Parasitic draw problem

[Mainuh]

We've got a 2008 MADP on Spartan K2 chassis. It has (4) 1 year old FullRiver AGM DC-250-6 house batteries, wired 2 pairs of 6vdc in series to make (2) 12vdc banks which are thenwired in parallel with positive and negative being hooked in at opposite corners which should be 500ah of storage. We hadn't done any boondocking until we got to quartzsite in late january and found our 500 ah battery bank couldn't make it 8 hours with no inverter, all LED lights and really only running a few LED lights and the oasis diesel heat as needed... the heater was faulting with low voltage at about 12vdc by 4am. Fit to be tied, I checked with a solar dealer at Quartzsite who just happened to have a FullRiver rep on hand. Unfortunately, they couldn't look at my coach for nearly 10 days and we weren't staying that long.

One thought was my connector wires tying the two banks of 6vdc pairs together were too small, so we increased the size on those with no change. The Magnum MS2812 inverter/charger can be on float with batteries at 13.6 or so and once shore power or generator removed, you can almost watch the voltage drop. It'll be down to 12.6vdc within 30 minutes or so and it should slow down there for a while but it keeps going and gets down to 12.0 within 4-6 hours. Was hoping with 500 ah we could go a day or two... refrigerator is a Norcold 2117 gas/elec so running on gas when on battery.

Batteries were tested by a FullRiver dealer in Tucson in February and all passed and tested again today (load tested) and all passed with flying colors so at least they haven't been damaged. We're in Maine now and I've used a clamping ammeter to monitor what's going out from the batteries when off shore power and with virtually nothing on, no inverter, no TV's or microwaves etc... the normal load drawing things like gas detectors etc are on... I can see the draw go from 1-4amps and spike to 22-28 amps without me turning anything on... it just happens and fairly often. Quite common to see 15-18 amp draw with no "big ticket" items on at all. Not the engine pre-heater (which is actually unplugged). And yes, I've gone into the DC fuse box and started pulling fuses, but nothing in there seems to make the big draw go down... some fuses might make it drop 1 amp or so, but it can still be drawing 17-22 amps at times... sometimes higher.

I did a soft reset on the inverter yesterday... didn't see to help. Watched the amps at 4.31 then jumped to 6.87, then to 17.8... all while no devices were being turned on in the rig. One thing that the Fullriver Rep and solar dealer had mentioned was that Newmar really screw up on this coach when they put the inverter mid ship while the batteries are adjacent to the engine, a good 20' or more away. They said that cable run should be 5' or less if possible.

When on shore power with batteries on float charge the ME-50 remote will show 0amps but will suddenly go to up to 41amps on the display while still remaining on float charge which seems odd but I guess could be normal if it's charging to replenish for 12 vdc items running, but going from 0 to 41 amps seems extreme.

Really pulling my hair out on this one... It's killed our ability to boondock unless it's a truckstop where no one will notice the generator coming on at 3am... Having paid $1400 to get 500ah of AGM batteries and not being able to get through the night with no inverter running and not even using TV's, only a few LED lights and whatever DC the fridge needs when running on gas seems insane.

Talking with a guy who does repairs here at the park we're at for summer but worked in the electronics industry for 25 years, he sort of suspects the inverter as very few other things could create such a draw. The other consideration is that this is happening while the coach is stationary.

Is there a way to bypass the inverter charger for a few hours and see how the batteries do without the inverter online? Are there diagnostics that can be done on the inverter to insure it's functioning correctly? I've done 50 or more searches on parasitic draw and Magnum inverter problems but haven't found a similar situation. Probably a call to Magnum is in my future...

Any thoughts or similar experiences welcome. Thanks.

[twinboat]

Find and pull the inverter fuse or cable off the battery.

You may not have the meters working but time will tell, if the voltage stays up thru the night.

[bluepill]

1. Do you have a dedicated positive cable from the battery bank to the inverter? This would be normal. If so, have you checked the current draw on THIS CABLE ONLY?

2. If you are wired as noted above, just disconnect that Inverter power cable and see if the problem stops. EDIT: as Twinboat just posted.

[ptw]

Are you sure you are starting with a full charge on the batteries?

First thing I would check would be the refrigerator. The 2117 has fans, defrost heaters, and an ice maker. All use a lot of power if they are on. Note below the defrost at 15A DC for the 2117 refrigerator.

