I have a system consisting of 4kwp of solar panels connected to a Sunnyboy 4000TL, 2 Jenko panels connected to a 1kwp Solis inverter and 2x9.5kw givenergy batteries connected to a 3kw AC coupled inverter.
Whilst performing well, it would be useful to add another battery and change th inverter Giv inverter for a 5kw version.
When the batteries were added to the system I was told that the DNO had specified a maximum of 8Kw installed inverter power.
Is this normal? I can’t find anything in the DNO paperwork about this.
Is there any workaround - eg another battery that can only discharge to the house - not export?
JUST TO BE CLEAR - I’m not talking about an export limit. That was set by the DNO at 4kw and is a separate matter.
1 yes the dno likes to know total inverter power and often limits to the single most powerful inverter. Though it shouldn’t matter if everything is set for export limit correctly.
2 there is no 5kw AC coupled inverter. You option would be a second AC3 with an EMS device or sell the AC3 and batteries and get an AIO
As darknite says there is no 5kW AC coupled inverter, the 3kW was the only one produced.
You could scrap everything and put an AIO in which will give you a 6kW limit. Or as suggested a second AC3 with an EMS which will give you 2x 3kW.
Or a cheaper option is to scrap the AC3 inverter and put a hybrid inverter in. Either a 3.6 or a 5kW. The inverter limit refers to how much DC solar it can convert to AC if you leave the Solis in place the hybrid can act as an AC adapter, or if you replace the Solis with a hybrid then you’d probably be OK with a 3.6 as rarely do you get the full peak of solar generation. Obviously if you put more panels in then you’d need the 5kW.
However, the hybrid inverters operate at a maximum of 3.6kWh charging and discharging from the batteries which is the most you can get out of your 9.5kW givenergy batteries.
Which route to take depends on what you are trying to achieve. If you want more power discharge into the home then a second AC3 would probably be best, if its just battery capacity then you can either just add the extra battery to your AC3 or swap it for a hybrid which gives a modest discharge uplift.
Also think about what financial case you are trying to meet. With more batteries on a single inverter you are still limited by the inverter charge rate overnight, so unlikely you can charge much more overnight without increasing your inverter throughput
Not strictly true, it is more the maximum AC output.
There can be say 3kW solar, plus 2kW from the battery to give a 5kW AC output from the 5kW hybrid inverter.
Not sure I entirely understand the question, but if you have a givenergy hybrid inverter with fast response functionality (which I think is anything beyond the original Gen 1 450/451 firmware), then the hybrid inverter can act as an AC coupled inverter as well as being a hybrid inverter.
I have two Gen 1 hybrids (with fast response firmware) and an older separate AC-coupled FIT inverter (no battery).
The Gen 1’s will both seek to let any excess energy be exported, so if one inverter is generating more than can be charged into the battery (e.g. generating 4kW, max battery is 2.6kW, so 1.4 would be exported), then the other inverter will use that excess AC and charge its battery,
Similarly the FIT inverter AC output can be charged into the GivEnergy inverter batteries as long as they are not already charging at full rate.