Hi guys, new to the forum and new to the Raspberry Pi. I myself recently got a Raspberry Pi 5 and I love it! I to, have considered building a portable cyber deck with mine, mainly as something more rugged than a laptop that I can carry from home to work and back, and to perhaps take camping as well. I have seen all kinds of ways to power them, hence how I came across this thread. I have seen all kinds of YouTube videos of people powering them with battery packs from drills and what not, as well as portable chargers, both of which have drawbacks. Power tool battery packs have drawbacks in they are expensive, have to be charged with a proprietary charger, (both of which you pretty much have to already have to make it worth it), as well as they are built for power tools so the form factor of what you are building has to be built around the whole power supply. I have also looked at portable phone chargers. They are easier, but what I have found in looking into those is most of the time, the actual current output is still not the 5 amps required by the Pi 5, and you never know if they are beefy enough to run one for very long. A lot of times you almost have to divide the mAH by 3 to get an actual realistic number. (lol, not including the 600,000 mAH ones you see on Ali Express the size of your cell phone.)
However, I do know quite a bit about Lithium batteries, and have a 3000 watt DIY solar array with a DIY 280 amp hour 24 volt LifePo4 battery, so let me throw some links and some numbers out there and see what I have come up with so far.
First, I would make it a 12 volt system, would make it easiest to charge, if all else fails, it could be charged off your car battery. I also have a portable 120 watt briefcase style solar panel with a controller to charge with while camping. So I bought one of these, and it works, it does put out 5 amps though I haven't tested it extensively, it seems to work really good.
https://a.co/d/ccT9V9X
It's a buck converter, but it does have a USB port built in and seems to have a USB mode, and I have connected up 12v to it, and powered my Pi 5 no problem.
Cost: $15.00
Next, the batteries, I would get two of these, this would give you 12, 7.2ah, 3.2 volt LifePo4 batteries. This would give you enough batteries to make 3, 12.8v batteries, which you can parallel together, for a total of 21.6 Amp Hours at 12 volts = 259.2 watt hours.
Cost: $90.00 (and quite a bit more available power than a drill battery which costs about the same not including it's charger).
Finally, you will need a 3S BMS (Battery Management System) for your battery, don't let this scare you, it's a very easy thing to set up. Once it's set up, it will make sure your battery doesn't overcharge, over discharge, all the cells will charge and discharge evenly making them last longer. Don't have to worry about short circuiting anything, it takes really good care of your battery for you. If you do short circuit your battery, all you have to do is unplug the harness, wait 10 seconds, plug it back in, and your back in business. Here's a link to one perfect for this project.
https://a.co/d/j6OZ422
Cost: $12.66
To make things easier to understand if you are unfamiliar with building LifePo4 batteries, I'm going to explain it like this, but you can make the battery any way you like to fit your project.
1. Get 3 pieces of PCV tubing, the batteries are 70mm long, by 32mm thick, so 3 pieces 280mm of pipe large enough to fit the batteries into.
2. Put the batteries in the pipe just like you would a flashlight, 4 batteries each.
3. Connect all three positives together and then all three negatives together to parallel them to make one big 12.8v battery. Picture them laying flat on the table in front of you. Also picture a big lead coming off the first battery cell's positive terminal, and a big lead coming from the last cell's negative terminal. (More on that negative lead in a minute).
4. There are 4 leads coming off the BMS, 3 red wires, one black wire. THESE ARE SENSOR WIRES ONLY, they do not carry any real current.
You just work your way across the plug like you have them laid on the table in front of you, first red wire on the main positive, second red wire on second cell positive, third red wire on third cell positive, and finally the black wire on the third cell negative. These wires are going to be super thin, next you will need at least a 20awg wire coming off the first cell positive terminal going to your charge/discharge point, (like the positive post on a car battery). {20AWG wire is the recommended wire size for carrying 5 Amps, I would personally use something a bit thicker myself, as the batteries themselves can be charged at higher than 5 amps}
5. Take another at least 20awg wire, again, I recommend a bit thicker wire myself to go from the main negative where the black lead is connected to and run that to the B- connection on the BMS, then run another similar wire from the P- to the main negative terminal, again, think of the negative terminal on a car battery.
