Off-grid 12-volt system for Overlanding

In the run-up to the start of my first World Trip, I had two simple questions; what capacity should the household batteries be, and how many solar panels do I need? Well... researching 12-volt system camper electrics was like trying to solve a Rubik's Cube while riding a unicycle on a tightrope over a shark tank. I was so overwhelmed with all the technical jargon and complicated diagrams that I started to feel like I was in an episode of the Twilight Zone.

And don't even get me started on all the conflicting advice out there. It was like trying to find a needle in a haystack, but the needle was invisible, and the haystack was on fire.

So, this blog isn't about volts, watts, and amp-hours but a straightforward story of how I survived a one-year World Trip with the 12-volt electricity setup I got after talking to many real experts (not the self-proclaimed ones on the internet).

The most common mistake is buying more than you need. I was going down the same road because I didn't want to run out of some of that delicious 'power juice.' Well, it's not about what you want but what you need. Spoiler alert: It's very little, assuming you're not traveling in a luxury expedition truck carrying a washing machine and flatscreen tv.

To paint the picture, this is a two-person setup using; two smartphones, one tablet, one laptop, two camera batteries, one flashlight, and two headlamps (no, the ones you put on your head ;). For the water system, I'm using an electrical pump and a water tank gauge. The refrigerator is an energy-efficient Dometic CoolFreeze CFX 40W and runs 24/7.

The portable 100 Watt solar panel

For my house batteries, I had two choices; AGM or Lithium battery. Yes, a lithium battery is way better, said the expert, and he told me the price. I swear I heard my wallet start to cry. So, I bought two AGM house batteries. Buying the perfect solar panel turned out to be a big surprise. According to the expert, an 80 Watt solar panel would be sufficient for the devices mentioned above. Still, it would be advisable to get a backup solar panel.

The only problem is that I have limited space on top of the Land Rover Defender. So, I glued a flexible 80 Watt solar panel on the roof box, as you can see on the right. I also got a portable 100 Watt solar panel with a 6-meter cable. Both panels can be combined with a total of 180 Watts. I made a connector on the back of the car to quickly plug it in when necessary.

The upside is that if the 100 Watt is sufficient, I can park the car in the shade, put the portable panel in the sun, and still get enough of that delicious 'power juice.'

Now, here's the surprise... The 80 Watt panel was more than enough. I barely used the 100 Watt one, but it's nice to know I have a backup.

The Victron SmartSolar charge controller collects the energy from the solar panels and stores it in my house batteries. I also have a Victron Cyrix-ct Intelligent battery combiner kit that charges the house batteries while I'm driving. This little device 'waits' until the car's starter battery is fully charged and then redirects the charging energy from the car's alternator to the house batteries. This will not affect the starter battery. In fact, the battery combiner kit can even help start the Defender in case the starter battery dies. It uses the power of the house battery for this.

If you're going to buy a converter, here's a tip; check your device that demands the most watts, probably your laptop, and you know which converter is sufficient. My laptop needs 130 watts, so my 300 W converter is already 'too much.'

My shopping list:

2 House Batteries // 95Ah VARTA AGM Accu 12 Volt (LA95)
1 Solar Panel // 80 Watt ETFE Flexible Monocrystalline 515x1020 mm
1 Solar Panel Portable // 100 Watt Portable
1 Solar Charger // Victron SmartSolar MPPT 75/15 12V/24V
1 Battery Combiner Kit // Victron Cyrix-ct 12/24V-120A
1 Converter // 300W Converter 12V to 230V Xenteq PurePower

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