You can get away without solar but you will be replacing the battery much more often.<br><br>A compressor fridge in the 30 to 50 liter size range will use, on average, ~24 amp hours per day. Too many variables to narrow it down more than that. <br><br>Most people act like a short drive is enough to fully recharge a battery, but there are several limiting factors that make this belief overwhelmingly false.<br><br>Getting the battery back upto a true 100% weekly is important for its longevity and performance during its lifespan, and the alternator is not going to do this unless you are highway driving for 8+ hours. Best to have a 10 amp + battery charger and be able to plug it in overnight to shoehorn in every amp when the battery has seen a week of powering the fridge and just short trips.<br><br>Thicker cabling between alternator and secondary battery will help get the battery to 80% faster.<br>You don't want to regularly take the battery below 50%.<br><br>If the battery is at 50%, with thick cabling and a healthy alternator, driving for an hour might return it to the 75% to 80% mark, but no more, and likely less.<br><br>The alternator's ampere rating has little to do with how fast the battery recharges. The battery decides how much it can take at the voltage allowed by the vehicle's voltage regulator, which was designed to safely keep a marginally depleted starting battery from depleting any further, not recharge a depleted deep cycle battery tacked onto the circuit.
