Can I charge the house battery with the engine alternator?

heyobie wrote:
Just added 2 digital volt meters to my dash. I can now see the house battery and car battery voltage levels with the engine off. When driving I can determine if I need to charge the house and monitor the alternator. Life is good

I have installed the same two digital voltage meters showing the same two voltages on the dash of our 2005 Itasca Class C E450 motorhome - all the time whether we're stopped with the engine running or not ... or traveling.

I also have a 3rd digital current flow meter on the dash that shows current into (positive numerical reading) and current out-of (negative numerical reading) the coach battery bank - all the time whether we're stopped with the engine running or not ... or traveling.

Our motorhome came stock from Winnebago wired to automatically (via a solenoid activated whenever the engine start key is turned on) connect the engine starting battery to the coach battery bank.

The two voltmeters on the dash read just about the same whenever the engine is running (if the solenoid has been activated and if it's contacts aren't too corroded). The preceding of course is assuming that the built-in generator isn't running or we're not parked on hookups.

Whenever the engine is running, the current flow meter on the dash shows how much current (positive numerical readings) the coach batteries are receiving from the engine's 130 amp alternator. When the engine is not running, the current flow meter on the dash shows how much current (negative nummerical readings) is being pulled from the coach battery bank to power the coach's 12 volt circuits. The preceding situations of course assume that the built-in generator isn't running or we're not parked on hookups.

By the way whenever we stop to gas up the E450's fuel tank, for safety I turn off the coach's 12V system switch so that the refrigerator's gas flame can't come on ... as the refrigerator's outside ventilation port is close to where I refuel the motorhome. Also after gassing up if I forget to turn back on the coach's 12V system switch (thus the refrigerator can't operate), the two voltmeter's on the dash don't read close to the same ... which immediately tells me to stop somwhere soon and go back into the coach and turn on the coach's 12V system switch so that the refrigerator can operate while we travel!

heyobie wrote:
Just added 2 digital volt meters to my dash. I can now see the house battery and car battery voltage levels with the engine off. When driving I can determine if I need to charge the house and monitor the alternator. Life is good

X2 :)

Just added 2 digital volt meters to my dash. I can now see the house battery and car battery voltage levels with the engine off. When driving I can determine if I need to charge the house and monitor the alternator. Life is good

heyobie wrote:
My 88 is in much better shape than you have deduced. My Onan generator works great. The inverter/charger has been updated. This unit only came designed with one 12v house. I now have 2 in parallel.
My issue was that the charging system with the car alternator had been kinda stripped out and modified.
With everyone's help here, I got it straightened out and now it works perfectly.
So I am good to go.

Sorry, I had your post confused with Scadaman's

My 88 is in much better shape than you have deduced. My Onan generator works great. The inverter/charger has been updated. This unit only came designed with one 12v house. I now have 2 in parallel.
My issue was that the charging system with the car alternator had been kinda stripped out and modified.
With everyone's help here, I got it straightened out and now it works perfectly.
So I am good to go.

If you can afford it, try to find a local RV repair service that can restore your rig's 12 volt DC power system. It should include two 6 volt RV "house" batteries connected in series for 12 volts, a battery converter/charger that converts 120vac "shore power" to 12 volts DC to power your interior lights and furnace blower and electronic appliance controls as well as to charge your house batteries, and a device to connect your chassis alternator to charge your house batteries when you are driving/running the engine. If you have an RV generator installed, the system will connect the AC 120volt generator to your converter/charger so that the generator will charge the RV batteries and provide 120 volt AC to operate your roof Air Conditioner, microwave oven and other 120vac items while it is running. The above describes a typical Class C motorhome electrical system and how it works.

heyobie wrote:
I just feel better with a switch while I'm trying to figure out how this works. One of the things is don't know is whether I have a regular solenoid starter switch or a battery switch (which is just a starting solenoid that can handle continuous power). The previous owner had a push button switch which tells me he was using it to jump the MH. But the batteries were not connected. I just ran it for an hour and everything seems fine. But turning the switch off makes me feel better.

The push button is a normal thing, it allows you to start the engine from the house battery in case the chassis battery goes dead or needs help. Kind of like hard-wired booster cables.

In my old Itasca, the switch was three position. Center was off, momentary one direction was for jumping to start rig with aid of house battery, other position was for charging battery.
You could use a single pole on/off switch with light. Connect it so when in on position, switch would be lit meaning battery charge relay is energized.

I just feel better with a switch while I'm trying to figure out how this works. One of the things is don't know is whether I have a regular solenoid starter switch or a battery switch (which is just a starting solenoid that can handle continuous power). The previous owner had a push button switch which tells me he was using it to jump the MH. But the batteries were not connected. I just ran it for an hour and everything seems fine. But turning the switch off makes me feel better.

Leaving it on could result in both chassis and house batteries being dead!