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Looking for some battery advice.

I have a scale crawler that I want to do some extream wading with, basically I want to be able to fully submerged it. I have waterproof ESC, servos and RX that have worked repeatedly and flawlessly under such abuse, the weak link seems to be the batteries.

I have run fully submerged with NiCads and NiMh packs in the past with varying degrees of success but always with the end result at best of dead packs after three or four dunkings

So does anyone have any proven ideas or experiance running any type of battery fully submerged?

Well, only 100% pure water - no impurities - is non-conductive. So any other water is conductive more or less depending on the impurities in the water. So every time you submerge your batteries, your shorting them out a small amount. seal up your batteries and electrical connections.

Also running r/c cars underwater is a very heavy amp draw load, but the water will keep the batteries and motor cool, so the amount of work your electronics is deceiving.

I didn't think you were supposed to fully seal NiCads or NiMh batteries as gaesious exchange is party of the charging / discharging cycle

LiPos maybe a different story.

I would make a battery box, one that has a rubber seal, I have seen these small tupperware type containers with a rubber seal and 4 cant clamp like snaps on the 4 sides. Something like that with a hole drilled for the batter connection inside, then sealed up with silicone would probably work pretty well. pop the 4 clamps, plug in battery, then snap up shut.

depending on the shape of the box, build your packs so they fit inside nicely. I would likely use Nicd. Lipo if you get wet, that is how you are supposed to disharge and dispose of them.

I would probably investigate what they use in boats.

That's a good idea but I'm a bit stuck for space.

I think it needs to be salt water for LiPo disposal and I'm almost sure you have to open them up before submerging but I could be wrong.

Synergy wrote:I didn't think you were supposed to fully seal NiCads or NiMh batteries as gaesious exchange is party of the charging / discharging cycle

They have vents to to release pressure to prevent violent rupturing of the case. Otherwise, they are sealed.

salt in the water just ionizes so that current can flow. and no need to open up, but after discharge, you are supposed to puncture. So the salt acts just like anything in the water(ie, not distilled).

if space is that tight, I'd probably do something like saran or cling wrap and seal off the best that you can.

What about packing the connector and such with dialectic grease? Hardcase lipos are sealed right?

This was what I sort of thought.

I'm pretty sure all LiPos are sealed which is why soft case ones balloon and hard cased ones pop just before they go up in a ball of flames, this obviously won't be a problem while submarining

I would think some liquid electrical tape on the battery connectors would do the trick. Hard case lipo is what I would use. I know when I run mine in the snow it doesn't seem to bother them (and they were completely PACKED in snow). I guess its not really the same as submerging in water but still - I think the hard case lipo would be a pretty good option. Just not as cheap if it doesn't work out!

that liquid electrical tape stuff can work wonders. Ive seen a few people completely coat esc's in the stuff for running their cars in water. The thing was is that they would add it directly to the circuit boards and put the cases back on. the case prevented a majority of water getting in and the tape prevented taht little bit of water from doing anything. my guess would be to take a hardpack and coat the outside.

on another note, what about cramming the battery in a balloon then finding a way to seal the open end.

I have a soft case Venom 3s in my crawler that's been submerged in clean water/muddy water/snow many times without any problems.

I just sealed up the ends of the shrink with silicone and put liquid tape around the solder joints on the connector, then wrapped the connectors together with electrical tape. I did the same thing for a smaller 3s in my Wraith but coated both ends and the wiring pigtail with spray Plasti-Dip...it hasn't been run yet though.

A friend of mine runs the cheap Hobby Parts 2s hard case packs that he submerges in mud and water almost every time we go crawling. He's never had a problem and doesn't do any form of waterproofing to them.

Depending on how deep you want to go (sea bottom crawler? ) you may want to have a look at how RC submarines seal their electronics - after a while water pressure builds up.

plasti-dip the case and where the wires exit & dielectric grease on the connector