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 > Can I charge the house battery with the engine alternator?

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heyobie

Maryland

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Posted: 11/25/22 05:29am Link  |  Quote  |  Print  |  Notify Moderator

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

bobndot

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Posted: 11/25/22 12:45pm Link  |  Quote  |  Print  |  Notify Moderator

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


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pnichols

The Other California

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Posted: 11/25/22 08:32pm Link  |  Quote  |  Print  |  Notify Moderator

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!


2005 E450 Itasca 24V Class C

heyobie

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Posted: 11/26/22 10:58am Link  |  Quote  |  Print  |  Notify Moderator

Love it

theoldwizard1

SE MI

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Posted: 11/26/22 12:10pm Link  |  Quote  |  Print  |  Notify Moderator

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

Some of those cheap volt meters are very poor quality. They can be off by a couple of tenths of a volt.

theoldwizard1

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Posted: 11/26/22 12:14pm Link  |  Quote  |  Print  |  Notify Moderator

pnichols wrote:


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).

Curious. What kind of numbers do you see when driving ?

heyobie

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Posted: 11/26/22 02:19pm Link  |  Quote  |  Print  |  Notify Moderator

Just compared my cheap digital gauges to my Klein multimeter. Identical.

Going down the road, the alternator reads 14.5 and the house reads 14.5 When I turn on the lights and the heat, both drop to 14.2

pnichols

The Other California

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Posted: 11/27/22 11:03pm Link  |  Quote  |  Print  |  Notify Moderator

theoldwizard1 wrote:

pnichols wrote:


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).

Curious. What kind of numbers do you see when driving ?

Both voltmeters read very close whenever the engine is running ... except for two times in the past of our 17 year old Class C when the two meters did not agree when the engine was running.

These were the two times when I had to replace the solenoid that connects the chassis battery system to the coach battery bank. Both times the solenoid had 12 volts on it whenever the engine was running and I had heard the "clunk" as the solenoid engaged as I started the engine.

I assume that the reason that the two voltmeters read differently in those instances was because the solenoid contacts had corroded/pitted surfaces badly enough such that there was resistance in the charging current path to the coach batteries.

This caused the reading of the dash voltmeter to be lower than that of the engine system's voltmeter. This meant that the coach batteries were not getting charged because they weren't seeing high enough voltage on their terminals from the coach's 12 volt system as we were traveling.

I replaced the solenoid those two times with much more rugged non-stock heavy duty 12V solenoids that had silver plated contacts - which were not carried in parts stores. I had to order them special.

So ... what these dash meters tell me as we go down the road is:

1) Is the coach refrigerator getting 12 volts as we travel so food doesn't spoil?
and
2) Are the coach batteries getting charged via enough voltage being applied to their terminals from the engine alternator?

pnichols

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Posted: 11/27/22 11:15pm Link  |  Quote  |  Print  |  Notify Moderator

...

heyobie

Maryland

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Posted: 11/28/22 05:24am Link  |  Quote  |  Print  |  Notify Moderator

Which solenoid did you buy? I'd like to replace mine

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