Efficiency Curves ?

[boB]

Vic, we have not had the time to make efficiency curves for the Classic versions. Having said this, the electrical efficiency of the Classic 150 compared to the larger controllers, such as the MX60 is not quite as good. The MX has huge inductors and more FETs.

I did do a measurement recently on the Classic with a 12V battery and a 72 Volt array (power supply).  The efficiency came out 1% worse than the MX60.  Something like 92% for the Classic Vs. 93% for the MX60.

As for daily harvest in kW-Hours go, we have seen the Classic out perform all other controllers except maybe the Morningstar MPPT 60 CC where we were on par.  Almost no difference and some days even more.

That outperformance has to do with the tracking ability of the Classic.  Even though its electrical efficiency may not be as good, the tracking efficiency more than makes up for it comparatively.

We hope to make curves for the other Classics at different battery and array voltages and do it "accurately" but we have so much work to do here right now that it will have to wait just a bit longer.

I do not want to publish any efficiency curves, even if I had them, unless they are done correctly and accurately. This is not easy to do.  I do trust that 92% number though, even though I don't like it.  However, lower efficiency is really to be expected at low battery output voltages because the losses are so much more a part of the output power that it just isn't as good as when you are measuring efficiency at higher battery voltages and higher output power.


boB

[Vic]

OK,  Thanks boB,

Appreciate the data on the difference between the MX-60 and the Classic.

This helps give me the confidence to move foreward with my new installation,  as I TRUST you folks.

The current plan is to use the existing Classic 150 with 12 ea SW-245s -- four strings of three in series (Vmp = 92.4 nominal),  and an MX-60 with its own "identical" array of 12 in the same configuration.  Later will probably change out the MX for an additional CL150.  This generational difference may not be ideal with a common bank,  but will see how things go.

73  Thanks again,  SRI for being needy.  Vic