The latest generation of small power stations are impressive. Ecoflow, Bluetti, Goal Zero. These are versatile, nice looking machines, great to have handy for emergencies or when visiting the great outdoors while still wanting to run your espresso machine and a small AC — modern glamping, in other words. I have one, love it, and highly recommend it. But I don’t actually use it. I mean, hardly ever. Let’s be honest, no one really uses these and, well, of course — that box sitting in the corner of the garage is there for peace of mind in case of TEOTWAWKI and for the half dozen adventure trips we had planned to take last year but only managed one. Grid power is just much more convenient. A powerhub does, however, come in handy when there’s a power outage, but in the USA that’s maybe a few hours here and there over the course of a year.
Contrast that with much of Africa, where there are several power outages lasting a few hours every single day, and that’s if there is any grid at all. Solar-charged power stations are a necessity here, not a luxury. Sadly, you almost never see solar-charged power banks being used in places like Nigeria. What is common instead are fuel generators. You can likely guess the reason. Poverty. A cheap fuel generator is $200, while my solar-charged power bank, with its fancy OLED display, is more like $1200 (plus $200 for a 300W panel to charge it). It’s a classic debt trap — lack of productive power keeps people from being able to afford productive power. This is why universal access to modern affordable power is UN Sustainable Development Goal #7. Call it SDG7 if you want to sound like you’re dialed into this sort of thing.
There is more to it than the high upfront cost however. Besides the obvious environmental downside to running legions of small fuel generators, fuel is expensive and getting more so. If you run a quick analysis of fuel costs to run 1 kW of power (inefficiently with these cheap gensets) for several hours a day, then over a year, you’ve spent about as much as if you had bought the cool solar thing. Still, there are relatively few takers though. Look closer and one can see why. The systems available today don’t quite work in the majority of African settings because they were never designed to. So, what’s wrong?
Everyday use is one reason. My system will see 80 hours of use in its 5 year lifetime, tops. A poor entrepreneur running his shop with one of these products will run more than that on her system in 2 weeks. Lithium-ion batteries are great for low cost, high energy density, but they wear out pretty fast when pressed. You know how you’re not supposed to run your cellphone dead every day, and if you do, it basically won’t hold a charge after a year? Like that. Expect it to die young.
Dirt and dust are another reason. Inverters and charging circuits make lots of heat, so most rely on fans to circulate air over the internal power boards. In most of the places I’m describing, that quickly means dirty PCBs, which is bad especially if the dust attracts some moisture and the clay is alkali or salty, or the box gets rained on, etc. These are high-voltage circuits, after all. Spritz some water into the side vents on your laptop if you want to see what I mean. Folks who use their power banks at Burning Man get close to the conditions in Africa and I’ve seen many inverter systems fail there. After just 2 weeks.
Then there’s too much heat. Li-ion batteries wear out faster when run hot, but more crucially, it is very dangerous to charge them above 50C, so all reputable makers of these systems (all of the ones I mentioned) cut off charging when interior temperatures climb above 45C. Just run a Google search on “battery fire” and see how many hits you get. 45C is easy to reach when running full tilt while ambient is 38C and you have circuits driving 500W of continuous power enclosed in a plastic box. I did mention the target market was Africa. Expect some down time.
And not enough power. If the goal is to give people a tool to replace a generator, then you need continuous power throughput. The inverter in my system can push 1500W (1300W after a few minutes). However, from solar, it can only charge at 300W. So 300W is the max throughput power. Which is totally fine for my usage. Fully charged from the wall before I head out and it will run my satellite wifi, laptop, portable fridge, et al for an entire long weekend whenever I need to get away from it all. But even the smallest generators can put out 800W continuously, so 300W is pretty anemic. Expect some disappointment.
In summary, what the African market truly needs is: A system that can survive running full blast, daily, for more than two years, without overheating or shorting its circuits or fatiguing its batteries.
Thus, the batteries should be LiFePO4. Though heavier and more costly, LiFePO4 batteries can cycle 5× more than regular Li-ion (cobalt) batteries and 10× more than lead. Also, LiFePO4 batteries are safer to run warmer and tend not to fail explosively, a common go-to move for Li-ion. The enclosure needs to be sealed, so must rely on passive external cooling. Lose the plastic and sport a ridiculously big heat-sink, in other words. More like this tank:
And the PV side should handle as much input power as the inverter can supply output power. You don’t need to design systems this way so long as you can afford, or don’t intend, to provide plenty of warranty support. Expect some returns.
But a power system thus designed could displace much of the over 200 million gensets currently used in Sub-Saharan Africa. It is sorely needed.
Customers are highly resourceful. Which is bad when you sell a product. Expect lots of short circuits and reversed polarity from homemade wiring. Here’s an example of a plugstrip:
Lot’s of use of these dangerous things.
About the author: Kurt Kuhlmann, Co-CEO of Amped Innovation, is a serial entrepreneur, tinkerer and the tech brain behind some of the best-known off-grid and outdoor products: TEG based stoves, UVC and electro-chlorinator water treatment systems, LED lights. Kurt founded a technology non-profit called D.Rev building low-cost healthcare products for emerging markets. He is easily distracted by pretty much anything technical, and he is pretty nervous about CO2 and especially interested in technology that appertains to poor people.
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Source: Clean Technica