watts-on's Cell Voltage Checker

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watts-on

Member
Joined
May 27, 2017
Messages
188
I came up with this 3D printed design for quickly checking the voltages of my 18650 cells:


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I doesn't do anything that you can't do with a standard volt meter, but it's much quicker and less fiddly than using the meter probes and can be used one handed.
And its powered by an 18650. :)

It uses a standard Chinesium panel voltage meter ( 26 x 46mm not including bezel ), rocker switch to turn it on/off and a single slot 18650 cell holder, which just clips into the back, plus some wire, solder tags and screws (M3).

The .stl files are attached in anyone wants to print their own.
 

Attachments

  • CellVoltChecker_V1_0.zip
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watts-on

Member
Joined
May 27, 2017
Messages
188
Walde said:
Which module did you use for the Volt display? Can you link that?

I don't have links to any of the parts, since I made it form stuff I had lying around the lab, so have long since forgotten the source. However I found this panel meter on eBay that looks identical:

https://www.ebay.co.uk/itm/DC-3-5-3...ter-Volt-Meter-Panel-Car-2-Packs/233097769199


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It's a five digit one, which are quite expensive. You could use a cheaper one with less digits, provided it is physically the same size.

Walde said:
Does it alone and from what voltage range or need it even a power supply or battery.

If I understand your question correctly, the panel meter requires a minimum 3.5V supply to to function properly. You could use the voltage from the cell you are testing as the supply voltage, but you will then only be able to test cells that are above 3.5V. So it is better to run it from a separate supply for which a low quality 18650 is perfect.
It can measure voltages from 0 to 33V and is not damaged if you accidentally try to measure the cell in reverse, it just doesn't show it as negative voltage like a multimeter would.
 

Cherry67

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May 13, 2018
Messages
493

watts-on

Member
Joined
May 27, 2017
Messages
188
Cherry67 said:
Even if it has 5 digit doent mean these are accurate.
Dont deny to check them.

That is true, although in my case it measures within 1mV of my two Fluke multimeters.

Cherry67 said:
With respect to your nice tool, have a look at the "swiper" as well:
https://secondlifestorage.com/t-Sto...Swiper-instructions-inside?pid=36885#pid36885

I did consider that, but in the end I wanted to take the measuring device to the cell and not the other way around. Mainly because after harvesting a bunch of cells, I already have them in a row on my bench and many are stuck to it, or each other, from all the goop.
 

Bubba

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Joined
May 9, 2018
Messages
300
I printed the Tongs portion... though I would put at the top an attachment to insert my voltmeter leads. I like the tongs idea.
It has just the right amount of spring to it.

I did however find the holes to be a bit higher then my hands like, but that's ok. I use the lower of the two holes and my thumb just under the other ring for easier closing.

Nice work.
 

watts-on

Member
Joined
May 27, 2017
Messages
188
Bubba said:
I printed the Tongs portion... though I would put at the top an attachment to insert my voltmeter leads. I like the tongs idea.
It has just the right amount of spring to it.

I did however find the holes to be a bit higher then my hands like, but that's ok. I use the lower of the two holes and my thumb just under the other ring for easier closing.

Nice work.

That's an interesting alternative that I hadn't considered.
I was just focused on a solution that did away with the dangly wires. :)
 
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