A small matter for start - as another forum user mentioned recently, I find that OB's string sizing tool does not allow system voltage selection (I'm using MS Office 2013) - for any of the four SCCs selected, system voltage is set to 48. I wonder if this is intentional, or a software problem - any ideas?
I'm seeking clarity on the max. array power for an FM100 on a 24V system. From different sources I get different figures:
- FM100 user manual March 2018, p. 65 - 3000W (STC conditions)
- FM100 datasheet April 2019 - 3400W (nameplate STC)
- (Neither of the above say anything about derating from the figures given.)
- OB's string sizing tool (downloaded this week) - states Max. power 6kW on 48V, so presumably it would be 3kW on 24V.
As system voltage in the tool is fixed at 48V, I enter double the intended # of strings, on the assumption that will give the same output current as the actual # of strings on 24V. Halving the power figures under String Sizing Options again - for 24V - gives 'good' for 2800W and 'caution' for 3360W.
- My equipment dealer - 24V (nominal U-batt) x 100A = 2400W
- OB Knowledge Base article 'How to size a PV array for the FLEXmax charge controller', May 2014 - gives data for FM60 & FM80 only, but states "For best practice the array should be 15% less than the maximum rating listed below [given as STC]. Multiply the maximum rating by .85 to determine best array size for your battery bank/controller setup. Downsizing the array from the maximum rating allows for longer controller life, greater efficiency, and reduces the chance of nuisance breaker tripping."
If this is applied to the figure from the April 2019 datasheet, it gives 3.4kW x 0.85 = 2.9kW.
I'd be grateful for a definitive answer from Outback, but if that is not forthcoming, perhaps someone else out there can help ...?
Thanks in advance!