Taking a fridge on a picnic, fishing on a riverbank, keeping a fridge in easy reach on a work site or running a fridge for extended periods where vehicle power is not available, is a great reason to add a dedicated lithium battery to a compatible Brass Monkey Fridge/Freezer. The battery fits into a dedicated battery cradle installed in the fridge and then it is ready for independent operation.

Battery Compatible Fridges

Compact Fridges with Carry Handle: 8litre GH2026, 18 litre (blue/white) GH2046, 18 litre (grey/dark grey) GH2047 

Compact Fridge/Freezers: 15 litre GH1623, 15 litre GH2068, 25 litre portable dual battery GH 2028

Ultra Portable Fridge/Freezers: 42 litre GH2030, 52 litre GH2032, 62 litre GH2034

Fishing Dual Zone Fridge/Freezers: 75 litre GH 2040, 95 litre GH2042, 115 litre GH2044

Portable Dual Zone Fridge/Freezer: 35 litre GH2020, 45 litre GH 2022, 55 litre GH2024

Low Profile Dual Zone Fridges/Freezer with Wheels: 75 litre GH2036, 95 litre GH2038

Low Profile Dual Zone Fridge/Freezer without Wheels: 75 litre GH2080, 95 litre GH2082, 115 litre GH1684

Picking the right battery size

There are 3 battery sizes available, 5.2AH, 7.8AH and 15.6AH. To get an idea of which battery size is the most suitable choice for any fridge:

1. Check the fridge Amp rating on the specification page.
2. Consider how long the fridge needs to operate independently of vehicle power.
3. Make a judgment about how long the fridge will need to run independently each hour to maintain the set temperature. For heavy use where the fridge is frequently opened or sitting in the sun, say 50% run time. Reduce this run time if use is lighter, say, located in a shaded area and not frequently opened.
4. Multiply Amps from 1. by independent running time from 2. and 3. and use the next size battery up.

Example calculation:

1. Fridge amps = 5 amps,

2.Working on site for 8 hours independent use,

3. Fridge in covered area and opened for meal and drink breaks - say running 30%/hour.

Battery size in AH = 5 Amps x (8 hours x 30%) = 5 Amps x 2.4 hours = 12AH.

Closest size up is the 15.6AH battery

Note: This is a very rough means of estimating a suitable battery size. Fridge running time will vary depending on daily ambient temperature, the fridge set temperature, where the fridge is located, and the volume of food stored versus air space (a full fridge has less air to lose when opened). Weather and use conditions will vary on any given day, so estimate the battery size using the heaviest likely use, to find the most suitable battery size. If in doubt, buy a bigger battery and/or consider a supplemental charging system (below).

Lithium Battery Charging

There are 4 methods of charging the Brass Monkey Lithium Batteries:

1. Plug your fridge into a car cigarette lighter socket and charge the battery from the car while travelling. The fridge will continue running from the car, while the battery charges.
2. Use a dedicated 12.6 volt Mains Power Supply GH2059 to charge the battery while removed from the fridge. This is a great option if the trip home is too short to fully charge the battery ready for the next use, or where multiple batteries are used alternately, for extended independent use.
3. Use a dedicated 6 Amp mains power supply adapter GH1628 to run the fridge and charge the battery.  This is a great option where the fridge is used at home, as a spare or party fridge, or when it is used for work most days. This allows either continuous home running or overnight running and charging without any overnight draw on a car battery. The fridge is charged, cold and ready to stock with food and drinks every morning.

Use a dedicated folding 100 watt solar blanket GH2015 designed to plug straight into the DC socket on the fridge. Great for any extended independent operation, particularly where there is no access to mains power. Note that this is not intended to be a completely-off-grid solution, and will supplement powering the fridge from external sources only.