Big Boys Hobbies

Digital Multimeter...How do I use this thing? :)

SalemScott

SalemScott

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I recently put in an order to Harbor Freight for their 2 drum rock tumbler and while on their site I noticed the digital multimeter for cheap money, I think it was 5 or 6 bucks. I figure, hey, I can use that to test the battery on my Sovereign GT and E-trac to know if it needs to be recharged. Here's the problem, I'm a complete dolt when it comes to electricity. I remember covering it in school but have no recall of what any of it means. Did I buy the right meter to test my batteries? I put it on what I thought was the right setting but it was a AA eneloop rechargeable and the number said 3.3....but 3.3 of what? I'm pretty sure the battery said it was a 1.2 volt battery. I just need to figure out how full the battery is. I'm clueless.:laughing:

Duh, here is the pic of the multimeter and just an extra pic I snapped yesterday.

IMG_0305.JPG

IMG_0302.JPG
 
Put the selector on DCV (DC Voltage) at 20 and it should read any of your batteries.
 
Ok, so I put it on DCV at 20 and it showed 1.19 which I assume is the voltage. BTW, I just took this battery out of my wireless mouse because it died so interesting it's still showing 1.19 volts. Anyway, is there a setting on the multimeter that will tell me how much juice the battery has left? I think that's MAHs? Like I said, I'm a real dimwit when it comes to electricity.:p
 
Try the battery test mode selected in picture and see if AAs voltage reads differently (looks like it may put a small load in place on batteries)

A load will help give better idea of actual voltages.

No real way a dmm could tell you anything mah avail as is.

Display can go to 1.99 so 2-20-200 are normal dmm ranges available.
 
Never heard of a battery capacity meter,and not real sure how useful one would be. The mAH rating is how much current the battery can provide for one hour, which can be misleading, since a load typically draws as much current as it needs. Batteries have a limit to how much current that can be drawn at once. AA batteries are considered dead, at 0.6 volts, basically only getting half use out of them...
 
Batteries are funny like this, even up to car batteries. They can show a good voltage level, but once a load is put on them, they are useless. The DMM is just a good indicator that the battery may be usable. I have pulled batteries out of flashlights and such that checked fine, after sitting a few minutes, but could not be used to operate anything.
 
CopyTech99 said:
Try the battery test mode selected in picture and see if AAs voltage reads differently (looks like it may put a small load in place on batteries)

A load will help give better idea of actual voltages.

No real way a dmm could tell you anything mah avail as is.

Display can go to 1.99 so 2-20-200 are normal dmm ranges available.
Click to expand...

:?: :?: :no: :( :?:
 
The battery charge measurement of that meter tests the ability of the battery to supply current under a small load.

note: This setting is for testing the charge of small 9V or 1.5V batteries only.
Never use this setting to test automotive or lead-acid batteries. Damage to the meter and/or severe personal injury could result.

The battery amperage under a load of 370 mW will be displayed to a resolution of 0.1mA.

Normal amperage readings to be expected:
For a standard 9V (6LR61) battery = 25 mA
For a 1.5 V “AA” (LR6) battery = 4 mA
 
All I can say is I took a truck battery to a local auto parts store. They have a load tester that puts the battery under load tests it, sees how much it drained, etc. I took about 20 minutes to do a complete test. I asked the guy why the test took so long and he said it put a load on the battery and then started charging it to get it back to the same spot it was before they put the load on it. Either way it seemed complicated enough that I doubt there is a simple accurate way to test the batteries true charge.
 
Thanks for all the replies, I was hoping to have a way to test my Sovereign GT rechargeable battery. The GT has no screen so the only way you know how much charge it has is when it starts making the 'running outta juice' sound. By then it's too late if you don't have a backup on hand. Oh well, it was worth a try. Thanks again.
 
back when we powered our house with a kite string...

Electricity can be compared to a flow of water. The pressure in the water pipe is like the voltage in an electric line, and the flow of the water - gallons per minute is like amperage.

