NeoPiGamer

agentKrowka

@mrvanes Hi. Great job man :) Interesting choice for the battery. Are those 2x 2500mah ? Did you had any chance to check how long they last in "real play" conditions ?

mrvanes

They're ordered as 2900 (per AA!), but I don't believe they have that much juice, or I destroyed them while soldering the pack. I get about 1-2 hr pure playtime on a full charge. I'll time it someday. I did tweak config.txt back to 30fps refresh for the piTFT overlay instead of 60 yesterday, so that may add some stamina? I also made a GBZero and that one lasted way longer on a single 2600 Adafruit LiPo.

agentKrowka

@mrvanes Well if you went for 14500 Li-ions - I know what you mean. I am yet to meat a good quality bat. of that sort (they usually have around 900 mah :/ ) Maybe you could try to squeeze in some 16650 bat. But they are a bit too long as far as I can see.
I am trying to go with a 3.7v 3000mah flat lipo (64x48x8 mm) ... I think I cna fit it in if I rly try hard this weekend :D

mrvanes

Yes, they're 14500's. I made the mistake of ordering 18650's (pack) before I knew the difference (I allways call them AA's when I buy alkalines). Was a bitter surprise when they arrived after 3 weeks transport. But why would they print/sell/advertise 2900 when it's actually 900 (apart from blatantly lying for profit)?

And yes, you will never fit 18650's in the GBA.

agentKrowka

I was asking myself the same question and started to dig around to see if there is some similar bat. to AA size which would be better in terms of capacity .
Found this most helpful thing:
https://en.wikipedia.org/wiki/List_of_battery_sizes

As per this apparently the "common" capacity for 14500 Li-ion is 700-800 ... So I guess they print it there just for profit ...perhaps ? Honestly - no idea :/

One note.. Finding the best battery for the job was always a problem in all my projects that required batteries :/
Mostly ended up using li-po packs. But with them comes the problem ----- size. They are super nice and flat which is pretty much useless int his project since a 3000mah will be somewhere around (60 to 80) x (80 to 100) x (around 3.5) mm.
Best I found is 64x48x8 mm
http://www.ebay.com/itm/3-7V-3000-mAh-Polymer-rechargeable-Li-battery-For-GPS-DVD-PDA-Tablet-PC-814864-/121823784043?hash=item1c5d436c6b:g:5xMAAOSwn8FXRm~T

There is a option to take smaller capacity and make it as a pack 1s2p (1 series 2 parallel). Not good, since unbalance charging of parallel lipos is dangerous. So unless you find/make a suitable pack that you can take out and charge in external charger this option is useless.

Last option is to just find one fitting Li-po and go with the capacity that it provides. I think you can find a 2500mAh li-po that would fit your design (with some plastic cutting) .

If you figure out something different/better I would appreciate if you let us know.

mrvanes

I'm sticking with the 1s2p 14500 Li-ion pack I made, if not for the sole reason of aesthetics. I like the look of the blue pack that snuggly fits the original AA container ;)

moosepr

I have thought about using the 14500 batteries in mine, but changing the battery box so they are actually in parallel rather than in series. The pi will happily run from 4.2-3.3v if you pipe it straight into the 5v connection on the gpio, and most USB devices will work ok, the only thing I have had issues with, is a cheepo wireless keyboard/mouse from china. tp-link wifi sticks work ok.

with that setup you will be getting 1800mah from the 2 batteries, but only 4.2-3.3v of course

I have also thought about keeping the battery box intact, and running from alkaline batteries as a normal GBA would. I have heard (but yet to test) that the pi will run on as little as 2.7v, and if we believe everything we read on the internet, alkaline batteries are in the region of 1800–2600 mAh if you buy good ones. so a nice posh set of Duracell's could actually yield reasonable runtimes!

Flavor

We are using 2 14500 batteries in series in our current Game Pie Advance build. At some point, I'd like to move to using a different lithium pack, but this is quite nice for now. As you guys have said, it's nice to have them fit right into the AA holder of the GBA.

