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Battery power choice
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Battery power choice

by joeldodenhoff on Thu Jul 18, 2019 9:09 pm

Hi all,

I'm not too confident that I know how to choose the right battery for the situation. I just want to make sure to I don't start any fires or waste money on something too weak.

I've got two 1.8" Color TFT LCD displays with MicroSD card breakouts and a Micro-Lipo Charger for LiPo.LiIon Battery w/ MicroUSB jack.

If I want to run both screens simultaneously off the same battery, which would be a recommended battery for this kind of project? Ultimately, I'd like to have the project run on the battery or be plugged in via MicroSD for power.

Thoughts?

joeldodenhoff
 
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Re: Battery power choice

by franklin97355 on Thu Jul 18, 2019 11:20 pm

What are you running the displays with and are there any other items you plan to power? How long do you need this to run on battery power?

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Re: Battery power choice

by joeldodenhoff on Fri Jul 19, 2019 1:31 pm

I was under the impression that by powering yhe screens that it would display an image file on the onboard Micro SD card slot. If i need some kind of controller, I'd go for something as small as possible, like a Trinket or something (if that would work). It's only supposed to display one image. I'd imagine adding the option to cycle through multiple images would really require the controller to specify the time between image changes. This is all I'm looking to power. Just want to have the screens show the same image. That's all.

joeldodenhoff
 
Posts: 37
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Re: Battery power choice

by joeldodenhoff on Sun Jul 21, 2019 4:46 pm

Hi all,

Just following up on this. I (probably incorrectly) assumed that the LCD screens with breakout and Micro SD would display images on the card kinda out of the box as it were, without an arduino or RPi controlling it. So if I throw in a Trinket or a suggested small controller to power two of these screens simultaneously, could someone suggest the proper Li Ion battery to use? It would be nice if images could be displayed for a few hours, using aMicro-Lipo Charger for LiPo LiIon Battery w/ MicroUSB jack to recharge.

joeldodenhoff
 
Posts: 37
Joined: Wed Aug 13, 2014 5:27 pm

Re: Battery power choice

by joeldodenhoff on Tue Jul 23, 2019 9:00 am

Any suggestions anyone? I'm sorry if this is a stupid question.

joeldodenhoff
 
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Re: Battery power choice

by adafruit_support_bill on Tue Jul 23, 2019 9:33 am

You will need a processor of some kind to drive these. A Trinket does not have enough pins. Something like an M0 Feather would have sufficient pins - as well as a built-in LiPo charger.

To determine battery size, you need to know the current draw of your load. And you need to decide how much run-time you need.

The displays draw about 50mA each with the backlight on. And an M0 Feather is probably going to average about 25mA. So you are looking at roughly a 125mA current draw. Multiply that by your run-time requirement to determine the minimum battery capacity required.

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Please be positive and constructive with your questions and comments.