Runs my 6000watt split phase inverter under load with a single chins 100ah 48v battery. Less load the longer the runtime but it works even at high loads.
Eg4 inverter future
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FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The Amp hour rating of the battery only determines how long the inverter will run on a given load.
Whether the inverter can run at full power is determined by the total Amps the battery(s) can produce. For a 6.5KW inverter... I will assume a 94% efficiency. That means at full power the battery needs to provide (6500W/.94)/52V=133A,
Most 48V server rack batteries have BMSs with only 100A discharge capability. Consequently, a single battery would not be able to provide enough current for a continuous 6500W. At about 4.9KW the current draw from the inverter would trip the BMS to shut down. There are a few server rack batteries that have 200A BMSs. A single one of these would be able to handle a 6.5KW inverter at full power.
Some of the wall-mount batteries that are coming out also have 200A BMSs. As an example, the wall-mount battery that EG4 just released has a 200A BMS and could run a 6500W inverter at full load.
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timselectric
If I can do it, you can do it.
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But only for about 45 minutes, at full load.
Subdood
Photon Wrangler
Thanks for the reply. Yeah, I know a 6.5KW load would be over 100A for the battery, my question is with say just a couple KW load, with no solar and no grid, the battery ought to be able to start the inverter? I was thinking along the lines if the battery had enough "juice". Something about enough power to charge the inverter's capacitors. May not even be a relevant question.
Another question- my array is rated at 3.6KW, with the 5kwh batt fully charged, and it being a sunny day, the inverter ought to be able to handle a 6.5KW load, correct?
One more- if the inverter is in SBU mode on a sunny day, and you have say a 4KW load. As long as the battery is not near low voltage disconnect, both the PV and battery ought to be able to provide power to the load, correct? How much of that 4KW comes from the array and how much from the battery?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Most server rack batteries have precharge and current limits that pretty much eliminate the old pre-charge problem.... I would not worry about that. As long as it is a 48V battery with a capacity of just a few amps it will start the inverter. (I have used 10A power supply on the battery input to start up an inverter.... I just could not put any load on the inverter.) Once there are a few amps to get the inverter to turn on, it is 'just' a matter of how much current is needed by the load on the inverter.
The only answer I can give is 'probably'. However, the definitive answer depends on the internal design of the inverter. I don't have enough experience on systems with undersized batteries to say much more than that.
Again, my definitive answer is 'Probably'. Unfortunately, most of the lower-cost inverters don't explain things to that level of detail. Furthermore, it seems like people see different behaviors on different Inverters.
I would expect the inverter to use everything it can from solar before it taps into battery power. However, people have reported odd behavior with the various settings so I can not say with confidence that they all behave the way I suspect.
BTW: I suspect that a lot of the settings are not independent of each other. Consequently, 'SBU' might behave differently depending on what some of the other settings are. This would explain why people observe seemingly different behavior between two different inverters. (Not to mention all the different firmware versions that can change things)
Capn D
New Member
Good question. I have replacement 6000EX New in box.
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