Victron Multiplus Hybrid/Boosting Inverter/Charger Install

[CA_Tallguy]

Hey folks! I'm about install a new Victron Multiplus Inverter/Charger into my 1977 31' Excella 500. This unit is similar to the "hybrid" inverters from Magnum. These units have the ability to "boost" shore or generator power by augmenting the available power from one of those sources with inverter power coming off the batteries. As such, I should be able to run my AC with a very small Honda/Yamaha generator, and I could even run it for some time WITHOUT a generator running or shore power at all.

Here's a link to the product (I've got the 12/3000/120-50 model - 3000w inverter and "50 amp pass-through max).
MultiPlus - Victron Energy

First of all, let me say that I fully realize the implications of running an AC off of inverter power alone and how fast it can suck the batteries dry. It isn't my intent to build this system to run the AC off batteries... just saying that it can do that. I'm going to have a LOT of power generation potential along with 400 to 1000 amp hours of power storage to work with so I could see myself firing up the AC for 30 minutes before I get to a campground, for example, or running the microwave at a rest stop for lunch. But the goal isn't to do anything like that for hours on end without using a generator or shore power.

Soooo... here's my loose thinking about install right now and some areas I'm looking for suggestions...

INSTALL LOCATION - the unit is pretty heavy (40lbs) and it is made for vertical/wall mount install. I have a question into the maker to ask about laying it down so it could potentially go in the front of the trailer where the current converter/charger is located. But I'm leaning towards vertical mounting it under the tv/credenza area or further back on the street side of the trailer. There will be a pretty fancy color touchscreen wall control panel coming off it along with other related bits such as battery monitor and solar charge controller.

WIRE SIZE/TYPE - Regardless of install location, it will need some heavy gauge 120v and 12v cables running to and from it. For 120v, I may want to directly wire up the incoming 30 amp power to the unit and then do a 50 amp wire run back to the main circuit breaker panel. (The unit can "boost" the 30A incoming to 50A by adding in power from the inverter.) Any advice on how and where to run this wire? In the belly? Conduit along the wall? Eventually inside the wall? Thoughts on if I should use stranded/solid wire? Any problems/considerations running both the incoming 30 amp and outgoing/breaker panel run 50 amp wires in the same bundle/conduit? I think I have the info I need for the 12v wire run. I'm just not as certain about AC 120v wiring and best practices.

Any and all advice and suggestions and/or questions about the unit are welcome!

[lewster]

Looks like their requirements for DC cables are significantly less than Magnum's . If you are getting the 3000 watt unit, it calls for 50sq.mm cable for runs up to 5', which is roughly 1/0AWG and 70sq.mm cables for up to 10', which is just a bit smaller than 2/0AWG . Interestingly, Magnum requires 2/0AWG up to 5' 4/0AWG from 5'-10' and double 4/0AWG from 10'-15'. Longer runs are not recommended.

If you fully intend to operate this unit at the 3000 watt level, I would strongly suggest upgrading the DC cables to US standards and locate the inverter as close to the batteries as physically possible. Where do you intend to locate your batteries and how big a battery bank are planning to use?

Also, with the established authorized repair network for Magnums, 3 year warranty and the fact that they are made in the USA, why did you decide on the Victron?

It also might be beneficial to read this thread on Victron owners' experiences: http://www.cruisersforum.com/forums/...ent-92560.html

[CA_Tallguy]

Hey Lewster! Thanks for the reply. I'm chomping at the bit to get some LiFePO4 batteries so I could be upgrading from my current 400AH battery bank to most likely either 400, 700 or 1000 of LiFePO4.

That complicates my decision on where to locate the unit as my batteries are currently in the front of the trailer under the couch and depending on the dimensions of the upgraded LiFePO4 pack they may need to be located elsewhere.

The next most likely location for the batteries would be a few feet behind the rear axle, under the queen bed. I'd try to put them as far forward there as possible for weight distribution.

If I do start to plan for batteries in the rear, then the unit could be back there too, and that's close to the incoming power cord so that makes a lot of that very convenient. I would then need to run a pretty beefy 12 volt run up to the front of the trailer to feed the fuse panel there, plus I have quite a large charging current coming from my tow vehicle as you may recall. So that would be adding on 20 to 25 feet on that high current run.

