Community Forums

BFlinn181 · 04-23-2015, 10:47 AM

I'd remove alternator and take it to an auto parts store and have it tested.
12.3 v is only about a 70% charge for a 12v battery.

twinboat · 04-23-2015, 12:44 PM

Your start batteries are run down or shot and your alternator is not working.

Probably why your start batteries are low.

Charge the batteries for 6 hours, change the alternator and drive to a Auto Parts store and have them test your batteries.

Lakescepter · 04-23-2015, 01:01 PM

Have chassis batts on external charge and they are charging ok. once at 100% will load test but they seem to be fine. will pull alt. tomorrow and have it checked. if need new one can have one in 24hrs. Want to thank everyone for responding, it is nice to have sounding board to bounce stuff off of.
Don

YC1 · 04-24-2015, 06:45 AM

Don't "assume". Measure the voltage on the COACH batteries while it is running. You could get fooled using a digital voltmeter with the test you did. You did NOT measure the voltage at the alternator with the engine running.

A bad Diode Isolator could leak voltage back to the alternator and you would measure the voltage mentioned.

If I understood your original explanation you indicated the coach batteries stayed charged but the engine battery did not. Again, If I understood correctly this was with you driving.

In any case, it would take just a couple of minutes to do the test and might save you some knuckles.

Lakescepter · 04-24-2015, 01:08 PM

Just so I don't put out bad info I will recap all checks. With all batt disconnects off I checked batt volts house and chassis. chassis was low, house was full. ran engine and checked at batts read same volts. at high idle saw no charging at chassis batts. activated boost switch and read house voltage at chassis batts. was able to finally hook to alt with engine running and read the low chassis batt voltage as before, no increase. the leece/Neville alt I have has a remote sense term. and is also ignition excited. after charging chassis batts to full charge with external charger ran all tests again and still did not see any charging from alt. chassis batt voltage was always present at alternator so it would seem wiring was ok and any relays or diodes were working. since the alt is ignition excited I hit batt boost to give it a jolt and no improvement to alt output. new alt on order. thanks again everyone.