Quote:
Originally Posted by Cobb
Id like to do something like this, but my car also draws 60ma when "off" and it can easily kill a small battery in a week if not driven. I guess the addition of a solar panel to the hood would help prevent that? Then got the worry of over charging the lifepo cells or over volting the electrical system with the caps.  |
A solar panel in the 2-4 watt range would probably be fine for lead-acid, but I wouldn't use it for LiFePO4 or capacitors. However, I do have balancing LEDs placed in parallel with each of the 6 cells of the Supercap, and those could bleed 120mA of excess current once the voltage was sufficiently high. The voltage required to bleed off that much current might still be too high for a LiFEPO4 though. Perhaps a small solar panel in the 1-1.5 watt range would be fine?
I don't know what I'll do about the insufficient capacity issue, but I have to do something because the car often sits more than 2 days. Now that the weather is nice, I ride Lafawnda instead of driving the car.
The aftermarket radio and alarm is likely contributing to the high draw, but even if I cut that in half, I'd still only get about 4 days of sitting time.
I have ordered 2
current meters and plan to measure every aspect of energy consumption in the charge/discharge cycle. Unfortunately the meters themselves consume 7mA, so that further shortens the amount of time the car can sit.
If I have to buy more batteries to run in parallel, I might end up getting enough capacity that an alternator kill switch becomes a feasible option.