Power Draw and Battery Curves

Battery life here is calculated using the estimated energy in two AA eneloop pro batteries (6.24 Wh) or this Jauch Lithium-ion battery (5.37 Wh). Times are generally rounded to the nearest 5 minute interval. The equation used to determine the battery life is:

Time = Battery Energy (mWh) / Power Consumption (mW)

If the mWh rating is not directly reported, you can find the battery energy by taking the nominal voltage and multiplying it by the mAh rating.

Comparison Between Models

For reference, here is the power consumption of various GBA boards with no game, no screen kit installed, and the audio muted. These measurements were made using a benchtop supply providing 2.4V (nominal output of 2x NiMH AA batteries) or 3.7V (nominal output of a lithium-ion battery) depending on the board. A Fluke 117 was used to measure the current. Power is then calculated by multiplying the voltage and current.

Board	Idle Consumption
Stock GBA	134 mW
AGBM-02	149 mW
AGBM-11	160 mW
AGBM-01	170 mW
Funnyplaying GBA*	288 mW

*Note: The FP GBA had the LEDs turned off.

This does not give the entire picture, though. I used the same set up, but also installed the Funnyplaying GBA IPS Max kit, and measured steady state power draw (no game inserted, no audio) across every brightness level. While the stock GBA pulls the lowest amount of power at baseline without any screen installed, the AGBM is more efficient with loads past ~500mW. The Funnyplaying GBA replacement board is less efficient than the original, but that's likely because there's a microcontroller on-board to handle the LEDs. (Again - these tests were run with the LEDs off)

AGBM-01 is excluded because I didn't have a board handy for testing, but it uses the same converters as the AGBM-11 so power draws should be similar. The graph will be updated with AGBM-02 and -12 data once those boards are completed, because they use a different converter.

The caveat to these findings is the audio. The AGBM has a higher maximum volume than the original GBA, and also uses a less efficient power supply (roughly 75% efficient) specifically for the audio compared to the original GBA, which drew power directly from the batteries (no conversion stage, so 100% efficient). Because a design goal of mine was to achieve the clearest possible audio with a higher volume level, this is a sacrifice I was willing to make, and it does bring down the total efficiency. It's important to note that the power draw from the audio is not catastrophically large, something like 50 to 100mW at max volume. The GBA's speaker with the quieter max volume only uses ~15mW!

A point of comparison: running an OEM GBA at maximum brightness on an IPS Max screen running Pokemon FireRed with the volume maxed out takes about 840mW - for the AGBM at these settings with the higher maximum volume and clearer audio quality, that power draw is ~900mW.

AGBM-01

Summary Table:

Screen Kit	Max Time	Min Time
FP IPS Max	10h15m	6h
FP ITA	15h30m	8h
Hispeedido IPS	11h	5h20m

The baseline power consumption for the AGBM-01 (no cartridge, no screen kit, audio muted) is ~170 mW (measured at 2.4V input).

I tested a handful of these configurations myself with brand new eneloop pro batteries (battery curves seen below) and the times roughly line up with the calculated values. I found that many settings yielded battery life a bit longer than calculated, so you can consider these estimations to be somewhat conservative (depending on how old your batteries are and how many cycles they've seen). I did one test with alkaline AA batteries (Energizer) and the battery life was cut by roughly 50%.

The low battery LED turns on when the voltage passes 2.3V. This represents roughly 5 to 7% battery left. The LED begins blinking when the voltage passes 2.1V, which represents less than 1% battery life remaining. The Game Boy shuts off when the battery voltage hits 2.0V.

Hispeedido IPS (Laminated)

Battery life can range anywhere between ~5 hours and ~11 hours, depending on settings. The "medium" brightness test case below represents my preferred play settings, which yields 9 hours of gameplay.

Brightness	Cartridge Type	Volume	Headphones?	Power draw (mW)	Calculated Battery Life	Low Battery Threshold	Critical Battery Threshold
Max	Everdrive	Max	No	1175	5h20m	20m	3m
Max	Everdrive	Max	Yes	1058	5h55m	25m	3m
Max	Everdrive	Mute	N/A	1050	6h	25m	3m
Max	Original	Max	No	1025	6h5m	25m	3m
Max	Original	Max	Yes	980	6h20m	25m	3m
Max	Original	Mute	N/A	973	6h25m	25m	3m
Medium	Original	Max	Yes	690	9h	35m	4m
Min	Everdrive	Max	No	705	8h50m	35m	4m
Min	Everdrive	Max	Yes	643	9h45m	40m	5m
Min	Everdrive	Mute	N/A	635	9h50m	40m	5m
Min	Original	Max	No	608	10h15m	40m	5m
Min	Original	Max	Yes	573	10h55m	40m	5m
Min	Original	Mute	N/A	568	11h	45m	5m

Note 1: These tests were done with Pixel Mode 1.

Funnyplaying ITA (Laminated)

Battery life can range anywhere between ~8 hours and ~15 hours, depending on settings. The "medium" brightness test case below represents my preferred play settings, which yields 12 and a half hours of gameplay.

