Battery Bag Cable Waterproofing

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420b   100 W

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Battery Bag Cable Waterproofing

Post by 420b » Aug 17 2018 8:44pm

I’m looking to use this (https://www.amazon.com/Ibera-Bicycle-Tr ... B00H1KUCQY) Ibera bag to hold my battery and controller. I don’t think it has holes for the wires so I think I will use grommets. I found fabric grommets online that have a hole and punch through the fabric. I want to make it insulated against water, so I found cable glands which are meant to mount in holes in a solid material. I also thought about using rubber between the grommet and then punching a small hole for the wire to go through. I was wondering if there is a better solution.

dustNbone   10 kW

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Re: Battery Bag Cable Waterproofing

Post by dustNbone » Aug 17 2018 10:10pm

Careful putting your controller in a bag. Unless it's very low power it's going to appreciate having some air flow over it.

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amberwolf   100 GW

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Re: Battery Bag Cable Waterproofing

Post by amberwolf » Aug 17 2018 10:12pm

Even a 250w system's controller may burn up inside a bag.

The case is made as a heatsink for a reason--stick it in the airflow.

420b   100 W

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Re: Battery Bag Cable Waterproofing

Post by 420b » Aug 18 2018 3:28am

amberwolf wrote:
Aug 17 2018 10:12pm
Even a 250w system's controller may burn up inside a bag.

The case is made as a heatsink for a reason--stick it in the airflow.
A shame to hear, I enjoyed the relative stealth of a battery and controller in one bag while it lasted.Image
Perhaps I can compromise by creating an opening in the front of the bag to allow airflow.

dustNbone   10 kW

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Re: Battery Bag Cable Waterproofing

Post by dustNbone » Aug 18 2018 4:02am

I'd just strap it to the seat tube right behind the bag. Maybe spray paint it black if it isn't already.

420b   100 W

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Re: Battery Bag Cable Waterproofing

Post by 420b » Aug 18 2018 4:43am

dustNbone wrote:
Aug 18 2018 4:02am
I'd just strap it to the seat tube right behind the bag. Maybe spray paint it black if it isn't already.
It’s a silver case, but with the spray paint I do like that idea.

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wturber   100 kW

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Re: Battery Bag Cable Waterproofing

Post by wturber » Aug 18 2018 10:12pm

420b wrote:
Aug 18 2018 3:28am
amberwolf wrote:
Aug 17 2018 10:12pm
Even a 250w system's controller may burn up inside a bag.

The case is made as a heatsink for a reason--stick it in the airflow.
A shame to hear, I enjoyed the relative stealth of a battery and controller in one bag while it lasted.
Perhaps I can compromise by creating an opening in the front of the bag to allow airflow.
Exactly my thought. Replace the front and rear fabric panels with either a mesh cloth or perhaps a wire screen that will help the controller bag keep its shape. If you do that, you can re-route your cables into the front and out the rear for extra stealth.

BTW, if you are thinking about adding a bike rack, the underside of the rack makes a nice place to "hide" a controller if you paint it the same color as the rack (usually semi-gloss black).
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changeissimple   10 W

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Re: Battery Bag Cable Waterproofing

Post by changeissimple » Aug 21 2018 10:18am

420b wrote:
Aug 17 2018 8:44pm
I’m looking to use this (https://www.amazon.com/Ibera-Bicycle-Tr ... B00H1KUCQY) Ibera bag to hold my battery and controller. I don’t think it has holes for the wires so I think I will use grommets. I found fabric grommets online that have a hole and punch through the fabric. I want to make it insulated against water, so I found cable glands which are meant to mount in holes in a solid material. I also thought about using rubber between the grommet and then punching a small hole for the wire to go through. I was wondering if there is a better solution.
I have two of those if you want one. Free of charge. Pay shipping. I am on the east coast of USA.

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fechter   100 GW

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Re: Battery Bag Cable Waterproofing

Post by fechter » Aug 21 2018 10:30am

If you really want the controller inside the bag, one option would be to replace one side or most of one side with a sheet of aluminum and mount the controller to the inside. The aluminum sheet could be anodized black. Trick would be to attach the plate to the fabric. A combination of glue/clamping strips might work.

As far as the wires go, the best thing is route the cables so they all exit the bottom of the bag at the lowest spot. Water can't follow the wires inside that way, and any that does manage to get in can drain out.
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420b   100 W

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Re: Battery Bag Cable Waterproofing

Post by 420b » Aug 22 2018 12:25am

changeissimple wrote:
Aug 21 2018 10:18am
420b wrote:
Aug 17 2018 8:44pm
I’m looking to use this (https://www.amazon.com/Ibera-Bicycle-Tr ... B00H1KUCQY) Ibera bag to hold my battery and controller. I don’t think it has holes for the wires so I think I will use grommets. I found fabric grommets online that have a hole and punch through the fabric. I want to make it insulated against water, so I found cable glands which are meant to mount in holes in a solid material. I also thought about using rubber between the grommet and then punching a small hole for the wire to go through. I was wondering if there is a better solution.
I have two of those if you want one. Free of charge. Pay shipping. I am on the east coast of USA.
Gee, thanks for the generous offer! Alas, I already purchased and received the bag. It seems really hearty and it’s much more spacious than I thought it would be based on its dimensions. Hopefully someone who needs it for an build will receive it, because it’s a really sweet bag.

420b   100 W

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Re: Battery Bag Cable Waterproofing

Post by 420b » Aug 22 2018 12:29am

fechter wrote:
Aug 21 2018 10:30am
If you really want the controller inside the bag, one option would be to replace one side or most of one side with a sheet of aluminum and mount the controller to the inside. The aluminum sheet could be anodized black. Trick would be to attach the plate to the fabric. A combination of glue/clamping strips might work.

As far as the wires go, the best thing is route the cables so they all exit the bottom of the bag at the lowest spot. Water can't follow the wires inside that way, and any that does manage to get in can drain out.
Interesting idea with the aluminum sheet! However, I’m becoming skeptical of whether or not I’ll actually ever push my bike hard enough to need cooling on the controller. I only have 8.8 ah at 36v and it runs out quick if I go too hard on the throttle, so I’m constantly helping it along. I’ve done a few checks with the back of my hand, anticipating some crazy heat, but it’s never there.

I think I will just buy some generic grommets, and as you suggest, attach them at the bottom and run wires that way via the bottom tube of the frame.

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