question

Nicholas Wessels avatar image
Nicholas Wessels asked

Enabling Multi AC output 2 during grid outage

We have our system setup and have been using ESS for years now. We have critical loads on AC output 1 and non-critical loads on AC output 2 so that critical loads continue to receive power during grid outages. Today for example we have a scheduled power outage for the whole day.

We have more than sufficient PV/battery power (over 2500w) now to also power the AC output 2 loads (around 1200w).

Is there a way to manually enable AC output 2 during such times? If not this might be a nice feature to add to the ESS settings on the CCGX.


This is what is currently being used without anything on AC output 2:



I have manually plugged in a few items into the AC output 1 circuit to show what is actually available on PV:

Multiplus-IIESS
victron-nick.png (49.5 KiB)
victron2.png (48.5 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
nigelfxs avatar image
nigelfxs answered ·

Update: since about a year now, all Multiplus II models -do- have a relay controlled AC2-output, and can be controlled just like all other models with a dual AC output.

old text:

This is not possible on the Multiplus II since the AC-Out2 is internally connected to AC-In. Connecting power to AC-Out2 (and hence AC-In) would be dangerous since this would feed power back into the grid during the outage.

A possible solution would be to install a change-over switch so that non-essential loads can be connected to the backup when needed.

11 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Nicholas Wessels avatar image Nicholas Wessels commented ·

Thank you. Let me chat to my Victron installer and see what he can come up with.

0 Likes 0 ·
nbezanson avatar image nbezanson commented ·

Is the situation different on the Quattro? The block diagram for that unit suggests that AC-out-2 has a separate relay and could be software controlled in the desired way. (I don't believe there's currently an assistant for that, but maybe there could be...)

0 Likes 0 ·
mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ nbezanson commented ·

the MultiPlus and the Quattro have indeed a software controllable relay that can enable ACout2 even when in inverter mode.


The MultiPlus-II has no relay; ACout2 is hardwired onto the input.

0 Likes 0 ·
byrons avatar image byrons mvader (Victron Energy) ♦♦ commented ·

So will programming the ACout 2 relay with say the programmable relay assistant override it switching off with mains failure ?

0 Likes 0 ·
geomz avatar image geomz mvader (Victron Energy) ♦♦ commented ·

I'm curious about this too. Can an assistant be triggered (physically or logically) to enable AC2-out on a Quattro -with mains failure?

0 Likes 0 ·
boekel avatar image boekel ♦ geomz commented ·

Yes very easy, and you can even use it to disconnect the ACout-2 when battery get's lower than a set voltage / SOC.

Just use the 'configurable relay' assistant, like in this example:

0 Likes 0 ·
screenshot-2019-03-22-132935.png (22.0 KiB)
geomz avatar image geomz boekel ♦ commented ·

Awesome! Thanks @Boekel!

Wish I'd known that before crimping Feed 1 and 2 together <face palm> :)

Might have to just undo that and move "non-essential" loads back to AC2.

I don't really "have" to do it, but in that CYA mode where we lost mains and the heavy loads are still happily sucking the batteries down to 0 :D

0 Likes 0 ·
dylan avatar image dylan boekel ♦ commented ·

Hi I tried this setting, but it sheds ac-2 out even if there is grid power available. Is there a way to set a setting to shed ac-2 at a set SOC only when no grid is available?

0 Likes 0 ·
Warwick Bruce Chapman avatar image Warwick Bruce Chapman dylan commented ·

@Daniël Boekel (Victron Energy Staff) is there an answer to this?

0 Likes 0 ·
Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ Warwick Bruce Chapman commented ·

Hi @Dylan @warwick

Easiest to use for this: the generator start/stop assistant, you can use more options easily with this, like us AC input present as another variable.

0 Likes 0 ·
guydusautoy avatar image guydusautoy Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

I want to use generator stop start assistant to control the AC2out relay as mentioned above.

Should I put the "generator start stop" assistant before or after ESS?

0 Likes 0 ·
Martyn Duerden avatar image
Martyn Duerden answered ·

Pahaps a contactor, 2 NO & 2 NC Coil on mains...

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

geomz avatar image
geomz answered ·

What I did was crimp the wire-panel lead for AC1 and AC2 onto the same lug and attached that to AC1-out. Probably not ideal, but works and a quick win. My (old) system was setup with a similar "crucial" "non-crucial" config and the new system rendered that obsolete.

Makes for a thick wire-lug, but should be electrically safe as long as you have appropriate wiring and output rating limits.


2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.