I would like to use PowerAssist to supplement our shore power with a bit of inverter power on occasion, but it appears there’s no way to program the Multiplus to drop down to charger-only (or disable PowerAssist) when grid power is lost?
So if there’s a power outage and I’m not at the boat, it will try to invert all of our AC appliances, which will either deplete our batteries or put the inverter into overload since it will exceed its capacity (Multiplus 2k on 30a 120v shore power). This is obviously not ideal. So I would need to remember to switch the Multiplus back to charger-only (instead of “On”) every time we leave the boat. Since we liveaboard, that inconvenience would exceed the small convenience that PowerAssist provides.
Is there really no way to program Multiplus to change its state when grid power is lost? It already knows when grid is lost (I have it set to notify on this). I don’t see any Assistants that allow me to accomplish this though.
one simple way to do this would be to use an AC relay with the coil powered through the shore power. The contacts (N.O.) can then be used to interrupt the remote control loop of the inverter. You would also need a bypass switch to enable the inverter when shore power is intentionally disconnected.
Thanks, I will look into Node Red. There are guides and YouTube videos on it but looks like it will not be trivial to setup quickly. I was hoping Victron would just have a flag for setting this. As is, it seems like PowerAssist is a great idea that is hampered in my case from Victron omitting like 2 lines of code.
Ex:
grid.onDisconnect( () => { if( userPref.powerAssistOnlyWithGrid) multiplus.state = Charger-Only; })
@Ludo Yes, technically that is true power assist is only active with grid by definition, since it augments grid power. I should’ve titled my post “How to drop to charger-only when grid power is lost.”
The Multiplus has 3 active states: Charger-Only (charge and pass-thru AC), Inverter-only, and On (charge + pass-thru + inverter). The main difference between Charger-Only and On is that On has the ability to invert as well. For my use case, the only purpose to On is to augment shore power (PowerAssist). I realize that others may have other use cases for it perhaps.
I just find it weird that they designed it this way. “On” works well for the UPS (uninterruptible power supply) use case where you want to keep a small AC appliance load running through grid failures, but not for the PowerAssist use case, where you want to use a small Multiplus (2kva) to occasionally run a bit more AC than your grid can support.
The parameters of a 2kva Multiplus (120v/30a) aren’t capable of inverting more than their AC input, so by definition PowerAssist cannot function without grid, and the inverter cannot invert the amount of AC amps you’d be using when taking advantage of PowerAssist. So that’s why I think it’d be better if they had just made it by default drop to charger-only (or make it selectable for those who really prefer UPS use case but also have PowerAssist enabled for some reason).
@MikeD I think you’re suggesting using the programmable relay? Not sure how that would work (I thought those relays are for < 12v, not 120v). But anyway I cannot do that because I’m already using the programmable relay to program the Multiplus to have an absorption charge duration of 2 minutes rather than 1 hour minimum, since my lithium batteries specify not having so long of an absorption charge.
All my aux ports are basically used up since the 2kva Multiplus doesn’t have an Aux 1 and 2, so I am using the TSense and programmable relay (NO and COM) to fix the charge profile.
The Multiplus 2000va doesn’t have an AC Out 2. That is a good idea though if I had bought 3000va. However even then I probably wouldn’t go to all the trouble of wiring in dedicated shore-power-only outlets for our boat. Running extra AC wires on a boat is no easy matter, given the somewhat inaccessible conduits they need to be run through, and I’d need a distribution point to split 30a into two 15a outlets with circuit breakers (since we do use almost all the 30a on non-critical / shore-only loads). It also limits where you can place your appliances on the boat then. (Currently we have 7 AC outlets on a 43’ sailboat, and appliances get rotated through almost all of them, based on where they’re needed).
That’s a lot of wiring work just to occasionally use PowerAssist. I was basically hoping there was a simple programmatic change or flag that could enable us to use “On” more without worrying about overload during grid interruptions. Sounds like there is no simple switch for that.
Without rewiring or adding anything, you will have to switch to node red.
It will be the only way to detect when shore is lost/regained and change states.
Additionally (or alternatively) he could set the low voltage cut-off very high.
That way the inverter would switch off quickly after disconnecting the grid.
Just use non essential loads on ac input and critical loads on ac output that way when AC in fails only the essential loads would available , appreciate this requires another consumer unit
Or as suggested use the AC out 2 and program the relay for what ever condition you want SOC, Load, Volts etc I using VE config
I used that for the immersion control based on SOC
Or change or add another inverter and increase battery size if still require all those loads
