Tips on waterproofing my battery

[TheSlogger]

Need some help waterproofing my dolphin style batteries. The connection at the base of the battery seems to be the weak point. It's disappointing that these batteries come with the wires just wrapped in electrical tape, seems pretty half-assed. Maybe some heat shrink tubing?
I just emailed Anna at greenbikekit.com about a waterproof battery on that website but she said they don't have any and even she covers the battery when it rains? It's like she's an executive with the company and even she does it half-assed.
Not really interested in a bag of some sort. The battery as a whole seems OK it's just the connection at the base.TIA

 

[spinningmagnets]

All connections should be gooped with dielectric grease (or vaseline in a pinch). Both are insulators and DO NOT conduct electricity. If the housing is loose on the battery case, goop the joint with a permanent "liquid tape", found in the electrical section of any major hardware store...

 

[dogman dan]

Cover your e bike when you must park it in the rain. That's just common sense, not doing it wrong.

But if you need big time water proofing for riding through a deluge regularly, then you might want to re think the type of battery. A bag or box mount that is possible to make truly waterproof.

If you mean just a ride where the rain catches you from time to time,, you can always seal the seams of the battery with a strong caulk, to back up the seals with another layer of defense. Rain Gutter caulk is the stuff, it even sticks to polyethylene, so a metal or PVC seam can be sealed really well with that stuff. Chances are though, your battery box does not leak,, it will have some kind of seal at the seams.

Re think your battery connection,, Permanently seal that wire from the battery at the box. Then use a connector with a water seal to connect to controller.

But really,, a wet connector at the battery never stopped me. I live in a dry climate, but when we get rain I immediately go mudding on my dirt rides. The battery connector is exposed andersons, and always gets soaked in water and mud. no problems.

If your battery is not leaking so that water gets on the cells and bms, then you have no problem,, just a perception of a problem. You might want to worry a lot more about water entering a controller.

But,,, cover the bike to park in the rain anyway. :wink:

 

[TheSlogger]

I guess the sticky point for me is I prefer using 18650 cells which come in dolphin style cases which I've had cut out on me in a rainstorm far from home. I masked off the base of the battery and coated it with rubberized undercoating, the kind used on car chassis. Super messy and cracked off after a year or so, not professional at all.
Anyways thanks for your suggestions.

 

[dogman dan]

Was the problem really a wet battery plug? or was it a wet throttle wire or halls wire connection? the 5v stuff is more prone to disconnect for many reasons, not just wet.

For a caulk or sealer that don't crack, use the specialty caulks that are made for plastic rain gutter. Nothing can beat that stuff. It can permanently repair a polyethylene surf board, which nothing else can stick to. Undercoat made to stick to steel,, not plastic wires.

A dolphin pack is constantly sprayed by the front wheel,, got a full length fender? You need one. In fact, the really effective tip is stop carrying the battery in a wet place. if no fender, a dolphin pack is the wrong choice in a wet climate.

 

[TheSlogger]

Thank you dogman it was definitely a wet plug because I've had no problems since dousing it with undercoating. Just looking for some better solutions, thanks.

 

[dogman dan]

then,, you don't have a front fender?. a full fender that reaches past the axle height?

If you ride in the wet a lot,, then you need that. even if your battery is mounted in a drier place.

Definitely, better caulks for sticking to plastic than undercoat, although that is a pretty good idea. Definitely, silicone caulk is not the answer.

 

[cell_man]

A wet discharge connector is unlikely to cause the battery bms to trip and lose power, sorry, but it simply isn't. I'd guess it is just a coincidence that you made the change and the issue was resolved.

Water getting into the pack and resulting in damage to cells or the bms is a possibility of course. Sealing all joints with silicone should help to avoid this, and also in any connectors, plugs etc. Of course, you'd also want to avoid large amounts of water spraying onto a battery.

Run cables so water runs away from parts, not down the cables and into a controller, throttle etc.

 

[dogman dan]

Gluing down a connector that likes to vibrate loose could fix a problem. I've ridden with some very well soaked Anderson connections to battery.

Throttles are vulnerable to wet though.

 

[Joost]

You can two thing to protect a corrosion.

1- seal the battery with EPDM rubber.

