I just thought I would share how I diagnosed and fixed a little problem we have been having with our battery and fridge while off grid.
I noticed that after a couple of days on battery only, our fridge would start up, then cut out about 10 seconds later. The fridge is a Webasto chest fridge 40litres. Its a really great fridge and I thought it was pretty efficient. Anyway, a little reading of the fridge manual showed that it was behaving like this due to a low battery voltage. I measured the battery, but it was reading about 12.5v not the 10.6v that the manual said that battery protection kicked in.
After a bit of head scratching, I measured the voltage closer to the fridge and on the positive wire it was a whole volt down compared to the battery, the thin wires put in by the converter were causing a 2volt drop (1vin the positive wire and 1v in the negative).
So, a trip to Hafords to buy the thickest wires I could find. After replacing the feed from the fuse box, with 27amp wire (looks like 4mm? ) the voltage drop is down to about 0.25v per wire, 0.5v total.
So in conclusion, thin wires in the fridge feed meant a 2v drop and with the fridge cutting out at 10. 6v, this meant that it cut out when the leisure battery was 12.6v! With the new thicker wires it should be OK till the LB gets down to 11.1v. Time will tel if the solar panel can keep that up!?
Hope this is useful to someone.
I noticed that after a couple of days on battery only, our fridge would start up, then cut out about 10 seconds later. The fridge is a Webasto chest fridge 40litres. Its a really great fridge and I thought it was pretty efficient. Anyway, a little reading of the fridge manual showed that it was behaving like this due to a low battery voltage. I measured the battery, but it was reading about 12.5v not the 10.6v that the manual said that battery protection kicked in.
After a bit of head scratching, I measured the voltage closer to the fridge and on the positive wire it was a whole volt down compared to the battery, the thin wires put in by the converter were causing a 2volt drop (1vin the positive wire and 1v in the negative).
So, a trip to Hafords to buy the thickest wires I could find. After replacing the feed from the fuse box, with 27amp wire (looks like 4mm? ) the voltage drop is down to about 0.25v per wire, 0.5v total.
So in conclusion, thin wires in the fridge feed meant a 2v drop and with the fridge cutting out at 10. 6v, this meant that it cut out when the leisure battery was 12.6v! With the new thicker wires it should be OK till the LB gets down to 11.1v. Time will tel if the solar panel can keep that up!?
Hope this is useful to someone.
