Discharged and Full Lipo Battery

[Tankbear]

Well I've been using LiPo batteries for 3 years now and yesterday I realised I had overdishaged one by leaving it connect to electrics and turned on over night.

People know the smarty pants chargers will refuse to recharge overdischarged batteries as a safety feature, anyway I wont go into detail how but I managed to get a charge into the battery so the voltage was high enough for the LiPo charger to charge then I put in 1/2C charge rate in for 15 minutes whilst I stood by listening for gasous hisses and puffyness.

I wasn't certain if the battery was safe to use so today some internet reading and looks like what I did was correct although note if the battery has been over discharged for 5+ days the chemicals breakdown the copper inside which leads to internal shorts which equal bang/fire/dead model/agree wife/etc.

One other comment from a so called expert stated that a fully charged battery is under the same stress as an ove discharged battery. I've never heard of this and admit I often charge my batteries and dont always immeditaly use them leaving them in fully charged state. Which might explain why some of my batteries have puffed up even though I had over discharged them.

Anyone heard of this or any experience to add?

Ian.

[billpe]

What I understand is a fully charged battery is under no stress so long as its not plugged in. And leaving a battery charged for longer than a few days will reduce the potential number of cycles. At least that's what SMC told me when I asked them.

Can't say anything about the over discharge, all my cars have ESCs a customisable low voltage cut off, which I put at 0.10w above the manufacturers stated limit so there is no chance of damage. That lower limit appears to be different to each manufacturer too - the SMC ones I have will go to 3.20v per cell but the Gens Ace will go to 3.00. I wouldn't even trust the Turnigy or overlander ones below 3.5 despite what the instructions state.

[Tankbear]

Interesting about the full charge could lower the charge cycles. Something I wasn't aware of.

Slightly off topic last time I read Royal Mail regs on posting lipo batteries it said can only send lipo batteries if connected up to the device I.e. Iphone, computer otherwise cannot be posted not certain why the reason for that, surely there's a risk of discharging a battery into a damaged product.

[ONeal]

Need some input about charging. I have a new Turnigey TB6B charger and a 5000mah turnigy 2s battery 7.4v Will not start charging. I keep getting an error message Battery Check...Low Voltage battery is down to 4.75v I have triple checked all the input parameters and can not find any problems Weird , of course its low voltage... that's why I want to charge the thing. Any suggestions? How low can it go before its ruined" Thanks, O'Neal

[MichaelC]

Check this out on the web, but I had a completely discharged lipo and the charger won't charge it, saw somewhere on the web that if you charge the lipo as a NiMH for couple of minutes it will bring in enough charge that the charger will be able to charge it as a lipo again.......... I saw this on the web and did it once and it worked, but please *** Do it at you own risk ***.

MichaelC.

[Tankbear]

Oneal if you've bought the batteries get them exchanged if lipo are over discharged for a long (longer than a week I read) the chemical break down inside which could leave low resistance leading to a short which is very bad with lipo batteries.

[ONeal]

Don't know what happened to my 2nd post.... I did the nimh charge to 6.5v and it charged up fine on LiPo setting afterwards. I'm glad I was on the same page as yall. NOW I have a new problem!

Hooked my Tarr up changed out some connectors and took the Tiger out to play! Everything is looking good.... except the turret will not go counterclockwise. I checked:
motor on turret .... changed the polarity .. motor turns both ways
transmitter is a 2.4 toggle looks ok but I'm still suspect

Any input Por Favor? O'Neal

[ONeal]

Kaiser, Everything else works Do have to hit the start up toggle twice to get it going. I will change the batteries and cross my fingers. I have ran the tank maybe a total of 30 minutes including my bench testing.
Thanks, O'Neal

[MichaelC]

ONeal, what electronics are you using on your tank, and is the rotation unit the standard Heng Long fair or is it Tamiya ? It sounds like it is one of the motor control or FET units on the electronics side. One way to test this is to flip the leads on the rotational motor, and see if it will not turn clockwise. If it is then it is likely your electronic's motor control.

[ONeal]

Michael, Kaiser changed out batteries NADA!! I checked the motor yesterday by switching leads motor does turn either direction

I have the Taigen 2.4 Where are the FET units? More treoubleshooting..... O'Neal