Sorry for the long delay since my last update! Work has been continuing, though was a bit slow through January as I had a lot of other things taking up my weekends. While the car is at a friend's place for the mechanical work, I can only work on it one day a week.

That doesn't stop me from working on things at home though. I've been getting a lot of questions about my Chevy Volt battery BMS ECU. I'm still working on it, and it's been getting a bit more of my attention recently as it'll be one of the first electrical systems to go in to the car once the mechanical work is done. So I want to have it as far along as possible by that time. I spent a full day last weekend coding on it. It's going to be very nice. So far I've got the J1172 interface working and tested. Precharge and contactor weld detection coding is done. The framework for the main state machine is in place as well.

Mechanically, the rear lower battery boxes are still coming together. The sheet metal cut from the car is all closed in now, so all that's left to make it water tight again is to skin the flat sides of the boxes. That will be the last thing that gets done before painting, once the structure for the rear upper battery is complete.

Here's a photo of one of the rear lower batteries in its home.

The tubes mounted above it will have feet which press it down in to the box, securing it in place. There's a channel in the bottom that fits with the stock clamping point on the battery to keep it from sliding rearward. The top battery will rest on top of the tructure, also on its side, with a channel on the rearward steel box section serving the same purpose as in the lower batteries. The top battery will be held down by a strap/frame which uses the same mounting points as the lower battery tie-down.

Here's the assembled rear upper battery.

It's a lengthened module, 10kWh total. I used threaded rod to clamp the batteries in the lower section and pallet strapping to clamp the top of the module. At the front of the car, the hard points for the front battery are coming together. I'm using the front sway bar mount to secure the front of the front battery. These mounting points are the same points used to mount the front subframe on AWD versions of the car, so it should be plenty beefy to support the battery. The rear of the front battery will

be supported by a bar which will be installed bridging the original motor mounts. The inverter, charger(s), heater, and DC-DC will all mount to the front battery enclosure. The power steering pump and air conditioning compressor will mount to the same bars that the front of the battery will rest on. The vacuum pump (and reservior) will live in the cubby behind the passenger side strut tower.

The water pumps will mount along the bottom of the radiator.

I had some blanking plates printed for my battery coolant ports.

These will be used in the front battery as I'll be paralleling the coolant circuit with T-pieces rather than passing through one battery to the other. I have the STL files for these parts if anyone is interested. I had them printed at Seeed studio and they came out very nicely, though expensive for what they are.

This weekend we'll hopefully get the rear battery mounting structures completed so that I can start on some wiring/plumbing. I wouldn't say it's getting close, but progress is being made! Registration for this car is due in July, so I want to have the conversion done before then so I can get the DMV to verify it doesn't need SMOG testing in time to not have to register it as non-op.