How reliable is the Multiplus II?

[Overtaxed]

I'm considering installing a MultiPlus II 2X120 into my RV however, I'm concerned that as all the power goes from the transfer switch to the MP-II then to the rig, a failure of that device means "game over" for power. Even more concerning since we travel with pets and no power means no AC, and potentially dangerous conditions for them if we're away from the RV.

Anyone have one and some experience to report? "Had a Victron inline for years, never had it cut power" is what I want to hear; but, please, good, bad, otherwise, very interested if you've found Victron inverter/chargers to be reliable.

[A.Texas.Yankee]

I'm considering installing a MultiPlus II 2X120 into my RV however, I'm concerned that as all the power goes from the transfer switch to the MP-II then to the rig, a failure of that device means "game over" for power. Even more concerning since we travel with pets and no power means no AC, and potentially dangerous conditions for them if we're away from the RV.

Anyone have one and some experience to report? "Had a Victron inline for years, never had it cut power" is what I want to hear; but, please, good, bad, otherwise, very interested if you've found Victron inverter/chargers to be reliable.

Have there been failures? Sure. But you rarely hear about them, and often enough, those failures are user or installer error. I wouldn't hesitate for a moment to install them. It's always good to have redundancy, though. I did have a generator, solar backup battery, and the indepth knowledge of the system to troubleshoot and repair it of needed.

[Overtaxed]

Have there been failures? Sure. But you rarely hear about them, and often enough, those failures are user or installer error. I wouldn't hesitate for a moment to install them. It's always good to have redundancy, though. I did have a generator, solar backup battery, and the indepth knowledge of the system to troubleshoot and repair it of needed.

I think they make very good products, it's not a knock on Victron, it's a hesitation putting anything that sophisticated in line between the shore power inlet and the RV. Just seems a lot of things that can go wrong that wind up with "no power" situations in the RV, which, of course, is exactly what I'm trying to avoid.

I'm thinking of reversing the wiring order, instead

1) Shore power - transfer switch - Victron - Coach
go
2) Shore power - Victron - transfer switch - coach

The advantage here is that my generator autostart monitors the "shore" line already on the transfer switch. If the Victron went out, it would appear that shore power was dropped, the generator would start and then power would be restored. This moves the single point of failure to the transfer switch instead of the Victron, not sure which is more reliable, but transfer switches are dead simple, so a lot less room for user/configuration error. I have no need for PowerAssist on my generator line, it's a 7K generator, more than enough to power anything we need in the RV. The only issue with this configuration; if the generator is running and there's no shore power, the batteries won't be charged by the Victron (there won't be any power to the inlet side of the Victron). But with solar, I don't see that as a showstopper.

What do you think, crazy to move the SPOF to a 200 dollar transfer switch instead of a 2000 dollar Victron? Or good idea?

[A.Texas.Yankee]

I think they make very good products, it's not a knock on Victron, it's a hesitation putting anything that sophisticated in line between the shore power inlet and the RV. Just seems a lot of things that can go wrong that wind up with "no power" situations in the RV, which, of course, is exactly what I'm trying to avoid.

I'm thinking of reversing the wiring order, instead

1) Shore power - transfer switch - Victron - Coach
go
2) Shore power - Victron - transfer switch - coach

The advantage here is that my generator autostart monitors the "shore" line already on the transfer switch. If the Victron went out, it would appear that shore power was dropped, the generator would start and then power would be restored. This moves the single point of failure to the transfer switch instead of the Victron, not sure which is more reliable, but transfer switches are dead simple, so a lot less room for user/configuration error. I have no need for PowerAssist on my generator line, it's a 7K generator, more than enough to power anything we need in the RV. The only issue with this configuration; if the generator is running and there's no shore power, the batteries won't be charged by the Victron (there won't be any power to the inlet side of the Victron). But with solar, I don't see that as a showstopper.

What do you think, crazy to move the SPOF to a 200 dollar transfer switch instead of a 2000 dollar Victron? Or good idea?

I have seen more transfer switches freeze up than victron units fail. That being said, I like redundancy, but even I think it's a bit overkil to go your route. You could run two lines from the transfer switch with a manual transfer switch that would bypass the inverter in case of failure.

People worldwide rely on Victron products for livelihood and off grid living. I did for over 15k miles, never a hiccup I didn't cause.

