Hello RV'ers!I'm a few weeks in to full-timing, in my '89 Mallard RV. I got the Onan generator working, finally, and realized that to use it I need to plug my 30-amp hookup into a jack in the power hookup compartment.When I run the generator, afterward the Test Panel is completely dead, the Propane powered fridge shuts off, and in general everything behaves like there is absolutely no power in the house battery. So I run the engine for a bit, and within a few minutes usually, everything comes back on.I'm wondering how I can avoid this. It can't be healthy for the electrical system. When I try to shutoff the 30-amp breaker before I turn off the generator, it doesn't seem to help. I don't know if it is actually helping to unplug the 30-amp hookup from the generator power outlet, but I do.I'd like to keep the 30-amp hookup plugged into the generator outlet most of the time, so I can use the generator periodically without getting out and attaching the coach to the generator in the power compartment.Any help would be much appreciated!

You should not have to unplug from the generator unless you find utility power.Do you have a meter to check the battery voltage on the terminals?Compare with generator running and stopped.May as well post the converter or inverter/charger brand that is supposed to be doing the charging.

Hi,What make and model of converter do you have?

It sounds like the charger is not working and start with checking the battery voltage. Also be advised that in general with say 2 hours of gen run time the batteries will only be charged to 80-85% SOC. It takes many hours to fully charge batteries. So every day you're starting with partially discharged batteries. Full timers w/o power often start to consider solar.

You need to make sure you have a smart mode converter/charger setup. Your older RV may not have one unless it has been updated.Using smart mode charging will re-charge your batteries to their 90% charge state in a quick three hour generator run time...If your converter/charger only puts out 13.6VDC when being run by the generator it will take a good 12 hours to get your batteries up to their 90% charge state,A smart mode converter/charger will hit your batteries with 14.4VDC for two hours and then drop back to 13.6VDC for another hour. Roy Ken

The generator supplies AC which powers the converter which charges your coach battery. If you have the ability to read voltage - measure the battery voltage when either the generator is running or connected to shore power - should read about 13.6 volts ... if you don't have the equipment look at the interior lights, they should brighten when hooked to shore power.If you suspect a bad converter - look for an auto reset circuit breaker (Google it as it looks strange) near the battery - if that goes south then your converter can't charge the battery. It's also possible that the fuses on the converter itself have blown.

Coach battery seems drained after using generator.

20 Replies

kemeisland
Explorer
Feb 20, 2015
Yes, my fridge is 3-way, but I only use LPGA mode. Sometimes if connected to hookups I use AC, but never DC.

The power converter is MagnaTek, model 6345. Generator is Onan Emerald I Genset.
MrWizard
Moderator
Feb 20, 2015
When I run the generator, afterward the Test Panel is completely dead, the Propane powered fridge shuts off, and in general everything behaves like there is absolutely no power in the house battery. So I run the engine for a bit, and within a few minutes usually, everything comes back on

this has nothing to do with 110v use

fridge control uses 12v
most fridge are 2-way 120v or propane/LP
some are 3-way and include a 12v keep cool mode for travel
using the 12v mode when parked will suck the battery dead .. real quick

batteries are taking charging from alternator
and when using shore power ?
then generator output is probable problem
CA_Traveler
Explorer III
Feb 20, 2015
Most rigs have a transfer switch that powers the AC including the charger from either shore or gen power. Do your house batteries get charged on shore power? Your rig may/may not be designed to charge the chassis batteries from the charger.

Most rigs also have a isolator that charges both battery banks from the alternator which explains part of what you're seeing.
kemeisland
Explorer
Feb 20, 2015
Thank you very much everyone for jumping on my question! In a little while I will post models of the converter and generator.

But for now I have this generic answer: when the generator is running, and when the engine is running, on the Test Panel the "battery charger" light is green/on, exactly like when attached to a standard power hookup. I don't believe the battery is actually being drained, it just appears drained. I'm wondering how the battery could be used at all when the generator is running. The power outlets in the coach only work with the generator on or hookups attached, so I might be green to think this, but I believed the battery was impossible to drain with 110v power usage.

It's great to know the time it takes to recharge a battery is from 3 to 12 hours. I will try to get a voltage meter to see if I can read the actual level when the generator is turned off and everything appears to be dead.
MrWizard
Moderator
Feb 20, 2015
IF your batteries charge when on shore power but do not charge when the generator is running ( same power cord )

You need to check the generator voltage output, and control board
it may be too low for the converter to do in any charge output

The converter should be charging when the Onan is running
The Onan is using 12v power for the electric fuel pump
But it should not be pulling down the batteries to the dead point
ksg5000
Explorer II
Feb 20, 2015
The generator supplies AC which powers the converter which charges your coach battery. If you have the ability to read voltage - measure the battery voltage when either the generator is running or connected to shore power - should read about 13.6 volts ... if you don't have the equipment look at the interior lights, they should brighten when hooked to shore power.

If you suspect a bad converter - look for an auto reset circuit breaker (Google it as it looks strange) near the battery - if that goes south then your converter can't charge the battery. It's also possible that the fuses on the converter itself have blown.
RoyB
Explorer II
Feb 20, 2015
You need to make sure you have a smart mode converter/charger setup. Your older RV may not have one unless it has been updated.

Using smart mode charging will re-charge your batteries to their 90% charge state in a quick three hour generator run time...

If your converter/charger only puts out 13.6VDC when being run by the generator it will take a good 12 hours to get your batteries up to their 90% charge state,

A smart mode converter/charger will hit your batteries with 14.4VDC for two hours and then drop back to 13.6VDC for another hour.

Roy Ken
CA_Traveler
Explorer III
Feb 19, 2015
It sounds like the charger is not working and start with checking the battery voltage.

Also be advised that in general with say 2 hours of gen run time the batteries will only be charged to 80-85% SOC. It takes many hours to fully charge batteries. So every day you're starting with partially discharged batteries. Full timers w/o power often start to consider solar.
pianotuna
Nomad III
Feb 19, 2015
Hi,

What make and model of converter do you have?
time2roll
Nomad
Feb 19, 2015
You should not have to unplug from the generator unless you find utility power.

Do you have a meter to check the battery voltage on the terminals?
Compare with generator running and stopped.

May as well post the converter or inverter/charger brand that is supposed to be doing the charging.

Forum Discussion

Coach battery seems drained after using generator.

20 Replies

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