Do you have a remote operated circuit breaker which disconnects your string inverter when the generator is running? Based on the age of the system, I would expect one. If you look in your GSLC there should be a complicated looking two pole breaker with an extra pole?Swampdog wrote: ↑Mon Feb 10, 2020 4:52 pmAmp-hours... I have 12 x 220GH batteries. Don't know how to calculate and could not find a spec.
I would want to optimize grid sell, as since grid-tied, the back-up is only needed during outages. Generally, the array output is enough for our daily loads.
Not sure how to answer. I do not have a charge controller, but we can receive power during array production and sell at the same time, excess from array also charges batteries.
12x 220Ah batteries for a 48V system means four 12v batteries in series for 48v, and three sets of four in parallel. So as Raysun said 660AH of total capacity at a C20 rate (330AH usable). Each battery according to specs can be max charged at over 100A, so you don’t really have any limits on rate of charge with three sets in parallel. So no reason to limit the AC charger. If you aren’t load shifting and these are battery backup, then the must sit at float all the time?
When you say the array output is enough for daily loads, are you including net metering in that or are you using the batteries daily for a net zero loadshifting?
You goal when under generator would be to recharge as fast as possible. To me, that means running your AC charger at whatever rate your inputs support. 20 AAC for generator in, and 18 (or 20) for AC charger.
Net-net you want the solar or the generator to recharge the batteries as fast as possible when not connected to the grid. The way AC coupling should work is excess to demand AC produce by your SolarEdge feeds loads (including the Radian charger). Once batteries go to flood or stop charging, that AC demand drops and it feeds other house loads and then grid. All you are doing by reducing the AC charger rate is increasing the time that it takes to top off the batteries. The excess to seep should be about the same.
When you go to generator to charge batteries, the ROCB you probably have should open, disconnecting the AC from your SolarEdge and knocking it offline. Hooking a grid-tie inverter together with a generator is a no-no and will result in you likely needing a new generator - thus the ROCB.
If you lose the grid, the max your SolarEdge could put in currently is 7.5AAC or 1800 watts or 37ADC. Presumably if you are using the Radian in backup mode you might never be able to recover your batteries from AC coupling in a grid-down faster than you use the power with charging choked down to 7.5AAC.
Any sense of what your average AC load is when running in backup mode? You could drop the AC charger rate by that amount just to keep the Radian from having to juggle / throttle charging up and down as loads vary.