(Not much going on on the beer front of late, thanks to COVID-19. Yaaaaaay.)
One of the topics of van design and builds I’ve been researching a lot is the electric system, and more specifically, batteries. There’s a fairly wide range of options when it comes to batteries, as far as capacity and cost. Many people with minimal needs will run a single 100Ah (amp hour) AGM batteries, a type of sealed lead-acid design. The big pro on this type of battery is the cost; the big con is the usable capacity. On the other end of the spectrum these days is the LiFePo4 battery – lithium iron phosphate.
These batteries have a much greater discharge capacity than AGMs, meaning you can extract much more juice out of them from a fully charged state without reaching a discharge level where the battery is at risk of being damaged. These batteries are also available in higher capacity units – 200Ah batteries are becoming more available – and these batteries have a much higher total cycle capacity than AGMs, meaning they should last far longer before reaching their end-of-life. However, the cost of LiFePo4 batteries is quite a bit higher.
The rabbithole I’ve gone down of late, however, is the do-it-yourself world. There’s a whole mess of people out there who are buying small cells from Chinese manufacturers, connecting them up to form standalone battery banks, and using these to store charges from off-grid solar systems and the like. And the more I dig into this world, this subculture, the more I’m leaning toward going this route with my future van build.
One of the folks on YouTube I’ve found lately is this fellow Dan, who has a channel titled “Freely Roaming”. He’s got a nice series of videos on this topic, going through the whole process of assembling a working battery from various components that will end up in his van. Dan does a good job of explaining things, he gets technical but not too technical.
There’s another fellow out in YouTubeland named Will Prowse, who has a channel titled “DIY Solar Power”; Will covers all sorts of related topics, does tear-downs and reviews of a wide range of related equipment. He also has an online forum populated with quite a lot of hobbyists and off-grid enthusiasts, and those folks are looking at all of these options and going over them with fine-tooth combs; its quite the amazing resource for information and advice.
These days, the hot ticket is the 3.2v 280Ah LiFePo4 cells from various Chinese manufacturers. Connected up in series, four of these cells gets you a 12v 280Ah battery – a capacity well above the 100Ah or even 200Ah options available for purchase currently, and for a fraction of the price. Depending on the source, you can expect to pay $1,000 or more for a 12v 200Ah battery; these cells can be had, including shipping (if you’re willing to wait for sea freight), for around $100 per cell, so $400 for an equivalent voltage battery that has forty percent higher capacity! Now you still have to invest in other components; a battery management system, proper bus bars for connecting the cells, other cabling, etc. – but even with those added costs, the cost saving is insane.
Many people will shy away from this route if they knew about it. You’re not going to have a warranty on your battery if something goes awry; customer service is going to be tricky, dealing with folks in China; and the idea of putting all of this gear together can be intimidating. I know I’m intimidated, even after having watched a good half dozen different folks’ videos working with these cells; but as time goes by, I’m feeling more comfortable with the idea.
So, my working plan at the moment is, when the time comes, to order eight of these cells, build up a pair of 12v banks, wire those together in parallel so they remain at 12v (wiring in series would result in 24v, 12v * 2). That would give me a whopping 560Ah of capacity – far greater than I think I would need, based on my estimated usage levels. The usual big power draws in vans come from AC 110v devices, the things with a normal wall socket plug, and the inverter needed to convert power from 12v to 110v to power the gear connected up. I’m planning to keep my AC devices to a bare minimum as it is. But with this larger capacity, I’ll have no problem adding to my system should the need, or desire, arises.
Thank you!!1