cause to try to save it. I've revived many batteries, but it certainly isn't good for the battery, nor is it a best practice!

Boss73

I have been waiting on one for a couple of weeks from Amazon, once I get it I will give it a try.i have to be honest, I am a bit afraid of something bad happening cuz I have no idea what I am doing.. But wait to get the alarm is a good idea to me.. I got this truck used so I am not sure what kind of life the battery had before me.

RC Juice

iTrader: (140)

I've successfully "jump=started" many a LiPo pack. It really only usually takes about a minute on a NiMh setting to get it to register enough to charge in LiPo mode. It's sending power to your battery either way, it just would not cut off if it was in NiMh mode so you couldn't just fire it up and walk away, but other than that there is no problem in doing it.

Boss73

Sounds good..

Makes me feel good to knows others have done this many times before..

On a side note your not to far from me. I am over in Santa Cruz. Have you been to NorCal's track ? I have been going there with my kids and we are having fun...

Boss73

Ha! It totally worked !

Charged it in NiMh mode for about 25 seconds until I felt the pack start to get warm.. Switched it over to Lipo mode and it started to take a charge! So stoked it worked and I did not blow myself up

Thanks everyone for the advise !

spookie

iTrader: (25)

Worrisome thread, full of disinfo. Bumping a battery is not recomended, due to chemical changes thast occur in the chemistry of the battery, when it's discharged too far.

...The entire process of building up that lithium oxide usually takes around 300-400 charge/discharge cycles to reach a tipping point. That's a typical lifetime of a LiPo battery. But when we heat the batteries up during a run, or discharge them lower than 3.0 volts per cell, or physically damage them in any way, or allow water to enter the batteries (and I mean inside the foil wrapping), it reduces the life of the battery, and hastens the build up of Li2O....< puffing<
http://www.rogershobbycenter.com/lipoguide/

I don't what's worse, advocating bumping or claiming it's all good, especially from a battery retailer per sig. In short, the battery will probably never be the same, the life will probably be shorter, the internal restance most certainly went up, at least on the severlly depleted cell, eqauting into higher battery heat upon discharge. Severe out of balance voltage upon recharging, could indicate different cell resistance.

I won't even get into the crystal changes that occur in the chemical, when discharged too far.

Boss, imo and per many manufactors, just buy you another battery and replace that one, when the new one comes in.