Defrost settings

[conachair]

After the mechanical thermostat gave up on my small top loader refrigerator, evaporator plate and bd35 compressor, I replaced it with a microprocessor so can program in pretty much anything. But what would work well as a defrost cycle? Keep the compressor turned off for a few hours once a week? Or let it heat to, say, 12degC overnight every 10 days? No idea, Google didn't help much either, any ideas welcome thanks.

[a64pilot]

Wouldn't you want to do that manually, as needed?
I believe frost accumulation is highly variable, depending a lot on how often the door is opened, plus I'd hate for it to go through a defrost cycle the day after I bought those nice steaks.

[conachair]

Ah, didn't try very hard on Google, seems most now have a heating element in the plate, every so often the plate is heated to above a set temp. That sounds easy, but what sort of temp and how often?

[a64pilot]

Originally Posted by conachair

Ah, didn't try very hard on Google, seems most now have a heating element in the plate, every so often the plate is heated to above a set temp. That sounds easy, but what sort of temp and how often?

That is describing a frost free fridge like in your house, it works of course, but is horribly inefficient from an electrical use standpoint. If you felt you needed this anyway, I would wrap "heat tape" around your evaporator, heat tape is used of course to keep pipes from freezing. I think you'll have to determine how often and for how long to power the tape from observation.
You are plugged into shore power, right?

On edit, another way of course is a reversing valve and use the refrigerant as the heat source, more efficient, but more complex. That is how a house heat pump defrosts when in heat mode, except of course the heat strips come on the re-heat the air so your not blowing cold air into the house, of course in defrost mode your AC is battling your heat strips and your paying.

[conachair]

Wasn't thinking of usong heat tape, just let the plate heat up until a set temp. If that would work.