I am installing an inverter and solar panel setup in my Volante 380MD 5th wheel. I have a Magnum 2812 inverter, 2x 100AH lithium batteries, getting 400AH more of batteries soon. What I am thinking of doing is making the current primary electrical panel the subpanel and installing a 2nd panel as the main panel with shore power and AC, converter and other services I do not want to run off the inverter in the new panel. I also plan to move the shore power plug from the rear of the RV to the front, closer to the inverter for a shorter power run. Looking for suggestions or cautions on my plan. I have most of the gear but might need more cable to move circuits to the new panel. Thanks in advance ...

The only caution I'd say, is Li don't want to be float charged. Better to cease charging at 90% of full. Their lack of voltage drop may make that hard to find.I hate wasting solar power.

Where is the power centre now and your inverter and batteries? BTW nice unit! (I watched the video but they didn't show any electrical stuff)scroll down to the 380MDhttps://www.rmrv.com/product-crossroads-rv/volante-fifth-wheel#libraryDetailTabsNote-you don't need to shorten a 120v line for saving any power like with a 12v DC line. It might be more convenient, depending.

“ I also plan to move the shore power plug from the rear of the RV to the front, closer to the inverter for a shorter power run.“Your shore power goes to your inverter?

robertdmunn wrote:What I am thinking of doing is making the current primary electrical panel the subpanel and installing a 2nd panel as the main panel with shore power and AC, converter and other services I do not want to run off the inverter in the new panel. I also plan to move the shore power plug from the rear of the RV to the front, closer to the inverter for a shorter power run. Why do you want to make the main panel the sub panel vs the standard installation per the Magnum manual?There is no reason for the plug shore near the Magnum or for the Magnum to be near either panel. The pedestal for many sites is in the rear so you'll need a longer cord to reach it. There are a lot of reasons for the Magnum to be close to the batteries. A say 125A load on the 12V wires will have 10x the amps then the amps on the 120V wires - plus about a 10% loss due to the charger/inverter power loss. Hence the 12V wires must be larger/shorter.

600ah of Lithium ..? You could run anything in your coach, and probably your a/c for a while. I'll try to convince you to skip all that work and do it the much easier way: Do a hard-wire whole house install. Forget the sub-panel stuff, forget the moving the shore cord. Is that Magnum an IC? If so, you've got it made. a) install an spst switch on the converter and turn it off. If it has a separate breaker, even better, just turn that off. Use the charger in the Magnum. Caveat: Make sure the Magnum can be adjusted to charge Li'sb) Move ac panel's shore input to output of Magnum. Move shore cord power to ac input of Magnum. Most inverters that large have hard-wire functionality. I use household Romex. Did you mean you were going to plug your shore cord into it? I don't see any outlets on it.c) Done, and you can run anything you want. Now, having said my peace, if you absolutely cannot remember to turn your HW to gas and your refer to gas when inverting, then forget all this and do it your way.

Inverter/solar install questions | Good Sam Community

23 Replies

pianotuna
Nomad III
May 27, 2019
Hi,

If adding cooling fanS, make sure they are 12 volt. The Magnum uses 120 volt fans internally--and when you switch off the inverter the fans shut down. DAMHIK.
robertdmunn
Explorer
May 27, 2019
Itinerant1 wrote:
I have the Magnum 3012 inverter and as suggested a sub panel was added. The new panel had the main, inverter, hot water moved to it making the original the sub panel.

The last time I hooked up to a power pole (50a) I would just flip the hot water switch on in the main panel. This is the hybrid unit so on the me-arc I would adjust the incoming ac to 50a to power everything off of the power pole.

Like yours the panel is in the middle of trailer and the inverter, batteries, pt controller are in the front compartment.

OK, so that's essentially my original plan, which is in part based on making as few changes as possible to the existing wiring. I need to put the new main panel in the front storage compartment, which is why I was thinking of moving the plug rather than make a new run all the way from the rear to the front of the RV.

So my version of this plan would be:

1. Move plug from rear to front. There is already a properly sized hole where the vent from the original flooded battery was.

2. New panel with main, ac, wh, and 30A breaker to inverter AC input in front.

3. Current run from rear plug to main becomes the run from the inverter AC output to the old main panel, now the subpanel.

