Looking to make a small ups battery back up for a 3-6.5 1.1watt fan

Thread Starter


Joined Dec 7, 2016
I just bought a small in cabinet usb powered fan. (it came with an AC adapter) Its 3-6.4v 1.1watt fan.

After talking to the people at the electronic store, the only thing they could suggest is a HUGE 8-outlet computer battery backup power strip.

I want to make something that is much smaller and can stay plugged in, with the fan running through it using a UPS. It would need to have a trickle charge or something to keep the battery from overcharging and shortening the life.

I have some knowledge of electronics and wiring, and I am willing to learn much more! I would love if someone could walk me through this!


Hypatia's Protege

Joined Mar 1, 2015
Inasmuch as the fan is DC operated, no inverter is required -- Keeping matters very simple you may merely connect a 6V (NiCad or NiMH) battery to a charge maintenance circuit thence to the fan (via a LDO linear regulator)... All in all you're talking maybe $20 in parts (excluding battery and fan):)

Note: in the interests of fire safety, I do not recommend use of LiPol or Li-Ion batteries sans availability of comprehensive charging specifications therefor -- Moreover, please be advised that said chemistries are ill suited to your stated application...

Best regards