I used a Multifunctional USB Digital Tester to record the power draw of a few handheld gaming devices. I've previously posted a lot of this information in various threads on reddit, but I've decided to collect them here as the new canonical source.
PowKiddy V90
I was curious why my V90 seemed to die within a few hours if I did a software shutdown but didn't flip the power switch, so I got out a USB-C power meter and took some measurements of the power draw in different scenarios.
Interesting tidbits
- Gaming is going to draw give-or-take 1W, depending more on screen brightness than anything else.
- Volume is second place for determining power draw, system and game complexity doesn't seem to have much effect.
- The range seems to be about 0.7 - 1.3W.
- Miyoo draws a little less power than the stock firmware in the menu, Suspend, and software shutdown modes. About the same in gaming.
- Software shutdown draws slightly more power than suspend mode (?)
- Both are essentially the same reduction you'd get from just turning off the display while in the menu - the CPU seems to continue operating at full speed.
- The battery charges at about 2.5W
- The maximum power it will draw from the wall, when gaming and charging, is around 3.5W
This was connected to an official raspberry Pi USB-C power supply - I chose this one because it's rated for over 15W, and it provides power regardless of what's connected to it.
(Amusingly, the initial batch of Raspberry Pi 4's had the same issue as the V90 where they wouldn't charge from a USB-C port. But, unlike Powkiddy, the Raspberry Pi foundation quickly fixed that mistake.)
Update: I added the missing resistors and fixed USB-C charging on mine!
More details
When playing Crash Bandicoot on PS1
- Maximum power draw was 1.3W with the screen brightness and volume maxed out. The power ranged from about 1.1W to 1.3W depending on how loud the ambient noise in the game was (I was standing by the beech.)
- With the volume turned down to 0 and the brightness at the lowest visible setting, it went down to 0.68W
When playing Asteroids for Game Boy
- Power draw ranged from 0.73 to 1.15, depending on volume and brightness.
- It didn't seem to get as loud as Crash Bandicoot, even at maximum volume.
Stock Firmware vs Miyoo Custom Firmware
- Menus are lower in Miyoo, 0.62-0.89W, depending on brightness. 0.47W if you turn the brightness down to 0.
- Stock Firmware is about 1.09W in the menu, I'm not sure how to change the brightness.
- Suspend mode draws 0.47W steadily in Miyoo (same as awake but screen off)
- Stock draws 0.68W in suspend mode.
- After a software shutdown but before flipping the switch, it draws 0.47-0.52W in Miyoo.
- Stock draws 0.68-0.73W.
- (In both cases, it bounced between those two numbers. The real number is probably somewhere in between, but my meter isn't quite precise enough to detect it.)
- In-game was about the same with the stock also going up to 1.3W
PowKiddy RGB10 Max
I took some measurements of the power draw of the PowKiddy RGB10 Max (running the OGS build of EmuELEC 4.2), here's a few interesting take-aways:
- The on-screen battery charge level is slow to update. Based on my measurements, it actually stopped charging when it was reporting 73% charged. Later on it reported 100%.
- In EmulationStation, the power draw depends on how much activity is on screen.
- A basic screen draws ~1-2W
- A screen with video playing and scrolling text draws 2~3.5W
- When gaming, power draw depends somewhat on the game.
- The Legend of Zelda on NES draws 1-2W
- Valkyria Chronicles 2 on PSP draws ~1.5-2.5W in 2D parts and 2-3W in 3D parts
- In general, the power draw is very jumpy when awake, going up and down from one second to the next
- Brightness and volume seems to have a fairly small effect. I'm sure they make some difference, like maybe 0.15W to go from 5% brightness to 100%, but it mostly seems to be getting lost in the noise.
- Wi-Fi does make a noticeable impact, something like 0.5-1W of additional power draw
- When in sleep mode, the power draw is a steadily ~0.26W (with the battery installed but at 100%). Wi-fi does not cause any additional power draw when the unit is sleeping.
- The highest power draw I saw when it was sleeping and charging was 4.4W, but the battery was already fairly full. So it may draw more when the battery level is lower. Charging rate decreased over time, as the battery was approaching 100% charged (despite the UI claiming 73% every time I checked).
Unlike when I tested my V90, I did not remove the battery from my RGB10 Max during testing, so it may be contributing somewhat to the "noise" I mentioned above.
Anbernic RG351P
The Anbernic RG351P has the same CPU as the above RGB10 line, so these number should be inline with the above device, or perhaps a little lower due to the smaller screen.
Recorded numbers are power draw from wall, with the battery disconnected.
- Off: 0.21W 🤷♂️
Stock Firmware
- Home screen, 100% brightness: 1.77-1.87W
- In-game in Ridge Racer for psp: 2.39-3.88W
- Sleeping: 0.21-0.31W
With Wi-Fi dongle attached
- Home, stock wifi attached: 2.08-2.39W, one spike to 3.12
- This seems to break the controls sometimes, I think when it is in the OTG port but not when it's in the DC port (?)
