Mounting and security options for rectangular battery...

Hello!

I have a Surly Big Dummy cargo bike with Xtracycle bags and a BMC rear hub motor. I recently bought a rectangular battery pack for it that's 324mm x 140mm x 80mm. I'm trying to figure out the best way to mount or house it and wanted to get ideas from the community.

For now, I've placed the battery pack in one of the inner compartments of my Xtracycle bags. The good thing about that is that it's very stealth and you can't really tell there's a battery there unless you're snooping. The main downside is that the weight is all on one side of the bike and it jiggles when I go over bumps or rough surfaces; a secondary downside is that cargo compartment is not available for other uses...though that's not a huge deal.

I was thinking maybe I would try to figure out a way to mount it on the seat stays that go from the bottom of the seat tube back to the rear wheel. Another option would be to put it in a trunk bag and mount that to the deck on the back of the bike.

I plan to use the bike quite a lot and would like to find a way to feel like the bike and battery are secure while I'm inside a restaurant having lunch, getting groceries, etc.

So that leaves me with a few questions:

1. any suggestions or advice on what may be the best way to mount / house the battery pack?

2. Has anyone fashioned a bracket of some sort for mounting a rectangular battery pack to their bike? I'm asking in case the best option for me is to mount it somehow on the seat stays going back to the rear wheel. and in that scenario I'm not sure what would be the best way for me to mount the battery pack.

3. I'm sure I'm not the first person to be concerned about how to secure a battery pack and was wondering what other folks do in that regard.

Thanks!

deleted since OP never came back to thread.

+1 with a front rack since it helps balance the front/rear weight bias. This is the system that I employed on my DD rear hub conversion. Has worked perfectly with foam insulating the battery from road undulations. I'm ride a rigid bike since the roads and bike paths in my neck of the socal woods are well maintained. Of course you'll need to be creative to find a way to "lock" the battery which isn't something I worry about.

Triangle bag works for me on my Big Dummy.
Photo taken under a bridge on the Nachez Trace parkway during a storm 2 weeks ago.

I use two plastic, waterproof, foam lined "equipment" cases. They were being sold as pistol cases at Frys Electronics. These particular cases are probably a bit small for your battery, but these things are available in many sizes. I use a small nut and bolt and a small "nusiance" padlock to keep the cases from being easily opened. But there is much more that could be done to make it even harder to open the cases. I've since mounted a milk crate on the rack, so it is even less obvious how to get into the cases in the current configuration.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=90369&start=100#p1380508

https://endless-sphere.com/forums/viewtopic.php?f=2&t=90369&start=150#p1405129

I was using plastic ammo cases for awhile.
I made a box out of wood, used hose clamps.

Triangle bags are great!
The weight distro is great!

markz said:

I made a box out of wood, used hose clamps.

Click to expand...

Box of scrap wood, 3 big hose clamps, and ... bailing wire. (Green plastic coated, but basically bailing wire.)