My new Multiplus II 2x120v rejects the single phase 120v from my newly rebuilt 9kw Westerbeke and refuses to pass it through or charge, but it successfully accepts the split phase 240v from my 50A shore power connection. I have a typical mid-size boat AC configuration, i.e. these inputs each hit a pair of breakers at the AC panel where I can select what feeds the Boat’s AC Panel. The single phase 120v Gen feed is currently bridged to L1 and L2, while the Shore power sends a separate inverted 120v feed to each side.
I CAN convert the Gen to 240v split phase, but it’s a PITA, and I want to confirm that I’m not just missing a Victron setting somewhere, and that changing the Gen to 240v is 1: the best solution, and 2: will actually solve my problem. Any insight or experience in this area would be really appreciated… Greg Page
Greg:
I’m not an expert, and can only ask dumb questions…
Have you used the Westerbeke with the MultiPlus II before the rebuild? Did it work then, has something changed?
I looked at the Generator training , (Victron Energy - Victron Professional) and the Westerbeke is one of the generators that was tested in their white paper, so in theory, you’re using a model/brand that is known to work.
My first thought is that the generator may not be producing power that is clean enough to meet Victron specs. There is a setting in MP2 that says “Accept Wide Input Power”, it increases the acceptable frequency range to 45-65 Hz. I’m very new to Victron units, but I had a similar problem on my home solar system and had to widen the input and voltage range in order to attach my rip-start generator to charge the batteries.
My suggestion would be to get someone with an Oscilloscope to look at the output power waveform of your newly rebuilt generator. That will tell you where the boundaries of the input parameters need to cover.
Second dumb question…could this be a under-load problem? When you connect the to the MP2, have you tried it with only some lights connected? I’m wondering if is something that under load the generator waveform goes wonky?
I’m out of ideas, hopefully someone else comes along with additional thoughts.
Good Luck
Thanks for the ideas. The Multiplus II is new to the system, and has never passed the Gen signal. But the Gen rebuild is not my issue, as we bench tested it under load before installing. Voltage and frequency are good. I’ll still try making the change to the settings you suggested. My primary question is whether the single phase 120v from the Gen is actually compatible with the multiplus II 2x120v, or if I must change over the Gen to 240v split phase.
Yes the 120v generator output will work fine with the 2x120. In this case the multi will simply ‘ignore’ L2 input, pass thru L1 input, and combine L1 and L2 outputs. This is precisely what the 2x120 was designed to do. As for the generator not being passed thru, have you tried enabling ‘weak AC’ in the multi’s configuration?
Unfortunately, it does not work fine, even with all the Multiplus settings as loose as possible. So today I changed over the Gen to a true 2 40v split phase, and tomorrow I’ll homerun a 2nd 6ga line from the Gen to the L2 side of the AC panel. Hopefully it will light up…
Barring a failure of the multi (although not impossible, it is unlikely) you most likely have an issue with the generator output, or somewhere in the wiring.
AAAHHHHHHH! MY GEN IS STILL Rejected by the Multiplus II 2x120 as an invalid AC source!
I now have a soild and stable 240v split phase reading verified from the gen at the Panel breakers, same as the 240v split phase shore power. These sets of breakers feed the Multiplus II, and then SHOULD pass AC through to the Electrical Panel. I have the “Weak AC” option selected, but the Gen is still rejected by the Multiplus, (flashing Mains LED) while the Shore power passes through just fine. I gave it at least 5 min to sync, but nothing passes through the Multiplus from the Gen WHAT AM I MISSING HERE?
You need to consider what’s happening in the generator when you instantly apply a load to it. There’s a few things here worth a look… MultiPlus Generator FAQ [Victron Energy]
The first thing I’d do is enable Dynamic Current Limiter, it winds up the load over a few seconds to give the gen time to react. A ‘soft start’.
Also, set a lower AC Input limit while you’re sorting it, you can raise it later.
Patience…
I now think the Multiplus II may have been damaged in the same Lightning near miss that forced the rebuild of my boat’s Generator. I had rejected this idea earlier since I run a split system, with the Starting and House electric as “disconnected” from each other as possible, and othing else on the “house” side was damaged, But last night I tested the inverter function of the Multiplus II. NOTHING. The fully charged Lithium bank that was driving the Multiplus inverter function before the Lighting Strike still works great for the 12v systems, but the inverter will not come on. So I think my 90 day old Multiplus II 2x120v is blowed up real good….