Having dived into the world of Lthiums - I reckon it would useful to get a multimeter - however seems most of the budgety instrumenst only measure to the nearest 1 volt. Are there any availble that can measure down to 0.1 volts - do I need such accuracy? Are there horribly expensive?
Multimeters
- Thread starter JimmerG
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Marduke
Flashaholic
You can get a digital multimeter capable of measuring +/- 1mV for $3-5
OK - it seems I've been misled, it would appear that any old cheap multimeter can down to 1mv.
BUT having done a bit of reading - many websites carp on about how you can't accurately test a battery using a multimeter, as it doesn't offer any resistance.....
So do you have to stick the cell into a flashlight, turn it on, THEN check the volts??
Or am I confused - AGAIN!
BUT having done a bit of reading - many websites carp on about how you can't accurately test a battery using a multimeter, as it doesn't offer any resistance.....
So do you have to stick the cell into a flashlight, turn it on, THEN check the volts??
Or am I confused - AGAIN!
Carpenter
Enlightened
The "tool" I use to work with my CR123's is the ZTS Tester.
It doesn't give you the most percise results since it only tells you the strength of the battery on 20% increments. But it does put a load on the battery (like a camera strobe).
The results I get are close enough to know how much capacity the cell has left in it and if you start using multiple CR123 cell lights,this is a must to make sure the cells are at the same capacity.
It doesn't give you the most percise results since it only tells you the strength of the battery on 20% increments. But it does put a load on the battery (like a camera strobe).
The results I get are close enough to know how much capacity the cell has left in it and if you start using multiple CR123 cell lights,this is a must to make sure the cells are at the same capacity.
moldyoldy
Flashlight Enthusiast
Eh, the referenced websites are not being clear on which battery type is being checked with a multimeter. The ZTS is better for Ni-Cd, Ni-Mh, or the usual carbon-zinc or carbon-chloride or "alkaline" cells. For Lithium cells, the multimeter is of use. The working range of a "3.7v" Li-Ion cell is ~4.2 to ~3.6 volts. The working range of a primary Lithium cell is ~3.2 to 2.8volts or so.
There is a thread on CPF where Silverfox posted the % of charge left in a Li-Ion cell based on voltage alone. I would encourage you to look up testing by Silverfox and others on Li-Ion or Lithium cells. A lot of education is available on CPF!
Bonky
Banned
anyone have a link to that post?
I have a little battery tester that can test from watch batteries to 12v remote batteries. It has 3 load settings (resistors) and I have used it to test lithiums with. I paid less than $6 local but you probably can find it online for less than $10. It is a BT21 model (digital). It is cheaper to buy a DMM and get a resistor of the right size(s) for testing but this thing is small and easy to use.
qwertyydude
Flashlight Enthusiast
- Joined
- Aug 10, 2008
- Messages
- 1,115
The Innova autoranging dmm from walmart is a very good one. It has a protected low current mode and a load test mode, albeit one useful only for alkalines as it's such a low load.
Northern Lights
Flashlight Enthusiast
I just paid $30 for this:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98674
It does , light, sound, temperature as well as electronic functions. Has back light, timed power off and the lead sockets illuninate to show where you should place them when selecting a function. I have seen this meter sold under various names upto $100!
But a good selection is available from the vendor, the smaller ones are accurate and sell under $3 on sale. Those have a common battery test circuit too.
The company has many reasonable meter.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98674
It does , light, sound, temperature as well as electronic functions. Has back light, timed power off and the lead sockets illuninate to show where you should place them when selecting a function. I have seen this meter sold under various names upto $100!
But a good selection is available from the vendor, the smaller ones are accurate and sell under $3 on sale. Those have a common battery test circuit too.
The company has many reasonable meter.
Mark_Paulus
Enlightened
What do you guys think about DMMs with RS232/USB connectivity for logging/graphing? I have a home grown light that works fine with one set of AW "C" cells, but doesn't work fine with the other set. So, I want to see if they are cutting out because of discharge rates, or thermal cutoff, or what. Unfortunately, the cutoff happens like 20 minutes into a run, so it would be nice to plug it up to a computer and let it run, while capturing the current draw, and/or voltage drops.
Northern Lights
Flashlight Enthusiast
I find that interesting and if I could do that with my equipment I certainly would use that feature. I like gadgets.
I think it could tell you a lot about your situation.
I think it could tell you a lot about your situation.
Harbor Freight Tools has them on sale all the time, usually in the $3-$5 range.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90899
wildstar87
Enlightened
- Joined
- Nov 12, 2007
- Messages
- 369
I can vouch for both Harbor Freight DMMs, the cheap ones are ok, definitely good enough for the money, the more expensive $39 is very nice, and I let people know about that one on CPF a little while ago. It's probably the nicest DMM I have ever owned. I'm kinda miffed though, I bought it online because they didn't carry it in the store, and had to pay like $10 in shipping. Then like a week later they had it in the store.. Grrrr... Oh well..
It even has lighted indicators to tell you which holes you put your connectors in, so you are using the right connections to measure.
It even has lighted indicators to tell you which holes you put your connectors in, so you are using the right connections to measure.
Northern Lights
Flashlight Enthusiast
I used mine to measure solder iron tip temperatures tonight with the remote sensor. I forgot it also does relative humitity, LOL.
http://www.harborfreight.com/cpi/cta...emnumber=98674
http://www.harborfreight.com/cpi/cta...emnumber=98674
lumenal
Enlightened
I've seen that one, but have enough DMMs already.
Auto-ranging multimeters are definitely the way to go.
You can get "cheap" multimeters that RESOLVE to the 1mv level. That has absolutely nothing to do with the accuracy, i.e. whether that 4.23V is really 4.23 or 4.33. Even cheap multimeters claim accuracy below 1% or below. On a Li-Ion, 1% is 0.04V, so your meter could be off by that much. Some of the cheaper ones claim 0.5% or 0.02V .... and some even claim better, but unless you are paying good money, you are not going to get that. If you are just planning to use infrequently, try to find something with 0.5% accuracy, likely on a 20V scale. That should be fine.
One issue to be careful of with cheap meters is they tend to fail prematurely with bad readings...have had it happen to three now... I think likely internal corrosion on the switches. To that end, you are better off spending a little more money on an autoranging meter. There is less to go wrong.
Semiman
One issue to be careful of with cheap meters is they tend to fail prematurely with bad readings...have had it happen to three now... I think likely internal corrosion on the switches. To that end, you are better off spending a little more money on an autoranging meter. There is less to go wrong.
Semiman
VidPro
Flashlight Enthusiast
yup leetel more, or at leas one that someone recommends who has tested it for some time.
i had a low battery in a cheap one (no indicator), and the voltage read WAY off, so i changed the curcuit, and fixed this and did that, and then tested it , going between a "good" meter on the bench and the "Bad" meter in the project, and i wasted a whole DAY, Confused before i realised that THAT cheap meter, was going to meet Mr Trashcan
