I would like to be able to do this, not so much for very heavy load days, but rather as a backup in case of an extended power cut.
The do it LOL
However, my supplier has no idea how to plug a charger into my GivEnergy home battery. He said something about taking the front cover off but it was an emergency connection in case the battery had discharged so far that it wouldn't charge normally. I have no idea and I'm not sure he has either.
This is so simple, he probably hasnt really thought it through or he doesnt have knowledge of how the systems work. He's clearly trustworthy in so much he's advising against it rather than having a go so credit to him for that.
Most batteries have 2 sets of DC terminals to allow them to be paralleled together with 2/3/4/5 batteries etc. On my Growatt system I can plug my DC supply in there, the inverter doesnt know anything about it nor does it need to. It sees the 53v supply coming in and it uses it. I set the power supply to 53v which equates to 80% SOC for LifeP04 cells. If your batteries don't have a second set of terminals (most do), then connection needs to be made onto the DC cables either with a Y lead if they're plug and socket or simply add cables if they're going into terminals.
By doing it this way it also means a generator can also be fed into the system in just the same way if necessary. The maximum power of the inverter is also available for the wholes house. In my case I tried running heat pumps, ovens, immersion all at the same time, the car was giving 3 kW, the batteries making up the rest to the 14kW load I was running.
However, I'm not trying to run the house normally during a power cut, just to keep the (kerosene) central heating going and power the WiFi, the computer, the TV and a couple of table lamps. Also boil the kettle and run the microwave from time to time.
Why not run it normally? It's not difficult to achieve.
The setup I have lets the heating continue to run from the home battery, and gives me a live double power point in the fuse cupboard from which I can run extension cables to power the rest of the stuff. Should be fine. (I would run the fridge and the freezer overnight.)
Most inverters have the emergency output capability which is what youre using here.
This should be fine unless the power goes out just as I've exported my battery. Obviously if there was any reason to anticipate a power cut I simply wouldn't export the battery, but you can't always second-guess it.
I'm sure that well known law will come in to play.
In an extended power cut I could spare the battery by running an extension lead directly from the car for the appliances, and keep the battery for the central heating. This would probably be OK because the battery would be replenished from the solar and allow indefinite operation. However, on cloudy days around midwinter, maybe not. It will probably never be necessary but I'd just like to have the capability of topping up the home battery from the car just in case.
Yep, sounds like a plan.
My system, I installed an automatic change over switch to isolate the incoming mains in the event of failure. The Emergency Supply switches in less than a second and normal power through house is resumed. when the mains is restored, it changes back after 5 minutes (just in case it goes through the on/off/on/off routine as often happens).
As I've said before, it's really not difficult, if some bloke in Lincolnshire can do it, anybody can