I did hear back from Victron and they said the unit could be mounted laying down as long as there was good ventilation (I'd need to sort out something for that). As such, it could potentially be located up front near the existing batteries, but they do say in the install instructions to avoid putting it above (or near?) the batteries. I could try to get LiFePO4 batteries that would fit in the existing spot too.

It would be nice to get the battery weight off the tongue but I fear the front might end up being TOO light with all that weight gone and put behind the rear axle. If weight were not an issue, I'd love to bury them in cabinets along the street side of the trailer... but it seems out of the question to load up that heavy on one side.

As for why I went with Victron -- the main thing is that they have a lot of other equipment that integrates together nicely. I'm switching to their solar charge controller and also installing a battery monitor. The whole thing is controlled by a REALLY beautiful mini-linux computer with a color touch screen and data gets logged to a website for you. They are giving me the linux login so I can muck around and hack the system too so that is a huge plus.

As for that thread on cruisers forum -- I have indeed seen it and the next to last post there is mine (asking if the OP had any update). Most of what I've read on victron is highly positive but I did find that thread right after ordering all my equipment so it got me nervous!

[CA_Tallguy]

PPS -- the other reason I got the Victron is that I found a new-old-stock unit on eBay a few weeks ago and snagged it at a DEEP discount. I had pretty much decided on Victron anyway and just randomly thought I'd check ebay and there it was so I decided to jump on it.

[CA_Tallguy]

Here's a video of the control panel for the system. They can't keep these things in stock.... mine is back ordered a few weeks.

https://www.youtube.com/watch?v=p5haxiVUXi0

[CA_Tallguy]

Although I posted the control panel for the "neat" factor, there is a lot going on in that video so maybe I should add some commentary. It appears that the setup is actually grid tied there, so when there is extra solar generation and the batteries are full, they are feeding power back into the grid. Of course, my unit won't be setup for grid-tie. Then it looks like they take power consumption over solar output so they supplement from battery power for a few seconds. When load drops, they top off the battery and then start feeding to the grid again.

The integration is what I really love about the system, especially with the solar controller telling the rest of the system exactly what it is doing and what is available.

[CA_Tallguy]

Some of the first accessories I purchased to install with the Victron inverter/charger have arrived today, including the BMV-702 battery monitor. The designer over in the Netherlands was pretty clever when coming up with the shunt for the system. It has a little circuit board on it to calculate the passing amps along with inputs for voltage sensors. Then, the board transmits the data to the main control unit and display via a UTP (think telephone type) cable. This makes for a very clean install.



Above image was borrowed from a fellow going by the name Maine Sail on the boating forums. He is EXTREMELY knowledgeable about a lot of things, especially electrical for boaters but that also applies to RV'ers.

Rather than detail the install myself, I'll just link over to his very thorough and detailed install of a similar unit...

Installing A Battery Monitor Photo Gallery by Compass Marine How To at pbase.com

Along with the link from the shunt and battery sensors, there will be a link between the head unit and the computer control/touchscreen. Same thing for the solar controller.

My goal is to be a lot smarter about charging and power consumption than I am now. For example, my solar panels currently sit idle a lot of the time, especially when hooked up to shore power. I'd rather use the solar energy first and then shore power as needed to augment it. Another area is my high current charging setup from my truck alternator. That system seems to always want to charge and repeat the whole charging cycle. With the victron stuff, I believe I'll be able to setup a "not OK to charge" disconnect relay to disallow that when it isn't needed.

The extra precision and control will be a lot more important when I upgrade to LiFePO4 batteries in the near future. You don't want to be willy-nilly about what you do with those.

EDIT: just found an installation video for the BMV-600 series which is pretty similar to the BMV-702 I have. Not sure but I think the 700 series may just be the current model replacing the 600 series. The main feature added in the 702 is "midpoint voltage monitoring" so if you have batteries in series it apparently can help make sure you catch one that is going bad.

https://www.youtube.com/watch?v=JO8AGV4Z7K0

[Brav]

Any update on this system?