Installs are getting bigger, restrictions on what you can connect as an ESS are getting tighter, what to do….
So, what are the options…. Latest job for me is a 3.6kW export limit with a 5kW inverter max (this seems to be getting very common), for this site it would be near impossible to meet the export limit in ESS mode (already has 3kW solar) and to make the numbers work a 5kW inverter would be too small anyway. I am seeing this more and more, especially on outskirts of villages and towns with little existing generation (think conservation areas etc).
So, are we going to see more installers taking people off-grid [like we do with boats and caravans etc], I think this is really the only way forward for properties that have big power demands on ‘weak’ single-phase supplies?
Several issues,
Its more complex to recreate some of the ESS functionality, like timed charging, weather look ahead etc.
Needs careful design to ensure the size of the system can cope, or reconnect to the grid if load gets close to the max etc.
Convincing the DNO that this type of system needs no G98/99/100…
Smaller properties will use Multiplus 5000 on G98/9 grid tied, would be interested to here from other installers, any thoughts?
Would it be possible to install two inverters to one set of batteries, and split the property into two separate consumer units.
Inverter one is grid tied, and within the DNO limits, it handles charging of batteries from the grid in the winter. Supplies mains to one consumer unit.
Inverter two supplies power to the second consumer unit, and has no grid connection.
Obviously this will greatly increase costs, and I’ve no idea if you can run two Victron invertors in this manner.
For that I take it one system of the solar is AC or both AC solar in which case turn one into DC using Victron kit I’m not too upto date on that DC side as I’ve done just AC, it does depend on your DNO and location to be honest my own install I got DNO approval for 14kW I imagine that if I want my north side roof all AC I may have to jump more hoops or just means I push the AC inverter Clipping
Correct, an existing solar system exists which we are probably going to DC couple now to get around the inverter size issue. Also looks like we have a G100-2 solution coming (not from Victron) which solves the export limit, so I think we are back on track!
The Multiplus does meet the old G100 requirements and as far as I know that still covers that part of the G100-2, but G100-2 has further error checking and logs excursions out of limit vs time, it then shuts the system down if it repeated events.
Victron have stated that they will not go through the process to get the GX device approved to the new spec, so someone has done it and is now on the ENA database.