Originally Posted by burgman50
Finally picked up the new to us Revolution this afternoon. Still have a list of dealer to do items but needed it for the weekend.
Issue 1-Every time I try to start the engine it will not turn over unless I press Auxiliary start switch. Then it fires up every time. Dealer checked chassis batteries before I left today and they were testing fine. Ideas?
Ok, I take number one Cause, it's gotta run, right?!!
The 12v system the very Heart and sole of a Motor Home!
Two possibilities with schooling and recommendations;
1) Alternator is not charging or not charging enough.
I recommend a higher amperage Alternator and new belt.
These days you can get 200 amp one wire alternators for the same
price or less than OEM!
Motor Homes are VERY Alternator/Battery Power dependent.
First thing that the Alternator does when ya get the MH started is
charge All the batteries. ...in less than a day?!! Aaaaah, NO!
Alternators and Batteries on Motor homes should be checked
every time you do anything or go anywhere.
Battery voltage engine off and unplugged for two hours with all power
draw off is 12.6 volts at the lowest. Engine Running is some where
between 13.5V to 14.8V.
No start with new starter is at or below 11 volts and more than 11 volts with used starter. So, if your starter draws down system voltage to less then 11 volts it's not gonna start PLUS some charging systems will not charge until above 11 volts. Meaning; Engine will start but, NOT run for very long AND the newer engine systems need more than 11 volts to run
Meaning; Engine will turn but, NOT start or not run correctly.
Motor Homes sit for months and then are expected to run and started with a jump or as you stated off the house battery. Most batteries
no matter how much charge will only take, realistically 5amps an hour on charge. So, for the 100amper hour starting battery = 20 hours from dead and the 400amper hour house battery 80 hours=100 hours charge time. Now, keep in mind the on board charging system isn't designed to do that for 100 hours, before then (2-8hours or less constant) without cooling time will burn out, burn out half the rectifier or quit completely.
Also, the run time of your hole trip will most likely not completely charge the batteries!
So, all motor homes should be parked with a Battery maintainer (A Battery charger that turns off when batteries are fully charged and on when needed by it's self) or 100 watt or more solar charger hooked up.
The onboard charging system when the Motor home is plugged in most cases over charges the batteries making system voltage low or boil the batteries completely dry making the Batteries unlessly dead. In both cases will not take a full charge again.
Yes, of course Batteries exist which charge faster but, they are more expensive and in most cases can't discharge at the high amperage needed to start your motor home.
Batteries that can still be charged but, always draw system voltage down and never reach full charge. There again burning out your Alternator, Charging system AND your Battery maintainer; ARE BAD BATTERIES!
2) Bad starting battery; Recommend replace with Optima red top battery
Not very likely to be the problem;
2a) All multi-battery vehicles have to have a Battery Isolator.
All you have to do is find it, remove it, have it tested and if it is bad then
you have the rare opportunity to replace it with (and I recommend)
a higher amperage Battery Isolator or rather just replace with higher
amperage. In this case, (Some MHs Not all) are wired to charge the
House battery off the Alternator and isolated to charge the starting
battery. However, the opposite is the norm.
Charging the House Battery first is the best system because, the House battery maintains average or nominal system voltage and through that the starting battery does NOT get too much charge.
The house battery and battery circuit isn't designed to start the Engine.
The house battery is designed to discharge slowly for a long time.
The start battery is designed to supply a large amount of power for a
short amount of time. However, a low start batty combined with the house battery usually will do the trick.
All said and done; Recommend a new starter, Starter Battery, Fan Belt(s), Battery isolator AND a Battery maintainer.