How to waterproof 18650 packs / cells?

This is going to sound weird but I am looking for ideas on how to fully waterproof a 18650 pack. As in submerge the whole pack in salt water a few times a year and it will be fine.

Living in a tropical country I deal with heavy rain several months a year. I found that water is really good at wicking under shrink wrap and will get into everything eventually.

I have used lipo up to this point and found its very easy to waterproof them as they are basically a plastic pouch with two aluminum contacts at the end. The aluminium tabs is the only spot that can corrode.

But on 18650’s the can is steal. I have seen a few guys with water damaged packs, and the can rusts out pretty bad then cells start to leak.

My current plan would be to remove all the shrink wrap, spray the cells with a colored silicone conformal coating, masking the positive and negative ends. Then building the pack. After the pack is built the exposed joints could be conformal coated with the brush on style @b264 suggests. Then clear shrink wrap the whole pack for easy inspection like @psychotiller does. Or forgo the shrink as I have found its better to just let it get wet and then dry it off after a ride with a fan then let moisture stay trapped under a wrap?

Got any other ideas?



@b264 calling

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@lrdesigns Maybe after the pack is built dip or spray it with some sort of coating, like flex seal or Plastidip. Idk tho, I’ve never done this before

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@lrdesigns Another way is to pot the whole thing in 2-part epoxy. You would need to make a mould for the battery pack and pour the epoxy around it to seal it completely.

There are epoxy compound that will cure rubbery/easy to break off in chunks so you can still break down the epoxy if u need to service the battery pack.

source: work with potting compounds and potting electronics into enclosures

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Could I use regular old epoxy you get from hardware store, or do I need the potting one for electronics?

One advantage of this method that its more robust from vibration etc. But can a cell be swapped if it goes bad is the main disadvantage.

typical regular epoxy from hardware store would dry hard and be impossible to break apart. You would need to look for something that will dry rubbery and bouncy. You might even be able to use silicon mold rubber kits such as This

The main disadvantage is you would need to break chunks off to get to the cell and then fill in the removed material again afterwards

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Take a look at LiGo battery’s from , they are completely poted, I think there is a thread on endless sphere about all the development including resins testing and etc

That being said my olde build I rode a number of times under heavy rain and really deep puddles and never got water inside using silicone to seal everything

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Check this out

Does the pack need to flex? If no, why not just pack all cells in a waterproof box with only two wires for power supply coming out? I mean theoretically a strong plastic bag over all cells, suck out the air and close it with a rubber band where the wires come out. „Sound a bit strange thou“ :thinking: but I hope you get my idea

That will eventually fail no matter how good it is. To be really safe, design your esk8 to keep water out — but also to work correctly even if saltwater gets inside…


Agreed! No matter how waterproof… there is still a chance since esk8 is subject to way more vibrations and impact than most personal mobility devices due to the hard urethane wheels… water will find a way in always… good to have some form of protection inside the enclosure itself and always open it up for a wipe down after riding in the wet

I’d argue it’s more likely than not likely that water will eventually get inside while you’re riding, no matter how much effort is put into sealing it.

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No flex needed but would like it to be thin under the deck so that illuminates waterproof boxes.

So where do I buy horse condoms? :horse: :baguette_bread:


This may sound dumb but why not a water proof bag and bring wires through membrane glands…Amazon has plenty of options for less than 10 dollars US.

Just get a trash bag or shopping bag from your women’s last shopping tour and you good to go :stuck_out_tongue_winking_eye:

Unless your enclosure is airtight… yes water will definitely get in somehow if you’re riding in a downpour in my experience. If it’s just a few puddles it’s down to chance.

Waterproofing is a combination of sealing, proper diversion of water(making the path of least resistance away from the electronics), and making sure the electronics don’t explode at the slightest moisture

OIt’s all about layers of protection… do best with enclosure, bag electronics…and if you want put conformal counting on PCBs. I think is definitely possible to make a very good water resistant Esk8 however waterproof is a different story. It’s important that all gasketing is closed foam and compliant. I ride in the rain through puddles and never have had an issue and still have a well cooled board that can easily be worked on if necessary. A quick fix would be to duct tape all edges of enclosure. Good luck.

I call it “making water resistant” and “waterproofing” which are two distinct and very, very different things.

One is treating water as-if it cannot be inside.

The other is treating water as-if it belongs inside.

The best esk8 in the world do both.

So they are designed to not let any water inside, but they are also designed to operate correctly when the enclosure and motor are full of salt water.


ive got a titan battery from @hyperIon1, and while I understand its not what youre looking for I think its perfect for the protection of cells against water and dirt

let me get a pic


The pack is wrapped in some sort of protecting foam and has layers of other protection like shrink wrap and kapton tape under it, but on the outside its sealed shut with a rubber type… skin? As far as I can tell nothing will ever get in there :thinking:

20181101_125111 20181101_125106

sealed top and bottom, with a liitle extra adhesive to seat the battery in the enclosure :stuck_out_tongue:

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Hey guys, @b264 is correct. It’s an approach from both aspects. @Hyperion2 has work on off grid systems that had to withstand the elements and be corrosion proof because of sea blast and salt water. He has developed a layer system that in each prevents moisture from getting in and becoming trapped. The close cell foam acts as a multi barrier that cushions, protects and repeals water than a shrink wrap with a rubberized UV protectant. As water proof as the pack is it’s self , the connectors are not. So the kink in the armor