[Overtaxed]

I have seen more transfer switches freeze up than victron units fail. That being said, I like redundancy, but even I think it's a bit overkil to go your route. You could run two lines from the transfer switch with a manual transfer switch that would bypass the inverter in case of failure.

People worldwide rely on Victron products for livelihood and off grid living. I did for over 15k miles, never a hiccup I didn't cause.

Thanks, that's exactly the kind of intel I'm looking for. I'm just petrified of the rig losing power on a hot day, so doing everything I can to assure that doesn't happen. Never had a problem in my old rig, the autostart did kick on 2-3 times though when the park lost electric, so that was certainly a valuable modification, at least for me. The new unit from RV Automations is nicer than the one I had before, but still does the same thing, it's as dead simple as they come; if there's no power, start the generator. No temp monitoring, no battery sensors, no trying to figure out "do I need to start the generator", just DO IT. That's the kind of system I'm looking for when you're dealing with critical/life supporting equipment, don't try to determine if you can save a gallon of gas or if it's quiet hours, or 10 other criteria, if this, then that.

I think that's what scares me about having the Victron directly in line, it's so sophisticated. A forgotten adjustment to your PowerAssist setting, lights go out. Yes, entirely user error, but with so many settings and configuration options, it's easier to make those errors. I think I'm going to do it the standard way and just "build confidence" in the system over time. I really wish there was a way to wire 2 of them together in a failsafe configuration though; you can do it to increase inverting/charging capacity, but not so A will take over for B in the event that A fails.

[A.Texas.Yankee]

Thanks, that's exactly the kind of intel I'm looking for. I'm just petrified of the rig losing power on a hot day, so doing everything I can to assure that doesn't happen. Never had a problem in my old rig, the autostart did kick on 2-3 times though when the park lost electric, so that was certainly a valuable modification, at least for me. The new unit from RV Automations is nicer than the one I had before, but still does the same thing, it's as dead simple as they come; if there's no power, start the generator. No temp monitoring, no battery sensors, no trying to figure out "do I need to start the generator", just DO IT. That's the kind of system I'm looking for when you're dealing with critical/life supporting equipment, don't try to determine if you can save a gallon of gas or if it's quiet hours, or 10 other criteria, if this, then that.

I think that's what scares me about having the Victron directly in line, it's so sophisticated. A forgotten adjustment to your PowerAssist setting, lights go out. Yes, entirely user error, but with so many settings and configuration options, it's easier to make those errors. I think I'm going to do it the standard way and just "build confidence" in the system over time. I really wish there was a way to wire 2 of them together in a failsafe configuration though; you can do it to increase inverting/charging capacity, but not so A will take over for B in the event that A fails.

Unfortunately, there's no such thing as failsafe. For specifics, I was able to get up 11 days, off grid, straight (family of 3 at the time, running 2 ACs, electronics, microwave, etc.), burning through about 3-5 KW a day with 2k watts solar. I never once ran into an issue. My system was a lot of Victron (2 MPPT, 2 Lynx, various components like the Cerbo-GX and BMV, etc.).

I will say the ONLY time I ever ran into an issue was when I had the settings in my BMS wrong because I was playing around with SOC and forgot to change back to normal settings. I had the AC running while traveling. The batteries dropped below 10.4v (or maybe 10.6v, whatever the floor is for the inverter), and the inverter shutdown and went into protect mode. There is absolutely no way to override that safety setting even though the battery was not technically 0%. EVEN IF you hook up to 120v shore power or run the generator. It will ignore AC and not allow pass through of the AC input. The inverters rely on 12v only for that setting. Of course, it was at night when we arrived to our destination, so I had no solar. I had to "jump start" the unit from the truck (I now have a lithium junpstarter). So even this issue was operator error.

HTH.

[LMagelitz]

@Overtaxed
I think somewhere buried in the Victron documentation (can’t tell you where off the top of my head), they actually recommend a bypass be installed for times when you may want to take a unit out of service. Here is what I did:

Shore power to Prog Dynamics EMS to feeder panel.

Feeder panel to Quattros to WFCO transfer switch shore contacts.
Feeder panel to WFCO transfer switch genny contacts.

WFCO transfer switch out to coach panel.

