Inverter Question

[CINPHIL]

Hi y'all. I noticed that my inverter, even with the coach and chassis battery switches off, stays powered. I can tell because of the hum that the inverter makes and when I go into the coach and turn the inverter off, the hum stops. I have a 2008 Monaco 40PDQ. Is this normal? Perhaps it is wired that way so I can hook to shore power with the chassis and coach disconnect switches off and still charge the batteries via the inverter. Thoughts?

[CA_Traveler]

Turning my Magnum charger/inverter off puts it in standby, it cannot be turned off and still draws power along with sorted other equipment when the Monaco installed switches are turned off.

[CINPHIL]

Thank you to all! This was a great discussion, and quite informative. When I leave the coach...chassis and house batteries "off", inverter "off" as well. Thanks again.

[CA_Traveler]

Monaco did not design their RVs for boon docking or storage - ie Significant current draw for either case.

I added switches to the negative battery post for both banks. Here's the house battery switch and battery monitor shunt.

[pianotuna]

Doug,

Yes. I added them. The other alternative would be to remove the cable from the negative post of the battery bank.

My solar is also switched, though, of course, with a much lower capacity.

[dougrainer]

CINPHIL wrote:
Hi y'all. I noticed that my inverter, even with the coach and chassis battery switches off, stays powered. I can tell because of the hum that the inverter makes and when I go into the coach and turn the inverter off, the hum stops. I have a 2008 Monaco 40PDQ. Is this normal? Perhaps it is wired that way so I can hook to shore power with the chassis and coach disconnect switches off and still charge the batteries via the inverter. Thoughts?

AS long as your shore power control system sends 120 power to the Inverter when Chassis and Coach are turned OFF, you can keep the coach batteries charged by plugging in. You can easily verify this by disconnecting both battery banks and connect Shore Power and see what the Inverter wall display tells you. Your comment is a basic mistake LOTS of RV'ers make when it comes to Inverters. They FORGET they are ON and when they go to storage without 120 shore available, the Inverter is ON and within 2 or 3 days the coach batteries will be dead. I see this all the time when customers bring their RV in for service. The basic rule of Inverters is, if you are NOT Inverting, LEAVE IT OFF. This way you do not have to worry about it being ON in storage. The Inverter will still transfer 120 from shore and charge the coach batteries even when OFF. Doug

[dougrainer]

pianotuna wrote:
My inverter DC power is switched. I have two banks of batteries. Each switch is rated for 1000 amps contacting.

You obviously have added those switches. Regular OEM installed Inverter/Chargers are wired DIRECT to the Coach Batteries. They do this because as another posted, the Disconnect switches used in RV's are either 100 or 200 amp rated switches. THOSE are not heavy duty enough to run Inverted large amp draw thru. Doug

[wa8yxm]

Large inverters can easily draw 100-200 amps at load. so they use big heavy cables on the 12 volt side of life and hook 'em to the batteries DIRECT, no switches to add resistance and loss.. How it was on my rig and How I'd do it if I were doing it. Short Fat cables and no switches.. Just a "T" fuse. between battery and Inverter.

[pianotuna]

My inverter DC power is switched. I have two banks of batteries. Each switch is rated for 1000 amps contacting.

[DrewE]

time2roll wrote:
Basic battery switch probably does not have the amp capacity so the inverter may go around it.

Exactly this--and you probably also don't want the additional resistance (and wire length) in the inverter feed circuit, either. It is very common for the battery disconnect to not disconnect the inverter and sometimes a few other high ampacity loads (such as the generator's 12V connection, since its starter motor is a high current load, albeit one of short duration).

Sometimes there are other constant loads that bypass the disconnect switch because the maker deemed it best to not have them interrupted for various reasons. Common examples include propane and/or CO detectors, power entry steps, and radio preset memory power.

[time2roll]

Basic battery switch probably does not have the amp capacity so the inverter may go around it.

[CINPHIL]

Thanks, but that would be a battery drain when one thought by turning off the chassis and house switches everything was off. I appreciate the response! Take care.

[Flute_Man]

Probably the way it is wired. I certainly would not lose any sleep over it. I never tested mine that way.