Analog Multimeter on Li-Ion?

I'm planning on buying a cheap $5 bucks analog multimeter solely to test my RCR123 batteries. Is this ok to use? Or should I go digital for around $20 bucks. Also how will I use it to check the voltage of my batteries coz this will be my first time using a multimeter either in analog or digital upon your suggestions. Help and suggestion is needed. Thanks.

don.gwapo said:

I'm planning on buying a cheap $5 bucks analog multimeter solely to test my RCR123 batteries. Is this ok to use? Or should I go digital for around $20 bucks. Also how will I use it to check the voltage of my batteries coz this will be my first time using a multimeter either in analog or digital upon your suggestions. Help and suggestion is needed. Thanks.

Click to expand...

.
Spend your $5 on a digital meter it will probably be as accurate as a $20 one ... If you want real accuracy, get the $5 digital meter plus a 5 volt reference (see other threads) then you can check your meter against something that is ultra accurate ... The total price will still be about the $20 level.

You will only be using the meter on DC volts, probably the 20 volt range, and should be able to read (for example) 4.19 volts (two decimal places) ... You will be within 10 millivolts particularly if you check your meter against a genuine five volt reference supply.

Someone will tell you the name of the supplier of the cheap digital meter that lots of people seem to be using ... I use the UK version though it is a bit more expensive at four or five pounds here.

Edit ... The seller of the cheap meter is Harbor Freight.
,

My analog meter, expensive in its day, read 3.7 volts on an imr that was actually at 4.02 v. Could have had bad consequences had I believed it.

After you get your multimeter you can get good basic instructions to use it here at CPF courtesty of member HKJ. Go to Candle Power Forums>Flashlights>Electronics-Batteries Included. Click on the sticky at the top of the page entitled "Threads of Interest" then scroll down to the fourth link from the bottom. The link is called "Simple guide to using a DMM for measurements". Please consider bookmarking it after you read it. It might prove to be a useful guide to have around.

For $28.99, you can get one of the Mini ZTS battery testers from Lighthound that will test the batteries under load. For any application that uses multiple lithium ion batteries, it makes a very good way to be sure that cells are matched and less likely to cause an explosion.

Theatre Booth Guy said:

For $28.99, you can get one of the Mini ZTS battery testers from Lighthound that will test the batteries under load. For any application that uses multiple lithium ion batteries, it makes a very good way to be sure that cells are matched and less likely to cause an explosion.

Click to expand...

The mini ZTS doesn't test the rechargeable lithion ion batteries that are in the 4.2 to 3.7V range. Its a great little tester but it won't read those batteries. You need the much more expensive model to test those, which the original poster may not want to pay for.

A $5 analog meter will be useless for testing batteries for voltage as a way to indicate level of charge. Far too little resolution.

A digital voltmeter with at least 3 full digits is necessary. Nothing wrong with investing in a good digital multimeter to have around anyway. You can go to some hardware stores and get a halfway decent one in the $20 price range. You can go to radio shack or some other electronics store and buy very cheap a 10 or 20 ohm resistor to use as a load on the battery. You would need to get at least a 5 watt rated resistor for a quick load test per battery.

By using a digital voltmeter with the resistor across the terminals when you test the battery it will put a load on it and give you a more realistic voltage reading of the battery. This is very useful in comparing to other batteries of the same type and brand. If you are checking RCR123's that range from 4.2V under no load to 2.7V when nearly fully discharged (as seen under some level of load), then you can get a better feel for them when you test them with the resistive load. You only need to test them long enough to get a reading, like 3 seconds. If you are using flashlights that take two or three of them in series it would be best to use the ones with the most closely matching voltages or see which ones are not holding a full charge and not use them at all.

Putting a group of batteries on the charger and when they are all done some read 4.15 V and some read 4.05V under the load, you wouldn't want to mix those together. You would want to use in this example all the batteries that were within just a couple of millivolts of 4.15V together and not throw in one that only read 4.05V. If you just charged your batteries and 10 minutes after it cooled down it read 3.87V on the meter under load, its indicating its not holding a full charge, its getting old and weak. May not want to use it at all, or just use it in a single cell light that doesn't put another battery in series with it.

These are just example numbers to give you an idea of how it would work. Not a set of absolute numbers. I do personally have lith ion batteries that read in these ranges that I keep track of and separated.

4.2V under a 10 ohm load is 420 mA of current draw through the resistor, none through the meter. That is not a bad load for a quick 3 second test on rechargeable battery to separate the weak from the strong.

4.2V under a 20 ohm load is 210mA which is also not a bad load. I paid like a buck each for these resistors in a 10 watt rating. A cheap investment.

Also this should be in the battery thread section not in the LED light section.

Harbor Freight- for $3 to $5 is nearly as good as my Fluke that was $$$$ IMO.

Sanity check any new meter you get.

Measure a few batteries, check the wall outlets, etc. Compare them to the readings from other meters if you have them.

Watch the batteries on digital meters, too. Readings may be inaccurate if the batteries are low. Batteries also tend to stay in the meter for a long time unused and leak.