Battery Isolator Not Working
I just installed a new pair of 6V batteries and rewired everything pretty much the same way, except for wiring them in series. Everything's working great except for the isolator that is supposed to gi...
Forum Discussion
pianotuna wrote:
Hi CA Traveler,
I use a 2500 watt inverter and want an even larger one. A 500 amp surge is within the parameters of my system while using the inverter. I understand why he wants to measure--but if his inverter is as large or larger than mine my personal view is that I would not want the shunt involved.
I also have a 1500 watt inverter and shunt that it is connected to. I think my largest amp draw through the shunt was only about 175 amps, running the microwave via the inverer on battery power. (I don't do this anymore with the replacement microwave). Even so, the shunt is not distroyed by a 500 amp load, it is rated at 50 mV drop at 500 amps. It would take many more amps to damage the shunt.
With the engine off while the short circuit might have happened, I do not think the problem was with the isolator while it was energized. However the isolator might have been damaged several weeks or perhaps months ago, and caused the problem to progressively beome worse.
My guess is the contacts wore out a little at a time over the past months. Check the voltage on both sides of the contacts without the RV plugged in, and the engine off. Put some load on the battery until the battery side is about 12.5 volts or less. Then start the engine with a few lights still on in the RV, and measure the input and output voltage. Then measure from one large terminal to the other. A measurement over 0.2 volts across the terminals indicates the isolator relay is bad.
Grainger.com sells a forklift relay with silver contacts, 110 amps, runs all the time, and only about $25.
If you have 0 volts on either terminal, then start looking for a bad fuse.
Fred.