Tekkaman_Slade

@mrvanes - Congrats on completing your build. It looks great. Nice to know the NeoPiGamer has a spiritual cousin out there.

@moosepr - There are benefits to using a good quality 2500mah lipo vs AA cells with capacity and the ability to safely charge directly in the unit being some of them. The pi zero is very energy efficient so 2500mah should get you many many hours of continuous play (6-8+ to be exact).

@Flavor - Keeping the AA holder sounds nice, but it takes up valuable space. Removing it will actually give you space for a bigger better battery with adequate breathing room.

mrvanes

I updated the wiki with some storytelling and comments.
http://wiki.mrvanes.com/wiki/mrvanes/view/Raspberry+Pi/Advance+Zero/

I am very dissapointed in the so-called 2900mAh 14500's I ordered so I'm doing a second attempt using 900 Trustfires I found at AliExpress. Hope they're more honest and supply better stamina than what I get now. Will do a constant-load stamina test (using some game demo mode) from full charge to Pie lights down before and after to compare.

Flavor

@mrvanes Nice update, thanks. I did some research on 14500s, too. It seems that most people claim the Sanyo UR14500P cell is the best. I believe the P is for PROTECTED. You can find them on eBay, but they probably won't be as cheap as the ones you already tried.

After having played with it for a while now, how do you like the X/Y being microswitchy (as opposed to the A/B being rubber pads)?

mrvanes

I have no issues using the microswitches as opposed to the rubber pads whatsoever. And my kids (who have never used the original) neither ;)

The Sanyo's seem to be great indeed!
http://www.dampfakkus.de/akkutest.php?id=20

This is the Trustfire (2012)
http://www.dampfakkus.de/akkutest.php?id=19

Flavor

With some drilling, 3 new wires, and a fair bit of brainstorming/planning, we were finally able to add X and Y buttons to the Game Pie Advance.

space cadet

Awesome build man!

dukeofhentai

I would love to see a step by step tutorial on how to do this. I want to breath new life into my old gba.

THanks.

_INNATE_

Hi, I'm sorry if you've already answered this question but I can't find it anywhere. I know you replied awhile back to someone asking about how you connected the screen. I understand how you modified it up until what you connect directly to the pi. I'm really just trying to finish up my schematic of my own project like yours so if you have a picture of the connections, that would be extremely helpful. Thank you and wonderful build!

Tekkaman_Slade

@_INNATE_

The link in my previous post has all the pinout information for the display I used at the bottom of the page. Use the image in this post to match the display pins to the corresponding raspberry pi GPIO or SPI pinouts.

mrvanes

Here are the results of the long overdue AA stamina tests of the Trustfire 900's:

Load: NES Donkey Kong Classics Demo mode (start, then leave it alone).

GBA Zero (2 AA's, 3.2" PiTFT, USB hub + USB audio)
Old pack: 1.37:08
Trustfires: 3.21:00 (207%)

GB Zero (4 AA's, 2.8" PiTFT, USB hub + USB audio + USB Teensy + USB Wifi)
Old pack: 2.16:54
Trustfires: 4.36:00 (202%)

So, conclusive it's safe to say that over 3 hours of gameplay are possible on a GBA Zero using 2 Li-ion AA's.

Flavor

@mrvanes Excellent. I recently bought a couple Sanyo cells, so I plan to do some similar testing when they arrive. This is very encouraging!

I added your info along with some battery test info that I generated over at http://forum.freeplaytech.com/thread-4418.html

Flavor

BTW, I updated the aforementioned forum post with a new result. While I was previously getting less than 1.5 hours out of 2 14500 cells (which were the cheapest I could find), I now got almost 3.5 hours out of a new pair of the Sanyo UR14500 cells.

This almost perfectly matches mrvanes' test with the 3.2" TFT (which is also what I'm using) with Trustfire batteries.