Since I work in the Solar industry (at least for now), there’s really no excuse for not having a few things sorted out. One of the issues that bugs me when I go camping is the lack of refrigeration. An Esky and ice just doesn’t cut it. You end up with a pool of water with soggy things floating in it and food you have to throw away. The problem with a car fridge and solar charging system is that it is quite expensive to set up so the cost/benefit ratio is poor.
Not to be put off, the company for whom I work, Solar Newcastle, recently set up a Recreational Solar department and the pricing they got on 12v panels was amazing. This prompted me to explore the project again and with the help of our senior design engineer, Lee, I pieced together a plug and play solar charged fridge system for my car camping needs. First things first, there’s no point having a good deep cycle battery if you can’t keep it maintained so a proper multi-stage charger was the first thing to buy. Plenty to choose from but Projecta kept popping up as a big player and I scored this thing from my friendly Ebay store:
This thing can handle any chemistry battery up to 10A. It can recharge a car battery in situ and still connected so in short it is ideal for the job.
Next was the battery. Now, I am an electrician and electronic engineer but, in truth, batteries were never a thing I studied much. Fortunately, Lee is a battery master and he schooled me up good and proper. So now I can do batteries, me. I really wanted an AGM 100Ah deep cycle but the cost was more than I could justify at $369. So I opted for a 100Ah SLA which I got for $200 from Newcastle Batteries, our sister company.
So now I have a battery and can keep it charged and in good order. With an Engel 50l fridge at 2.5A maximum draw, this will give me about 20 hours of autonomy time before the battery gets below its critical 50% discharge. That will do for an overnighter but I need solar panels to make it permanent. The panels our company now sells are OK and the pricing is very good at $480 for a 130W bi-fold with regulator. This price is hundreds cheaper than similar at the big retailers like Ray’s Outdoors and Camping World but then I found this:
This setup is 120W, waterproof with protective corner guards, a superior tilt stand, Anderson plug connector and only $355. A steal and it’s on its way.
Now I have the ability to keep my battery charged for years without the need for mains connection. Unfortunately, all I can do is look admiringly at my system because the battery has nothing to run. Sure I can charge my iPod but I could do that in the car. Naturally, the fridge is next.
These days there are several good car fridges to choose from but I will pick from either the Waeco or Engel ranges. The Engel runs much lower current draw because it uses a Sawafuji swing motor which is more efficient than Waeco’s Danfoss compressor. It’s a difference between 2.5A and 5A maximum draw and this will impact on autonomy time for the battery. Both fridges are highly recommended with impressive track records for serviceability but the Engel’s higher price might be worth paying. I only need 50 litres so I expect to pay around $1k unless I can get a great Ebay deal. I will keep you informed when it arrives.
Finally, my next step is plug and play so Anderson plugs will go on all connections and the battery will live in a box with Anderson plugs, car d.c. socket and a little recharge inverter for all my electronic gadgetry. My next post will show it all together and working.