4. Old converter is disconnected and removed as Magnum 2812 is an IC.

5. Main breaker on old main panel switched to 30A to match output of inverter.

6. 400A fuse on DC wire from inverter to batteries.

7. #0000 wire connects inverter to batteries.

I am planning on mounting the inverter on the bottom of the front storage compartment, and I'm thinking of adding some kind of heat sink/spreader under the base. Since the bottom of the compartment is metal, it will spread the heat, though it could get quite warm. I might use the small output circuit from the solar charge controller to power a small exhaust fan, something like a 120mm computer case fan.
robertdmunn
Explorer
May 27, 2019
time2roll wrote:
robertdmunn wrote:
Good points, thanks. We often connect to shore power at 30A and haven't really had issues with it, but am I limited to 30A in pass-through mode using shore power with a single unit? We don't really need A/C or elec. water heater, so when inverting, 30A is enough.
I believe if you feed the full 50 amp split phase through the inverter transfer switch the main breakers in the RV should be swapped down to 30 amps.

good point ...
MEXICOWANDERER
Explorer
May 26, 2019
And here I have 1,600 USABLE amp hours @ 24 volts

And I wouldn't DREAM of extended bedroom use of a 5,000 BTU air conditioner UNLESS I had 50 amps worth of solar.

Must be a new kind of math? :)
CA_Traveler
Explorer III
May 26, 2019
time2roll wrote:
I believe if you feed the full 50 amp split phase through the inverter transfer switch the main breakers in the RV should be swapped down to 30 amps.
Also call Magnum and find out if you need a dual 30A CB on the Magnum input to protect the Magnum.
time2roll
Nomad
May 26, 2019
robertdmunn wrote:
Good points, thanks. We often connect to shore power at 30A and haven't really had issues with it, but am I limited to 30A in pass-through mode using shore power with a single unit? We don't really need A/C or elec. water heater, so when inverting, 30A is enough.
I believe if you feed the full 50 amp split phase through the inverter transfer switch the main breakers in the RV should be swapped down to 30 amps.
Itinerant1
Explorer
May 26, 2019
I have the Magnum 3012 inverter and as suggested a sub panel was added. The new panel had the main, inverter, hot water moved to it making the original the sub panel.

The last time I hooked up to a power pole (50a) I would just flip the hot water switch on in the main panel. This is the hybrid unit so on the me-arc I would adjust the incoming ac to 50a to power everything off of the power pole.

Like yours the panel is in the middle of trailer and the inverter, batteries, pt controller are in the front compartment.
wa8yxm
Explorer III
May 26, 2019
First the panel in the RV now is technically a "SUB" panel. (Neutral and ground NOT bonded".

Normally when installing an inverter you add a second (Sub/Sub?) and move inverter powered circuits. BUt from a technical viewpoint. What you purpose.

Same thing.. SO it should work just fine. The only difference is the main breaker on the existing panel should be changed to match the output of the inverter. Or rather the maximum pass through. IE for my 2000 that's 30 amps
robertdmunn
Explorer
May 26, 2019
time2roll wrote:
This one?

I assume 50 amp RV?

MS 2812 has a transfer rated 30 amps per pole. You can parallel them for 60 amps on one leg. For a 50 amp RV and using the built-in inverter transfer switch you really can only power one side of the RV. You will want to load the inverter items onto the inverter side and non inverter items on the other side. In a way this resolves the sub-panel issues. Also you only need 6/2 wire to make the round trip forward to the inverter and back to the main panel.

2812 Manual see p25

Good points, thanks. We often connect to shore power at 30A and haven't really had issues with it, but am I limited to 30A in pass-through mode using shore power with a single unit? We don't really need A/C or elec. water heater, so when inverting, 30A is enough.
robertdmunn
Explorer
May 26, 2019
CA Traveler wrote:
My 30' cord normally reaches, but I do carry an extension cord when needed.

Whole house is an option and might work very well for you. A/C run time on batteries will be limited, but dependent on your solar capability.

I bought a 50' 30A cord as backup. We don't use the A/C much, so generally 30A is ok for us.

Space-wise I could mount as much as 1600 watts of panels. I saw a recent post here by someone who is boondocking in a similar setup- 500AH of lithium plus 1200+ watts of panels. Sounds good!

Now if I can just get my wife to agree to the composting toilet.