Most uninterruptible power supplies (UPS) require AC voltage and use specific batteries that must be changed every few years. But those may be oversized and not the most efficient if you just want to keep single board computers (SBCs), low-power mini PCs, routers, or security cameras up and running during power failures.
Luckily, some mini UPS solutions use standard rechargeable 18650 batteries, output 5V, 9V, or 12V DC, or even PoE (15V/24V) which may be more suitable for those use cases. Many mini UPS solutions come from WGP (Wonderful Green Power), so let’s have a look at the WPG103A model.
WPG103A mini UPS specifications:
- Batteries – 4x 16850 batteries for a combined 10,400 mAh capacity
- Protection – Overcharge, over-discharge, overcurrent, and short circuit protection
- Misc – Power button, status LEDs
- Power Input – 12V/2A via DC jack
- Power Output
- 5V via USB Type-A port (likely limited to 1.5A or 2A TBC)
- 9V via DC jack
- 12V via DC jack
- Max power – 24 Watts
- Dimensions – 205 x 80 x 31mm
The mini UPS ships with a Y cable in case two devices use the same voltage, a DC cable, a 5.5/2.5mm to 3.5/1.35mm jack adapter, and an instructions manual. The main use case of such mini UPS is to power a WiFi access point and an FTTx broadband router. However, I imagine it could be used as backup power for a security camera and some SBCs and mini PCs. Sadly, the company only mentions the total power output (24W), and I doubt the 5V USB will deliver the ~5A needed to power a Raspberry Pi 5 under all conditions.
The WPG103A mini UPS can be purchased on AliExpress for about $30 shipped.
Other cheaper options are the DC1018P or DC1036P from another manufacturer, still using four 18650 batteries internally, but also supporting PoE.
The company has different variants, and this time the output capabilities of each port are clearly listed.
Basically, the USB port supports up to 10 Watts (5V/2A), the 9V port 9W or 18W, and the 12V port (if any) 12W to 24W depending on the selected model. The PoE port supports either 15V or 24V DC output as set by the user with a switch, and up to 24 Watts again depending on the model.
Unless I’m mistaken, it’s cheaper than the WPG models because the 18650 batteries are not included, and instead, the user can select the capacity needed for his/her application. Talking about price the DC1018P goes for about $23 on AliExpress and $22 on Amazon after ticking the 10% off coupon box. You’ll also find plenty of other models on AliExpress or Amazon.
Thanks to Onebir for the tip
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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Nice! Till now I’ve been making my own by combining charging and step-up circuits with laptop batteries. It’s important to check if these devices contain a balancing charger, which is unlikely despite the super low cost. The reason is that over time batteries will diverge and will no longer be fully charged. In addition, it’s normal for such use cases to employ salvaged batteries because you don’t need much power.
Ideally such small UPSes should have only one cell. It costs less in charging/discharging circuit and simplifies the battery management. The flat prismatic batteries are great for this (my DSL router UPS uses this BTW), but using parallel 18650 will work optimally as well. But that of course will not permit to deliver 2A under 12V.
Is small, but at its price I can install a standard 600VA UPS + POE Gigabit injector
The link to the WPG103A actually goes to the DC1018P.
I guess none of these have a communication port for status notification, not useful with a router o camera but necessary for an orderly shutdown of a mini-pc when the battery runs low.
MARSRIVA KP7 seems better choice due to LiFePo4. Sure, price will be different, but it will last much longer.
I’d like to read more reviews of smaller UPS devices. A connection diagram for the *another company” devices mentioned here could be great as well. In the same way a diagram is supplied for the first item. was supplied for the device.