When I turn the ignition I'm showing 11.3V. With the boost I'm getting 11.9V. The chassis batteries themselves are showing 12.59V. The house batteries are 12.79.
With the engine running I'm getting 12.64V in one red top and 14 in the other. Both house batteries are getting 14.28. Both red tops are two years old but have been completely discharged in the past. I had them load tested and were told they were good. I had the alternator and battery isolator replaced a year ago. When plugged into house power it doesn't look like the chassis batteries are charging. If I use a separate charger they'll take a charge.
Is it normal to lose voltage between the battery and the ignition. Is it possible I have a bad battery even though it tested as good when load tested?as always any ideas are appreciated.
There is SOME voltage loss between batteries and dash gauge-- long runs of "not overly large" wire.
BUT, be careful here. With ignition turned on (not to start), it is quite likely that you have activated the very large draw intake manifold heater. If that is the case, 11.3/11.9 is not unreasonably. Yes, if intake manifold heater is not engaged, that is low.
You need to find out why the two red top (assume chassis batteries) read so differently. Something is AIN'T right.
OE, your coach had no means of charging the chassis batteries from shore power or generator. Most have installed "work arounds".
You have a bad connection somewhere. Even if one red top is bad, they are connected in parallel and with the engine running you should be reading exactly the same voltage on both batteries which is actually the charge voltage from the alternator.
Maybe I should swap the red top positions to see you if I get the same reading. If something feeding both batteries wasn't right wouldn't I see a abnormal reading in both batteries?currently they're wired positive to positive and negative to negative. Not sure if that's in series or parallel.
That is (correctly) IN PARALLEL.
Make sure the main neg cable from the start batteries comes off one battery and the main pos cable comes off the other battery. It wouldn't hurt to carefully disconnect the start battery cables and clean every connection and then reassemble.
With just two batteries rotating them won't make any difference. With three it does.
I cleaned the terminals and made sure everything is snug. I'll try another cable to see if it makes a difference. Also I thought when the inverter was set to share power I was charging my chassis batteries. Is that not the case?If not my work around is to separately charge them.
If the red tops went totally flat they are dead. Killed two sets the same way. Dead is dead
It's hard to tell from a distance but if both of your batteries were at a low state of charge, the first one in the pair may have been hogging all of the current. Only time will tell.
A good technique for quickly checking the patency of connections is this: With current flowing, test across the connection with a volt meter. Any voltage indicates loss in that connection. Remember, with 12 VDC systems every one-tenth of a volt is important.
P.S. I use the boost switch to keep my chassis battery charged. While they all look like Ford starter relays, some are designed to be on all the time.
On most inverter/chargers "Power Share" does not mean "share the battery charging power between
all the batteries"
"Power Share" usually means limiting the AC power consumed by the battery charger so as to avoid exceeding the breaker rating on the shore power pole. See example below:
"So in our scenario, if you are on a 30 amp incoming power source, and you set the combi-inverter/converters power share or incoming breaker setting down to say 15 amps or lower instead of the default setting of 30 or 50 amps, the charger will limit the amount 110VAC amperage it will pull from the incoming power supply and slow the charger rate down and thereby allow it to "share" some of the available 110VAC with your other power needs inside the RV. It will just take longer to charge the batteries at the lower rate."
Sounds like one dead redtop.