batteries dead again

kingwood390bh · 05-05-2012, 08:42 PM

I have a Magnum MM-1212. 1200 watt continuous modified sine inverter/converter on my 390bh. I have it stored indoors plugged in to 50amp service. I had the chasis batteries turned off and the house batteries turned on. My assumption was that the house batteries would charge since it is plugged in and the chasis batteries would remain charged since they were turned off(two weeks ago). So today I returned to find both sets of batteries dead. The Magnum remote indicated a "low voltage fault" by blinking once every 4 seconds. None of the interior lights come on(I think they are fed by the 12 volt system). Also, interestingly, the microwave/convection oven seems to work just fine. I just put the chasis batteries on a battery tender so I can start it tomorrow. What did I do wrong?

VinceU · 05-05-2012, 08:59 PM

Seems the 115 VAC is on and connected, it also appears its feed to the converter portion of the Magnum is interupted or the Magnums output fuse or brk for the 13.6 volt DC is open. Could be either fuse or CB, not familar with that device. With the converter working or connected you should have interior lights even with dead batteries. This will give you a start hopefully. Both supply and output of the Magnum could be at fault.

kingwood390bh · 05-06-2012, 12:59 PM

Update; I went back this morning after leaving the chasis batteries charging all night. Engine fired right up. Using the aux start button, I started the generator. I left everything running for about an hour, and when I left, the house batteries were fully charged and the "fault" indicator was off. I then turned off the Magnum from the remote, disconnected the battery from the front of the coach and shut off both sets of batteries from the battery compartment. I did not plug in the 50amp service. Lets see how this works. Also, where is the mechanism to open the generator door?

papap · 05-06-2012, 01:04 PM

I know on mine if you check the batteries to see if they are charged while the generator is running. They will show full charge even if the are not. You have to check the panel when it is turned off and not hooked to shore power.

tmmar · 05-06-2012, 01:42 PM

In the outside fuse compartment which is under the drivers seat you wil see a black 'T' handle. If you pull it, the generator compartment will open. To close, just push the generator back in until it locks in place.

kingwood390bh · 05-07-2012, 12:48 PM

Update: Spoke to the Magnum rep this morning. He suggest that the fault may lie in path from the shore power to invereter. The romote should indicate "ac in" whenever the unit is plugged in. I did not have that. I have to locate the circiut breaker that is tripped to fix the problem. He says that the system is fully automatic and that when working properly, the Magnum will charge the house batteries till full, then charge the chasis battery, then float charge to keep all batteries at optimum. I told him I wish there was a video to explain the system. Is there a panel in the coach with circuit breakers?

**F.R.O.G.** · 05-07-2012, 01:00 PM

Do you have the manual for the Magnum MM1212? If not, you can get it here:
http://magnumenergy.com/Literature/M...%20Series).pdf

MotoWood · 05-08-2012, 12:06 AM

One thing I found with mine, although it is probably not the cause of your troubles, is that my battery connectors were crimped poorly are the factory. So, in essence only 1-2 of my batteries was actually connected, so things wore down quickly. New crimps (and of course I upgraded the batteries while I was at it) and all is good. Worth checking if all else fails.

kingwood390bh · 05-13-2012, 12:26 PM

Update: Went back to the coach yesterday, having left the unit unplugged and batteries turn off in the rear compartment. Engine started and the house batteries still indicated full. I found the "power center" and none of the circuitbreakers had been tripped. Oddly, upon leaving, I tried to switch the front battery disconnect to store but it was unresponsive. I rocked it up and down yet it remained lit. I shut the batteries off in the rear compartment. Next week I'll return to plug it back in. If the "ac in" lights up on the inverter remote then most of my problems are resolved. If not, I still have to find the problem from shore power to inverter.

**Herk7769** · 05-13-2012, 01:15 PM

Quote:

Originally Posted by kingwood390bh

Update; I went back this morning after leaving the chasis batteries charging all night. Engine fired right up. Using the aux start button, I started the generator. I left everything running for about an hour, and when I left, the house batteries were fully charged and the "fault" indicator was off. I then turned off the Magnum from the remote, disconnected the battery from the front of the coach and shut off both sets of batteries from the battery compartment. I did not plug in the 50amp service. Lets see how this works. Also, where is the mechanism to open the generator door?

An hour will not "fully charge" your house batteries. It most likely brought it up to about 50% capacity on the fast charge part of the cycle but that "surface charge" voltage will drop off about an hour after you switch them off. After an hour disconnected; check your batteries with a voltmeter to get an accurate "state of charge" according to the chart below.

kingwood390bh · 05-19-2012, 01:44 PM

Update: I figure I'd update the latest incarnation of my electrical issue. I went back to the storage unit this morning to bring the Berk home. Its been unplugged for 3 weeks with batteries turned "off" in the battery compartment. It started right up and house batteries indicated partially charged( I just noticed they weren't fully charged). I got it home, plugged it into my house(20amp) and the inverter indicated "ac in" and "bulk". Mysteriously my problem is solved. So, my guess is that the 50amp service at my storage facility is to blame. I'll bring my multimeter with me when I go back to the storage facility to check the plug voltage.

NO3putt · 05-19-2012, 10:20 PM

Don't know if I'm right or wrong, but we never turn off the batteries unless we are doing some kind of maintenance. When at home we just plug into a 20amp outlet. Always check the battery water levels once a month. Hope this is the correct procedure. skip

kingwood390bh · 05-19-2012, 11:27 PM

Skip, I'm going to have to check the battery water level. I had to shut the batteries off because I was coming back to dead batteries at my storage facility(even when plugged in). Now my bulk charge light has gone from solid to flashing, which indicates a problem with heat or low voltage. The book says the proper charging format would be solid bulk to solid absorb to solid float. Before long, I'm gonna be an expert at this.

Triguy · 05-20-2012, 07:41 AM

Kingwood,
Glad to hear things are working better for you.

Years ago in the 90s I picked up this book. It was updated in 2002 and I recently picked up another. I find it to be a great reference while camping. Its stored permanently in my trailer.

Managing 12 Volts: How to Upgrade, Operate, and Troubleshoot 12 Volt Electrical Systems

That will help you to become an expert.

kingwood390bh · 05-20-2012, 09:46 AM

Thanks Scott. I'm getting a clearer picture of what my 12 volt system should do.
This morning, I got up to check the water levels in my coach. The batteries are Lifeline deep cycle "maintainence free" so no way to check the water. The big surprise, the Magnum remote was on solid "float"!!! This leaves me with several questions. Why did the batteries die when plugged in at the storage facility? Why did it initially work when I brought it home(solid "bulk" to flashing "bulk")? And finally, What happened over night to fix the problems so that the batteries are now on "float"? Never did I reset a circuit breaker or replace a fuse. Is my Magnum named "HAL"?

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