How to measure battery capacity

[iocheretyanny]

I would like to know the capacity of my NIMH C cells over time, to see how they discharge?

I see many folks here measure mAH for various batteries. Please tell me how?
What equiptment needs to be used - voltmeter?

Thanks.

 

[SilverFox]

Hello Iocheretyanny,

This is what I use. It hooks up to your computer.

Tom

 

[LuxLuthor]

Hello Iocheretyanny,

This is what I use. It hooks up to your computer.

Tom

Tom, so for $110 do you get everything you need to test all types of batteries that we discuss? I'm not sure if you also need any of the other items in this pricelist menu. I have really gotten more interested in seeing what is happening with my various batteries. How do you set it for NiMH &/or Li-Ion?

Does this hook into an existing charger to run the D/C capacity....or does it do all that itself with the settings you program via USB?

 

[wptski]

It's a discharger all on it's own! The temperature probe is good to have if not just for a safety shutoff. It comes with PowerPole connectors, so you have look at "how" your going to attach to a cell or battery pack. I've never seen the "CBA Amplifier", not sure what it is or what it does.

All you really need is the CBA-II, temperature probe and a "way" to connect. A good solid mechanical connection to limit added resistance is very important!

EDIT: It is possible to set the discharge current to zero and monitor voltage on another charger or whatever too.

 

[SilverFox]

Hello LuxLuthor,

If you go to the support section for the CBA II, you will find the owners manual. It should answer most of your questions.

Tom

 

[iocheretyanny]

Thanks for the reply, nice set up.

Can a cheap tool like a Voltmeter measure Capacity in mAH?

I want to figure out the discharge rate (just lying around) fo rmy NIMH C Cells.

Thanks.

 

[SilverFox]

Hello Iocheretyanny,

No.

You need a volt meter, a timer, and a load.

Tom

 

[brightnorm]

I was hoping my ZTS tester would give me an idea of capacity remaining. I know little about this area but I thought suplementing a DVM with the ZTS would be useful.

Brightnorm

 

[HarveyRich]

Hi iochereyanny: I use a La Crosse Technology BC-900 charger. The Maha-9000 also works well. You put up to 4 NiMH batteries into them and they discharge and then charge to full capacity. The capacity is listed on the lcd charger read out. It's simple and elegant. Try Amazon for the BC-900. Not sure about the Maha-c9000.

 

[LuxLuthor]

The only thing that I still have a question about is using this with lithiums requires close proximity to the PC via USB...so are you guys using a laptop in a safe, protected area?

I did order it with the temp probe. Thanks for this info.

 

[wptski]

The only thing that I still have a question about is using this with lithiums requires close proximity to the PC via USB...so are you guys using a laptop in a safe, protected area?

I did order it with the temp probe. Thanks for this info.

I never have worried about that but it's probaly easier to contain the battery in something or other. I have a few Li-Poly 9V batteries which I even charge in a "Battery Bunker", BB Site .

I have blown up a PowerEx 170mAh Ni-MH 9V battery but that was my fault while charging. I wasn't there when it happened but upstairs when I heard the pop. No burn marks but flying debri could have been dangerous!

 

[yellow]

much work: setting up a current meter into a load circuit and check readings and time till the batt is drained

no work, but costy: get a charger that can show You what You want.
But be careful, there are quite much chargers that show what they pumped IN the cell for getting it to full, while just few that show You what came OUT of the cell (after the dis-/recharge cycle). There is quite a difference between.

I have a model labeld for a shop here but usually these are makes from VOLTCRAFT (if these are available at Your place). Its one of the "larger" models: up to 8 cells (D, C, AA, AAA) together and 2 for 9V, Ni-Mh, Ni-Cad, RAM possible, several modes (I use dis-/recharge most and cyle for breaking cells in)
Has a fan and makes some noises, not connected to temperature. Often blows when charging is already finished for some time.

 

[SilverFox]

Hello Brightnorm,

The ZTS can be very useful, but you need to "calibrate" it for your batteries.

If you take a light and log a runtime you can stop every so often and check the batteries with the ZTS. Your actual numbers may not match the ZTS % figures, but you should be able to get an idea of where you are.

The hardest measurement is in the middle range of the capacity of the cell. The voltage holds steady in this range and it is difficult to tell where you are.

You can use the color indicators for a gross quick check. If your cells test in the green range, you are good to go. In the yellow range you are about half way down, and if they test in the red range you will have to pay attention to your light usage because you may run out of power.

The problem is that the ZTS tests at one load, and your lights may use a different current. This is why you test with your lights. If you light usually runs for 8 hours on a set of batteries, when you get at reading of 20%, you may be down to 3 hours of runtime with that light. However, if you have a light that gets 30 minutes on a set of batteries and they check out at 20%, you may only have a few minutes of life left.

As you can see, you need to "calibrate" the readings to the lights you are using.

Tom

 

[barkingmad]

Grrr - the CBA-2 is US$109 and the UK price is almost the same in pounds - i.e. near enough double the cost!!!!

 

[brightnorm]

Thanks Tom,

Brightnorm

 

[LuxLuthor]

Just starting to play with this new CBA-2. I'm slightly freaked out about interfacing this with my precious PC.

Maybe I'll get out that retired PC for this. I was encouraged when reading their FAQ's:

[font=Arial,Helvetica][/font]

[font=Arial,Helvetica]DO I NEED TO BE TECHNICIAN OR ROCKET SCIENTIST TO USE A CBA?[/font] [font=Arial,Helvetica] [/font][font=Arial,Helvetica]No, not at all. You only need to know the basic information about a battery that you wish to test. You must know the type of battery (chemistry), the capacity in amp-hours and either the voltage or the number of cells. The CBA will figure out the rest and run a test automatically. A CBA and it's companion software is designed so most anyone can do a laboratory quality test and verify that a battery meets its specs or a CBA makes easy to compare battery performance between different batteries.[/font]

[font=Arial,Helvetica] [/font]

 

[barkingmad]

Do any of the dealers on here sell the CBA-II or do we have to order direct?

 

[SilverFox]

Hello Barkingmad,

Amondotech had them at one time, you may want to check and see if they still have them.

Tom