How much power do i need for a compressor refrigerator?
I’m trying to size my off grid setup for a 12V compressor fridge and I’d appreciate some advice from people with experience.
This is my current setup:
-Compressor fridge with its own built-in lithium battery (15,600 mAh)
It can run about ~20 hours on its internal battery when fully charged
-Boat leisure battery: 80Ah Exide Dual (lead-acid)
From what I understand, only ~40Ah is realistically usable
-Solar: 21W panel
-Chargecontroller: older/basic PWM controller (no display, no MPPT)
What I want to achieve:
Run the fridge 24/7
Ideally for 4–5 days at a time without shore power
Mostly during boating season (spring/summer in Scandinavia)
How much battery capacity would I realistically need for this fridge setup?
(Would something like 100Ah LiFePO4 be enough, or more?
How much solar wattage would you recommend to keep it sustainable?
(I assume 21W is way too small right now)
Is it worth upgrading to an MPPT controller in my case, or is the difference minor at such low solar wattage?
Would it be better to run:
fridge on its own internal battery + solar recharge
OR
fridge connected to a main house battery system?
Any real-world experience would be really appreciated. I’m trying to avoid over/under-sizing the system.
Thanks!