Batteries for the Raspberry Pi
tyler wrote 09/29/2021 at 02:20 • 0 pointsI have a project I'm working on that needs a power solution. The issue is, what I need to power is a Raspberry Pi 4 and a very hungry screen.
I've found that the screen is happy only with at least 10W of power, so that leaves me trying to fit a ~5A@5V into a rather slim package. I've looked at the most powerful offerings that are made to power the Pi, and some look great - good form factor/size, good software, not unreasonable price. The problem is, they fit the Pi's spec of 3A and I'm not comfortable leaving the Pi with potentially less than an amp to run off of.
There's also building a LiPo pack or something similar. I've hunted around a bit, and didn't find any reasonably performant charge-discharge controllers in a good price range - on the sites I visited.
So the answer seems to me be a slim USB battery bank. Does anyone have a suggestion of any one of those Pi solutions, a DIY path, or a good power bank that won't break my bank?
Thanks, Tyler
ask
Discussions
Become a Hackaday.io Member
Create an account to leave a comment. Already have an account? Log In.
Filip Mulier's suggestion 4 sure! And buy a 5A 3S battery management board (BMS) of Aliexpress (3-6$) for doing charging and safety stuff. At 3-5amps I think you could get away with standard li-ion cells-use vtc5 or hg2 cells, they're rated for some hi currentz. For more current draw go for lipo packs made for multi-rotors, if you plan on integrating a BMS they already have balance wires coming out from each cell so no need for soldering on batt poles.
Are you sure? yes | no
Soldering directly to batteries? Who would do such a thing? Not me for sure....
(And thanks for the wisdom everyone, I'll see if there is any place to actually buy things these days.)
Are you sure? yes | no
You might want to consider a lipo pack as used for RC planes or cars. You could get a large capacity 3 cell pack pretty cheaply (~12v - see hobbyking site, they have a handy search by pack dimensions). They do not have any safety (over current, overcharge, etc) so either be careful or find boards to cover that. Some RC battery chargers (< 1A charge) are very cheap and small and could be used for charging this type of pack.
For power conversion from the pack I would consider using 2 buck converters (to get 5v regulated), one to power the pi and one for the monitor. Each could be 3A or less. This would give the option of shutting off the monitor to save power while letting the pi do its thing. Some buck converters have an enable, so you could use the pi's gp-io to control the enable pin of the converter to the monitor.
Are you sure? yes | no
pixelQ have very good screen, or look this https://hackaday.io/project/169103-low-power-esp32-handheld
Are you sure? yes | no
You can get a 5-cell lithium battery pack hat for the pi, or salvage a battery from an old laptop and interface it to the pi, or grab several laptop batteries and take them apart and check the individual cells - most of them have only 1 or 2 failed cells, and you can mix and match to get a full battery pack up and going again.
You can get lithium cell battery testers on eBay that will discharge them and tell you their capacity, this would allow you to salvage cells from old laptop batteries. The local hackerspace will probably let you have old laptops for free, or put an ad on craigslist and get a bunch of people to give you their old laptops.
https://www.ebay.com/itm/114317051039?hash=item1a9dd3c49f:g:C2gAAOSwgxRfF-mj
Are you sure? yes | no
Perhaps use a PiZero instead? Somewhat less power usage due to not having wifi, and IIRC only 1 core, so should use less power overall.
Are you sure? yes | no
Yep, that would do it. But (oops) I forgot to mention that this is in a laptop, so the extra power is a must-have (and dual displays are nice too).
Are you sure? yes | no