Top mounted battery - what about the board flex ?

Searched and couldn’t really find much info about this.
This is my first top mounted battery build.
How do you guys secure a top mounted battery to the deck while keeping it out of stress when the deck bends / flexes ?
I’m building a 3D printed box and thought of securing it to the board with 4 bolts, but what happens in case of a flex ?
What’s the best way to approach this ?

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The stress on the box can depend on a few variables like: spacing of the mounting bolts, deck flex specs and the gasket/bushing setup between the deck and the box. In general, the tighter the bolt spacing, the less deck flex articulation between the mounting bolts.

That said, I’m running a top mounted boxes on two different MTB decks (MBS Comp 95 and the Haero Bro). They both have boxes with a 12" (length) x 8" (wide) footprint and mounting bolts on the 4 corners of the box. I haven’t had any issues with stress on the battery box with either setup.

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I do 4 corners as well and find the rubber washers for washing machines to be perfect for the application as they are thick, wide, but have a narrow hole for bolts. They seal off from water well too.

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Basically just letting it float so that the board can still flex plenty and compress the washers instead of the battery box.

On another build, the deck had a lot of concave to it so I used a neoprene wedge to support most of the box and velcro on the edges to reduce rattle. Still went with 4 corner bolts but did barrel/sex bolts instead of M5 inserts.

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This way was easier and probably stronger in the long run but does limit the rail grinding a bit.

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I use a ratcheting strap, secured through the handle and tightened to hell. I also made sure to apply my grip tape in a way the top box can just sit on the grip and not move, when ratcheted down. I intentionally wanted my box to be easily removable, with as little work done and sealing issues as possible

No issues on flex whatsoever

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I’m an odd one out but I just use 3M VHB with a 3d printed spacer.

I found as long as the spacer is thick enough and you add an extra layer of vhb on the edges where the board curves it has no problem with flex, is silent and look super slick.

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Ditto though I’m getting a smaller case in the next weeks.

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This is my plan, idk if itll work, but im hoping so

Was planning on drilling through the box and rtv silicone on the inside?

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I was talking with @jack.luis on best ways to utilize those holes on that deck. I have the Apex version, but the cuts and drilled holes are identical.

He mentioned for a flush fit, it’s best to have those screws mount to a plate and then velcro or screw the box to the plate. I’m eventually going to do that on my set up as well, on top of keeping the ratcheting strap.

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Dogbone TRAMPA Classic sized DOG BONE is used to mount the Classic Monster box securely to the deck

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ATM I have a dw2 deck with a similar 12x8 inch “ish “ carbon fibre box. I’ve have 2 6mm bolts with locking nuts and washers on the centre line (slightly off set so didn’t create a weak spot between the two holes.)
Again some foam (yoga mat ) between the deck and battery box.
It’s sold I’ve flipped my board multiple times at speed and it’s lived and not set of fire (always a bonus). Forgive the background me and my grubby projects are relegated to a storage cupboard.



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Update:

the new box with the new battery is here, I screwed it down with halved barrel bushings inbetween deck and case.
The deck flexes a little but not too much so it’ll be fine.

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I just want to come on here and say if you plan on using VHB like I was saying before probably don’t lol. It’s been great for 6 months, yesterday I was on my way back home and the battery ejected. LA streets are no joke

Ratchet strap ftw

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Battery ejected from box? Or box ejected from board?


I still have to attach box permanently, but i got a bit of wiggle from the mounting bolts, hoping that goes away with a couple washers and rtv silicone, but the nanuk cases have double action latches, so im hoping neither of those will present issues for me.

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Sorry Yeah the box ejected. I dunno how tf it didn’t eject the battery as I was doing like 30mph.

Honestly after putting the ratchet strap on I would say any actual mechanical fasteners are the way to go.

IF there’s a little bit of wiggle I would get on top of it asap as you don’t wanna wallow it out.

I think silicone would do better than washers, because you want some movement but not much.

As long as you have good hardware I don’t think you’ll ever throw the box off unless something catastrophic happens (ie. Bolt snaps, nuts back out etc).

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Here are from my point of view two functional solution, ratchet or silent blocks. To be honest Iam surprised why silent blocks are so unknown solution. It was on my engineering middle school one of solutions which I remember til now. Check 2:15-2:23 in this video

Advantage of this solution it is that You can choose 3 x big silent blocks for layouts like on Trampa or Apex deck or You can use 4 x small in square layout like I did. Both will perfectly work. Next point is that compared with bushings and screws combinations, silent blocks will not jamming holes in battery box. Silent blocks are standardized engineering parts in 4 basic types. Nut-nut, screw -nut, screw-screw, and just screw if Iam not wrong. Both sides are connected just by rubber, thanx to this silent blocks eat lot of vibrations. Hope it was helpful.



I took and made a big plate for the bottom of the box and a small plate inside countersunk so the heads are flush with the plate. And then beneath the box is a 10 mm spacer about 2 inches wide to hold the box off the deck. And then to button it up I have a petg spacer to make a hard barrier between any metal and the battery. Probably overkill but if a tornado came by my batter would still be attached to the board when it lands 3 towns over :rofl:

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