thoughts on the battery mount

Posted by aero_sock@reddit | ebikes | View on Reddit | 40 comments

has anyone had any kinds of experiences with large downtube mount batteries

my frame is aluminum so I've kinda been worried that a 6kg+ battery(14s5p 21700) will just rip out the mounts from it, or even worse crack it

what I've done is added a very tight hose clamp around it, and that seems to have gotten rid of all play it had, but I'm still kind of worried, especially on bumps and cobbles and such

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zachleedogg@reddit

Usually these bottle-mount style batteries have up to 4 mounting holes.

I would use 5mm riv-nuts and add them to the extra mounting points. This means very carefully drilling a few holes into your frame.

Alternatively, check out ebikes.ca for something like this: https://ebikes.ca/ebike-parts/battery-stuff/battery-accessories/triple-bob.html

Your solution will not work long term, and will likely loosen up over time, gouge your frame, and cause cracks and permanent damage.

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aero_sock@reddit (OP)

it's already holding onto 2 bolts for the stock bottle holder mount

i will think about additional rivnuts for more mounting points tho

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sc_BK@reddit

Just add the extra rivnuts, it's quick, easy, and cheap. You might also need a right angle drill attachment.

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plungerism@reddit

Grins triple-bob is great! Rock solid on my Omnium Cargo build.

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IndividualActive786@reddit

Yes, Grin's Triple Bob is what the OP needs.

That single tight hose-clamp will eventually collapse the down tube from the stress of hitting pot holes.

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Sszaj@reddit

Worried about cracking the frame...

Fits very tight hose clamp around down tube.

Good luck.

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aero_sock@reddit (OP)

the tightness of the clamp is nowhere near as high to endanger a multiple milimeter thick aluminum tube

in worried about cracks that would be caused by the bolts in the bottle holder mounts in case they get ripped out on rough terrain

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Sszaj@reddit

FYI most people avoid clamping their bikes in work stands due to stressing the tubes.

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aero_sock@reddit (OP)

the generals consensus in the comments seems to agree that grin triple Bob mount is the best option, and that involves not one but two tight hose clamps

so I dont think that that specific thing is gonna be a big problem

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zachleedogg@reddit

But the pressure around the whole tube is uniform with a grin mount. The pressure in your picture is pinching the frame.

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aero_sock@reddit (OP)

the contact area of the strap with the frame is pretty big since the downtube has more of a square profile.

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_enesorek_@reddit

The tubes aren’t multiple millimeters thick in the middle. Maybe not even at the ends.

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Which_Perception_384@reddit

You should get a tool for bolt rivets. Much cleaner.

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Leeroywildman@reddit

You need something like this.

I use two of them on mine and they’ve been great.

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Laserdollarz@reddit

I have the exact straps. They're ok until the plastic part starts wanting to rotate.

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When you say rotate do you mean the material air of pulls off to one side on the buckle? I have that happen as well. What I do is put my finger underneath it while I pull the other side. Keeps it straight.

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Laserdollarz@reddit

Yea, I just took a pic for reference: https://imgur.com/a/hsiTxNu

Mine didn't start doing that until it was nearly 2 years old, though. Worked fine up until then!

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Leeroywildman@reddit

I can’t access imgur in my country but do you mean this?

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Laserdollarz@reddit

Yep, exact thing!

I'm on mobile and I can't directly post pics to reddit comments because of it lol sorry

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aero_sock@reddit (OP)

thanks for your replies guys

I'm going to look into either rivnuts or that grintech mount

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plungerism@reddit

I used straps of EPDM rubber underneath the mount and hose clamps. Saves your paint and secures the mount even more because nothing is gonna slide around.

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KindaDim@reddit

I have a 52v25ah jumbo shark on my Surly Ogre. I would not use a hose clamp for that specific use case. Like others have recommended, I use a Grin Triple Bob as the mount point because it's much more solid than the default battery mount. Then I use two hose clamps to secure the Grin mount to the frame (wrapped in cloth tape or heat shrink to protect the frame and make it look prettier). Then put the battery mount on the Grin plate with a solid cloth strap or two (others have recommended some heavy duty Velcro straps) to further secure the battery to the Grin plate because even with the Grin plate the battery mount plate is flimsy aluminum and plastic. I wouldn't do less than this if you want a long term stable solution, especially with an aluminum frame.

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aero_sock@reddit (OP)

cheers! also your build looks so good

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KindaDim@reddit

Thanks so much! Still a work in progress, but I'm very happy with it. If you have the means, do what you can to value the aesthetics! It makes for a great conversation starter and overall just feels very gratifying. Don't listen to the folks just trying to shit on you for an ugly choice. You asked a question and that's what matters. Hope you can find an option that keeps it secure and makes you feel proud to ride it!

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Great_Egg_5545@reddit

Next time to make things even uglier, you can use duct tape

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aero_sock@reddit (OP)

not worried about the looks as long as it does it's job

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Relative-Display-676@reddit

what i've seen people do is drill bottle cage mounts through the frame and secure with nuts on other side of downtube.

the other alternative is to use bag mount from top tube

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Responsible_Earth393@reddit

Cheap shit buy a real ebike

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KindaDim@reddit

Show your bike if you're so self absorbed

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Responsible_Earth393@reddit

I think we done talking

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ShigodmuhDickard@reddit

Dick

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aero_sock@reddit (OP)

Just making do with what I have lol, happy that you are able to afford what you like, but I'm just making the best setup my wallet can afford

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Ohm_Slaw_@reddit

It looks kinda skanky. If you mount the battery on the downtube like that, the bumps will force the battery downward into the frame, which is good. Then all you need to worry about is the battery sliding down towards the seat tube. Do you have mounts for a bottle holder under the battery? If so, I would use them. An alternative is a Grin bottle bob.

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aero_sock@reddit (OP)

there are mounting holes in the down tube, 2 of them, and I've used them, but I'm worried that on bad roads those would just get ripped out of the brittle aluminum frame

without the clamps even with very little force the battery jiggles left-right when you tilt the bike, and that's definitely not good, so the clamp has helped a lot

probably will just add another clamp at a further point of the battery and stick to how it is right now

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Kooky_Aussie@reddit

Is there any reason you think the aluminium is brittle? It's typically quite a ductile material?

I'd say you could add another 2 rivnuts at the same spacing as the current threads, just keep well away from any welds.

If it were me- I'd 3D print or fab a cradle that fixes to the two drink bottle holder mounts on the vertical post. This would take a lot of the load from the battery wanting to topple/rotate around that downtube.

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Ol_Man_J@reddit

This bike deserves better