Lipo battery questions

[J.J. Walls]

Ok, I have a Traxxas Spartan and just got the biggest badest batteries you can get for it. I ran it twice for about 10 minutes and had to quit because Indiana isnt the warmest state right now. So I got bundled up and went out and ran the boat for as long as the batteries would go then the low voltage detection sensor kicked in and I brought the boat back in. Come to find out one battery had swollen up a little and the other one is fine. I let the swollen battery sit all day and nothing has changed on it. So my question is, is this battery already bad and if it is how do I prevent that from happening?

 

[Paul Traufler]

Well sounds like you have a "puffed" pack. This comes from either over charge, or too much heat from running them in a high drain setup. This can also happen if you run the packs below say 3V per cell as this is hard on them also. I SMALL amount of "puffy" can me ok, but when I say that I mean a SMALL amount is like you could hardly even tell it is puffy. If you can push in on it and feel the gas under the sealed plastic, that is bad. Time for that pack to be gone.

1. Watch the charge rate and do not over charge

2. Set the LVC to around 3.2V (or higher) do not run them down

3. Keep temp. of the pack below 140 Ded F at end of run time, and over 32 Deg F always (ie DO NOT FREEZE)

This will help, oh and a good pack will last longer under abuse even that some cheap packs. BTW what brand/size is the puffy one?

I hope this helps!

Paul

 

[J.J. Walls]

The battery is a Traxxas power cell Lipo 3 cell. 25C 11.1 volts. 8400 MAH. Also I chencked all 3 cells and the second cell is not holding a charge what so ever. The battery is still puffy as well and its been more then 24 hours since ive run it. This has helped a lot too and I do appreciate it. Ive been charging them at 3 amps because I did learn to nevere trickle charge a lipo battery. Is that a good enough charge?

 

[Paul Traufler]

Well with a dead cell that thing is a goner for sure. BTW at 3A you are charging at a VERY low rate about 0.3C so that would take a LONG time to charge up. LiPO's should be able to do 1C (or in your case 8.4A) anything over 1C charge you will have to see what the specs for the battery say it can do. Most "good" LiPO's can do 3-5C with the 5C being the real good packs. IF the Traxxas was 5C rated that would be 42A charge rate! Not many charge setups can do that!

Bottom line that pack is a a goner, drive a shovel through it (or a nail but do NOT hold it or be near ANYTHING that could start a fire. Soak it in a salt water bath for a day or two and then dump it in the trash. Be careful with a LiPO and tossing it in the trash with a charge on it!

Paul

 

[J.J. Walls]

Thank you Paul it's for sure a lot of help. I just looked and they do have a charge rate of 1C. Again thanks.

 

[Paul Traufler]

Sure no problem, just be sure to get rid of this pack safely and soon! If you do not have time to "kill it" soon I'd store it outside away from any thing that could burn. (Just in case!) Perhaps if you have a BBQ grill? The "puffy" part can be a big deal if it leaks out the gases as it can create a nasty fire in some cases. I DOUBT this is a pack that would do this being it has a dead cell and all, BUT that cell could be charged and the strap that connects the cells inside the pack could be broken so the cell is still charged.

Paul