- Home, 3rd-party 2.4/5Ghz wifi attached, connected to 2.4ghz: 2.49-2.65W
- Sleeping: 0.21-0.31w
- Internal wifi power goes from 3.3v with screen on to 0v when sleeping
- It also goes to 0v when "enable wifi" is turned off in the menu
351Elec Firmware
- Home
- 100% brightness: 1.71-1.82W after settling down (initial spikes up to 2.29W while browsing through)
- 1% Brightness: 1.46-1.51W
- Sleeping: 0.21-0.31W
- Internal wifi power goes from 3.3v with screen on to 0v with screen off
- However, it remains at 3.3v with the screen on when "enable wifi" is turned off in the menu. So an internal dongle will always draw power on 351Elec, vs only drawing power when in use on the stock firmware. I opened a ticket, but it was closed as "won't fix".
With Wi-Fi
- Factory wifi dongle
- 1% brightness: 1.25-2.66W, mostly 1.7-2
- 100% brightness: 1.92-2.39W
- WiFi dongle also seems to break the controls in 351Elec sometimes
- 3rd-party wifi, 100% brightness
- Enabled, not connected: 2.34-2.44
- Disabled in menu: no change
- Connected to 2.4 ghz: 2.34-2.39
- Sleeping: 0.21-0.31w
GPD Win Max (1st gen)
The GPD Win Max is basically a small Windows laptop with active cooling, so it's in a completely different league than the above devices. Nonetheless, it's a handheld gaming device, so I think it fits here. (Note: that link is for the 2021 edition, I have the 2020 version, which has a previous-gen CPU, but is otherwise largely similar.)
Can it be charged with an Apple USB-C Charger?
Yes, it works fine. I just tested it with my 87 watt MacBook pro charger. My Win Max's battery is at about 50% and sleeping, and the power draw at the wall is 51w. I fired up Halo Reach in the power draw jumped all the way up to 85 watts.
But as far as I know, Apple follows the standards, so the GPD should work fine with any Apple laptop charger.
What about a Nintendo Switch charger?
Nintendo did a really shoddy job with the USB-C power delivery on the Switch. Because they didn't follow the standard correctly, it's potentially a fire hazard, or more often just doesn't work with devices that do follow the standard.
I don't own a Switch, but I have tested my Win Max with a handful of other chargers, and everything 30 watts and higher that I tried seems to work fine. (Obviously the 30w one charges more slowly.)
Are the Thunderbolt 3 and USB-C ports equivalent when it comes to charging?
I don't think so. For context, the GPD Win Max supports charging at 15v and 20v. The USB PD 1.0 specification allows the voltage to be negotiated to one of 5v, 12v, or 20v. The USB PD 2.0 spec split the 12v option into 9v and 15v. So the Win Max supports 20v only on the USB PD 1.0 spec, but both 15v and 20v on the USB 2.0 spec.
The USB-C (only) port definitely supports 15v charging, but the TB3 port sometimes gets stuck at 12v, and then it doesn't actually charge. My guess is that perhaps it only supports USB PD 1.0(?)
Wayback machine link for my 27W charger, since the amazon page seems to be dead now.
Low Power Charging
Works great with a 27W charger. The system will alternate between charging the battery in less demanding applications and running from combined wall and battery power in more demanding scenarios.
GPD Win Max 2
The Win Max 2 is an upgrade to the original in just about every concievable aspect: better performance, larger battery, larger and higher resolution screen, improved keyboard, more storage options, etc. Low-power charging seems to be the one exception here.
While charging the battery
The max power draw I was able to get on my WM2 was 85W with an average more like 75-80W. This was running borderlands pre-sequel at stock TDP (24W, I think) and the video set to 1600p with the framerate uncapped, while charging the battery from about 50%.
I also maxed out the brightness and volume, but they didn't seem to make much difference.
Going in the other direction, pressing FN+Shift to enable "silent fan mode" (15W TDP), the peak dropped to 81W, but the average was about the same. It did seem less "jumpy".
Initial testing done with the USB 3.2 port with an Apple 140W PD3.1 charger, and a 100W e-marked cable (I don't have any higher rated USB-C cables right now). I then re-tested in the USB4 port and with the stock 100W charger and cable, and got essentially the same results each time.
Given all that, I think the charging circuitry is probably designed for 80-85W and you're not going to get much more than that from any charger. I think when the system's power demands increase, it just lowers the battery charging rate in order to stay within this envelope.
On a full charge
Peak power draw I saw with a charged battery was 52W, with an average probably around 40~45W.
In "silent fan mode", the peak power draw I saw was 38W with typical being around 25~30W.
Brightness and volume probably made some difference, but it was small enough to be mostly lost in the noise.
Low Power Charging
Does not work well. On my Aukey 27W charger (that seems to actually deliver more like 21W) and an Apple 30W charger, the system will enter an "ultra low power mode" where the CPU runs at ~4W and the entire system feels sluggish and undresponsive. I believe it does this in order to ensure it does not use more total system power than the charger can provide; it does not appear to be able to combine power from the battery and the wall at the same time.
60W and above worked well for me and, while I don't have anything in between 30W and 60W, I believe I've read that 45W is sufficient to avoide the ultra low power mode.
I've seen some reports that the system can errantly enter this mode even with higher-powered chargers, but I have not been able to reproduce this. Tested with chargers from Anker, Apple, and others.
(Original power draw post, orginal ultra low power mode post)