2- filling the battery with oil.
The only problem is wen there is a leaking.

Another option is epoxy, but then you can't repair it because epoxy is very hard/massive. It fills all the holes and make it a solid block. Good for cooling but terrible too solve issues.

 

[Wheazel]

Do you have to use a dolphin style case?
Best would be to build a case that fits your application that is rain and splash proof.

Otherwise I would try silicone sealant, like the one used for aquariums etc.
There are many alternatives when it comes to sealant in general.
If the gaps are too large, maybe a 3d printed plastic part together with sealant.

 

[999zip999]

Silicon is silly. It attracts or holds water. Use the mac daddy Rain Gutter goop. Answer number one. It is not cheap. Go to a roofing sampler. Must be 8- 15 usd a tube.

 

[Lurkin]

The best solution I have had for dolphin batteries is to use a waterproof cover. I started with shower caps, just because they were available, but the plastic is a bit on the thin side and they don't last long. Cheap, effective, and no modifications which are likely to void a manufacturers warranty.

A single use plastic bag is usually the perfect size, and the free dog poo bags in Australia parks is about right for a BBS motor. Electrical tape to bind, makes the perfect, virtually free waterproof covers. The only disadvantage is its creating landfill each time it goes in the bin.

I have some daypack waterproof covers on the way, which I intend to make smaller and spray with waterproofing. I'll sneak it into the same compartment as the commute backpack cover compartment, perfectly ready for a surprise rainy day. This solves the disposability issue. In hindsight a helmet cover probably would have been a better out of the bag fit.

Whilst I've never had an issue with the waterproofing on a dolphin pack, in fact, the battery has been the most reliable part of the kit to date. However, I have killed a C965? display unexpectedly due to water ingress which was a major pita when it occurred. I don't take chances with waterproofing anymore.

I should also note I use a downtube guard and rear guard to deflect most of the water anyway and I've added additional protection to all connections to ensure water doesn't get in there. The greater risk area is not the base, as Paul has said, its usually in a position where water runs away, rather than to it. My greater fear was accidentally forgetting to put the charge rubber bung back then getting caught out in the rain. Putting the overbag on every time forces me to both check the bung when putting the bag on, and would cover it anyway if I had forgotten...

 

[cell_man]

Silicon is silly. It attracts or holds water. Use the mac daddy Rain Gutter goop. Answer number one. It is not cheap. Go to a roofing sampler. Must be 8- 15 usd a tube.

I just want to clarify. Silicon to me as a Brit, means the stuff that is used to seal bathroom sinks, showers etc. It is generally clear, but can be coloured. I'm guessing it is called something else in the USA.

It is intended to seal sinks and showers, so I figure it should be ok on a case as well. We use this all the time and since we started using it, on the frame (dolphin cases) quite some time back, I don't recall hearing about too many water damaged batteries (we did get a few before we started to do this). It only needs a very small amount on the joint and any places you could possibly get some water ingress. Once it has set, just peel off any residue. Seems to work for us.

Adding a plastic bag as well, would of course give you additional protection and certainly wouldn't hurt.

 

[Wheazel]

Silicon is silly. It attracts or holds water. Use the mac daddy Rain Gutter goop. Answer number one. It is not cheap. Go to a roofing sampler. Must be 8- 15 usd a tube.

You can not be speaking about the same product. Do you think sealant in showers and aquariums attract water?
Silicone sealant is not the semi conductor silicon used in electrical components etc.

Just an example, have not tried myself:
http://solutions.3m.com/wps/portal/...-Silicone-Sealant?N=5510818+3293194251&rt=rud

 

[999zip999]

I mean the rain gutter stuff is Superior . Silicon can crack on plastic and water puddles on common silcon. Lots of different stuff call silicon that comes in tubes or has silicon added to it.

 

[Punx0r]

"Silicone sealant" in the UK is often used as a generic term for liquid sealant/gap filler that comes in the big plastic cartridges and used with the common squeeze-grip cartridge guns. I believe in the U.S. the equivalent is "calk". So, yes, bathroom/sanitary sealant is usually called silicone.

IIRC the gutter stuff is polyurethane...

 

[999zip999]

Ok thank you. So it is a glue. It tough.