I’ve been using the bypass pretty frequently. When I get back from a trip, and it will be several weeks before traveling again, I’ll run the lithium batts to about half charge, close the bypass breaker (in about 30 sec the transfer switch closes), which removes load from the inverters, and then I’ll turn them off.

When we get ready to travel again, I turn on the inverters and switch off the bypass breaker in the feeder panel. At that point they bring the batts back up to full charge, and pass thru power to the coach.

[Overtaxed]

@Overtaxed
I think somewhere buried in the Victron documentation (can’t tell you where off the top of my head), they actually recommend a bypass be installed for times when you may want to take a unit out of service. Here is what I did:

Shore power to Prog Dynamics EMS to feeder panel.

Feeder panel to Quattros to WFCO transfer switch shore contacts.
Feeder panel to WFCO transfer switch genny contacts.

WFCO transfer switch out to coach panel.

I’ve been using the bypass pretty frequently. When I get back from a trip, and it will be several weeks before traveling again, I’ll run the lithium batts to about half charge, close the bypass breaker (in about 30 sec the transfer switch closes), which removes load from the inverters, and then I’ll turn them off.

When we get ready to travel again, I turn on the inverters and switch off the bypass breaker in the feeder panel. At that point they bring the batts back up to full charge, and pass thru power to the coach.

Interesting. Because you have the Quattro, you can do this with a single transfer switch, I'd need to have two of them. This is kind of what I was thinking though, having a downstream transfer switch where I could monitor for "shore power" (which would be the output of the Multiplus" and, if not present, start the generator.


Shore power ---- Multiplus --- Transfer switch -- Coach
Generator ----^

Still thinking about options here, wish there was a way to get redundancy on a Multi or Quattro!

[LMagelitz]

Interesting. Because you have the Quattro, you can do this with a single transfer switch, I'd need to have two of them. This is kind of what I was thinking though, having a downstream transfer switch where I could monitor for "shore power" (which would be the output of the Multiplus" and, if not present, start the generator.


Shore power ---- Multiplus --- Transfer switch -- Coach
Generator ----^

Still thinking about options here, wish there was a way to get redundancy on a Multi or Quattro!

I didn’t set up the bypass I have for the purpose of being automatic, but I suppose it could be used that way. The shore contacts on the WFCO transfer switch pass thru with no contactor coil being energized. The contacts have to fail for it to go bad. The genny contacts on the other hand, only pass thru when a contactor coil is energized, so there is an additional point of failure. The genny contacts have priority (if they are energized).

If I leave my bypass breaker turned on, shore has priority. If shore goes out, it would transfer to the Quattros. So that arrangement is kind of what you want in reverse, I think.

Separate issue: my genny goes thru a second input on the Quattros, so I can charge the lithium batts. They will use over 6kw of the 8kw diesel genny pushing 120a to the two 48V server rack batteries! So I do have to use a current limit on the Quattros if I’m running the coach AND charging. Depending on what you have for batteries, you may run into this on what otherwise seems like more than enough genny power.

[Overtaxed]

Oh, I didn't realize the WFCO used a normally closed on the shore power line, I thought both were normally open and it energized the correct contactor.

I tend to think that if you have a normally closed contactor, it's very unlikely to fail except when moving between sources. If the switch is closed though (as it would be when shore power, or, as diagramed above, the Multiplus is online) seems like it would be a very, very unusual failure mode for that to stop passing power suddenly. If the MP fails, then the generator autostart would engage and the transfer switch would have to work (energize) to move the power source over to the generator. At that point, we're talking about cascading failures, the MP failed first, and then, at the same time, the transfer switch (or autostart/generator) failed.

I think that would be more reliable than going with shore power to the transfer switch then to the MP directly into the coach. Just seems there are a lot of things that could fail in a MP compared to a transfer switch.

The potential issue (or benefit, depending on your perspective) is that there would be no way for the generator to charge the batteries. If your on generator, you're "beyond" the MP already, it won't be able to use anything other than shore power to charge the batteries. That would be a problem for some applications, a benefit for others (as you described, the MP can pull a LOT of power and easily overload a small generator). Our rig has a 7K Onan and your Quattros can charge much faster than a MP, so it would be workable either way, but I think I prefer the configuration we're talking about here with the MP and the generator as the 2 inputs to the transfer switch with the transfer switch directly connected to the coach.