So a few of you may have noticed in the 6.6kW Effective Charging thread that I have been toying with building a 'cheap' home DC combo charger for somewhere between 6.6kw-12.2kW of 208/240V charging. The key issue that I need to address before I can do so, however, is adding the DC fast charge components into my purchased Spark EV. The dealer had me sold on it, since it included the DC Fast Charge option, was the color I wanted, was right by work, and the dealer was absolutely not pushy and happy to run any numbers I asked.
Turns out they had been mistaken about the fast charge option, it was only on a more expensive ($1,000 more) Spark in a color I didn't want (Titanium... gets hot in the summer with the black leather seats already!).
So here I am, no DC Fast Charge option to even connect my home built (future project) DC boost charger. Well, simple enough I thought. I work with EVs, HEVs, and PHEVs on a daily basis as an Engineer, and I'm somewhat familiar with what's involved in doing a DC charge system, and more than familiar with the safety and procedure for doing high voltage surgery.
There are 3 primary components involved in doing a DC charging interface:
1. The charging receptacle and cables (internal) to connect it to the vehicle system.
2. Contactors which connect the receptacle cables to the vehicle DC bus during charging.
3. The charging controller, which handlesthe contactor logic, as well as communication with the EVSE and vehicle battery.
So I set out to find what I could about the Spark's specific system, and came across the following juicy document;
http://afvsafetytraining.com/erg/Chevro ... 2014_1.pdf
I see from this document that the DC charging assembly is in place, or in other words (2) may be there! (1) can be potentially sourced and wired aftermarket, and (3) may or may not bee part of the DC charger, or the vehicle controller. (3) provided me the point of greatest vulnerability here... if a reflash or entirely new controller is required, GM may simply be able to lock me out of my aftermarket upgrade.
So to my dealer I went and availed myself of the helpful and woefully out of his league parts counter guy. We poured through the available parts diagrams for both fast charge and non-fast charge option VINs... and woe be to me, (3) was not different, but (2) was! The issue? GM and most EV/HEV companies will simply deny the ability to purchase high voltage components. They must be done on a swap basis only, and only if a tech diagnostic demonstrates an issue. Likelihood that GM will let me swap for the option included unit? Zero.
On the flip side, GM went and did the annoying 'make our charging receptacle all unique to GM' thing, but they WILL SELL IT TO YOU with the fast charge cabling! For the one time price of ~$850 (should have just paid for the option up front and waited for the color I wanted, stupid me).
The to do from this point to keep this going:
1. Open up my DC Fast Charge Module and see what's pre-wired on the inside. Also verify that an available high current connector exists for the DC charge receptacle to connect to.
2. Find someone who has the DC Fast Charge Option on their vehicle and do the same to make a comparison.
3. IF it is possible to obtain any difference aftermarket, and IF the unit housings are the same so that its just a 'bolt in' task, purchase and install the components (including perhaps, GMs overpriced charging receptacle with DC fast charge prewired)
4. Determine if an aftermarket SAE CCS charging port can be installed (if it can even be sourced) to bypass GM's high cable price.
5. Generate the installation instructions and offer kits!
If it doesn't work out, then there is an alternate and less desirable path:
1. Install a high current, high voltage distribution tap into the vehicle main power cables.
2. Create a DC charge cable and receptacle (probably chademo)
3. Hack the necessary messages on the CAN network from the battery to determine safe charging current as reported by the vehicle battery.
4. Install a CAN to Fast Charge EVSE communication gateway to provide appropriate communication to the off-board charging equipment
5. Test it very carefully, many many times.
6. Generate the workaround instructions and offer kits!
OR if neither path works...
1. Find a local Spark or i3 owner to test home DC charger system on.
2. In three years, sell Spark and get a new EV with the fast charge option this time (like I should have in the first place).
Help and suggestions are very much appreciated. I am in the Davis and Sacramento areas (CA), so if you want to volunteer your fast charge enabled Spark for poking and prodding, let me know.