https://www.victronenergy.com/upload/documents/7-PHOENIX-MULTI--2-AC-INPUT.pdf
I noticed this schematic, but couldn’t find any documentation as to how is would behave in this configuration.
at the moment I just have both feeds into a changeover switch. I’m wondering how it would then differentiate between the two power sources does the one to the slave become ac input 2 on the CCGX?
could someone point me in the right direction if there’s some documentation I have missed!
Thanks
If I went to this I would likely just remove the jumpers from the back of the changeover switch I have already so I would never have both sources connected at the same time, just switching one source to the master and a second to the slave.
Although the schematic seems to suggest that’s fine!? Not something I thought you could do. Hence my question!
The other question with it is how does the battery charging function behave in this configuration. If your only using one ac input to one inverter does that reduce your charging current but retain the inverter capacity for power assist from both?
This schematic is quiet old. it is from before the time we had the Quattro.
In the schematic, one AC source is connected to Multi 1 and the other to Multi 2. They then are set up as a "special" parallel pair with using VE.Bus System Configurator software. As soon as one of the AC in sources is active it will be used for charging and feed through. But, there is one downside to this, when in charger mode, only one of the charge sources can be used. So only one of the Multis is charging or transferring AC. you will loose the capacity of the other Multi. But when inverting mode both Multis work together in parallel.
A better solution is to use an external transfer switch. this way both units are used during charging and inverting.
Or use a Quattro, it already has a build in transfer mechanism :-)
Hi,
Thanks @Margreet Leeftink (Victron Energy Staff) for your reply.
I assume the 'special setting' pictured below (Appreciate there are more steps to it) is the one you are talking about.
Would the colour control GX then realise there is two AC's and then tell you which one you are connected to? Or is that purely reserved for Quattro?
The charging actually isn't much of an issue for us as the multi's are set to 75% circa 100 amp between them; now anyway so 70amps from one won't be a problem since the alternators on the main engines will top up the difference most of the time anyway and the soon to be fitted MPPT as well. Indeed we are likely to run with the generator off quite a bit. The reason we have two 3000's is to supply our UPS load if we lose the generator (max UPS loads of around 4000watt) but at a higher temperature (thinking of those hot summer days) with a bit of redundancy to boot.
I presume we would retain the power assist feature from both multi's where the existing Gen is 7.2kva and so we get around 11kva theoretically in the current config.
I have to make the system really foolproof and therefore someone looking at a CCGX display that's telling them the powers coming from the shore when it's actually coming from the gen could cause confusion down the line. It's also why I'm not too fussed about huge charge rates.
It's all fitted on a 12m Commercial Power Catamaran, outfitted in all Victron gear, products which we really believe in and feel we can trust.
Ok, so I have run the system up today. All works!
Apart from when the second AC input is energised and the ac1 is off I was expecting to CCGX to display this, instead the red box just goes blank.
The multi control panel displays the power as coming from AC2.
is this a feature or is there some configuration setting I’m missing?
Thanks.
Relay is set to generator but I haven’t yet got that wired up
Unfortunately a GX device cannot show the incoming current correctly with such a setup, due to the way the VE.bus protocol works.
Why have you not used a Quattro for this?
@Daniël Boekel (Victron Energy Staff) i am wondering if there is a workaround for this at all, like using a grid meter or current sensor?
No, unfortunately that is not possible. scaling is not configurable and adding grid meter will create other discrepancies.
I'd just use a changeover switch in front of the units and set them up in 'normal' parallel mode.
@Daniël Boekel (Victron Energy Staff) thanks for the swift reply. My fears confirmed.
My issue with running in a normal parallel is that I'm having to use one multi with the LOM disabled (Due to issues with the multi and the generator not playing nicely,) It's Running perfectly now I switched to LOM disabled.
As it's on a boat, I'm having to use the other as the shore power so have to have LOM on for obvious reasons so having the two multis worked out pretty well (Not as well as buying a Quattro in the first place but ok)
I can't switch grid codes with an assistant, can I? Hence I'm looking at anti-islanding protection devices now...
If I do that there's still no way of telling what source the powers coming from, (unless there is?) so I'm no closer to my goal (Except that I would have a bigger battery charger I guess.
Other than this, the system works really well, onboard. Our survey gear and domestics systems all run off the multi's using DC power from the alternators the majority of the time. The AC Genny is just there to top it up when the system demands on auto start, which works great, saves us lots in emissions, fuel and maintenance. My hope is, once we supplement it with 1kw of solar and a bigger DC alternator running the generator will become a thing of the past most of the time.
Hi @Jwfrary
Are you allowed to feed-in to the grid from a boat? That's not allowed here on a 'plugged' connection.
@Daniël Boekel (Victron Energy Staff) no we are not allowed, and we wouldn’t want to which is why I have the generator multi with lom disabled and the shorepower one with it enabled in the normal way. Hence I have this strange setup. Compromise being the available charging current but that’s not a massive issue for us.
As I see it I’m really stuck where I am, which is ok. It’s safe working well, just a little frustrating on shorepower when the ccgx is saying unknown and the multi control panel displays the right info yet both are reading from the same source. Ve.bus. I guess the mechanism that feeds each is different?
Hi @Jwfrary
then why are you using a grid code? that is only needed when you want to feed-in / use ESS.
just select grid code 'none' and you don't have to disable LOM
@Daniël Boekel (Victron Energy Staff) Ok, I understand what your saying. The units arrive in the setting None. and this is the setting I was using, But I was still getting power back feeding to the generator and subsequently a fault overload and negative numbers on the GX device when it was faulting. so now I am using 'other' and LOM is disabled. which has cured the problem.
But you're saying they are the same thing?
hi @Jwfrary
the units cannot feed back to the generator without a grid code. the only possibility for that is when you have an AC PV inverter on the output.
it was probably due to the unsupported setup that a negative value was reported.
quote:
'But you're saying they are the same thing? '
what do you mean by that? I'm saying 'don't use a grid code'
@Daniël Boekel (Victron Energy Staff)
I mean,
You're saying that LOM is also disabled in the setting 'None'?
Yes, LOM detection is only active when a grid code is selected.
@Daniël Boekel (Victron Energy Staff) Thanks for clearing that up.
Is there any other behavior change between the two settings?
As I thought I understood, on a plugged install with the setting 'none' the multi would open the back feed relay on unplugging?
But in the setting I am in as in other with LOM off the back feed relay remains closed. Obviously not good on a plugged install!
