Sunday, October 9, 2016

Revamped Charging for the PorschEV

I have been so pleased with the new charging arrangement on the evTD that it finally got me motivated to rethink and rework the charging for the PorschEV. To recap, although I had plans to consolidate both the charge controller and the DC/DC controller in a single box, space constraints forced the DC/DC converter to the hatch area near the batteries, so the controller went along with it. Probably as a result of too much handling and user error, the DC/DC controller failed early on and Jack Rickard kindly replaced it with a newer version which has worked perfectly. The older version Charger controller has done its job just fine, but loses its configuration from memory between charges. That means that for every charge, I have to open the hood, drag out my trusty MacBook, plug in the USB cable, and reset the target voltage and termination amps before plugging in the J1772. It's a nuisance and pretty much negates the possibility of convenience charging while I'm out and about. Ideally, I should be able to simply plug in the J1772 like I do with the Nissan Leaf and now evTD.

Jack Rickard of EVTV told me that the controllers are all programmed to support the Volt Lear Charger, the Volt APM (DC/DC Converter), and the UQM Lear Charger and have enough processing capacity to run all three concurrently. Here's how he described it on the EVTV Forum:

Well, he did say "you could PROBABLY run all three at the same time", so once again I think I'm on the bleeding edge of what has actually been put into service. If not me, then who? I say go for it! Disassembling the Charger controller, it was clear that there were two sets of Can Hi and Can Lo connections, so that wiring harness will need to be thought out. 

There are also three separate 12v+ connections going to the connector, so it's clear that a junction box will be needed to organize the connections up front.  It turns out that the original black plastic housing for the controller will do just fine. The terminal post on the left is provision for a traction pack negative connection for a volt/amp meter for monitoring charge progress. More on that in a future post. The white and brown wires on the top are the CAN connections to the control box in the rear. The main reason I put this project off is once again twisting this old body into unnatural positions while snaking the CAN wiring through the firewall, behind the dashboard, through the console, under the arm rest, and through the rear seat upholstery and trim panels to keep everything tidy and mostly out of sight.

Once the wiring gets to the rear, it's threaded through the gland fitting into the rear controller and simply added to the screw connectors for Can Hi and Can Lo. The terminals are well marked on both versions of the controller, so it's pretty easy to make the right connections. Once everything is hooked up, it's time to test. 

I'm pleased to report that it all works as Jack described, "certainly" more than "probably"!

Here's a screen grab showing both the DC/DC (APM) and Charger active at the same time. I do want some visual feedback on the charge process without hooking up the laptop. The Leaf has three blue lights and the evTD has the JLD404, so I'll be adding a volt/amp meter for the traction pack that is only active during charging and visible through the rear glass near the charge port. More on that in a future post. Stay tuned ...