Using a capacitor to handle the inrush surge power of a fridge

Question

I have a household mini fridge connected to my off grid electrical system, and recently I bought a smaller inverter just for the fridge so that I can turn my larger inverter off to reduce power consumption. However the problem is that when the fridge compressor starts, the power surge flickers the lights and other DC devices and risk turning off completely.

Question is: Is there something I can buy or build that's relatively inexpensive to put between my inverter and slightly insufficient buck converter to supply the surge power for the first few seconds?

Buck converter ---> ? ---> Inverter ---> Fridge

Here is my setup: 120v AC mini fridge (Hisense 4.4 cu. ft.) that starts up to 450 watts for 2 seconds, 45 watts running --> 300w Bestek pure sine wave inverter, 750w surge --> 414w step down 24v to 12v buck converter --> 24v, 230ah LiFePo4 battery bank (self built from cells and BMS)

Would something like a capacitor work? E.g. stores energy needed until the discharge and once the discharge occurs, the power just flows through it until the device has stopped. Then it builds its charge up again, waiting for the next surge.

Unless there is an affordable small 24v inverter available, I can't justify buying an additional expensive inverter for the amount of power saved. I could revert back to plugging in my fridge to my 2000w inverter but the goal is to reduce the standby power consumption and usage of a less efficient large inverter. Also, I could buy a larger buck converter but I was hoping that I won't have to spend extra $ on a 2nd buck converter and also won't a larger converter increase power consumption?

Answer 1

You're likely to need quite a large capacitor to start the fridge, but not as extreme as those capacitor banks you see people use for starting cars.

But the first thing to check would be to try the small inverter powered from a 12V battery and conform that it is capable of reliably starting the fridge.