Nothing to do with uC: measuring parasitic draw from car battery

Author	Message
Volhout Guru Joined: 05/03/2018 Location: Netherlands Posts: 5991	Posted: 05:59am 16 Aug 2024       Tom, I had the same problem with out 35 year old camper van. The car battery would drain in the few month it was winter storage. After replacing the battery I used this method. I used a simple multimeter with 10A range. Then went to the fuse box, and one-for one took out the fuses and measured with the multimeter the current. When the engine is not running, almost all of them would be 0. But there are few fuses that carry constant voltage. I found that the car radio used 10mA...150mA depending I took the radio front panel off. 10mA is rather harmless, 150mA drains the car battery in 300 hours. To be sure, every time I park for winter time, I take out that fuse. And every spring I put it back in again. For the 10mA, you may have to select another range on the multimeter (200mA typical). No problems since... Volhout Edited 2024-08-16 16:00 by Volhout