Stop Using Multimeters, Build a Battery Swiper (instructions inside)

MattsAwesomeStuff

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Still testing cells with the probe leads on your multimeter like a *** caveman? Spend $0.75 on ebay and build yourself one of these instead with some scrap wood:


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How to build Voltage Swiper:

1 - Wire LED panel volt meter to two leaf-spring-like strips of steel, on a piece of wood. Put them underneath the wood in a channel or something obviously, not dragged across the surface.

2 - It's not rocket science, scrap wood, soup cans, voltmeter and screws. You just want something you can slide a battery through sideways so that the leaf springs drag across the positive and negative sides and tell you the voltage.

3 - Clamp/bolt it to the table so you can measure dozens of battery voltages at a time, fast, without holding stupid multimeter leads and needing 3 hands.

4 - Test voltages (especially ballpark voltages for sorting) super fast.

If you're left handed then switch the voltmeter to the other side so your hand isn't covering the panel meter all the time.

If you build one, post a picture of it here, I'm curious to see it and hear feedback.
 
Good Idea, that's what I had been thinking of doing.
What I settled on so far is that I just line up my batteries (which you would need to do regardless of the method used since it's fastest to measure voltage this way) on a table which I propped one side up on so the whole table tilts. That way I have a heavy item on the lowend to stop them from rolling off, and there is just a line of batteries going up the table. I sit at the end with a multimeter probe in each hand and I touch the battery. If it is above my cutoff voltage (3.15v) I use the leads to chuck the battery to the right, were it rolls off the table and into my "good battery" box. If it's low chuck it left, and if its really really bad, I use a sharper motion to chuck it even further to the left and into my "about to explode" box. Since I just removed the bottom most battery, the rest of the batteries roll down.

I went through a couple hundred batteries this way, but so far I've only started the first bit of my process which is sorting them for self discharge.
 
Could even connect the multimeter to the spring contacts instead of the panel meter, eg clip leads?
 
A good idea for high volume processing...

Most of those panel meters are garbage... that said, nothing stops you from building something similar with any meter you wanted.

I use a lightly modified single cell holder which makes taking the 18650 in/out a lot easier... they have banana leads attached to them and I can just plug it directly into my multimeter.

If one had some Arduino skills, one could easily automate the entire process. I've seen some pretty amazing sorting and counting contraptions made for other things using micro-controllers.
 
Could even connect the multimeter to the spring contacts instead of the panel meter, eg clip leads?

Too slow, multimeters refresh at like, 1hz, 2hz max.

Panel meters are just about instant.

Most of those panel meters are garbage...

How dare you. They cost me $0.75 including shipping.

And actually, mass-produced as they are, they're all at least as accurate as my cheap multimeter. In fact, my multimeters are probably far crappier build quality.
 
MattsAwesomeStuff said:
Could even connect the multimeter to the spring contacts instead of the panel meter, eg clip leads?

Too slow, multimeters refresh at like, 1hz, 2hz max.

Panel meters are just about instant.

Most of those panel meters are garbage...

How dare you. They cost me $0.75 including shipping.

And actually, mass-produced as they are, they're all at least as accurate as my cheap multimeter. In fact, my multimeters are probably far crappier build quality.

You need to start using real meters... those things drift over time. Can't trust them.

I couldn't handle not having at least 5, with at least one being an Fluke 87.

You can get a Chinese market real Fluke17B+ for $109 shipped. Even a Uni-T UT61E, a 22,000 count meter, for $50-60 shipped, perfect for low voltage DC electronics and battery work.

There is no reason to suffer, buy proper tools.
 
There is no reason to suffer, buy proper tools.

That's just elitist gatekeeping.

Just for conversation...


Look, if you've already decided something is going to be a lifelong hobby or a career, sure, buy nice tools.

But when you don't know how much you like a hobby, and when you can get tools for literally 1% the cost that you're suggesting I spend, I would rather have 100 shitty tools that are just good enough to work, than only 1 tool that's nice and then sit around with my thumb up my butt.

There's an old, kind of outdated adage "Buy once cry once." And if "cheap" tools cost 75% as much as good ones but didn't last 10% as long, as used to be the case, then they're a poor choice.

But when you can get tools for only 1% the cost (more often 10-20% the cost) of good tools, so what if you "waste" money on a cheap tool that later you want to upgrade? You're only adding a few % to the cost, and you'll use the cheap tool to decide what kind of expensive tool you need, what features, etc. You build experience on it.

Compare that with buying an expensive tool when the cheap one would've been fine your whole life, much more commonly the case.