DC amperage draw @ nominal 12 VDC
Automatic ignition ----------------------------------------------------------------------------------------0.50 A* Divider heater ------------------------------------------------------------------------------------------- 0.275 A* Defrost system ---------------------------------------------------------------------------------------------- 15 A* Flapper heater ------------------------------------------------------------------------------------------- 0.275 A* Lamp, fresh food compartment --------------------------------------------------------------------- 0.500 A* Gas valve ------------------------------------------------------------------------------------------------- 0.146 A* Fans (2) --------------------------------------------------------------------------------------- 0.950 A (per fan)* Valve, water dispenser -------------------------------------------------------------------------------- 0.830 A* Dispenser water line heater -------------------------------------------------------------------------- 0.167 A* Ice maker water line heater (IM Models) --------------------------------------------------------- 0.167 A* Ice maker water line heater (IMD Models) ---------------------------------------------------------1.25 A* Dispenser water valve heater ----------------------------------------------------------------------- 0.458 A*

[cruzbill]

Turn off your inverter, completely. My Xantrex invereter has a feature that 'scans' for an AC load, the scan threshold is variable (4amps, 10a, 40a) and can be set by the user. If the inverter 'sees' a load exceeding the threshold, it will turn on and operate the load. Could be that your inverter scan threshold is set low and your inverter is starting up to charge your batteries-now that would be a real tail-chaser!
Just a thought!

[bruceisla]

Originally Posted by ptw

Are you sure you are starting with a full charge on the batteries?

First thing I would check would be the refrigerator. The 2117 has fans, defrost heaters, and an ice maker. All use a lot of power if they are on. Note below the defrost at 15A DC for the 2117 refrigerator.

DC amperage draw @ nominal 12 VDC
Automatic ignition ----------------------------------------------------------------------------------------0.50 A* Divider heater ------------------------------------------------------------------------------------------- 0.275 A* Defrost system ---------------------------------------------------------------------------------------------- 15 A* Flapper heater ------------------------------------------------------------------------------------------- 0.275 A* Lamp, fresh food compartment --------------------------------------------------------------------- 0.500 A* Gas valve ------------------------------------------------------------------------------------------------- 0.146 A* Fans (2) --------------------------------------------------------------------------------------- 0.950 A (per fan)* Valve, water dispenser -------------------------------------------------------------------------------- 0.830 A* Dispenser water line heater -------------------------------------------------------------------------- 0.167 A* Ice maker water line heater (IM Models) --------------------------------------------------------- 0.167 A* Ice maker water line heater (IMD Models) ---------------------------------------------------------1.25 A* Dispenser water valve heater ----------------------------------------------------------------------- 0.458 A*

This problem sounds familiar but I couldn't find a link.
I'd try disabling the defrost or turning off the reefer and see what happens.

try here for aa service manual:

rvrefrigeratorrepair.com/wp-content/uploads/2016/08/Norcold-Service-2117

[ptw]

When we dry camp the first thing I do is turn of the ice maker and the moisture control in our refrigerator. Next I unplug the DVD players, TV Box, and the audio system. If we are not using heat I turn off the diesel burner and make sure the AC heater switch is off for the Oasis so there are no circulating pumps running. I have the setting on the "search watts" at 50 W for the inverter and make sure there are no chargers or any other electronics plugged in to make the inverter come on.

The big thing for us seems to be camping when cold and the burner, heater fans and circulating pumps use a lot of power. We also have a residential refrigerator.

Paul
2017 DS 4018

[Dutch Star Don]

Do you have an engine block heater? On my coach and on my 05 Diplomat, there was no switch for it. You turn it on by plugging it in, in the engine compartment. That would explain your cycling.

[DAJO]

When our 2000 Magnum started acting up at the FMCA rally in Chandler while running on the gen I could hear the gen speed up and then back to idle at different intervals with the charge amps following. A new 2800 PSW Magnum fixed the problem.

[Tigerfan1]

Ditto to what Dutch Star Don said. Had a similar problem and found the switch for the engine block heater which was located above the passenger area was on.

[cruzbill]

Isn't there a t-stat on that heater cord?

[twinboat]

The OP says; " not the engine pre-heater, ( which is actually un-plugged ) ".

That sounds like he has the block heater un-plugged.

[Mainuh]

Originally Posted by twinboat

The OP says; " not the engine pre-heater, ( which is actually un-plugged ) ".

That sounds like he has the block heater un-plugged.

Yes! The switch is off as mentioned in the post and the heater is unplugged from the receptacle. It was a long post I know, but tried to cover all the issues. For those sending me to the fridge... Have seen the same behavior with the fridge shut off as well as the inverter off.

[ptw]

Did you look at the fuse panel near the power cord reel? Did you turn off the hydronic heater? There are circulating pumps that run.