I have a ‘semi-grid’ situation where I bought an older house (1958) with a really old grid feed (25 kva grid transformer, shared with a neighbor) and my local grid energy provider has been unable to upgrade the service (been 18+ months…) We have heat pumps and electric stove and four EVs, so it’s been a challenge.
I addressed the challenge by adding a pair of Quatro 10 kva inverters for split phase with 5x 48V 100Ah batteries, then putting it into Power Assist mode. This is great because my grid power can easily provide ‘watt hours over time’, even when it can’t service my house’s peak demand.
The challenge I’m running into is that during peak demand house when my grid transformer is overwhelmed, I see voltage sag on AC-In-1, e.g. instead of 240V I see 230V or less. This is especially challenging because I have a second structure (workshop) which has a ‘parasitic’ feed from the house main panel which is 50 meters of 4 AWG aluminum wire, so there’s significant voltage drop between the house and the workshop. I’ve tried to combat this there by also installing a Quattro (in this case the 230V/15 kva model + autotransformer) put in power assist mode.
In both cases, the Quattros seem to ‘assist’ up to the voltage it sees on AC-In-1 instead of powering up to ‘nominal’ voltage without sag. Is there a different way I could configure my Quattros so they provide 240V AC-Out-1 even when AC-In-1 is 230V or less?
Unfortunately the units can’t modify incoming voltage. The only way for a unit to modify voltage on the output is when it’s inverting. If it’s accepting and passing-through AC voltage, power-assisting or not, its output voltage and frequency will be its input voltage and frequency.
There we have voltages go as low as 80V on AC-IN, average around 180V (should be 230v). What we have done as heatpumps were constantly in alarm mode. Went off-grid and connected DC rectifiers (Eltek FPS) to battery bank. Basically we use the bad AC to convert into 48V and feed the busbar. It works like magic!
Similar to @dansz ’s approach, can I turn off Power Assist, ‘convince’ my Quattros to use AC-In-Grid only for battery charging purposes, and then use inverter power only for AC-Out-1? Or will I have to ‘go all the way’ like @dansz did and use a separate battery charger from AC-In-Grid to the batteries?
For us Quattro’s can also charge but rarely or almost never happens as the network on all three phases needs to go above 181V for charging to start. To be honest I find this a let down from Victron, as they should allow in non-grid compliant scenarios or off-grid a wider range of input voltages. There is such a big market for this.
During the day we have a Fronius which harvests sun, and during cold nights the rectifiers take over to service the load.
Just a note for anyone thinking of buying the Eltek rectifiers. They are extreamly noisy under load (fan speed is crazy on them, small but powerfull rack server coolers in them). Be sure to acount for this, you will need a technical room.
I fully agree with you … They really are small monsters with high-speed fans that you have to accommodate well.
They do a great job … and also want to be cooled really well.
Have you already discovered the charging current limiter on the rectifiers via the Smartpacks … you can use it to reduce or switch off the charging current with an external contact …
Yes, and the console on them is very nice for configuration through PC. I am working on configuring a relay port to turn them off when sun kicks in and PV can cover LOAD. We need to stop as we highjacked the thread now
Ludo> Why don’t you install the transformer between grid and ac-in ?
In my case I’m using the auto transformer to generate neutral/120V from a 240V Quattro (it’s the 230V EU model which has been changed in settings to output single phase 240V/60hz US) that doesn’t output the split phase 120V/240V AC I need to run a US AC load center.
I suppose I could use a second transformer to up the AC-In voltage after sag, but I was more wondering if there was a ‘fewer parts’ solution that involved turning off Power Assist and separating AC-Out from AC-In.
Fine
Holy S****t … thats realy a lot of Elteks …
