Cheap Eneloop battery Tester

[nismohks]

Hi there, new to the forum but been a reader for a long time now haha

anyway, i just wanted to find a cheap budget AA and NimH battery tester.

i have minimal requirements for it, and as long as it can tell me whether or not to throw away my battery or recharge it, that will be fine.

As i said, my aim is to be CHEAP!

i was browsing on DealExtreme, but i dont know what to buy. Is there one that people recommend?

i had a look at these:
http://www.dealextreme.com/details.dx/sku.20342
http://www.dealextreme.com/details.dx/sku.21515
http://www.dealextreme.com/details.dx/sku.1260

Which is better? should i buy a multimeter, but i dont know how to use it..

I live in Australia, so my range is quite limited and even IF they have something, it will cost a lot which is why im trying to buy from DX or even Ebay.

thanks!!

 

[Turbo Guy]

IMO everyone needs a multi metter(DMM) and needs to learn how to use it.

http://www.candlepowerforums.com/vb/showpost.php?p=2727647&postcount=7

 

[LightWalker]

I've been using this multimeter for over a year.
http://www.dealextreme.com/details.dx/sku.594

I use it to test battery voltage on many different battery chemistries.

 

[nismohks]

so those other ones wont work?

i wont be using it for any other purpose. only for battery testing.

any idea on how that multimeter (http://www.dealextreme.com/details.dx/sku.594)compares to something like these:

http://www.dse.com.au/cgi-bin/dse.storefront/49d8d2ca11251104273fc0a87e010672/Product/View/Q1469

http://www.dse.com.au/cgi-bin/dse.storefront/49d8d2ca11251104273fc0a87e010672/Product/View/Q1467

i just ask because with the exchange rate the price is very similar to ones i can purchase locally.

thanks!

 

[Turbo Guy]

The ones you provided links to may be fine. Some of us and still on very slow dial up connections and do not really like to follow a lot of off site links, sorry.

Exchange rate?

I have no idea where you are located. Often it is very helpful if members takes a few minutes to fill out their user's profile at least their location. Different countries and / or different parts of countries have different stores. In the USA Harbor Freight often has decent DMMs for $4,Radio Shack sells 10 Ohm 10 watt power resistors along with other values cheap enough they also carry DMMs and other assorted useful items.

 

[cave dave]

You already have a tester. Its called a flashlight. When the batteries don't power it like they used to its time to replace or recharge.

A multimeter will not really tell you if your cells are still good or not. Most people arround here use a ZTS tester, It isn't perfect but its a lot better than a multi meter.

 

[nismohks]

i said i was in australian in my first post, but i also just added my location to my profile so sorry about that

haha flashlight... yer i guess... but id like something a bit more acccurate than that. the most important thing, is that whether or not cheap battery testers are able to test my eneloops as well?

would the 1.2V throw them off? what do they actually read?

thanks

 

[cave dave]

..

haha flashlight... yer i guess... but id like something a bit more acccurate than that. ....

In that case a flashlight + a stopwatch. :kiss: It actually doesn't get much more accurate than that. The cheap battery meters are pretty much useless.

 

[Turbo Guy]

Link in post #2 is to a post on how to use a DMM with a resistor to check NiMH and 1.5 volt alkies under a load. This is the same thing a battery tester does. A DMM with the proper load(resistor) can check most any battery there is. It is nice to have a deciated battery tester just as it is nice to have a real battery load,discharge graphing device such as a CBAII but sometime less expensive gear will surfice.

Sorry about missing your location.

 

[nismohks]

thanks for that!

however i was just wondering what would be the figures for a normal AA battery? ie when to throw it away

he says this for the NiMH: "approximatly ---- 1.37volts is full ----- 1.16volts is empty and time to recharge."

 

[chmsam]

You need to test them under a load to get a legitimate reading. It isn't just about volts. Unless you have a resistor to use with your DMM, you won't get a measurement that means too much unless the battery is pretty much toast. Like Turbo Guy said, use a 10 ohm resistor for testing AA's (you might need a different value for other batteries). Cheap, and a lot cheaper than a ZTS meter but nowhere near as versatile. The ones on DX are cheap but look pretty cheesy.

 

[buickid]

Keep in mind that Ni-MH batteries keep a much flatter discharge curve then alkalines, so a tester made for alkalines will give a false reading. This discharge curve also makes it harder to get an accurate reading, as volts will remain quite steady until battery is almost dead, at which point they'll drop rapidly.

 

[nismohks]

i got hold of some 10 Ohm Resistors and will get hold of a DMM tomorrow.

what voltages should i look for in alkaline AAs and rechargable NiMH like my eneloops?

 

[Turbo Guy]

From post at link provided in post #2 this thread.

putting a load of a 10 ohm resistor (or in that range) on a Nimh cell
while measuring the voltage gives you a good idea of its 'state of charge'

Non rechargable just use you best judgment. In some devices they will work down to less than 1 volt but they will also often develop leaks. I checj them no load and toss at 1.4 or so.

Just for grins I took a very old Energizer with what looks like FC date code(?) which reads 1.35 open. It will hold 1.2 volts under a 0.1A (100 mAh) load but drops like a rock under a 0.2A(200 mAh) load. FYI Three of these will still provide good light output in a 3cell Mag with a 3watt mag LED dropin.