I’m looking to do a winter project (well, Fall so far) and am thinking of doing a portable power station, DC only mainly USB output or output to jump start a car, run a tire inflator, other DC output device 5v or 12v. was looking at my options for this: either prismatic li-ion or a big 12v lifepo4 battery connected to a boost or buck converter for the 5v, 12v output.
That’s really expensive though even buying from China, so i was thinking why not use a bunch of li-ion batteries in parallel and make a huge battery pack? Laptop pulls? While I’m not thrilled about the prospect of that, it would be cheaper than a $200+ lifepo4 battery then electronics for the outputs, case, etc.
what kind of output device do you recommend for USB, etc.? I was looking at those power bank output boards with USB A, type C, with PD, etc.
Anyone done one of these before? Just exploring if this is even doable for cheap
@Parametrek is the DC-DC Wizardry guy, he really knows his stuff and you do want to talk to him. Last time I checked, he wasn’t accessing BLF very often, so you might want to try and send him a PM and, if he doesn’t answer after a couple of days, try contacting him on the ##flashlight IRC channel on the Libera.chat server; he’s usually online and I’ve learned a lot from him there.
Found nice, big LiFePO4’s for my Maglite project, maybe You could use them to build Your own power station:
When 4 are connected in series You get 12,8v - very universal voltage. Just add some 12v car charger with let’s say 4 USB ports and You’ve got a simple power station. Need 110/220v? Add a pure or modified sine inverter, this one is quite fine when it comes ti quality:
I looked at those also. Problem is to get the high capacity I’d need series/parallel. I think I may end up doing a crapload of good quality 18650 and go from there dince the good lifepo4 batteries are really expensive. Trying to do it on the cheap is turning out to not really be cheap.
A house fire is sure even more expensive than the price difference from the usual Li-Ions to LiFePO4. About 2 and a half years ago, I studied the matter closely and decided to pay the difference and get the much safer LiFePO4 chemistry rather than running that risk – YMMV of course.
Current requirements to jump start a car are fairly large, you could make a big USB power bank pretty easily though.
For some research, have a look at what the DIY powerwall guys have been building, I’ve seen a couple of large, power stations in peli cases, iirc there’s a vid on YouTube of a dude charging a Tesla.
+1
That’s why I went with LiFePO4. Right now I’m building power bank in Peli case (Peli knock off to be precise ), chose to go with 32x26650 LiFePO4 instead of “normal” cobalt Li-Ion’s - it’s more expensive and I get less Wh packed in, but I can sleep feeling safe. Which wouldn’t be the case with Li-Ions.
I’m mainly looking to run USB devices at the moment. Like electric blankets (DC-not AC, don’t want to mess with inverters) charge phones, etc. I had an idea for higher current applications but thats seeming a bit optimistic at this point. I can always get a standalone jump starter pack or something like that.
For Wh, not really sure? I was thinking 50-100 Ah batteries? Enough for at least 3-4 days.
Nice. Not looking to charge a Tesla. Just run USB devices currently. I would probably just pony up for a dedicated power station before I went crazy trying to build one like that.
I see. If You need just 5v, then You can go with parallel Li-ion setup - I find it safe enough. What I have is this “powerbank shell” from AE, put in 21x18650s - most bought for this project, some I had lying around in good condition. Mine has 56Ah at 3,7v, but if You would use at least 3000mAh cells - would be above 63Ah. This powerbank from link is not great quality, but works. If You want some cheap but working - I can recommend it.
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), chose to go with 32x26650 LiFePO4 instead of “normal” cobalt Li-Ion’s - it’s more expensive and I get less Wh packed in, but I can sleep feeling safe. Which wouldn’t be the case with Li-Ions.