The GPA is designed to use Lithium-Ion (LiIon) or Lithium-Polymer (LiPo). Do not use the GPA to charge NiMh or NiCd cells.
I thought I'd start a thread to post some battery test results in the hopes that other people may chime in. My tests usually involve booting up the GPA, starting a game, and leaving it in attract mode (full volume using the external speaker) until the batteries die. I have a script that runs at bootup that will write the time to a file every 2 minutes (in case I don't notice when it dies).
These tests were done on a GPA v1 board modified to use the Adafruit PowerBoost 1000c. This is meant as a test to simulate the GPA v2 board.
Marked “3.7v 600mah 25c”
Single Cell TEST 1: 1h 48m 108m
2 Cells in Parallel TEST 1: 3h 43m 223m
2 Cells in Parallel TEST 2: 3h 44m 224m
Single Cell TEST 1: 1h 05m
Note: This cell is small enough to fit 2 in the AA compartment of the GPA (wired in parallel). In fact, with some modding, I think maybe 3 could fit. Multiplying the number of cells by the TEST 1 time would give a good rough estimate of play time.
14500 marked “2300mah”
Charged using wall charger
2 Cells in Parallel TEST 1: 1h 25m
2 Cells in Parallel TEST 2: 1h 28m
14500 marked “2500mah”
2 Cells in Parallel TEST 1: 1h 40m
3.7V 750mAh Battery For MJX X300C X400 X500 X800 Quadcopter
Single Cell TEST 1: 1h 36m
Sanyo UR14500P 840mAh 3.7V - Unprotected 14500 Li-ion Battery
2 Cells in Parallel TEST 1: 3h 26m
2 Cells in Parallel TEST 2: 3h 26m
Note: These cells are the same size as AA batteries, and it's likely that (based on these results) they are what we will be recommending people use. They will likely require a single wire to be run, but then they will be easily usable/replaceable.
1200mAh Li-po Battery for Syma X5SW X5SC RC Quadcopter S1P5
Single Cell TEST 1: 2h 20m
Single Cell TEST 1: 2h 26m
Note: This cell seems as if it would fit in the AA compartment with some fairly minor modifications to the plastic, but I haven't tried fitting it in.
2 Cells in Parallel TEST 1: 5h 10m
Note: I think you could likely fit 2 of these in your GPA if you cut the entire bottom out of the AA compartment.
These tests were not done by me, and they weren't done on a GPA, but they are very relevant.
Over at https://retropie.org.uk/forum/topic/960/neopigamer/75
, mrvanes has posted some 14500 test results. If you look up higher (older) in that thread, we discuss some specific 14500 brands and such.
mrvanes Wrote: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.
I believe that the results mrvanes posted show that the tests I did with my as-cheap-as-they-come 14500 cells would be improved by ~2x if I used top-of-the-line 14500 cells.
UPDATE: I think this theory is even further solidified with the addition of the "Sanyo UR14500P" test results.