Stanley Battery Power Bank

This started as a Stanley battery adaptor from a download from Stanley Battery adapter (FMC688L FMC687L) by kicune - Thingiverse. Many thanks to kicune. Then it started to grow arms and legs.

Initially added a Winners DC-DC board to drop the 18V down to 12V. Then I added a couple of car cigarette lighter sockets and a switch. I then read it was not good practice to allow the battery voltage to fall below 15V so I added a LV cutout (the middle board), Then I thought it would be nice to check the battery capacity so I added the power meter. This is still a prototype and a work in progress, but it seems to work ok. Next step is to make the case more solid and secure.

Also many thanks to Arnas who I believe had some tutorials on using Totemmaker with Sketchup. (Can’t find them any more, have they been deleted?). Previously I was just building and dismantling if it didn’t fit. It’s good to assemble in sketchup to see if it works. Manipulating the beams and 3D parts has gone well but I’m struggling a bit with positioning the C-brackets etc. Anyway it keeps my 70 year old brain active in retirement.


This was an interesting project!
Also to design in SketchUp first will make the building more effective. There are many tricks to position e.g. the C-brackets. Sometimes pressing “k” so you can see back edges helps placing parts a lot.
Also to use finished corner parts from the library, so you don’t need to place nuts and bolts separately.

I do have a few tutorials here:

They are not quite finished. the 2 last lacks voice-over. But they help a bit.

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Finished. I added a fuse and moved the low voltage cutoff board internally. The bottom boards required to be recessed 2mm to stop the screw headed rubbing.

An 18volt 2Ah battery should have a capacity of 36Wh.
Tested one of my 2Ah batteries. Charged to 19.95v. When the voltage had dropped to 15volt and cutoff, I measured 27 Wh.

An 18volt 1.3Ah battery (23.4Wh) measured 18Wh.

The Winners board has a maximum output of 5A, with a 4.5A advised continuous maximum. At 12v this would give a maximum of 54w. Enough to charge a phone or laptop, car 12v air compressor, 12v cool box, lighting etc.

The unit is very sturdy and the perforated boards allow for ventilation. A good learning exercise.