[RE-wrenches] Direct PV-EV charging: possible?

[Allan Sindelar]

Wrenches, We have a customer who has built several EVs, and wants to eventually develop a business around them here. A few years ago we installed a GT system on his home. He has now moved and wants to install a system on his new home as well. This time, he'd like to develop a means by which to charge his EV directly from his array, avoiding the inefficiencies of inverting to the grid and then running a grid-based charger. I know of no way to do this, but then, I'm a veggiehead (drive an old Mercedes on waste fryer oil), not an EV aficionado. I suspect that there are folks out there trying to do this, as it's a logical objective. Can anyone suggest products, links, or websites for this customer to explore? Here are his notes about this effort: ...this is essentially the idea. to use the EV as rolling battery backup to dual-purpose the investment in battery. The second plus is avoiding loss from two inversions dc-ac-dc, the third being relatively high-amp charge without buying another charger! and dual purposing the inverter to avoid cost of high-amp inverter only used for emergencies for a backup. The tech details of EV battery packs that are going to make this a challenge is the high voltage. The DIY pack running DC are going to be 120, 144, 156vDC nominal most commonly. Guys running AC motors and OEMs might run much higher.... closer to 300v. The charge controller or voltage limit switch needs to be user settable and fairly accurate (+/- 1 volt). The DIY people usually use a 'finish' voltage of 3.65volts / cell being 'done'. So for a 120v nominal system I would want to set the DC charge to come up to 139v and either shut down right then, or if it COULD just hold at 139v until amps drop or a specified time, that would be even better. I am planning to do a grid-tie system at my new house, and yes, the intent is to 'stub-in' capability to both quick-charge the pack direct from the DC side of PV if possible, AND use the car pack as night-time/emergency backup just to show its possible.... My little car has 12kWhr on board, one I'm working on right now will have 20kWhr onboard. Thank you in advance for any assistance. Allan -- Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc. 3209 Richards Lane (note new address) Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com

_______________________________________________
List sponsored by Home Power magazine

List Address: RE-wrenches@lists.re-wrenches.org

Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org

List rules & etiquette:
www.re-wrenches.org/etiquette.htm

Check out participant bios:
www.members.re-wrenches.org