Lipo battery swell

[cerberus]

Hi Guys

might have a battery prob ,when i charge the battery its fine but after use the battery swells and is hot. the heli is eratic in flight with the tail swinging and is difficult to get any hight .the heli was flying ok up until yesterday when i noticed the swelling.its a 11.1v 1000 mah i saw an earlier post about cheap lipos they have a 11.1v 950mah would that be any good as a replacement. thanks .

[Thomas]

Sounds dodgy to me, replacement sounds very wise, after these thing swell they explode with big flames. there are a few videos floating around of exploding LiPos, after you see one you'll be very afraid when they swell.

Personally I wouldn't buy a cheap LiPo, they are a bit erratic at the best of times, all mine are FlightPower and all are the same thickness now as when I bought them, as long as you use a decent charger, don't let the voltage drop below 9.6 volts and avoid drawing high currents for long periods of time they're fine, balancer is also a good idea.

[bandicoot]

Heres an example http://rchomepage.com/~dna/LipoFire.wmv

[chappers]

WOW!

[Smoothound]

Just follow the rules, it's not rocket science.

Use the correct charger
Max charge rate 1C on most cells
Don't over charge
Don't over discharge
Absolute minimum cell voltage is realistically 3.0v, can be as low as 2.7v but stopping earlier is advisable.
Try not to discharge below 80% capacity, if you are putting 1000mAh back into a 1000mAh pack you are using it too hard. 800mAh would be better.


As far as I've made out so far, if your heli starts to sag while you are flying you are killing your cells.

The video is a bit of a red herring shoved about by old timers who are scared to use Lipos, yes it can happen but it can also happen with NiCd's ask the bloke local to me who torched his BMW charging an RC2400 pack on the passager seat.


Bottom line is just be careful and pay attention to what you are doing :lol:

[Butuz]

The one thing you left out of your great advice smoothhound is that as soon as a cell starts balooning the internal chemistry is going haywire, if the cell casing bursts, lithium explodes on contact with air as you can see in the various videos around.

DO NOT CHARGE A PACK THAT HAS A BALLOON!!!!!

Butuz

[Smoothound]

I have a TP Prolite 2000 4s pack I use in one of my T-Rexes that has ballooned but I'm not sure why...

It's never got hot, always stays in balance and performs exactly the same as a non ballooned one. I'm still using it and have done for a good few cycles so far with no ill effects yet.

I'm not saying you should do it but it's worth checking the pack out before you write it off totally...

[Sao]

the battery swells and is hot

Sounds like a classic case of cheap cells having too much current drawn from them.


Oh look the scaremonger video yet again :roll:


All rechargeable batteries = dangerous when charged by incompetant fools


I speak from experiance :P

[Smoothound]

incompetant fools

Yep that fits the bill nicely :P :twisted: