[Mixednutz1]

Hi, I did a silly thing ... I left my lipo battery plugged into my plane ... for two days. She's dead as a door-nail. I was wondering if there is a way to "jump start" it. It wont take a charge. It is a 3 cell 1300mAh.

[Mike Anderson]

Been there, done that.

I'll assume your charger has a feature that won't initiate charging unless it senses some minimum voltage. So you need to get the pack back to that min voltage. (Some chargers have a way to bypass the min voltage check)

Do you have a Tx wall charger? If so you can use it to trickle charge the pack up to that min resting voltage. The smart way to do this would be to use an Astroflight wattmeter (or one of the many equivalents out there) between charger & pack. Start the charge and keep an eye on things, checking every 15 minutes or so. This really does work.

When you can start a charge with your normal charger, choose a very low charge rate and bring it to full charge. Then go fly.

[moo]

Originally Posted by Mike Anderson

Do you have a Tx wall charger? If so you can use it to trickle charge the pack up to that min resting voltage. The smart way to do this would be to use an Astroflight wattmeter (or one of the many equivalents out there) between charger & pack. Start the charge and keep an eye on things, checking every 15 minutes or so. This really does work.

Unless you have a 'LiPo repair charger' a TX wall-wart is the way to go.
Sit there and watch the voltmeter, do not move. Get your 2.5 Volts or whatever it takes to start your other charger.

[Cougar429]

Doubt you will be able to recover it, regardless of the amount of life support equipment you have.

When LiPos fall below a key voltage, (if memory serves 3.2V/cell) irreversible chemical changes occur in the electrolyte, which is why monitoring the voltage is so important.

Being able to withstand this total discharge is one of the reasons the A123 cells are a step up, despite a higher cost and weight.

There are still valuable pieces to remove when a pack goes to disposal heaven. I always keep the obvious Deans and cables, but the balance connector is worth having as a spare.

[tatestate1]

Some engine speed controlers (not all) have low voltage cut off. This may have protected your Li-po.
Use a balancing charger, and give it a try. Remember to monitor the battery when charging. See Li-po aggrement printed on every package.

[Cougar429]

That Low-Voltage cutoff is for the motor circuit only, there to tell you your voltage was near critical yet still allow the radio to function. It is that side of the ESC that probably delivered the killing blow.

[Hanzuki]

Even if you can jump start the battery it will never deliver the same flight times or power. You also run the risk of having it puff or even combust during flight causing a total loss of the aircraft. I would strongly recommend replacement.

[marcham]

I don't know ... I've recovered 2-3 Lipos from below 3V and honestly can't tell the difference between those packs and other ones. As long as you didn't have a high amp draw below 3V then you are probably good to go.

[Mixednutz1]

Thanks for the insightful help will give it a try. get back to you if it works.

[Mixednutz1]

Well, tried it and it worked ..... kinda. My turnigy 420 lipo charger ony "see's" 2 cells out of the 3 .... any Ideas on how to get that third cell online?