More fun with Renogy MPPT and LFP
Toying with a new to me 12V compressor car fridge. Cheap Chinese box, LG compressor, 50L volume split ~28L fridge, 22L freezer. The goal was to see whether my added insulation made any difference: Ref...
Forum Discussion
Im not sure what the question is exactly.
What the fridge uses to determine SOC is unknown. Is it when the fridge is running and erroneously showing a lower voltage, or when it is not running and can sense the real voltage from a still battery?
When my fridge runs the voltage will show 0.6 to 1 volt lower charge than what it actually is, this is bc the fridge is using voltage right then. As soon as it shuts off voltage goes back up (or at least the voltage shown on the fridge display).
I am guessing that the low voltage shut-off function is actually a low voltage do-not-start function, so when voltage is below your preset cut-off then the fridge will not start. As opposed to - the fridge shuts off in the middle of a cycle when voltage is low.
I would connect fridge directly to the battery and not the solar controller/ load terminals (if this is what you are talking about). You will get the best power straight from battery. You may be seeing issues with the controller not knowing exactly what the batt voltage is. Are you on solar with 18 volts of solar coming in? The charge controller should see the battery voltage, but with a full charge voltage running down the same line it might get confusing for the controller. The controller might stop charging for a milisecond to read the battery, but IDK.
Your fridge will not use enough amps in a day to run a good battery (pair) down, so as long as you charge back every day and are not using huge amps for other devices at night you should not have to use a cut-off option. Mine just never draws the batts down that much over night and my fridge is double yours.
I too put massive insulation around my fridge. Not those near useless blanket velcro things they sell for hundreds, but real styrofoam held tight to the fridge. I put foam on the base and the sides, but just use a towel on the top for ease of use (chest-style top open).
The fridge runs way way less than it used to as the insulation really works, and a big bonus is that the fridge is super quiet now. I can't hear the compressor if I have a small slow fan running at night. if I listen really close I can tell when comp comes on but it is so faint now compared to before.
I think the biggest thing you can do is use insulation. Mine is 2 inches thick, it is the packing styrofoam that the fridge came with around it. No air gaps, no pockets, keep it tight fitting.
No matter how much or how little amps it pulls, when it is insulated and runs less the total amps used is less and this saves the battery.
What the fridge uses to determine SOC is unknown. Is it when the fridge is running and erroneously showing a lower voltage, or when it is not running and can sense the real voltage from a still battery?
When my fridge runs the voltage will show 0.6 to 1 volt lower charge than what it actually is, this is bc the fridge is using voltage right then. As soon as it shuts off voltage goes back up (or at least the voltage shown on the fridge display).
I am guessing that the low voltage shut-off function is actually a low voltage do-not-start function, so when voltage is below your preset cut-off then the fridge will not start. As opposed to - the fridge shuts off in the middle of a cycle when voltage is low.
I would connect fridge directly to the battery and not the solar controller/ load terminals (if this is what you are talking about). You will get the best power straight from battery. You may be seeing issues with the controller not knowing exactly what the batt voltage is. Are you on solar with 18 volts of solar coming in? The charge controller should see the battery voltage, but with a full charge voltage running down the same line it might get confusing for the controller. The controller might stop charging for a milisecond to read the battery, but IDK.
Your fridge will not use enough amps in a day to run a good battery (pair) down, so as long as you charge back every day and are not using huge amps for other devices at night you should not have to use a cut-off option. Mine just never draws the batts down that much over night and my fridge is double yours.
I too put massive insulation around my fridge. Not those near useless blanket velcro things they sell for hundreds, but real styrofoam held tight to the fridge. I put foam on the base and the sides, but just use a towel on the top for ease of use (chest-style top open).
The fridge runs way way less than it used to as the insulation really works, and a big bonus is that the fridge is super quiet now. I can't hear the compressor if I have a small slow fan running at night. if I listen really close I can tell when comp comes on but it is so faint now compared to before.
I think the biggest thing you can do is use insulation. Mine is 2 inches thick, it is the packing styrofoam that the fridge came with around it. No air gaps, no pockets, keep it tight fitting.
No matter how much or how little amps it pulls, when it is insulated and runs less the total amps used is less and this saves the battery.
