If a multiplus-ii 12v 3000 is connected to shore power with L1on a 15 amp and L2 on a 30 amp will it boost and if so how? I have a power dongle that has a 15amp and a 30 amp with them split between L1 and L2. It's not enough to run both ACs which are on separate circuits. Can the multiplus work with this arrangement?
Multis configured for multi-phase input use the same AC current limit for all legs. The legs must also be 180 or 120 degrees apart (not in phase).
If you are talking about the 120X2 model then this is different. The inverter is only in the L1 path. The L2 path is pass through with no assist. Again, the two legs must not be in phase or L2 is rejected. When the grid is absent, L1 and L2 are both connected in phase to the inverter output.
Your power adapter is unsafe. You should never be connecting neutrals from separate sources together. You would never be sure the neutrals are from the same source or at the same voltage and connecting them together will cause currents to flow in the neutral. Any current imbalance could overload one of the neutral wires. If you happen to plug into a GFCI outlet, it will trip.
The best hope of running multiple RV air conditioners on a single 30 amp circuit is to use soft starts on both of them. But keep in mind, a 3000 VA Multi will output at most 2400 watts (20 amps) at 25 degrees C. IIRC, my one AC draw about 1300 watts so two would put you over and doesn't take in to consideration the startup surge.
Many people run a separate cord from the pedestal directly to the second air conditioner unit. This takes a bit of rewiring but it is really the best/safest way to run the two air conditioners with limited shore power.
Kevin,
Thank you for the great detailed response. So the 2400 Watts is in addition to the 30Amp 3600 watts (assuming we get 120Volts). And with that I can run both ACs. One AC pulls 1500W and the other 1750Watts, plus some other camper AC loads. Everything runs great on 30Amp shore power. Multiplus 2x120 is assisting. But if I try to use my 3000Watt Generator. The system fails. On the face of it, it would seem 3000 Watts plus the Multiplus 2400Watts would be enough. But the Gen bogs down on the second A/C start, and drops off, then the Multiplus follows and reboots. I have a soft start on one unit. On the second bigger start the off brand softstart didn't work so I removed it until I get a brand name one. Do I just need a bigger generator or is there a setting to help with the generator lag?
There are a couple soft start units I'd trust. The one I use is the MicroAir. Another carries the name SoftStartRV. Besides soft starters, there are "hard start" kits that add an additional starter capacitor to the unit. These do little to reduce the inrush current.
Hi Kevin,
As I finally got a moment I enabled the dynamic current limit. I also slightly increased the Power Assist by .2 (do you have an opinion on that? Sometimes I'm on the gen and sometimes a 30 or 50 amp shore power). I've got a MicroAir easy start on order. I had tried two offbrand ones. On the smaller A/C it seems to work. But on the 15,000 BTU unit it would not start. I saw the MicroAir starts the compressor in four increasing steps. Maybe that's a difference from the Chinese copy. I'll find out Sunday hopefully. Thanks again
