DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Fri Apr 06, 2018 1:25 am

Hi.

I've been looking around for a USB power bank for the Raspberry Pi 3B and also the 7" touchscreen. I would like to power both but there are certain things that I would like to know and most importantly what kinds of power banks (Names) I could use that can do my requests.

So I have the SmartiPi case and the "small" back cover. I was thinking of a USB power bank that can fit inside and can power both the Pi and the screen for at least two days or longer for Retrogaming.

So first thing is a power bank that is 5v 2.5 or 3A. One that does not interrupt power at random or shut down after some time, like some do.
Can still run the Pi when the power bank is being charged. That one is important because it's going to be a permanent install and I don't want to disconnect if I want to plug it into the wall. (Use on Charge) and can support a small fan connected to the GPIO pins.

I was first thinking of an internal battery but I want to go this route instead. I thought it would be best to ask you guys instead of buying a USB power bank and all the sudden it's not what I needed. I'm sure some of you know of one that would work perfectly and it's a cheap power bank.

If you do know of one please put the name of it so I can check it out. Thanks :)

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Gavinmc42
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Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Fri Apr 06, 2018 4:49 am

Powerbanks are not designed for continuous use or use while charging.

You are better off getting a higher voltage battery pack and converting the voltage down to 5V.
A Hobby RC battery bank, LiPo for lightness, NiMH is you want safety.
Get something like a 3-4 series LiPO 11-15V
8-10 series NiMH - 9.6-12V

Powerbanks work be taking a 3.7VLithium voltage, boosting it up to 5.0- 5.2V which goes into the PI3 which steps it down to 3.3,.18V etc.
There is probably another booster on the LCD for backlight.

All this means is the Powerbank needs lots of current into it's booster to get amps output at 5V.
Then to charge it and power the Pi/LCD at the same time a power supply would need to provide 5.2 at least 5+amps.
Easier to get 15-20V supplies at 2amps
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Fri Apr 06, 2018 3:49 pm

Well, that's not the comment I wanted to hear. I'm sure there's a power bank capable somewhere. I guess I'll keep looking around for now. I have a small power bank with one cell that runs the pi just fine with the screen but however, it's lacking power so it does show the yellow lightning bolt indicating it doesn't have enough to run properly So I don't use it because I do not want to risk data corruption.

I really don't need 5A, 2.5A to 3A does the trick. Anyways. Thanks for the reply.

bobsalmon
Posts: 2
Joined: Fri Apr 06, 2018 3:53 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Fri Apr 06, 2018 4:00 pm

I use my RPI 3 daily and is fully portable.
I use a "PocketJuice", dual USB port with an off/on switch, 8000maH. Available from Amazon for $8 on sale. It comes with a 3" USB cable.
It will run the Pi all day and better than any laptop that I am aware.
My screen is powered separately by a 11.1V Li-Po battery.
Photos available.

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Sat Apr 07, 2018 3:15 pm

bobsalmon wrote:
Fri Apr 06, 2018 4:00 pm
I use my RPI 3 daily and is fully portable.
I use a "PocketJuice", dual USB port with an off/on switch, 8000maH. Available from Amazon for $8 on sale. It comes with a 3" USB cable.
It will run the Pi all day and better than any laptop that I am aware.
My screen is powered separately by a 11.1V Li-Po battery.
Photos available.
Ok. I checked out the pocket juice. It's perfect for size but it plugs into the wall to charge. Big downer for what I need it for.
But 8000maH daily just for the Pi is a great start. Still needs to run both the screen and the Pi. I'll do some purchases and figure it out myself.

Thanks for helping though guys. I'll look into USB Power Banks for laptops.

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Gavinmc42
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Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Sun Apr 08, 2018 3:06 am

I have used a 7.2V 6 cell 3300Mhr NiMH RC car pack to power a Pi3 and the LCD.
A good power supply and a few diodes and simple LM317 charging circuit can charge and run it at the same time.
You will nee low drop-out(SW) regulator to step 7.2 down to 5.1V.

A 8000Mhr power bank will just have 3 x 3.7V 18650 2600Mhr cells in parallel.
Use 3 or 4 of these in series and then Sw reg the voltage down to 5V.

A very simple version is 2 x LiFePO4 cells in series with just a linear regulator.
But these LiFePO4 have lower capacity :( They will not catch fire as easy :D
4 x 18650 LiFePO4 in 2 series, 2 parallel will give you 2600mhr 6.4-7.2volts.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Tue May 15, 2018 3:11 pm

So I thought I would give an update. Since I hate some threads never have solutions to problems. I'll continue to update it to until I see it should be complete.