6. You're DONE! Congratulations, you have just built your very first LifePo4 battery!
A BMS shuts the battery off in an emergency by disconnecting from the negative side of the battery rather than the positive side. I realize there is a diagram on the link that shows how it connects up, but they show two different diagrams, and it might be hard to tell what is what, but they all work the same, just remember B- goes to the Battery, and P- goes to Power.....lol one diagram shows a C-/P- (they are one in the same, though all of the BMS's I've had experience with are B- and P-.This BMS is pretty small, but it does do a lot.
On another note, it says this BMS is for a Li-ion battery, it's just fine, they have a cell voltage of 3.7v instead of 3.2v, but the charging range is the same, however you can't make a viable 12v battery with those types of cells as the fully charged state of them is 4.2v, while a LifePo4 battery sits around 3.65 fully charged. That is why you always see the lithium car type batteries advertised as 14.6v. My cat is currently sacked out on my datasheet for the buck charger, but I believe it can handle input up to 30 volts and turn it down to 5 volts for your Pi.
Total cost for this project: $118.00 plus shipping and other odds and ends.
Ok, the upsides to this route are:
You can build your battery however you want to to fit your project
Lithium is lighter than other options.
Lithium chemistry holds it's charge constant all the way till it's done.
LifePo4 can be discharged no problem down to 0% with no ill effects, though it is thought 5-10% is a good place to stop and charge.
You can charge this battery with anything from a wall wart left over from an old router to a pair of jumper cables on your car battery.
You can fast charge LifePo4 batteries as well. Without seeing the actual datasheet on these particular batteries, I can't say for certain, but it wouldn't surprise me if you could charge them with a 10AMP car charger.
Now the downsides are:
Water = VERY BAD! Never let lithium batteries of any kind get wet!
NEVER charge LifePo4 batteries in the cold! 0 degrees Celsius, or 32 degrees F, if you charge, they won't catch fire, or explode, but it will absolutely DESTROY your cells, and they will never work again.
Lithium is a bit pricier than other options, but in this case, it's not too far out of range especially if you aren't in a hurry to get it all put together.
I apologize for such a long post, especially as it's my first, but maybe it will give some folks some ideas, and leads on things and help a few people out!
However, I do know quite a bit about Lithium batteries, and have a 3000 watt DIY solar array with a DIY 280 amp hour 24 volt LifePo4 battery, so let me throw some links and some numbers out there and see what I have come up with so far.
First, I would make it a 12 volt system, would make it easiest to charge, if all else fails, it could be charged off your car battery. I also have a portable 120 watt briefcase style solar panel with a controller to charge with while camping. So I bought one of these, and it works, it does put out 5 amps though I haven't tested it extensively, it seems to work really good.
https://a.co/d/ccT9V9X
It's a buck converter, but it does have a USB port built in and seems to have a USB mode, and I have connected up 12v to it, and powered my Pi 5 no problem.
Cost: $15.00
Next, the batteries, I would get two of these, this would give you 12, 7.2ah, 3.2 volt LifePo4 batteries. This would give you enough batteries to make 3, 12.8v batteries, which you can parallel together, for a total of 21.6 Amp Hours at 12 volts = 259.2 watt hours.
Cost: $90.00 (and quite a bit more available power than a drill battery which costs about the same not including it's charger).
Finally, you will need a 3S BMS (Battery Management System) for your battery, don't let this scare you, it's a very easy thing to set up. Once it's set up, it will make sure your battery doesn't overcharge, over discharge, all the cells will charge and discharge evenly making them last longer. Don't have to worry about short circuiting anything, it takes really good care of your battery for you. If you do short circuit your battery, all you have to do is unplug the harness, wait 10 seconds, plug it back in, and your back in business. Here's a link to one perfect for this project.
https://a.co/d/j6OZ422
Cost: $12.66
To make things easier to understand if you are unfamiliar with building LifePo4 batteries, I'm going to explain it like this, but you can make the battery any way you like to fit your project.
