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thompooley · 04-29-2016, 03:49 PM

I would get a pro to design and install your PV system. You will most likely require construction and electrical permits and inspection from the municipality, event though the Airstream is not a permanent building. Perhaps you can install most of it yourself to save money. Safety first when it comes to electrical power and batteries. Good luck.

Bill M. · 04-29-2016, 03:58 PM

I would give it a try with the generator for a while. You probably will anyway while designing the solar. No permits, drop it on the ground and start it, and you will only have to run it for 2 hours every 3 days if you are reasonably careful. A good generator is pretty quiet. Small solar panel at first just to keep the batteries charged while away.

paulbmccarth · 05-09-2016, 02:53 AM

The MSH3012M manual has good diagrams, but just to be sure, I have scraped together relevant knowledge from others on this forum, and pasted it below. I will be getting a local marine electrician to consult with me as I install some of this (some with his help). I promise to make sure the system is designed properly before I start doing anything stupid. Thoughts?

The specific cable order on the positive leg of the batteries should be like this:

• 2 Trojan T105RE batteries, wired in series (using copper bar or 4/0 cable)
• 2/0 cable up to 5' for the total length to the inverter positive, 4/0 up to 10' (it's in the MS-2012 manual), double 4/0 from 10-15 feet maximum run length
• 300 amp class T inverter fuse
[I think the Midnite Solar 150 MPPT controller can tap in here, with a breaker?? Or does it need to have its own fuse? That then leads with appropriate sized wire to combiner box at the ground mount solar area, with 3 breakers going to 3 x 280 watt panels]
• 300 amp inverter disconnect switch
• final run of appropriately sized welding cable
• positive terminal of the Magnum MSH3012M inverter

And on the negative side of the battery: 2/0 cable up to 5' for the total length to the inverter positive, 4/0 up to 10’; going to ME-BMK shunt (magnum battery monitor) — also the temp sensor is wired to the negative side of battery directly.

The only place to tap off this positive run is at the battery side of the inverter fuse, not at the switch [what does “tap off” mean in this case?]. The cable should be unencumbered from the fuse to the inverter by any other DC loads. For a feed to the house positive bus bar, typically use a 50 amp marine circuit breaker and 4 AWG cabling.

*****Remember to place all fuses and circuit breakers within 18" of the positive battery terminal to meet NEC code!

Then you need to run an ' in loop' and and an 'out loop' to and from the inverter for 120VAC, plus a couple of 30 amp breakers.

Then re- wire of the existing breaker box's 30 amp 120 VAC input, all 10/3 cabling minimum, depending on the length of the wire runs. Maybe put new panels in the space of the old converter and fuse block (Progressive Dynamics PD5500 on top and the Progressive Dynamic PD6000 DC panel below) — using 30a since I have a 2007 airstream with one A/C unit.

Mount control panels and run wiring to Midnite Solar classic 150 solar charge controller, Magnum battery monitor & temp sensor.

What am I missing or getting totally wrong here? I would love to be able to give the installation manual for the MSH3012M and the notes from here to the electrician I am working with, so we can get started making sure we have all supplies to get to work. Thoughts?

paulbmccarth · 05-09-2016, 02:57 AM

One other quick thing: the solar folks I have talked with say I should have a grounding pole in the ground at the panels, and another in the ground near the trailer -- with both bonded to each other. How will this play with the trailer setup? Is that not a good idea with a trailer? The electrician I am working with has abyc marine electrical certification so I'm sure he knows his stuff, but I just want to get any other opinions before we launch into things together.

OTRA15 · 05-10-2016, 05:41 AM

I can't answer you questions, but it makes sense. It is my understanding that even a small generator used to charge trailer batteries is supposed to have its own local ground pole, which many experts here point out. Not many people do this . . .

switz · 05-10-2016, 08:33 PM

Not much fun driving a copper clad steel grounding rod eight to ten feet into the ground let alone get it back out again.

OTRA15 · 05-11-2016, 04:23 AM

Quote:

Originally Posted by switz

Not much fun driving a copper clad steel grounding rod eight to ten feet into the ground let alone get it back out again.

Interesting that the Honda 2000 manual does not seem to require a ground rod IMO.

http://cdn.powerequipment.honda.com/...X31Z076200.pdf

Is this because this unit is double-insulated with no exposed metal parts which can be touched by human hands, like some tools? There is a ground terminal shown in the manual, but no indication that it must be used. [pp. 17, 38-39]

Maybe only larger metal-framed generators require a ground rod?

Next question I guess -- for use on the road, is a 2-3' solid copper ground rod a better ground than no ground rod at all? [for convenient carry in trailer or tow vehicle]

Hmmmm . . .

lewster · 05-11-2016, 07:42 AM

Paul,

Your ABYC electrician (I have the same certification) will definitely know the appropriate marine standards to apply to your rig (which are much tighter than RVIA).

It seems that you have gleaned the important requirements so you are on the right path.

You can 'tap' your house DC and also add your solar positive charge line directly to the positive post at the battery. All of your negative leads will go to the downstream post of the shunt that should come with the ME-BMK.

No additional grounding of your solar is really necessary or even required as the system grounds are all tied together at the frame.

Looking good!!!!!

Lew Farber
RVIA/RVDA Nationally Certified Master Tech
ABYC Certified Master Marine Electrician
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center*AMS Lithium Batteries
Lifeline AGM Batteries**Magnum Inverters***Victron Energy Components
541-490-6357

paulbmccarth · 06-16-2016, 01:35 AM

Okay, been away a little bit but I'm back and preparing to get things together. I'll have my electrician look before I connect power, but I'm hoping to do everything myself before he comes to inspect

My airstream had a 600 watt WFCO inverter, which I'm getting rid of. I've already pulled out the wires that went from that inverter snaking down (a bit circuitously) to the battery terminals.

My question is: should I keep the 6awg wires that go from battery up to DC bus bars? They are taking up valuable real estate in the hole that goes through the floor, and they are also filling up the hole through the steel chassis that makes the shortest route to the battery box. Should I pull those out too, so I can have a nice clean and short single pair run of 4/0 to the batteries? And then to feed the house bus bars, tap off the battery side of the inverter fuse to go to the DC positive bus bar, and the inverter side of the shunt for negative? It seems cleaner to do that rather than have two pairs of thick wires running all the way to the battery terminals.

Also, when I add solar, can I tap that into those same places, or do I need to run an additional pair of heavy gauge wires from my MPPT all the way to the battery terminals? Since my run of 4/0 is only going to be about 2-3 feet total, it seems pretty robust... And I'm going to need to start drilling new holes in the floor to fit all that cable through. I'd love to avoid that.

Thoughts?

- Paul