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Dunked my battery in saltwater

Pulling my ROV out of the water today and the battery tube slid open and dumped the battery into the water. I was able to dive down and retrieve it but was wondering if that’s the beginning of the end for it? Are circuits sealed? Any advice in what to do with it? I dried it and it is still holding a charge. Should the tube open from just the weight of the battery? New O rings are needed maybe? Pressure test is good and never leaked before and has always been real snug. Any thoughts would be appreciated.

I’d never take a chance on it…definitely don’t attempt to charge it…take it to a local battery dealer who can dispose/reclaim materials from it responsibly

You’re right. Those things are dangerous enough without saltwater working it’s magic on everything metal.

I don’t know if this helps but the best way to neutralise a ”Li" battery is to put it in water, this chemically renders them inert. Has the battery puffed up, if yes dispose of it in a bucket of fresh water for a day. you could put a battery tester on the balance leads to see what the cell voltages are, above 3.8v per cell, it may recover. To wash the battery use Isopropyl alcohol, this is non conductive however if you are in any doubt put the battery in a tin box outside for a few days and observe, these are not cheap batteries if its the 18000ma version then put a load like a car bulb across it to push the chemistry for 10, mins if it looks ok and cells are ok all is well. Did you ascend quickly before the cover popped off?

It fell out when I pulled the ROV out of the water. It does look like there was a leak as the battery enclosure was wet. It ran fine though. Reviewing the video, it looks like a had a pretty bad vibration going on. I did suck up some eel grass which probably caused that, which may have shook the battery end cap loose.

The battery has not swelled up but I’m worried about it holding saltwater in the wrap. It was submerged for about 5 minutes, My concern is that while it may check out fine right now, something may fail in the future. It is a the big BlueROV battery.

To put your mind at rest cut the outer sleeving off carefully and wash with alcohol being carful not to pull the connectors off, then get some monster heat shrink to reassemble again. you can put it into a bath of alcohol. once you have the outer sleeve off you will see if any of the connections or the protection circuit have started to corrode then make decisions based on observations. liberal coating of silicone grease will keep the cleaned parts protected. the batteries are quite robust as long as they haven’t been punctured or crushed. Do have a bucket of water when you cut the sleeve off. I realise some would not take a risk but how do we learn if we don’t expand our knowledge…

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