[brucepick]

Nice project.

I did a similar project on my Civic (RIP) and then transferred the batteries and switches over to my Accord. My commute is just over an hour each way, with a lunch or errand run often added. So I need about three hours' capacity for daily use.

I use two dual purpose marine batteries, in parallel. Those total about 160 AH. And a 40AH lithium pack. The lead-acids are wired to power the headlights and all fans. Everything else runs on the lithiuum pack. Oh yes - a regular starting battery runs only the starter. It easily goes several days between chargings; starting alone is not very taxing.

Running the car without headlights or other major draw seems to be about 10-15A. Headlights, about 15A. Small corner lights alone, about 5A. Various fans, about 5-15A each.

Here's something I did that I like a lot. It boosts the lead acid circuit's voltage by 1.2V. Under heavy load it still boosts it by 1V.

I wired 8 NiMH D cells in parallel. They are 1.2V and 10,000 mAH each, or 10AH. So the pack paralleled is 80AH, 1.2V. They have solder tabs and I used pretty heavy wiring to support heavy current draw. That pack is put in series with the lead acid cells. The headlights and fans run much better on the resulting 13-13.6V than on just the lead acids at about 12-12.5V. For charging purposes, a quick connect harness wires the eight cells in series so a fairly common NiMH charger can do that job well.