I have one of those units that Tom linked to, I fitted Anderson plus onto mine but you can also buy them already fitted.
I have 2 x 160W solar panels running through a Redarc BCDC1225 with a 100AH battery fitted beside the drawers.
When I was planning this I ran my 40L Engel freezer plus my 32L Waeko beer fridge for a week for each and worked out the current draw over that period. Below is my results
Waeco 30L Engel 40L Total
Watts Peak 74.1 85.3 159.4
Ampere Hours 16.96 11.84 28.8
Watt Hours 473.8 589.1 1062.9
Amps Peak 5.54 6.15 1 1.69
Volts Minimum 13.28 13.33 13.33
They are a very handy unit to have in your kit, only problem is the short leads.