From My Design to My Installation: New AC Power System

[s/v Jedi]

Today, I experimented with the virtual switch in the Victron Quattro unit. This is a programmable software switch, that can change settings within the unit, or it can drive a relay.

We are in a marina with shore power and have a small 8kBTU window A/C unit going 24/7. That A/C unit draws 8A at 120V which is a big load, so I moved it to a separate shore power connection for these tests, making it much like when at anchor or sailing.

I attached 4 images, and will describe what's happening for each one:

1. This is the main Virtual Switch tab where you choose the usage of this function. The Quattro actually has two virtual switches, but I am only using one for now ;-) I choose to use it for ignoring AC input (or not).
   Confusing is that "Invert virtual switch usage" setting. You have to write it down to prevent mistakes. When I activate the virtual switch, I ignore incoming DC so I "disconnect" shorepower. You could turn that around by setting this "invert flag".
   On the left you see typical values during 99% of the time with my programming active: There is 257V incoming AC available but it isn't used (IMains = 0.0A). The voltage is high because there's no load and it's coming from the isolation transformer. AC output is 240V at 1A so it is in inverter-mode. DC voltage is 13V and it is drawing 21A from that. This means it is consuming 13x21=273W and delivering 1x240=240W. There is 33W overhead/loss which translates in 88% efficiency, a normal value for a 12V DC inverter at 8% utilization.
   Last but not least: the "Ignore AC" is "1" so active. This is the reason that the unit is using it's inverter instead of the available shore power. But the battery voltage is high at 13V because all of the 21A used is coming from the solar array (it is delivering more, which is used for charging the batteries).
   Think about this: 100% of solar power is used. First, all AC loads are powered from it without using the batteries, so maximum efficiency. The rest of the solar power is used to charge the batteries. This is the very best thing that can be done with the power from the solar array!
2. Here I configured when the virtual switch must be activated. I choose to do so if the AC load is higher than 750W for 3 seconds or when battery voltage drops under 11.75V or if any of the pre-alarms are active. You can even activate the switch when the fan is running for x seconds. Nice, nice.
3. Here you define when the virtual switch must be de-activated. I did the simplest config: de-activate 1 minute after bulk-charge phase is finished. Look at all the other options available!!
4. Here's some additional options. The only thing I used is a 1-minute minimum on-time of the virtual switch, solving possible problems when the settings in step 3 lack a hysteresis. I don't need it now because there's a 1 minute delay in step 3 already, but it doesn't hurt either. But look at the other option... you can change the output frequency of the inverter with the virtual switch (50/60Hz) !!!
   Also, just for fun and demonstartion, I switched the water heater on, so load increased from 1.0 to 4.1A This is a 1kW load so well over the 750W I defined in step 2, so 3 seconds later the virtual switch was activated and the "Ignore AC" value is now "0". So, the unit switched to the incoming AC and switched it's inverter off-line. It is now drawing 11.0A at 247V (still pretty high huh!) of which 4.1A is sent to the boat (3.1A used by water heater) and the rest for charging the batteries. The DC output is 103A at 13.6V.
   A couple minutes later the charger switched to absorption mode and 1 minute later, shore power was cut off again and it resumed in inverter mode. Wow!

There are many combinations possible, plus there's two of these switches that can be used in certain combinations, plus a relay that can be driven with it. The relay contacts are available as terminal positions on the Quattro unit (relay is inside the unit). You can even make a program like mine above and add automatic genset starting stopping using the 2nd virtual switch coupled to the relay contacts. The only wish I could come up with is to be able to control the powerAssist function and charger output-current too, so I emailed a request for that additional feature to Victron ;-)

I don't know of any other brand offering all this. I do know the next step: running your own programs/scripts on the Quattro's CPU... I might even try to hack it so I can do that ;-)

On to more discoveries with the new system!

ciao!
Nick.

