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On 12/13/2021 at 11:15 AM, Merner said:I did a quick experiment last night with charging. I had an input voltage of 249vac and my battery bank was just under 60v with the bulk charge set to 64v. At 25% inverter setting I was putting in 9 amps DC and was 54% efficient. At 50% I was at 69% efficiency. Both 75% and 100% charge rate dropped to 64% efficient. I would be curious to try this again with a lower battery voltage as I was only putting in 37amps dc at 100%
So what is the nominal voltage of your battery bank?
So what is the nominal voltage of your battery bank?
I believe @merner is running a 16S Li-Ion battery bank, so that's a nominal voltage of 57.6, normal "full" of 65.6v. Way higher than I would normally like to see for a 48v nominal inverter--but the GS inverters don't seem to mind.
For a normal 48v inverter, I would recommend 14S Li-Ion (=nominal 50.4v, "full" of 57.4v). Or if they're using LiFePo4 cells, that'd be 16S (=nominal 51.2v, "full" of 57.6v).
Due to the fixed transformer ratio, very high charge voltages WILL operate at a significantly lower efficiency due to losses in the boost process. And at the increased ratios of lower voltage setups (i.e. 36v, 24v, etc.), the output amperage will correspondingly increase as a result of the transformer ratio.
Odd voltage unless you went straight DC to AC