Corrosion on batteries at the bottom.

[Calaca]

I have 16 120ah lithium batteries, I took them out of service for inspection and under the blue shrink wrap or tape I’ve found white powder substance on the batteries, Are the cases made of aluminum? I’ve used a steel brush to remove the oxidation and have sprayed with a rubber paint. Is this a mostture problem? Strange because it’s not on all batteries the same amount. Did I get a few cheep batteries or is there some reaction going on that requires attention monthly? I do live in a high humidity location. Attached photo is worse case…took it out of service as i thought it could leak electrolyte.

 

[sunshine_eggo]

that looks like moisture damage.

Do you have something non-conductive between adjacent cells? If not, you need to.