Mounting a battery on Triangular tubing?

[Matt Jones]

The downtube of my Boardman bike is triangular in shape, with the flat part being at the bottom, and the apex being the top.

I can’t help but feel this makes the bottle mounts weaker than they would be even on a rounder tube? Does anyone have any experience doing this? I feel like I’d be happier if I could make some kind of rubber support, if that makes sense … or maybe a rack mount.

 

[saneagle]

It's pretty easy to make a moulded support out of fibreglass. Basically, cover everything with cling film, mount the battery, slap a load of fibre glass under it to make a support, when set, disassemble everything and grind the fibreglass into a neat shape with an angle grinder and sandpaper. See here post #61 to #63:

Electric2011 Dahon Jetstream P8

I've now got a nice Shimano Hydraulic brake on the back. It was a real bonus that Dahon had the forethought to put a mounting point on the frame for it. They must have realised that their brakes are rubbish. Here's the next step. I guess you can see what's coming and why I'm doing this:

www.pedelecs.co.uk

 

[Jodel]

My 'El Cheapo' Apollo Belmont hack bike has a similar triangular shaped downtube. Like you, I was also a bit concerned about the potential stress on the bottle mounts, so I fitted one of these:

BBB Cycling - AdaptRail

The AdaptRail is a rail that allows you to create extra mounting points wherever you want them. Size S allows you to position your bottle cage up or down. This way you can create more space if you have a small frame but want to take a frame bag with you. With size M you can mount a bottle cage...

bbbcycling.com

I attached the adaptrail bracket to the bike using the two bottle mount fixings and the rubber mounting blocks which came with my Woosh kit, but I also used two additional tie wraps to provide some extra support. Hopefully you can see this in the photo.


I also use a 50mm wide velcro strip to wrap around the battery and downtube for further assurance. Thus far I have not had any issues with the battery, it has has remained very secure.



On my tandem, I used a 'Triple Bob' from Grin bikes as my 'boom-tube' on the tandem didn't have any bottle mounts and I wasn't keen on drilling holes to fit rivnuts.

Triple Bob

Triple Bob and Hose Clamps for Secure Mounting of Hailong-01, 21700, and Reention Downtube Batteries Also Available on Amazon for US customers

ebikes.ca

However, I wasn't aware of the fibreglass moulding solution identified by saneagle in the previous post above. That might actually be a better solution as you could mould fibreglass along the whole length of the battery holder.

 

[Nealh]

I have had no issue fitting the sm01 as in the link below to my Boardman, I simply used the existing rivnuts wihtput issue, before that I used the DAS kit type dolphin batteries. Never used extra securing or strapping and have managed quite nicely on offroad routes and riding the nooks and crannies on the South Downs going truely off the beaten track where most riders don't go.

No Tax 36V 14.5AH Haitian Electric Bike Battery Pack Bicycle Lithium 18A BMS output 500W fits bafang tongsheng TSDZ2 (pswpower.com)

 

[esuark]

I`m sure not so long ago on this forum someone had the same concern and affixed a strip of "metal" down underneath the battery fixings on the down tube and then bent it up the seat tube to another riv nut fixing thus ensuring no rocking of the battery on the down tube.

 

[egroover]

always an option to add a third in the form of a rivnut. add some velcro straps, my hailong on a Boardman frame aint going anywhere