Van life: electricity

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This post belogs to my van life series. Check the first post

Electricity is a super important topic while living on a van, because your energy reserve on board is limited and you need to make sure you have enough of it, and you need to have the means to get more energy when needed.

Most vans and motorhomes have 2 electric systems in parallel. A 230V system, and a 12V system.

Note: I live in Italy and we have a 230V grid. Your country might differ but the concept is the same. When you read 230V, read “your home grid”.

The 12V system is what runs the whole van when it’s not connected to the grid.

The 230V system is activated when you connect it to the grid. When you do so, the electronics on board will take care of recharging the batteries, and in some cases the 230V will run the fridge if it’s a trivalent fridge.

A trivalent fridge runs on LPG (yes, surprise: LPG, which is a fuel, can cool down too!) when the vehicle is still, 12V when moving and 230V when connected to that. I had one in the past. I now have a compressor fridge that only runs at 12V and I’d never go back. It’s so much better.

Then some have an hybrid system that generates 230V from the battery. This is through a tool called power inverter.

The electric system mainly needs to power, at 12V direct current:

  • The lights
  • The 12V compressor fridge
  • The water pump
  • The heating system when it’s cold

And then it needs to recharge the tools. As a developer, I always have with me:

  • My iPhone
  • My iPad
  • My Kindle
  • My MacBook Pro

I charge the first 3 with some USB plugs I installed on the van. I can also connect the MacBook Pro to the USB plug, but it does not charge it. It just keeps it at the current charge, which is fine most of the time.

To charge it, I use the 230V power inverter (I have a pure sine wave 1500W inverter), so I can charge the MacBook Pro with its original charger.

The MacBook Air on the other hand charged just fine from the USB port, which is one of the reasons I love my 2018 MacBook Air. Great battery life, silent, no heating issues.. But I also love having 3 more inches of screen on my 16” MBP.

Sometimes I also use the hair dryer with this 230V power inverter. And the guitar amp, so I can live the rock and roll life and play my Telecaster 🎸 in the woods.

With my setup, I had zero problems during summer. Some more problems during winter, or mid-season in days without much sun.

For 7 years I had 2 100Ah AGM batteries to power my 12V system. They worked great for my needs.

One single 100W solar panel on the roof would help charge them during the summer, but during winter it’s almost useless.

During winter trips, it was more frequent for me to stop by a camping or a motorhome area that have electricity to recharge a bit the batteries. Mostly due to water issues (I tend to go in cold places), which I’ll explain where I talk about water.

I recently changed this 2 AGM battery system to a single 100Ah LiFePo4 battery. This completely changed everything for winter.

You need to know that with an AGM battery you can’t make use of 100% of its power. Due to its discharge curve, the voltage provided to the appliances quickly diminishes to the point that those 12V devices do not work any more.

We can use an AGM battery up to 30% of its nominal power, so with a 100Ah battery, we just have 30Ah in reality.

A LiFePo4, commonly called lithium battery, is VERY different. With a 100Ah LiFePo4 battery you can use up to 80% of its power, without any problem. This is because its discharge curve keeps the voltage high enough even when it’s very low on charge.

In the end, a single 100Ah LiFePo4 battery provides more energy than 2 100Ah AGM batteries. So that’s why I swapped the 2 AGM batteries I had with a single LiFePo4 battery.

This is not the only advantage.

The other advantage is that a LiFePo4 battery charges really, really fast. It sucks all the energy it can get, from the solar panel or from what is now my favorite source of power: the engine.

With my 2 AGM batteries system, if they were at 0% from my usage point of view (but as we discussed, still 70% charged!), yes the alternator would charge them when I was driving, but I had to drive for many hours in order to 100% charge them.

The LiFePo4 battery is a whole different story. It takes everything the alternator can give it. In my system, while driving it can receive up to 75A from the alternator. This is 100% free energy coming from the engine, that would be otherwise wasted.

I tested this a few times, one the night with lights, fridge, charging phones and heating running at 100% in a -28C night (yes, it can get pretty cold in Italy too, but we’ll get to winter talk soon), I got the battery down to 70% of its charge. The day after I turned on the engine, took a 40 minutes drive around the town I was staying, and I got the battery back to 100%.

It is great to just get 30% off the battery charge in such a night. The heating system had to work at 100% all night long. In a normal night, with heating turned on I might get -15% of the battery charge. And in summer, when just the fridge is turned on, the power consumed is even less. I will explain the heating system later.

This kind of autonomy is just amazing. That’s true independence. I also have zero need to go and connect to the electricity of the camping, or charge it at 100% in the garage before leaving for a road trip. It’s now a 100% fully independent system. If the power fails from some “The Walking Dead” event or like we heard about the Texas winter storm in Feb 2021, then I can just go on the van.

Oh another advantage is weight. Weight is an important topic. This van is sold as a 3.3t vehicle, and without additional load it weighs about 2.9t. So I have about 400Kg of loading “space”. The 100Ah battery weighs much less than an AGM battery. This in particular weighs ~14Kg instead of 30Kg. Plus, remember I had 2 AGM batteries. This made the whole system weigh 14Kg instead of 60Kg. Very cool.

The system is super secure, and it has its own control system that allows a simple drop-in replacement of the AGM battery. If you’re interested, this is the battery I installed: Usually when you start looking into this kind of battery, you can spend a lot of time digging and the more you dig the more confused you become. There are many kinds of different batteries, and configurations. This system I used is preconfigured and they give very detailed instructions which gave me the confidence to install it myself, which was a very fun project. And one in which you learn a lot (makes sure you do your research, these things can be very dangerous if not done 100% correctly!).

I had to change the solar panel controller with one with the right curve to to charge a LiFePo4 battery, from Victron Energy, and I also bought their 230V battery charger even though I never had the need to charge the battery from 230V.

Would I recommend the LiFePo4 battery to anyone? Yes, because it completely changes your feeling with electricity. You just don’t worry about it.

New high-profile camper vans are starting to get those batteries installed from the factory now, but most of the time you install it after-market. It’s just a matter of time until every van will have those installed by default.

A 100Ah battery and a 100W solar panel for me is enough because of my style. I never stay in a single place for more than 2 days, so I don’t have to have a huge amount of energy stored in the battery. In case of emergency I just turn the engine on, and the battery gets charged at 40A even though I am not driving around (but it gets charged faster when driving).

It all depends on your needs. I’ve seen people with 500W of solar panels on the roof, or with 300Ah lithium installations. At that point it might also make sense to have an induction cooking system (I use LPG for that).

I recharge my main machine, a 16” MacBook Pro, closed without using it, from 0% to 100% in 1h 30m, consuming 11-12% of the charge of the Lithium battery. It consumes about 6A when charging, including the power consumed by the power inverter itself, ~1A.

Then, once it’s completely charged, the power consumption of the MacBook Pro is about 4A.

A MacBook Air is much better for travel. It’s lighter, and smaller. And it charges 100% of the battery with 7% of the charge of the Lithium battery.

In a sunny day, I get more energy from the solar panels than the energy I consume while working. This means the energy balance is always positive, because it’s rare that I work at the computer more than 5 hours, while on a trip.

If I run out of power on cloudy days or during winter, I can just turn on the engine because I already have to move somewhere, or just to charge the battery a little bit. Or I go in a camping where I am more free with the things I can do (more on this in another post).

And in case of emergency I have a 50000mAh power bank that keeps the Mac running for the whole day.