In this situation, all I need the panel meter for is to roughly check whether the cells are any good or not. And whether they've drifted after a few days.

I'm not worried about 3 digit precision after 10 years. It's $0.75. It works great.

I've had my shitty multimeter for 20 years now, I think I paid $8 for it. I've never regretted that or needed a better one. I paid $20 for a 40-piece wrench set 5 years ago. Have never needed better wrenches. Etc.

For like, $300 I've got an entire garage full of cheap tools, happy as a clam over it versus spending $10k on them.

Different strokes for different folks.
 
It's not 3 digit precision... resolution and precision are two VERY different thing.

These panel meters drift so much its not even funny. You can't trust the reading. Even if you calibrate the pot for 12v, you hook it up to 24v and its off, hook it up to 5v and it's off again. You will always be chasing your tail.

When I put a meter on the battery, I want to trust the reading... that's the point I was trying to make.You want to see if a cell is self discharging with a panel meter vs a $50 22,000 count meter? Don't knock it until you try it... I can wave a finger over a solar panel and see the effect of shading clearly. Watching grass grow is fun when you can actually see it move.

I understand everyone needs to start somewhere, so did I. I've been into this stuff for over 20 years, the amount of value, insurance, piece of mine, investment value that comes from even having something decent is huge. I can't discount the amount of use I have received from owning a good meter. Chasing down resistance issues, measuring components, countless tasks that can only be complimented by having the right stuff. I even needed certain minimum specification to accomplish a specific task at one point (the reason I bought my first Fluke)

You don't need the best, you don't need to spend $500 on a meter to enjoy this stuff,the UT61E is considered the poor mans Fluke 87... for the price it's a bang up meter at a wonderful value price point for a entry level hobby work which is why I mentioned it. Good tools made the hobby that much better as it accelerates the learning curve.

Even if its more than you need, you can grow into it.

A good multimeter is probably one of the most important tools you can own playing with electronics and batteries.

Call it what you want, but over the course of 15years, my very first $100 Fluke meter is still with me and still holds value. It's been used countless times over the course of my life for LIFE stuff, not just hobby work. Chasing down electrical issues in my car, home repair stuff... it's paid for itself. So has every tool I ever bought.

You had a novel idea with your battery swiper, but it can only be improved by sticking a good meter behind it. You might be new to the hobby, but I think you will end up sticking around long enough to make use of what I am talking about.

Everyone has different budgets and life situations are different... if that's all you can afford to work with, have at it and rock on. Do the best with what you can afford. But if you can afford to make a purchase like that, I am trying to tell you that consider it an investment... mine turned out to be well worth it.
 
CrimpDaddy said:
It's not 3 digit precision... resolution and precision are two VERY different thing.

These panel meters drift so much its not even funny. You can't trust the reading. Even if you calibrate the pot for 12v, you hook it up to 24v and its off, hook it up to 5v and it's off again. You will always be chasing your tail.

When I put a meter on the battery, I want to trust the reading... that's the point I was trying to make.You want to see if a cell is self discharging with a panel meter vs a $50 22,000 count meter? Don't knock it until you try it... I can wave a finger over a solar panel and see the effect of shading clearly. Watching grass grow is fun when you can actually see it move.

I understand everyone needs to start somewhere, so did I. I've been into this stuff for over 20 years, the amount of value, insurance, piece of mine, investment value that comes from even having something decent is huge. I can't discount the amount of use I have received from owning a good meter. Chasing down resistance issues, measuring components, countless tasks that can only be complimented by having the right stuff. I even needed certain minimum specification to accomplish a specific task at one point (the reason I bought my first Fluke)

You don't need the best, you don't need to spend $500 on a meter to enjoy this stuff,the UT61E is considered the poor mans Fluke 87... for the price it's a bang up meter at a wonderful value price point for a entry level hobby work which is why I mentioned it. Good tools made the hobby that much better as it accelerates the learning curve.

Even if its more than you need, you can grow into it.

A good multimeter is probably one of the most important tools you can own playing with electronics and batteries.

Call it what you want, but over the course of 15years, my very first $100 Fluke meter is still with me and still holds value. It's been used countless times over the course of my life for LIFE stuff, not just hobby work. Chasing down electrical issues in my car, home repair stuff... it's paid for itself. So has every tool I ever bought.

You had a novel idea with your battery swiper, but it can only be improved by sticking a good meter behind it. You might be new to the hobby, but I think you will end up sticking around long enough to make use of what I am talking about.

