good points. in my experience, rivets will definitely become a failure point. a riv nut is almost like bonding the metals together. if they fail then its time for a new frame anyway. as far as mounting the battery box. I'm going to braze 1/8 angle iron to the top of the box and bolt it to the riv nut. there'll be 1/8 x 2'' steel bar, encasing and brazed to the box as well. lastly will be bolded to riv nuts underneath the downtube.
Just some advice from someone that has broken many many things over the decades, learned from the experiences, and would like to help others not have to go thru that.
Rivnuts aren't really anything like bonding the metals together. They are only as strong as the metal directly around the rivnut that the rivnut is clamped onto from the inside during the riveting process****, and only strong in a particular way (tension directly thru the axis of the bolt thru the nut). The mounting location you have is unsupported except by the bolts, so it will swing like a pendulum laterally constantly while riding, as the mass of the box moves at a different rate than the frame, and this will put stress on the bolts and hte nuts and the frame that none of htem were intended to take.
(for low-mass things like a waterbottle this isn't too much of an issue, but the battery is going to be more than several times that mass, and stick out much farther from the frame, and hang below rather than sit on top of the tube, all of which make the stresses much more severe).
Using clamps around the frame itself that provide a flat surface for the top of the box to apply some of the load to will significantly change this problem, and prevent that kind of failure.
Even these
Pair of Bottle Bobs and Hose Clamps for Securing Downtube and Water Bottle Batteries to Frames Without Eyelets. NOTE: Item Under Redesign, Updated Product Expected July 2024
ebikes.ca
would probably be better than the rivnuts, perhaps by a whole lot.
The clamps around the frame also distribute the shock loads from the mass of the box and contents over a much larger area of the frame than the tiny area around the rivnuts.
**** If you're using rivnuts that are actually just "nutserts" then they don't even have any connection to the frame beyond a tiny bit of friction where they're pressed in the thin tubing wall....rock them back and forth just a little and they can fall right out.
They're a new one around here, never read anything about them before (there are references to Affordableebike but not that specific address except for one item****). Hopefully they stick around if they're as good as you've had experience with so far...but if they were *really* good they would have given you all the info you needed to get things hooked up to start with, if you gave them the correct info on which specific motor, battery, and other hardware you were going to use that you didn't get from them. Or they would have advised you not to use the "wrong" type of controller / wiring harness / connections, etc.
Hopefully they really did set the controller up correctly for your parts (which is difficult to do without having them connected, especially the motor, unless they have setup this controller for that specific version of that specific motor before, for other people). Guess you'll find out once you get all the parts hooked up.
**** this post
I decided to update my under-the-cargo-deck battery setup on my Mongoose Envoy. I really wanted to easlily remove the custom battery when needed. The first order of business was grinding off the bracket for the rear tail light/reflector. And then a quick paint over the scene of the crime...
endless-sphere.com
references a poorly built battery from "affordableebikes" but doesn't link the site.
This post
Hello again everyone! So I decided against buying that used Biktrix pack and ended up having one custom built for me by the folks over at http://affordableebikes.ca The specs on the pack: 52v 19Ah Samsung INR18650GG cells all brand new and voltage matched prior to assembly The BMS is a dumb...
endless-sphere.com
references buying a new custom built pack from affordableebikes.ca specifically, but it is difficult to tell if the problems reported with it are actually for it or some other pack as the poster had multiple packs being discussed and was never clear, and never responded properly to the various questions.
This post
What would be a good petrol powered unit to get that 150A max off-grid?150A that's at the welding voltage around 10-15V, so not a crazy amount of power to worry about, under 2000W at the input. For structural aluminum work you're probably better off with the MIG (spool gun).Does that mean there...
endless-sphere.com
is by the actual person running the site you've bought from and gives his email address (which a google search turns up on that website). Hopefully they've learned a lot since they stopped posting here a couple of years ago, given some of their posts' content. :/
