I currently have 12x Somera VSMBB.60.305.03.04 panels - they are 305W 32.9V (Vmpp) / 40.5V (Voc) and are arranged in 2 strings of 6 panels in series.
These are connected to a pair of SunnyBoy HF2000-30 inverters and are grid tied.
The panels are on my garage roof, which is next to the house and often partially shaded by the house, so are not brilliant - though not bad during summer/winter.
I’m in the process of adding a MultiPlus II inverter and Fogstar 32kWh battery, mainly for the purpose of charging up over night on my Octopus IOG tarrif (currently getting 6 hours at 4p/kwh) and then discharge during the day when the solar is not covering the usage (which is obviously most of the time in winter).
My export rate is 12p/kWh, so it’s actually better for me to let any excess solar after house usage export to the grid rather than charge the batteries (assuming I then don’t run out of battery and have to buy at peak rates).
I could leave the solar and SunnyBoy inverters alone, but they are big + old and part of me would like to have it all Victron.
Looking at the MPPTs, it looks like I could get away with a 250v MPPT (6x 40.5v open circuit = 243v).
I’ve found some SmartSolar MPPT 250/100-Tr VE.Can units for £230, but i’d obviously need 2x as they will only do one of the strings.
Any advice?
What would be the benefits of going that route vs keeping the SunnyBoys?
Would the MPPT be more efficient / give higher output, or would it just be the integration/configuration?
Am I better off just keeping the SunnyBoys and leaving the solar alone?
For exporting, ac pv like the sunny boys is more efficient.
If you want to integrate them into the Victron Sphere (not control them) you can add energy meters to their output and add the meters to the victrons.
Shelly has some oretty neat ac meters that integerate easily.
If you don’t need the solar for power cuts, they can be on the ac in.
If you are able to at a later date add some victron mppts for self consumption. But for now you can set up when to vharge and discharge with ESS.
If you want to use Victron MPPT to charge batteries most efficiently pls use Victron’s MPPT Calculator. Panels will increase voltage on cold days. 250V is the absolute limit on MPPT 250.
If you have issues with partly shadowed panels, consider using micro grid inverters. I use Hoymiles HMS single-phase 4-in-1 having one MPPT for each panel. The three-phase HMT series have three MPPTs, one per two panels. All micro grid inverters can be controlled via frequency shifting if connected to AC_out while grid failure.
With Victron a mixture of AC-PV (grid inverter) and DC-PV (Victron MPPT) is the most efficient system.
I would substitute one SunnyBoy by an Victron MPPT 150/45. Than split the string into 3s2p.
The MPPT 150 is much cheaper compared to MPPT 250.
With than configuration you get best from both worlds.
High efficient battery charging with MPPT and high efficient grid feedback with the SunnyBoy. The MP2 will do the balancing between the two worlds.
Replacing the second SunnyBoy by an Hoymiles HMT 2200-3T could optimize the shadow, but must be calculated carefully.
