Alright, I’m back! took a break to figure out a plan for the DC-DC converter and wait for parts. I ended up taking a day off from work to have a little “me time” and mess around in the garage with the GEMs.
I was reading back on some old threads and @inwo asked me how the cells where holding up sitting. Figured it’s probably a good time to fire up the BMS and see where everything’s at. Looks good to me but I honestly don’t remember what it was when it arrived… @inwo - good to you?
Next up, the long pole in the tent for me was figuring out how I wanted to secure the battery in the rear compartment. I called around to a few local welding shops and they either 1) didn’t have bandwidth to take on a small project or 2) didn’t do aluminum welding. I was pondering this delimma with my barber who happens to be a car guy and he suggested trying something other than metal that didn’t have to be welded. I decided to order up some HDPE, cut it up, and make a battery tray.
Figuring out initial measurements with an empty battery shell… same that @inwo put it in.
Dry fit in the gem
cut out 1x1 sections and built blocks around the battery fiberglass tray.
Drilled from the bottom with SS screws countersunk so they’d be hidden and not hit the frame
This gets me so it won’t slide back and forth, side to side. Now I just need to secure it just in case I hit a bump and it doesn’t jump out.
I secured the new ploy battery tray to the frame using 2 of the existing holes and drilling 2 more. Now I have to figure out how I’m going to get the battery in the GEM. Could involve beer and convincing some neighbors to come over ;). or an excuse to buy a cherry picker.
Now back to the wiring and the DC/DC converter. Since I had the Delta-Q DCI charger, I had 2 options. I could either 1) power all the 12v gear from the charger or 2) replace the DC/DC converter with one that would accept 72v. I decided to replace the DC/DC converter and leave the DCI as an option for future expansion - stereo, lightbar, holiday lights, etc, etc.
The 72v DC/DC converter has 5 pins vs. 4. the 5th is an enable wire which can be jumpered to pin 4. original 4 pin wiring (took a picture so i wouldn’t forget - i do this before changing anything in case I need to go back)
New Harness - pulled the pins from old and added them to new. Waiting on a t-tap to come from amazon to tie into pin 4
Here’s the 72v DC/DC converter -
back to where we left off, coil wires and just to confirm before I cut -
Actual fuse block. Cut the red and brown wires at 48 and 43. connect the harness going to the relay. polarity doesn’t matter.
Trying to go through a checklist in my head but i think all that’s left after the coil wires are -
- install new delta-q 72v charger
- reconnect main disconnect
- connect 12v battery
- connect big tesla battery.
Am I missing anything?
PS. thoughts and steps i did but forgot to document to make this complete
- when i had the controller out, wish i had replaced the DC/DC converter then. Would have been easier but was able to do it without removing the controller.
- I should have mentioned that i had to disconnect the passenger side strut in order to get the motor in. I tried to get it in without doing that but eventually had to jack the car up, loosen the strut, and pull the strut out of the frame to get the motor in. I was too distracted lugging the heavy motor around that I forgot to take pictures. When I do 2016 Gem # 2, I’ll document.
Hoping to drive this thing over Labor Day! Almost there!