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April 7, 2025 10:11 pm
I am getting bids for a 28KV system with battery support and am considering EG4. A bit frustrating that there is no phone support from EG4 but my question is I think pretty basic. The FlexBoss21 has specification of 21KV PV support but only 16KV of output. Does this mean the efficiency is only 76%? In order to generate the required 28KV output do I need then two FlexBoss21's? My application is a bit more complicated in that have split 400 amp services with both water heaters and AC units split between the two. I seems impractical to separate these circuits so I am going to connect the system to both entrances without running dedicated circuits at this time. Thanks in advance for advice. There does not seem many solar installers using EG4 but I have found a couple here in Orlando.
April 13, 2025 2:49 am
You need to calculate your AC power needs. If your water heat is on AC power and your AirCon is on AC power, that is a pretty sizable load. IF your routine demand is more than 16kW of AC power, then you may need more than one inverter.
Having said that I run a 2200sqFt house in Oregon with a heat pump for cooling on 12kW of inverter power. So far so good. My 18kPV inverter only puts out 12kW of AC power, and the remaining 6kPV input can be converted to battery charging using DC to DC conversion. So your assumption about efficiency is not correct, it’s just that your inverter cannot convert ALL of its max input power into Alternating Current (AC) for your house. Since you (like me) will have battery bank as well, you should check your inverter specs - I suspect that the Grid Boss, like the 18kPV, has the higher rating for PV input power because it can simultaneously charge your batteries at 5kW and power your house or export to the grid with the rated 16kW AC power output. I had to adjust my mode of operation settings a few times to find the right combination such that I was ready to recharge by mid-day when the solar was at peak output. (My system is close to 18kPV solar modules on a good day, and the inverter MAXes out at 12.5kW of AC power output to house and grid).
Hope that helps !
April 15, 2025 3:35 pm
Call Signature Solar and they will help you out