Brightness	Cartridge Type	Volume	Headphones?	Power draw (mW)	Calculated Battery Life	Low Battery Threshold	Critical Battery Threshold
Max	Everdrive	Max	No	792	7h55m	30m	4m
Max	Everdrive	Max	Yes	739	8h25m	35m	4m
Max	Everdrive	Mute	N/A	732	8h30m	35m	4m
Max	OEM	Max	No	720	8h40m	35m	4m
Max	OEM	Max	Yes	682	9h5m	35m	4m
Max	OEM	Mute	N/A	670	9h20m	35m	4m
Medium	OEM	Max	Yes	502	12h25m	50m	6m
Min	Everdrive	Max	No	528	11h50m	50m	6m
Min	Everdrive	Max	Yes	475	13h10m	50m	6m
Min	Everdrive	Mute	N/A	466	13h25m	50m	6m
Min	OEM	Max	No	449	13h55m	55m	7m
Min	OEM	Max	Yes	415	15h	1h	7m
Min	OEM	Mute	N/A	410	15h15m	1h	7m

Funnyplaying IPS MAX (Laminated)

Battery life can range anywhere between ~6 hours and ~10 hours, depending on settings. I did not include low battery LED estimates because I did not collect battery curves for this kit, which is what I use to estimate the low power LED state and the blinking state.

Brightness	Cartridge Type	Volume	Headphones?	Power draw (mW)	Calculated Battery Life
Max	Everdrive	Max	No	1047	6h
Max	Everdrive	Max	Yes	930	6h40m
Max	Everdrive	Mute	N/A	922	6h45m
Max	OEM	Max	No	897	7h
Max	OEM	Max	Yes	852	7h20m
Max	OEM	Mute	N/A	845	7h25m
Min	Everdrive	Max	No	745	8h20m
Min	Everdrive	Max	Yes	683	9h10m
Min	Everdrive	Mute	N/A	675	9h15m
Min	OEM	Max	No	648	9h40m
Min	OEM	Max	Yes	613	10h10m
Min	OEM	Mute	N/A	608	10h15m

Battery Curves

Here's a handful of the measured battery voltages for various settings for the nerds.

AGBM-11

Summary Table:

Screen Kit	Max Time	Min Time
FP IPS Max	10h	5h
FP ITA	13.5h	7h
Hispeedido IPS	10h	5h

The baseline power consumption for the AGBM-11 (no cartridge, no screen kit, audio muted) is ~160 mW (measured at 3.7V input).

The low battery LED turns on when the voltage passes 3.5V. This represents roughly 20 to 5% battery left, depending on the load current. The LED begins blinking when the voltage passes 3.2V, which represents less than 1% battery life remaining. The Game Boy shuts off when the battery voltage hits 3.1V.

Hispeedido IPS (Laminated)

Battery life can range anywhere between ~4.5 hours and ~9.5 hours, depending on settings. The "medium" brightness test case below represents my preferred play settings, which yields 8 hours of gameplay.

Brightness	Cartridge Type	Volume	Headphones?	Power draw (mW)	Calculated Battery Life	Low Battery Threshold	Critical Battery Threshold
Max	Everdrive	Max	No	1165	4h35m	1h5m	3m
Max	Everdrive	Max	Yes	1048	5h5m	1h5m	4m
Max	Everdrive	Mute	N/A	1040	5h10m	1h	4m
Max	OEM	Max	No	1015	5h15m	1h	4m
Max	OEM	Max	Yes	970	5h30m	1h	4m
Max	OEM	Mute	N/A	963	5h35m	1h	4m
Med	OEM	Max	Yes	680	7h55m	50m	6m
Min	Everdrive	Max	No	695	7h45m	50m	6m
Min	Everdrive	Max	Yes	633	8h30m	45m	6m
Min	Everdrive	Mute	N/A	625	8h35m	45m	6m
Min	OEM	Max	No	598	9h	40m	7m
Min	OEM	Max	Yes	563	9h30m	40m	7m
Min	OEM	Mute	N/A	558	9h40m	40m	7m

Funnyplaying ITA (Laminated)

Battery life can range anywhere between ~7 hours and ~13.5 hours, depending on settings. The "medium" brightness test case below represents my preferred play settings, which yields 11 hours of gameplay.

Brightness	Cartridge Type	Volume	Headphones?	Power draw (mW)	Calculated Battery Life	Low Battery Threshold	Critical Battery Threshold
Max	Everdrive	Max	No	782	6h50m	55m	5m
Max	Everdrive	Max	Yes	729	7h20m	50m	6m
Max	Everdrive	Mute	N/A	722	7h25m	50m	6m
Max	OEM	Max	No	710	7h35m	50m	6m
Max	OEM	Max	Yes	672	8h	50m	6m
Max	OEM	Mute	N/A	660	8h10m	50m	6m
Med	OEM	Max	Yes	492	10h55m	45m	8m
Min	Everdrive	Max	No	518	10h20m	45m	8m
Min	Everdrive	Max	Yes	465	11h30m	45m	9m
Min	Everdrive	Mute	N/A	456	11h45m	45m	9m
Min	OEM	Max	No	439	12h15m	45m	9m
Min	OEM	Max	Yes	405	13h15m	40m	10m
Min	OEM	Mute	N/A	400	13h25m	40m	10m

Funnyplaying IPS MAX (Laminated)

Battery life can range anywhere between ~5 hours and ~9 hours, depending on settings. I did not include low battery LED estimates because I did not collect battery curves for this kit, which is what I use to estimate the low power LED state and the blinking state.

Brightness	Cartridge Type	Volume	Headphones?	Power draw (mW)	Calculated Battery Life
Max	Everdrive	Max	No	1047	5h10m
Max	Everdrive	Max	Yes	930	5h45m
Max	Everdrive	Mute	N/A	922	5h50m
Max	OEM	Max	No	897	6h
Max	OEM	Max	Yes	852	6h15m
Max	OEM	Mute	N/A	845	6h20m
Min	Everdrive	Max	No	745	7h10m
Min	Everdrive	Max	Yes	683	7h50m
Min	Everdrive	Mute	N/A	675	7h55m
Min	OEM	Max	No	648	8h20m
Min	OEM	Max	Yes	613	8h45m
Min	OEM	Mute	N/A	608	8h50m

Battery Curves