All-day testing/recording data of various solar panels?

[super_kev]

I'd like to test several sets of solar panels (no more than 5 per set) in various sun/weather conditions, and I was wondering what you folks would recommend for something that'll be able to record voltage and current output of the panel for 10-12 hours? I'd like to test sets of different panels at a the time and next to each other for as close to identical conditions as possible, and monitor/graph the data over the day to compare and see which works better. Should I get something like a Victron SmartSolar MPPT charge controller which I could then link up with BlueTooth and monitor the output over the day as it charges a battery (but then I'd need a battery that's in need of charging, like a car battery, and that still may charge within a few hours vs. taking all day). The problem is I would have to come up with dead batteries for it to charge, otherwise I won't get a full picture of what the solar panel(s) are doing since the MPPT would stop a load on the solar panel once charged.

I could go up a step to something like the EasySolar MPPT/inverter combo which will take power from the panel and kick it out to AC voltage so I could plug in a small heater coil as a load and see how it does all day, but I'm concerned just a few panels won't put out enough power to fire up a heater, thus dropping the voltage in the inverter and causing it to power off if I didn't have it hooked to something for backup like a car battery, and stopping me from logging in and monitoring things. But I don't know if that's how it would work anyways, or if it would just divert extra power to AC once the inverter takes it's cut.

I'm open to mfgs other than Victron as well - I've just had good experience with their vehicle battery chargers and have enjoyed being able to log in and see the charge data, so figured they'd make some killer solar stuff as well. I'm not against buying a few EasySolar units, one for each type/brand of panels as I'm wanting to test small strings or individual panels at the same time during identical weather/sun conditions to see how they respond before I invest in more panels for a final design, and winter is the best time to test these suckers due to all the different conditions. In full sun, any panel will work - it's the partial sun like shade, snow, fog, overcast, etc. that'll show a difference, and it may end up I do several arrays or positions/angles for various weather conditions... who knows, who cares, but I'd like to collect 10-12h of data on each panel type for my own curiosity... help me obiwan kanobi.

 

[rodrick]

I vote for 4 or 5 victron 100/20 scc because when your done with your tests they can be repurposed for systems from 12 to 48 volt
hook up a car battery and use some old car 12 items for a load to keep the unit’s charging, find a bunch of the old round headlights and mount them with a switch to each and you could very the load depending on your needs

 

[wpns]

How about using grid-tie to dump your power to the infinite sink that is the grid?

 

[AZ Solar Junkie]

The Tigo optimizers with the CCA and TAP do a great job of monitoring the panels - would work regardless of which solution you go with as far as the solar charge controller, etc. You can get watts, volts, and amps data for each individual panel throughout the day.