So I picked up the Pocket Juice Portable Charger. It's an 8000 mAh 3.4A Max Output. This thing is the right size to fit in the back case, well, almost need some tweaks. Anyways connecting the screen and the Pi to the same USB port will show it's lacking power because it shows the lightning bolt. However, if I connect the screen to one of the USB ports and the other to the Pi it disappears and everything works great.

I have not tested (Yet) how long it will last for. It cannot charge well using it. So that's a bummer but the size and so far the power works great.
I will be doing some testing to make sure this is a perfect battery. So stay tuned if anyone wants to use it.

I paid $20 CAN for it.
Here's a link to Amazon.com https://www.amazon.com/s/ref=nb_sb_noss ... 0+mAh+3.4A

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Imperf3kt
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Location: Australia

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Tue May 15, 2018 9:39 pm

Note that 8000mAh will take between 4 and 16 hours to charge, depending on the power supply charging it and the circuitry inside the powerbank.

8000mAh will most certainly not run a Pi and a screen for two days.
I expect around 7 hours when brand new, less with age.

That powerbank does not sound capable of your needs.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Wed May 16, 2018 12:50 am

Imperf3kt wrote:
Tue May 15, 2018 9:39 pm
Note that 8000mAh will take between 4 and 16 hours to charge, depending on the power supply charging it and the circuitry inside the powerbank.

8000mAh will most certainly not run a Pi and a screen for two days.
I expect around 7 hours when brand new, less with age.

That powerbank does not sound capable of your needs.
That's just speculation until I do my tests. You may be right or wrong but one thing is for sure, less with age is correct.
But yes 7 hours is around what I wanted it for.

Jdgriff82
Posts: 1
Joined: Mon Jun 25, 2018 1:10 am

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Mon Jun 25, 2018 1:12 am

Checking on followup for your issue. Did the power bank end up being acceptable? Also, what monitor did you use, and did you even notice any issues running the monitor through your Pi?

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Wed Aug 01, 2018 5:31 pm

Jdgriff82 wrote:
Mon Jun 25, 2018 1:12 am
Checking on followup for your issue. Did the power bank end up being acceptable? Also, what monitor did you use, and did you even notice any issues running the monitor through your Pi?
Sorry, late response. I better update all of you on what's going on.
I picked up a USB voltage meter that records all the data I need. My Pi uses the Dual Fan heatsink and the 7" touchscreen. Now Yesterday I did the tests for the 8000mAh battery. I'm not releasing the data just yet as I also picked up the PocketJuice 12000mAh battery bank.

I can say that it ran like it was plugged into the wall with the PocketJuice 8000mAh battery bank. Not once did I see the lighting icon in the top right. If you are looking for one that will last 2 days, you will need to look elsewhere. The tests I did are on the extreme end.

So yes it ended up being acceptable to me. However, it may not for you guys.
For the monitor, it was the 7" touchscreen here: https://www.sparkfun.com/products/13733


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Imperf3kt
Posts: 1382
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Location: Australia

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Tue Aug 07, 2018 1:15 am

Thanks for the in-depth review.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Tue Aug 07, 2018 2:32 pm

Imperf3kt wrote:
Tue Aug 07, 2018 1:15 am
Thanks for the in-depth review.
No problem. I consider this post now complete. I will keep my website post updated and redo those tests again in the near future when the batteries wear down.

Houkouha
Posts: 1
Joined: Wed Sep 26, 2018 9:05 am

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Wed Sep 26, 2018 9:07 am

Can I ask, if that bank and cable worked? Was the screen and Pi functioning normally and how long?

DestructiveBurn
Posts: 14
Joined: Fri Mar 30, 2018 3:30 pm

Re: USB Power Bank for Raspberry Pi 3B and 7" touchscreen

Mon Oct 01, 2018 4:20 pm

Houkouha wrote:
Wed Sep 26, 2018 9:07 am
Can I ask, if that bank and cable worked? Was the screen and Pi functioning normally and how long?
Hello, sorry for the late response.
I did some tests with both of these power banks You can view the data sheets here: http://www.destructiveburn.com/pocketju ... rry-pi-3b/
I use the 8000 mAh as my driving force for both the Pi and the screen. Since I've used it quite a lot now, it will last for around 5 hours. The 12,000 mAh is not worth my time as it won't stay at 5V on load. The Pi needs at least 4.9V to 5.2V to fully run correctly without overclocking in mind. That bank wouldn't do it as the data I provided shows.

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