Oddly enough, voltage is sometimes referred to as 'Electromotive FORCE' and amperage as 'CURRENT'.

Most devices require a certain pressure and a certain flow of electricity to work properly.

Since you know that the battery is providing proper voltage/pressure under no load (A Digital VM has high resistance, and is not allowing much current to flow).
You still have to determine if the battery has enough charge in it to actually push the required flow AT THE REQUIRED PRESSURE down the circuit.

All you have to do is to take your trusty amp meter and hook it in series with the load and battery and see what it reads when you turn on the device.


Start the meter on a high amp setting and keep switching down until you get a reading.

Somewhere on most devices is a label telling you the current draw of the device. That is the number of amps (maybe milli amps) the battery has to push out.
Hope this helps.
John Morton
 
If you want something uncomplicated and fairly reliable for testing 1.5v and 9v batteries, try the Dollar Tree Store's Sunbeam tester. $1. I've been using the same one for well over year now and although I have several voltmeters, I use the little Sunbeam most of the time. It will show 3 indicator lights burning for a fully charged battery, 2 for about 50%, and 1 for 'low'. It will show 2 burning and the 3rd will be burning, but not as brightly for a fully charged 'rechargeable' battery. In most of my electronics, I will change the batteries when the 2nd light is not brightly lit. Some electronics, like a mouse or keyboard, will work well until just 1 light is burning. I keep several flashlights; regular, LED, and halogen types. They all work well until the 2nd bulb of the tester is not bright.
 
jmorton04 said:
Electricity can be compared to a flow of water. The pressure in the water pipe is like the voltage in an electric line, and the flow of the water - gallons per minute is like amperage.

Oddly enough, voltage is sometimes referred to as 'Electromotive FORCE' and amperage as 'CURRENT'.
Click to expand...

Nothing "Odd" about it. Continuing your analogy, the force applied on the water is what creates the pressure in the water pipe. :grin:

To go down one level, the current –Ampere– is defined as 1 Coulomb/second. Where the Coulomb is the number of electrons and it is 6.241×10^18 electrons. :shock: So a current of 1 Amp is a flow of 6.241x10^18 electrons every second.

The Volt is defined as 1 Joule/Coulomb, or the application of 1 Joule of energy to 1 Coulomb's worth of electrons. :?:

To get an idea of how much energy a joule actually is, it helps to look at some everyday examples. A joule is the amount of energy needed to raise the temperature of 1 gram of cool, dry air by 1.8°F (1.0°C). An average person sitting quietly produces 100 J of heat every second. The amount of energy required to lift a small apple 1 meter (3.3 feet) against the Earth's gravity is roughly equivalent to 1 J.

Sorry to ramble. :roll:
 
Rudy said:
Nothing "Odd" about it. Continuing your analogy, the force applied on the water is what creates the pressure in the water pipe. :grin:

To go down one level, the current –Ampere– is defined as 1 Coulomb/second. Where the Coulomb is the number of electrons and it is 6.241×10^18 electrons. :shock: So a current of 1 Amp is a flow of 6.241x10^18 electrons every second.

The Volt is defined as 1 Joule/Coulomb, or the application of 1 Joule of energy to 1 Coulomb's worth of electrons. :?:

To get an idea of how much energy a joule actually is, it helps to look at some everyday examples. A joule is the amount of energy needed to raise the temperature of 1 gram of cool, dry air by 1.8°F (1.0°C). An average person sitting quietly produces 100 J of heat every second. The amount of energy required to lift a small apple 1 meter (3.3 feet) against the Earth's gravity is roughly equivalent to 1 J.

Sorry to ramble. :roll:
Click to expand...

I love it when you talk dirty! ;):laughing:
 
Martin_V3i said:
I love my Fluke meters but they ain't cheap.
Click to expand...

Fluke is a popular choice and very deserving.

I have a close to 30 year old Wavetech formally Beckman Tech 310.

Recently lost (died) my Weller WTCP soldering station, hard to function not having that any longer.
 
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