(Last Updated On: March 27, 2023)

If you’re searching for a portable power station, you’re likely overwhelmed with available options. There are power stations with massive capacities and high power output; at the same time, there are those with low capacities and low power output. Those larger power stations can be very expensive, and for the most part, most consumers aren’t looking for those.

Instead, if you want to opt for a mini power station that can power low-wattage appliances and be great for charging your devices, you should consider this GMM 300W power station. This power station from GMM isn’t anything spectacular or highly innovative. Still, throughout my testing, I found this solid mini power station that makes for a good buy.

Power Capacity

This GMM power station has a 296Wh capacity; it’s a decent amount; of course, what matters most is the amount of capacity you can use. This is why I ran an AC and DC capacity on this power station to check the efficiency of the two. I took the DC capacity test using a load test. I continuously ran it at 120W until the power station reached 0%: after about 2 hours, I ended up with 276Wh of used capacity from the DC cigarette lighter port on this power station which means that the DC capacity efficiency of this GMM power station is 93%.

 

I used a watt meter for the AC capacity and powered a crock pot at its high setting, which pulled about 200W. For the AC capacity test, I ended up with 260Wh, which gives me an 87% efficiency for this power station from the AC outlets.

So you can use most of the 296Wh capacity of this GMM power station; I’m impressed. Most power stations tend to have lower efficiency than this, so you are getting more of your money’s worth.

 

Then comes the question of how long you can use the power station. That depends entirely on what you’re powering from this GMM power station. With the DC capacity test, you can already know how long to use this power station within a 120W-130W draw, which would be about 2 hours of runtime.

A 200W appliance will last about 1.5 hours, and if you use a 300W appliance, you’re looking at a 1-hour or lower runtime for this power station. Not bad at all and fits into what the unit is capable of. If you stick with a 100W or lower power draw, you can use this power station for many hours.

Output Ports

The outputs included in this GMM power station are varied and useful. You get a DC cigarette lighter port, charging ports, and two AC outlets that can output 300W.

The cigarette lighter port has a 12V/10A (120W) output, and I didn’t have appliances to test it. However, I could test it with the load tester when I did the DC capacity test. I could pull the full 120W of the DC port; more so, I could pull about 15V and get nearly a 150W output from the DC port for a little while until the voltage dropped. So the cigarette lighter port on this power station performs better than it says.

The charging ports are a strong point of this GMM power station, with four charging ports in total. USB-C 1 has a 100W Power Delivery output, USB-C 2 and the USB-A 1 ports share a 12W output, and the USB-A 2 port has an 18W Quick Charge output.

I found it strange that a USB-C 1 and a USB-A port were paired together, but it’s fine. What matters most is that this power station has a 100W USB-C Power Delivery port that you can use to fast charge nearly any device; a 100W USB-C port on a power station is excellent.

I simultaneously charged a Baseus power bank at 65W from the USB-C 1 port and fast-charged my Galaxy Note 9 from the USB-A port for my charging port testing. I also charged my Lenovo laptop at 30W from the USB-C 1 port.

The selection of two outlets on this 300W power station fits well into what this unit offers. Each AC outlet can accept 3-prong appliances and output 300W of Pure Sine Wave. 300W is a decent amount of power, but it fits into the mini power station category meaning that you will mainly be able to power small lower, powered appliances.

For example, I was able to power a large crockpot at 200W and a mini crockpot at its setting at 90W simultaneously, and the power station was able to run the combined 290W load with no problems. The power station will automatically shut down if you exceed the 300W max output. 300W is a decent amount of power to use; as long as you know what you want to power, you can’t be disappointed. You can easily power select blenders, TVs, CPAP machines, and more from this power station.

Input Charging

Recharging for this GMM power station is good. The unit does not use a direct AC charging cable connection that some power stations use; instead, you get a 50W AC charging brick in the box. Recharging this power station has 50W only is pretty slow; thankfully, you can use the 100W USB-C port to recharge the power station, and the best part is that you can use the USB-C port and the DC input at the same time to recharge this power station at 150W.

You must provide your 100W Power Delivery charger to make the most of the USB-C recharging on this GMM power station.

Another recharge option is to use a solar panel to recharge the power station, as this unit has a 60W solar recharging speed. For my solar charging test, I used a Bluetti PV68 solar panel, and that got me about a 40W recharging rate, which is pretty decent, so if you want to recharge this GMM power station from a solar panel, you can; remember that you will need a DC 5521 cable though.

Design

This is a mini power station because it only has a length of 9 inches and a width/length of 4 inches, and the unit weighs 7 pounds. The large handle at the top of the power station makes carrying this unit around very easy, and you won’t have trouble taking it anywhere you want to, except for an airplane.

When it comes to using the power station, at the front is where you’ll find nearly everything, and that includes the charging ports, the DC cigarette lighter port, the screen, and the buttons. The screen shows the remaining power capacity, estimated runtime, input wattage, output wattage, and what section is activated on the power station.

The buttons on the power station include a main power button, a flashlight button, a DC power button, and an AC power button.

The flashlight is bright and draws 5W of power from the power station, and it has three settings that include high, low, SOS, and flashing modes. The DC button activates the charging and DC ports, and the AC button activates the two AC outlets off to the side of the power station.

Build

Even though this seems to be GMM’s first power station, I have to credit them for making a well-built one. The entire power station is plastic, which is fine because most power stations are. So you have to follow the same rules: not to drop this power station on the ground or expose it to water. The unit has an internal fan that does a good job of keeping it cool.

	GMM 300W 296Wh Mini Portable Power Station Specs
Power Capacity	296Wh
USB-C 1	100W Power Delivery
USB-C 2 / USB-A 1	Share 12W
USB-A 2	18W
AC Output	300W
DC Output	120W
AC Recharging	50W
USB-C Recharging	100W
Solar Recharging	60W
Size	9 x 4 x 4 inches
Weight	7.7 Pounds

Conclusion

Overall, I’m impressed by this GMM mini power station. It’s a 300W power station with excellent efficiency and 296Wh capacity. The screen even features an estimated runtime and dual recharging from the USB-C and DC input ports. The only thing missing from this GMM power station is LiFePO4 batteries; besides that, it’s a solid 300W power station.