rideadeuce

So everything is working. A/C is running off the batteries as we speak. Woohoo! Shore power to ATS to EMS to MP2 AC IN then AC OUT to panel. GFCI circuit hooked back in to panel, all shore power running through MP2. Finally.... WOooohooo... and power assist is so cool. Still have to mount the Solar charger.

So problem solved regarding no power to cabin. I had left off the main neutral to the bus bar. I had tucked it out of the way and with all those wires I just kept missing it. It was so nice to see the MP2 fired up and everything working in OEM configuration. @Ronbrink, I think you may be right. I have reached out to OTT and support at the place where bought the MP2. I will get it done eventually. At least the bulk of the install is done and I am ready to power some A/C when I get it figured out. Some other small things like the Can BMS port was removed from the new Ekrano monitor so Epoch battery Victron coms won’t work without a cable to convert CAn-BMS to VE.can. Old Cerbo GX has CAN BMS port. Now just to tidy up everything. Made a big mess. SIDE NOTE: OTT did reimburse me for my coupler and hitch. Jason was very helpful. Still investigating but looks like a one-off still. Best, Mike

I am going to be replacing my old Victron color display (push button) which took the place of the old Zamp solar charger. So yes, doing the same. For anyone reading the install, this is what I was trying to do without success so far, "The best place to insert a multiplus is inbetween the ATS (assuming you have a generator) or shore power input (if you don't) and the breaker panel itself. That way the shore or generator power will charge the batteries, and the inverter itself keeps the power on even without shore or generator. It also enables the power assist mode to function correctly, where you can dial down the current limit to match the available power, and then no longer need a power shedding device to avoid overload. Any outlets that have GFCI then continue to have GFCI as they should. Those that don't are probably better not to have GFCI, as heavy loads (air conditioner, electric heat) would end up often tripping the GFCI inconveniently and unnecessarily. The one drawback though is that you *must* then have the multiplus in on or charge only mode to have shore power pass through. If you turn it to OFF, there will be no power at any outlet, regardless of the presence of shore or generator power available. Also, no backfeeding. You don't want to deal with islanding, and you don't have to since the multiplus will do the right thing if wired correctly. Shore/gen (or ATS) is connected to AC IN1, and AC OUT1 goes to breaker panel. That's it. You *can* use AC OUT2 to switch additional loads based on other criteria (see relay assistant for control of ACOUT2 relay) but that would require an additional breaker as you couldn't then put that switched power through the existing breaker panel. Note that if you have an existing converter/charger plugged into power from the breaker panel, this will have to be removed/disabled to avoid setting up a loop (120->12->120->...) This is all assuming you have a single phase breaker panel, or one where the two phases have been merged with a jumper wire (also assuming 30a 120vac service here, not 50a 240/120 split, in which case get a multiplus2-2x). If you do have a 30a split panel (where an existing inverter has already been wired in) you would need to either connect it up the same way as the original inverter (one side of the split is "shore", the other side is "inverter"), or if you wanted to power everything through the multiplus (gain ability to operate aircon from battery) then you want to merge the two sides of the split (jumper between the two 30a breakers) and wire the multiplus in as above (shore/gen->ats->multiplus->breakers). I do this on a regular basis (upgrading mostly b, some c class RVs).

Day #3 Wired in the MP2, Pos and neg bus bars, smart shunt. Turned on inverter... Microwave works nothing els. AC plugged in... nothing. Oh well, had fun installing the hardware and attempting electrical. So everything is mounted except Ekrano display. May give the project a break for a few days and then wire the inverter back to OEM configuration and then hire an RV electrician or talk to OTT to make the changes necessary to use inverter for AC. Best, M

Mossimo, that is interesting. Figures I would pick the one epoxy that does not stick to some plastics. The good new is that is rock solid as of now and most of the weight is being held up by the aluminum supports. I did buy the Marine EP-11 which is stronger than the original formula. I don't know if that makes any difference. Thanks for pointing that out that information though. Best, M

HDPE Marine Board from Buyplastic.com. 12x27x1. It is heavy and expensive but turned out to be very well suited for this install. $57.00 PC-11 Epoxy adhesive paste. 1 lb in 2 cans. from Amazon.com

DAY #2 Yes, it is. Costly and ended up not fitting very well for this application without a lot of customization. So it gave me the idea of making my own mount with the heavy duty star board I did not want to use. Turns it out came in very handy!

Packed to the gills. I felt like a German mechanic changing a water pump connecting batteries but I am happy with the result. No maintenance and they have remote monitoring and shut offs so they shouldn’t need to come out.

Removed: Old Xantrex inverter, transfer switch including ac legs IN/OUT, charger from PD4000, Trojan batteries, Battery tray Mods: Wired Outlet and microwave circuit directly to breaker, mounted pos and neg bus bars using Star board (heavy), Pulled all wires from battery compartment except 4/0 pos and neg, ran wires for Epoch battery remote battery on/off switch and external battery level indicator, COM port from battery to MP2, Re-used all electrical wire (Used some new lugs and heat shrink), removed 10/3 main shore AC from EMS to PD4000Installed: POS and Neg bus bar, (2) Epoch 460 ah batteries, battery wire zip tie holders Waiting on MP2 stand to give lateral support since it will be mounted horizontally. May still bond starboard to fiberglass wall to fixate MP2 but it weighs 49lbs so I want the extra support from stand. We shall see if it fits with some modified aluminum support for feet.

Anyone know what the name of the material that is used in the basement for mounting electrical components. It is strong and lightweight. Most boating HDPE and marine lumber material is very heavy. Or any ideas for using something else? Trying not to use wood. M

@Galway Girl What are your thoughts about this. Connect the original jxn box AC IN and AC OUT together to complete circuit for outlets and microwave. Removes the transfer switch and inverter from circuit. Then take main shore power from EMS that goes to PD 4000 and run it to AC IN on MP2 Then run AC LINE 1 OUT from MP to PD4000 main input. ALL the power from shore/Gen runs through EMS then to MP2 and then back to PD4000 main, thus distributing to all circuits including air conditioner.

Thank you. I think we were reading the some of the same information. "AC-Out-2 supports loads that you only want to run when on shore power or generator. " Yes, unfortunately they don't show their electrical schematics on new systems with 3000 W inverters it seems.

Ok, Perfect. The MP2 has (2) AC line outs. So just a separate AC out line 2 from inverter to A/C 20 amp circuit.

Anyone with a Multiplus II 3000W upgrade able to share how they powered A/C from the inverter. MPII has transfer switch built-in. So the plan is to remove the OEM transfer switch and Jxn box. Then connect the AC IN and AC OUT to the MPII from the old junction box wiring to power outlets and microwave. The puzzle for me is wiring/powering Air conditioner off the inverter. On this schematic, the air conditioner looks like it is powered from the converter only. My OTT is a 2018 with a 2000W ProWatt inverter OEM. Planning stages of upgrading to MPII 3000W with larger lithium battery bank so that I can run the Air conditioner when off shore power.

Craig, so helpful. Thank you for explanation and pics. I am following you with everything but back feeding power thru the dinette GFCI to the A/C. I have a line 2 AC OUT on inverter if that helps.