mjderstine

Hey guys, I hope i get an answer that won't ruin my day...

I may have done the noob mistake on my lipos.

I think my batteries are shot. they will not hold a charge.


This started happening after my first full run of the batteries. they are 3900 mAh from smartrc. its a discount Asian company. After running the batteries the motor started to quit. I made it back and when i touched the batteries they were very hot. The heat shrink started to swell from the heat, but the packs themselves did not swell. I let them cool overnight and charged them both again. One charged for almost 3 hours on my Hyperion 0606i charger, and the other was just under 70 minutes. Neither one took a full charge, and i ran them both through the discharge-charge cycle.



When testing with the MPI voltmeter it initially reads 23.4ish volts, which is normal because i have two 11.1 volts packs wired with a deans series connector. as soon as i apply power the volts drop very quickly to around 14 and then then the motor quits.
When using my common sense low voltage cutoff the motor wont go at all, but when i disconnect it i can run the motor until the voltage drops to 14ish.

Have i ruined my plans for the weekend of using these batteries?

Are they NOT holding a charge anymore because perhaps i went below the voltage regulations on the cells?

guver

My Feedback: (325)

I hate to ruin your day, I think you have it pegged. I have some of those batts , they are not too good for high drain apps.

You could've either ran them too long (voltage too low) or ran them out too fast (current use too high) If your run was 30 minutes or more then they were pulled too low/too long. If the run was short (5-10 minutes) then it's the latter.

They may be dangerous to charge or even have around.

mjderstine

10-4, thanks for the tips. i ran them for about 20 minutes. so they went to low.

i'll be sure to buy batteries that i know the current rating.

i'll also be sure to buy some quality batteries.

and i'll make sure i dispose of these ones.

Tram

My Feedback: (6)

Yeh, it helps to know the rating of the packs, it can keep you from spending undue money..


Jeff
www.CommonSenseRC.com