I want to be able to charge from 240 generator but have two multis in parallel for 4000k output. if in charger only mode will the problem of the parallel output be removed.
asked
Can 2 multiplus 2k be in parallel and accept 240 if in charger only mode?
You did not say what voltage your Multiplus operate at. If they are the 120 volt versions then no you can not connect 240 volts to them regardless of mode.
Two 120 volt Multis in parallel would need 120 volts. You could step down the generator using a transformer.
Two 120 volt Multis in split-phase could accept 240 volts again by using a transformer to create two legs with a neutral from the center tap of the transformer. The legs would be 180 degrees out of phase. But you'd need your loads to be split phase also.
Switching between parallel and split phase requires reprogramming the Multis as well as rewiring all the AC inputs and outputs.
Thank you Kevin. The generator has two 120 hot legs, one to each multiplus which are 120 volt. I believe they would be fine if programed for series but I would prefer to have access to 4000 watts. I believe I also could run them both as stand alone. But what I want is that 4000 watt capability mostly so neither 2000 watt unit has to handle an 1800 load. So my original ask is whether while in parallel with units set to charger only, if the output side where the two hots are united will not cause an out of phase shutdown of the charging cycle.
Even in charger only mode, the AC output is active. Plus, in parallel mode all wiring has to be identical length for proper load sharing. If you separated the AC input wiring and fed a split phase source from your generator, the input would most likely be rejected, or even worse the out of phase hot legs would be connected together.
Your best approach would be to transform the generator output to 120 volts and feed that to the paralleled Multis
Hi Kevin
still trying to get some satisfaction from my pair of mulitplus 24 v 2000 w’s.
tried setting up in stand alone and connectEd the two hots from the 240 generator, one to each with a shared neutral, hoping to charge from my 12k Kohler generator. Still can only get one to go on at a time, one loads, as soon as other is ready they both click off. Charging ac in 15 amps, charging dc 40 amps.
seems like light load on generator but Kohler rep says it doesn’t have the umph, talked about kva32 max on generator. Thoughts?
You can't run two Multis in standalone mode with their outputs connected together. The two must run in phase for parallel operation and standalone mode won't sync their output phases.
You also can't run different sources into two Multis operated in parallel. They must have identical inputs (voltage, frequency, phase). You even need equal length cables (AC in, AC out, DC) in order for them to load share properly.
I guess I should have added that the ac outputs of the inverters are not combined, they feed different hot legs on my main panel. Inverters do feed in common the dc output to my battery bank. Is phase an issue on that end? I’m basically trying to determine if my generator has some sort of issue before I invest in an auto transformer or some other solution. Thanks for you continued support on this, I really appreciate it.
Then you can NOT run the Multis in parallel mode. They must run as totally independent units.
There may be an additional issue in that the Multi has a relay on the output that connects the safety ground to the neutral when inverting. This relay is open when connected to the grid. This maintains a single connection between safety ground and neutral for the system since that connection is made at the service entrance of the grid. Your generator should make that same connection. This is a safety issue.
The issue in your system is that you are tying the two neutrals at the output of the Multis together to feed your load distribution. This could be confusing the logic and testing around the ground relays inside the Multis. You can test that theory by disconnecting the AC output wiring (hot and neutral) from the Multis.
