Dual Tesla batteries on the RadMini

[Altema]

I was on the lookout for a bigger battery to go in the RadMini stock location, and contacted Unit Pack Power. They had an "off the menu" version and made it available, so I placed the order. The battery is a 52v 19.2aH unit, with Tesla 2170 cells instead of the usual 18650. The battery worked out great, allowing me to have range to spare on most trips, without needing to carry my heavy rack battery. This battery is thicker (front to back when mounted) at 137mm, so II had to put a spacer on the forward mount of the rear fender.

Things were looking good, and then I got a message from a guy who wanted to give me a 52v 20Ah battery from Brick Lithium, also made of Tesla cells. The plan is to make a shell for the battery and mount it where my normal rack battery usually goes, but as a temporary measure, I put in in my rack bag. For wiring, I made an 8 inch extension with XT-60 connectors on both ends, then got rid of the huge Anderson connector that was the input from my rack battery, and replaced that with an XT-60 as well.

So now I'm running both batteries in parallel for a total of 39.2aH, and the bike feels downright happy. I should note that the new Tesla battery weighs 5 pound less than the Joyisi rack battery, and affects the bike handling far less. Pics are below as usual, and let me know if you have any questions!

   

[surfer8210]

Very nice to not have range anxiety anymore.
I need to do this.


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[RadJohn]

Your lucky you don't have an OEM RadMini Rack!

Looks like the arms of your rack that connect to welded frame bosses on your RM4 attach on the outside.

With a Rad OEM Mini rack, they attach to the inside of those bosses, which limits the size of the battery that can fit between them.

With a bit of Dremel work to the front of the Rad Mini rack arms (didn't want to do anything to the frame of the Mini while it was still under warranty), I was able to squeeze in a 48V 17.4Ah battery but didn't have room of anything bigger, at least if I wanted to be able to remove it easily.

That's why the minimal clearance between your battery case and fender surprises me. That Unit Pack Power battery must release from its tray differently than my Rad or Bafang batteries. With them, after unlocking the key lock, the battery can be slid up only a short distance until the plastic locking tabs are clear to "lift", at which point one has to pull them away from the tray about 10mm to be able to continue lifting the battery the rest of the way up and out. Do the UPP batteries just slide straight up all the way in long continuous tracks without having to do a lift maneuver to clear the keyed tracks on the Rad and and a lot of other batteries and their mounting trays?   

[Altema]

Excellent observation on the rack mounts being on the outside. It helps a lot with the rack being completely out of the way. The design of the UPP battery has the tabs at the middle and top, so you pull it up, then pivot the top away from the mount. The bottom of the battery needs almost no room as you slide the battery out. The battery touches the fender when installing or removing, but offers no resistance.

I have a smaller UPP battery and a Joyisi battery that use the same mount, so I knew they had that advantage. The mount is actually designed to use a controller in the base as an option, but I use the extra space for wiring. The only negative that I would keep in mind, is that this mount is not good for an upside down hanging battery placement. In this position, the weight of the battery would place be too much stress on the middle tabs and connector. It's not a problem for other mounting positions though, and I've jumped my bike with no issues.

[Altema]

Just a follow-up to say that everything is working well so far. I've had a couple of group rides, about 15 miles each, and both ended with the batteries more than 96% full. Today I did a 34 mile ride, and even though I throttle most of the way back into a stiff headwind, I had 70% battery remaining. The second battery is still in my rack bag, as I have not located ABS plastic panels locally, and may have to order them online. Once I get the panels (plan on 1/4 inch thick), I'll build a box and make it so it latches into the rack. With the battery in the bag, I still have room for my tool kit, allen wrenches, patch kit, cleaning cloth, riding gloves, and the tow strap. For my nylon jacket, I roll it and use the elastic straps on top of the bag.

[Ryan]

Altema - your mods continue to impress. This is awesome!