|Plot of voltage over time|
The graph is a plot of the voltage of my battery bank from just after midnight until just before 8am in the morning.
Two important facts:
- My battery bank appears to be dying. The internal resistance of the batteries seems much higher than it should be. This means a load on the battery drops the voltage more than it should
- The voltage measurements are not accurate. According to my digital multimeter the tops of those peaks should be closer to 12.8v. So I think we are reading approx 0.1v too low. I believe this is due to a voltage drop over the earth connection in my test setup.
I had the compressor fridge on throughout the night and the cyclic nature of the plot is the fridge compressor kicking in. It was about 15 degrees C in the van and the fridge was kept closed and was fairly empty.
I had the Webasto diesel heater on at the start of the plot so you can it brought the voltage down low as the glow plug was on. I ran the heater twice more: around 1:45am for about half an hour, and again at around 7:20am for about half an hour.
|Zoom in of one section|
The time is missing from the X-axis, but the fridge is kicking in about every 5 minutes.