quick Q? charging lipo's back to life??

[ROLANDROCKSHOP]

have a friend who kinda killed his lipo..didnt charge it fully,then ran it down.

another friend said you can jump it with charger on nicad setting to get it back up..??


it doesnt sound very safe to me...


need some electric guru's help!
dont want to see a lipo fire at a friends house!

[indiana mudcat]

NiMh mode is what I've always heard. I've done it several times (10-20) and saw others also. Only takes a few seconds, usually about a ten count. You don't fully charge it, just "bump" it enough to allow the Lipo mode to work. I'd recommend doing it in the garage or outside, although I haven't saw it go bad yet, I still feel safer.

[ROLANDROCKSHOP]

^..thats what ive read as well..

just wanting confirmation from a trusted elec tech to be shure.

[spoo76]

When my Lipos go below voltage and my charger wont charge it I have a basic dummy 7.2 1A li-ion charger. I used to use it for my Xmod Li-ion cells but it has since saved a few lipo packs for me.

It looks like this one and has the same specs. One side plugs into the wall, other side has a deans plug
China Battery Charger. Shenzhen Manufacturer, Exporter

[Charlie-III]

Originally Posted by ROLANDROCKSHOP

^..thats what I've read as well..

just wanting confirmation from a trusted elec tech to be sure.

I may not be "trusted" but yes, I've used a NiCD or NiMH charge mode for ~1 minute or less to get a LiPO up in voltage enough to do a proper LiPO charge.

Reasons are:
-LVC is set incorrectly letting the pack or cell get to low
-LiPO was left plugged into something and drained down
-LiPO was run to LVC and put away

Sometimes just a LiPO charge (not balance) is enough to get to a safe minimum voltage, then balance from there.

[binaryterror]

Yup best ideas:

1. Try normal LIPO balance charge.
2. Try LIPO charge without balancing.
3. Try NIMH on 1C for 1 minute.

[Manning]

I've forced a charge in overdischarged lipos using nickel charging modes. Just watch things and make sure the voltage doesn't go over 4.2 per cell.

[JohnRobHolmes]

Same here. Just as BT stated you can also use a non balance mode to bump up the voltage. If it is a 3 cell pack, tell the charger it is a 2 cell pack and it will jump up to 8.4v pretty fast. Then charge as normal. If that doesn't work, put it on the charger in Nicad or Nimh mode until you get to 3v per cell, then switch to lipo charging profiles.


The biggest thing is that you don't try this on a pack that has been sitting discharged for a long time. At 2.5v per cell it could sit for a day. At 1v per cell you have just a few minutes to recover it. If a Lithium pack is over discharged, IMMEDIATELY bring it up to 3v per cell to avoid damage. The longer they sit with a low state of charge, the more damage occurs.


If the pack starts swelling, toss it. It indicates the anode has been damaged and there will be more risk for pack fire.

[ROLANDROCKSHOP]

awesome info guys!

thanks!

[mmatthews]

Good information. I was able to bring a 800mah 3s back to life. I did as mentioned by HH. Set charger to 2s and not on balance. After a few minutes it put enough voltage in the battery to allow me to switch back to a normal charge/balance.

Thanks for the information.

[muddbogger]

Set it on nimh@1amp and let it slow charge until the battery is high enough for the charger to allow a charge. As always when dealing with lipo's keep an eye on it while on the slow charge since there's always a risk.