Everyone has different budgets and life situations are different... if that's all you can afford to work with, have at it and rock on. Do the best with what you can afford. But if you can afford to make a purchase like that, I am trying to tell you that consider it an investment... mine turned out to be well worth it.

I have to agree. Test devices need to be reliable. There is noting worse than when your equipment leads you astray.

A perfect example of this is when one of the probes on my multimeter had a poor connection, it was not soldered very well at the factory. The number of cells that I set aside in my 0v pile, or mis-recorded the starting voltage on. It took ages to figure out.

Point being, having unreliable equipment is worse than having none. It is worth figuring out your desired level of accuracy. But reliability is important. Your test equipmentneeds to give consistent results.

Another example - I am happy to use an Opus to capacity check my cells. It is definitely not the most accurate device out there. Not even close. Tests can easily vary 10%. It defiantly overstates the capacity. However, it suits my needs - it gives me a measure that is consistent, reliable, and repeatable.
 
While on the subject of suspect test leads... Don't trust what the Chinese sell on eBay, AliExpress, BangGood...

Test your test equipment... US made leads on the left, " high quality" chinaleads on the right.

It was enough to read voltage, but myresistance measurementsfelt funny, meter wasn'tacting right, so I took a closer look.


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So guys dont go haywire jumping on each other. We all have different criterias and ideas and thoughts.

We all know that cheap gear are cheap for a reason. Some want to use them some don't. With that said its good that new people going here do get the information of both worlds. Im also one of those wanting to have proper gear for most things but still use as Geek said the Opus. The opus is far from what my fluke does but its important to understand how it do it.

Same goes with cheap meters. If you are aware of that they are cheap and will drift and such that still might be good for you. With for instance a resolution of 0.1V and accurazy of lets say 20% you may be fine with that for checking if your cells are above 2V. I use the cheap ones too but only for very quick overlook but I dont have them for my main system.
 
If your meter Is off a consistent amount Regardless of range Then it is still valuable to you as long as you know what it is off by. If you know your meter reads 20% higher than what the actual value is Thank you can open secret that no matter what value with reads Also no matter how much that cost Still calculate that into its readings
 
Ill agree with the comments about Opus, Lii-500, or similar testers not the most accurate tools in the world, but thats not why we buy them. We buy them to establish a baseline for cell capacity, not test ACTUAL cell capacity.

If your testing methods are consistent across the board, you will be able to establish a baseline figure that allows you to make an informed decision as to where that cell needs to go in the battery pack. For the most part the mAh figures generated by the tester are arbitrary values that allow you to place a cell.

It's when you start mixing your test methods (5) Opus, (5) Lii-500, (5) Discharge PCB, (2) hobby chargers whatever it is, your test methods are no longer consistent and you no longer have an established baseline. Thats a FACT. Expect balance inconsistencies in your final product.

But none of the above has anything to do with confidence in readings a panel meter is an accessory, not a tool. I need tools to make sure my accessories work.

Same goes for a good quality hobby charger its a tool that allows me to validate my dischargers. And in the world of hobby chargers, there is a gamut of quality from excellent to junk. I have owned the gamut, from cheap to expensive, there is a difference which is easy to appreciate.

My dad always said, there is no such thing as a free lunch, and my experience you generally get what you pay for. As long as you understand the limitations of your methods and tools, you will often times be ahead of the game.
 
CrimpDaddy said:
While on the subject of suspect test leads... Don't trust what the Chinese sell on eBay, AliExpress, BangGood...

Test your test equipment... US made leads on the left, " high quality" chinaleads on the right.

It was enough to read voltage, but myresistance measurementsfelt funny, meter wasn'tacting right, so I took a closer look.


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Best TEST video I've ever watched ! well done lol
 
I built one of these Battery swipers and I tell you It is the best thing I ever did.
Used some terminals from a cordless tool battery pack.

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mounted them on a lexan rail and wired to 2 brass screws. Drilled holes into them so the meter leads would stick in and a swiping we go.

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One of the benefits is the cheep Harbour Freight Meter fits right into the rail. Design bonus.

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It's actually fun now to check voltages. I got so carried away I now check precharging and post charging and well you get the point.

Wolf
 
Man I've been getting crazy about measuring Voltages too. I build a tray that holds the cell ( up to 8 for charging) that can also be plugged into my meter with the 4mm bullets. I'll post pics when I get home. Any Ive been using my good mastercraft 4 digit Meter to ready the voltages so I'm now used to 3 decimal places I cannot go back to 2 decimal places.
 
Well i think if we get out a flashlightand microscope and ameasuring device we can get to 5 decimal points maybe more I believe. :p

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Wolf
 
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