Helping Dave with a house battery charging problem,alternator putting out 13.7 volts,all connections and batteries good,have 13.7
going into isolator,13.7 going to start batteries,12.3 going to house batteries,house batteries are 1 year old standard batteries.Thinking the isolator is bad,when he turns on the boost switch both outputs of the isolator go to 13.7.Any other ideas?
What kind of isolator:
Diode based? If so, what are voltage readings at center lug and the two outer lugs with engine around 1.100 RPM?
Solenoid/relay based?
Diode based,looks like a Cole Hearse but no label,13.7 at center,13.7 at start battery,12.3 at house battery post,is 3 post isolator.
Indeed, bad isolator.
But a little confusing: Reading on center lug (direct connection to alternator B+ terminal should be about .7 VDC higher than the two readings on the outer lugs (one to each battery bank). That .7 VDC loss is turned on to HEAT. That is why the diode-based isolator has the fins-- to dissipate the heat. You posted same readings for center and chassis battery lugs??
Short term fix would be to move the cable from the house post and add it to the lug for the chassis battery. Note: batteries will not only charge together, but will also discharge together.
Will remeasure the voltage,thanks,got the message.
Thank you Brett & Dave! It was definitely the isolator, will replace next week.
Dave,
If you need to travel before replacing it, let us know. Several easy work arounds for a failed isolator.
No hurry, we're in Arizona till mid March. I was running the generator to keep them charged when the isolator went out.