Battery failure


#1

Seems like water leaked in the battery tube. The battery tube has been fine for a few pool dives. I didn’t see much bubbles when I did a quick check before diving on the side of the pool. Afterward I put the rov back in the water without the batteries to confirm the leak and I could not get any water to go in the battery tube… I only have this problem with the Li-NiMn batteries. The LiFePO4 make contact just fine in the battery tubes.

I did glue washers on top of the batteries because they were not making contact in the battery tube. Could it be the reason why this happened? Anyone has the same problem and has a better solution for making contact between the batteries in the tube?

Would you guys use the batteries again? Is there any test I can do to check them ? I don’t know much about batteries so any advice will be appreciated!

Thanks


On board Battery - Lithium-ion a no go?
#2

I had this same issue, i soldered brass washers onto the top of the batteries to ensure a conductive connection. (They need to be soldered quickly as heating batteries is generally not a good idea, these ones had a raised bit not flush on the battery so it was ok to solder) If you cant solder them id try silver paint its conductive and will give a connection.

I probably wouldn’t use them again as they would have discharged at a rate that they cannot handle but they way to test them is with a smart charger but usually these batteries are ruined as they are fairly inexpensive


#3

@guillaume.ethier:
The positive electrode on the blue Li-NMC batteries isn’t as high as the one on the white LiFePO4 batteries, so the blue batteries must be modified slightly before being used in the ROV. This dozuki article explains how, and is better than trying to put washers between the cells.

Your individual battery cells may or may not still be good. I would clean them off and measure their voltage. If they still hold a charge then they still should be usable.

-W