Coach Monitor Show Half VAC

[Jjfranke]

I have a 1988 Beaver Marquis, with a 6.3 Kw Onan propane generator. The coach monitor panel shows half the VAC even when plugged into a land line or the generator. All the receptacles have 117VAC when plugged or when the generator is running,

The batteries are not fully charged. I am charging them with a trickle charge right now.

We did run out of propane with the ACs running once.

Any thoughts will be helpful.

Thanks

Franke

[wolfe10]

Franke,

Welcome to the FMCA Forum.

Tell us what AC voltage monitor you have.

And, from your post, it sounds like you have confirmed proper voltage (you said 117 VAC) with generator and on the shore power you are currently connected to. That sounds like a bad monitor.

[Jjfranke]

I am not sure which monitor, I'll have to get the manufacture of the back. Currently not connect to shore line. Have charged two of the three batteries in coach to full, am taking them to be load tested right now. Third battery in coach went dead over night. I'll get back with the monitor type.

Thanks

Franke

[Jjfranke]

All three of my batteries have been fully charged and tested for load, all three are good. The monitor shows, with nothing on except the possible LED lights on radios or the panel, 5.7 DC. 00 VAC on both legs but both legs show phanton amps that rise and fall.

The monitor panel itself is the original one in the Beaver Marquis. When the generator is running the panel show about half the VAC that it should. It also shows about half the VAC when plugged into a shore line.

Any ideas will help,

Thanks

Franke

[wolfe10]

Franke,

If batteries show full charge when read at the batteries (i.e.around 12.7 VAC) and 5.7 on the monitor AND

Measured VAC on monitor while on generator reads half of that a digital voltmeter shows, check for good ground at monitor, etc and if you can't determine brand and model of monitor, replace it.

You might also post this on the Beaver Ambassador Club: http://www.beaveramb.org/

[RVerOnTheMove]

If you use a voltage meter plugged into an outlet are you seeing the correct voltage or are you seeing the same readings that the monitor shows?

[Jjfranke]

Voltage @ all plug in's are 117VAC when generator is running or when plugged into a shore line. The only piece of the monitor panel that seems to be correct is the fresh water tank monitor lights. Ha Ha. Everything in the motorhome functions properly. Both ACs blow cold air, all outlets have 117VAC. Would like to verify that generator and engine alt. are charging batteries properly.

Do I check DCV at the batteries with the generator running, then just the engine running? What should the voltage be? 12.5 or greater?

Thanks

[wolfe10]

Would like to verify that generator and engine alt. are charging batteries properly.

Do I check DCV at the batteries with the generator running, then just the engine running? What should the voltage be? 12.5 or greater?

Thanks

Start by disconnecting from shore power and generator and inverter (if fit) OFF.

With a digital voltmeter (starting under $20 from Sears, Radio Shack, etc), check and record voltage at house and chassis battery (AT the battery). 12.7= fully charged 12 VDC battery, 12.2 = 50% discharged battery. Anything over 12.7 is surface charge and will disappear if you turn a 12 VDC load for a few minutes-- do that if above 12.7 until it reaches 12.7 or slightly below.

Next, plug into shore power and make sure converter or charger or inverter/charger is charging: Voltage at any battery being charged will be 13.2-14.2 VDC depending on what device you have (actually, how smart it is-- smarter ones start at higher voltage). You house battery SHOULD be at this higher voltage. Chassis battery MAY be at this higher voltage-- some coaches are wired to charge both battery banks from shore power, some only the house bank.

Generator should do exactly the same, since from the ATS (Automatic Transfer Switch) on, the electrical system is the same on shore power or generator.

Disconnect from shore power and turn off generator. Get battery voltage at batteries at or below 12.7 VDC. Start engine. Speed engine up to high idle (1200 RPM or so. Check voltage at both battery banks. BOTH banks should read 14-14.5 VDC.

Brett

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