Classic 200 cooling fan running under light load.

[BigCountry]

Just fired off my offgrid system and trying to get things figured out. I ended up with 3920 watts of panels, sw4048, classic 200, and 8-cr430 batteries. I am in northern lower michigan, even in DEC on sunny days I have more power than I need and am working on figuring out how to best use the excess. Used the midnite solar design tool to design and everything is in the ok.  Anyway I have noticed that on sunny days I get to float early in the day, and the classics is only putting 1-2 amps through it for most of the day after untill loads are applied, however the cooling fan is cycling like crazy, the same as when I am putting 3000 watts through it. On cloudy days when I only have 2-3 amps running through it all day it barely comes on if at all. Where is the heat coming from? Is there something about having all of that potential energy available that is causing it to heatup even though there is such little load. Another classic owner confirmed his does the same. I just can not grasp why.


Thank You

[FNG]

As for heating and the cooling fans, The difference is, In float at low amperage the input voltage is a lot higher than if the controller is in bulk in clouds it will, in that case, drag the input voltage way down. As heat is a function of the differential voltages between PV in and Battery out the controller will run a lot warmer in float than in bulk on cloudy days.

[CDN-VT]

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