1. Get 3 pieces of PCV tubing, the batteries are 70mm long, by 32mm thick, so 3 pieces 280mm of pipe large enough to fit the batteries into.
2. Put the batteries in the pipe just like you would a flashlight, 4 batteries each.
3. Connect all three positives together and then all three negatives together to parallel them to make one big 12.8v battery. Picture them laying flat on the table in front of you. Also picture a big lead coming off the first battery cell's positive terminal, and a big lead coming from the last cell's negative terminal. (More on that negative lead in a minute).
4. There are 4 leads coming off the BMS, 3 red wires, one black wire. THESE ARE SENSOR WIRES ONLY, they do not carry any real current.
You just work your way across the plug like you have them laid on the table in front of you, first red wire on the main positive, second red wire on second cell positive, third red wire on third cell positive, and finally the black wire on the third cell negative. These wires are going to be super thin, next you will need at least a 20awg wire coming off the first cell positive terminal going to your charge/discharge point, (like the positive post on a car battery). {20AWG wire is the recommended wire size for carrying 5 Amps, I would personally use something a bit thicker myself, as the batteries themselves can be charged at higher than 5 amps}
5. Take another at least 20awg wire, again, I recommend a bit thicker wire myself to go from the main negative where the black lead is connected to and run that to the B- connection on the BMS, then run another similar wire from the P- to the main negative terminal, again, think of the negative terminal on a car battery.
6. You're DONE! Congratulations, you have just built your very first LifePo4 battery!
A BMS shuts the battery off in an emergency by disconnecting from the negative side of the battery rather than the positive side. I realize there is a diagram on the link that shows how it connects up, but they show two different diagrams, and it might be hard to tell what is what, but they all work the same, just remember B- goes to the Battery, and P- goes to Power.....lol one diagram shows a C-/P- (they are one in the same, though all of the BMS's I've had experience with are B- and P-.This BMS is pretty small, but it does do a lot.
On another note, it says this BMS is for a Li-ion battery, it's just fine, they have a cell voltage of 3.7v instead of 3.2v, but the charging range is the same, however you can't make a viable 12v battery with those types of cells as the fully charged state of them is 4.2v, while a LifePo4 battery sits around 3.65 fully charged. That is why you always see the lithium car type batteries advertised as 14.6v. My cat is currently sacked out on my datasheet for the buck charger, but I believe it can handle input up to 30 volts and turn it down to 5 volts for your Pi.
Total cost for this project: $118.00 plus shipping and other odds and ends.
Ok, the upsides to this route are:
You can build your battery however you want to to fit your project
Lithium is lighter than other options.
Lithium chemistry holds it's charge constant all the way till it's done.
LifePo4 can be discharged no problem down to 0% with no ill effects, though it is thought 5-10% is a good place to stop and charge.
You can charge this battery with anything from a wall wart left over from an old router to a pair of jumper cables on your car battery.
You can fast charge LifePo4 batteries as well. Without seeing the actual datasheet on these particular batteries, I can't say for certain, but it wouldn't surprise me if you could charge them with a 10AMP car charger.
Now the downsides are:
Water = VERY BAD! Never let lithium batteries of any kind get wet!
NEVER charge LifePo4 batteries in the cold! 0 degrees Celsius, or 32 degrees F, if you charge, they won't catch fire, or explode, but it will absolutely DESTROY your cells, and they will never work again.
Lithium is a bit pricier than other options, but in this case, it's not too far out of range especially if you aren't in a hurry to get it all put together.
I apologize for such a long post, especially as it's my first, but maybe it will give some folks some ideas, and leads on things and help a few people out!
Statistics: Posted by Bill768 — Sun Apr 28, 2024 8:23 am