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Pocketable Fuel Gauges: pictures and howto [serious]

Pocketable Fuel Gauges, let me see what you’ve got.

Discuss. Let’s see them and answer any questions about them.

This is one way to check a board’s charge level.

Other ways include experience, bluetooth/cell-phone, and ESC cutoffs. Oh, and of course building fuel gauges into the board itself. That’s so 2018.

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I’ll go first.

12S LiFePO4 (hardwired) and GX16-3 male and female charge ports

this unit has since died, it was in my pocket during a streetface incident and cracked in half

this was the price I paid to learn to always set the VESC fault timeout to 40ms, not 500ms



GX16-3 male and female charge ports, selectable multi-chemistry, multi-voltage



A really old one, selectable multi-chemistry, multi-voltage, 5.5mm x 2.1mm barrel jacks, male and female

And a really new one, selectable multi-chemistry, multi-voltage, 5.5mm x 2.1mm barrel jacks, male and female

See how much smaller the new one is, with the same functionality :smirk: Fits in my pocket much easier and more comfortably

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A great thing about including the female jack on there, besides being able to watch it charge if needed, is this:

You can also quickly verify the charger’s actual voltage.

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I definitely need to build one for my friend. He still uses his Evolve gen 2 board which has no Battery Led, gauge, meter or battery indicator at all so its always a question how long he has left to ride/charge.

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For some reason “Roasting your resistors” got a good laugh out of me.

Have you considered a switchblade type action or a hinge for the male port to reduce the footprint? (3D printed of course)

This obviously goes against your elimination of failure points but I’m just interested.

I feel if this was purpose designed as a product it could be made very small.

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I like to live dangerously :joy: jk I shorted the charge port the other day so I printed this

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I haven’t considered that, but I feel like if this was designed as a commercial product, it could be really small.

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disclaimer
For anyone reading, you should ALWAYS fuse your charge port and NEVER stick multimeter prongs into it. That’s really dangerous.

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Its fused and theres I cant short it with this print…

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Just have to put the disclaimer there, man.

You and I both have shorted out charge ports before… it’s not fun. Especially with no fuse.

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Guilty :wave:t3:

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Another non-obvious benefit of a design like this, with the flexible wire —

If you are at work or something and your board is plugged in, and your coworker trips over the charge cable, it’s a quick disconnect spot that simultaneously saves your coworker and doesn’t rip the charge port out of your board.

I use 30cm extensions on the end of the charger cable for that exact reason, but this fuel gauge looks like a nifty combination of the two.

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These are my newest favorite battery gauge

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I haven’t finished it, but using the same one.

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I have some photos of this one under construction. It took about 6 coats of epoxy, 2 of which were thickened with fumed silica and 2 of which were strengthened with milled glass fiber, and 2 of which were smooth clear top coats.

This top patch was thickened, the bottom two patches were strengthened with milled glass fibers

This bottom middle part was thickened with fumed silica

and the finished product