[cat man do]

Thanks for the thread Nick , real electricity is something I'll need and its always been a mystery.
Unfortunately all the books that I have on the subject make my eyes glaze over.

What do you think of something like this ENERGO-TEC ?

I already have cummins B3.3 65hp X 2 so don't want an additional diesel generator, but thought the energo-tec may be the go for rapid charging of the banks and occasional heavy load 240v.

Dave

[s/v Jedi]

Dave,

When you mount that on your engine, you have a genset. They say this is new but I saw it on yachts 20 years ago and it works well. Just feed the output to an inverter/charger and you're good to go!

You could mount one on each engine so you can alternate between the two. But look at the picture when you are running on both engines. If you go this way, I would replace both standard alternators with 220V ones and buy two Victron MultiPlus units (each half the capacity you need, so smaller units) and connect them in parallel. Now you can run any engine configuration and you have back-up. The multiplus will charge your batteries instead of the standard alternator.
The smallest they have is 1200W inverter + 50A charger. When you run both engines you can charge with 100A and you always have 2400W inverter power available. If you need more charging current, you can go up to units with 70A, 80A or 120A each and double that when both engines run. This will bring the inverter part to something bigger than you need but that is the price of a big battery bank. If you want to charge with one engine running, the smallest 50A unit is good for max. 500Ah battery bank. Select the charger to supply between 10% and 20% of total Ah capacity.

ciao!
Nick.

[Christian Van H]

Nick, thats amazing! The amount of control this system offers is off the charts. Please post pics of the actual installation when time allows. Thanks, Chris

[bobfnbw]

Nice setup nick. Nice to have the space for all that I bet.

Question...
I wanted to use a victron inverter charger, the phoenix 12v/3000w/120 amp
But my shore power connection is 120/240v at 50 amps, or will be once its installed. The phoenix only inputs 120v. Does that mean I need to split the line voltage at the distribution box first then power the other circuits via the inverter to a different distribution ? How does one intergrate a 120/240 circuit into a 120v inverter ? The install manual at the victron site is unclear on that.


Bob

[s/v Jedi]

Originally Posted by bobfnbw

Nice setup nick. Nice to have the space for all that I bet.

Question...
I wanted to use a victron inverter charger, the phoenix 12v/3000w/120 amp
But my shore power connection is 120/240v at 50 amps, or will be once its installed. The phoenix only inputs 120v. Does that mean I need to split the line voltage at the distribution box first then power the other circuits via the inverter to a different distribution ? How does one intergrate a 120/240 circuit into a 120v inverter ? The install manual at the victron site is unclear on that.


Bob

Bob,

If you look back in this thread, you see how I did it. I used 240V versions of the Victron units, instead of 120V. After that, you can use a auto transformer to create the two 120V legs again.

The only other way to do it is by using two 120V units, one for each leg. The two units are configured and synchronized to do that. The big disadvantage is that you never get the full use of available power because it must be balanced over the two legs. An example:

You have two 120V 3000W multi-plus units bridged for 120/240V service. In inverter mode, you can load each leg up to a maximum of 3000W, even if the other leg has room. So, if both legs are at 2000W, you can't switch on a 120V 1500W device because that would bring one leg to 3500W. You can't use the 1000W left at the other leg.

With my system, you don't have that problem, plus you only need one inverter/charger if that provides enough capacity. But you need to order the EU version (230V/50Hz). In the configuration you can change that to 240V 60Hz. You finish the install with the $400 or so auto transformer and you can use all power on any leg. The auto transformer can take a maximum of 32A in-balance, like 10A on L1 and 42A on L2. On the 240V side, you just have 26A at 240V in that case because there's no neutral there.

cheers,
Nick.

[lorenzo b]

s/v Jedi
So did you load your genset 75% for 50 hrs or 100 hrs?
I'm doing mine for the full 100 but now that I'm done with that, is it OK to load it lightly from now on? I've got a 20k.
Thanx