Testing Battery Voltages

[chamellieon]

Recently, after getting some very short performance life out of my batteries that are used in both the D700 and D300s, I was wondering if anyone knows how to/ where i can take my batteries in their "fully charged" state to test if they're performing to the right voltage?

Ive got one battery that came from my preivous camera, the D200, and then one each from my D700 and D300s, but haven't had a way of marking which was which.
any help, tips, comments or places i can go to get this (cheaply) tested would be much help!

[Kym]

http://en.wikipedia.org/wiki/Lithium-ion_battery

Li-ion batteries have a limited life.
You need to measure their full cycle not just fully charged voltage to determine capacity.
As for voltage, a multi-meter will do that for you. You can get a cheap one from Jaycar or Dick Smith.

$10 http://www.jaycar.com.au/productView.asp?ID=QM1500&CATID=12&form=CAT&SUBCATID=546

$17 http://www.dse.com.au/cgi-bin/dse.storefront/4c0c59fb01e0b2702740c0a87e0106b1/Product/View/Q1467

[JorgD]

I use a digital battery charger / discharger to check my batteries. The device lets me discharge my batteries at a fixed rate until they reach a pre-determined voltage and then it tells me the capacity of the battery.

Speaking in plain English, I charge my battery normally, I discharge my battery at a rate of 500mah until it reaches 6V and then the device tells me how much capacity the battery really had.

Now most manufacturers are a bit optimistic about their battery capacities and like to overstate them. My 7D battery claims to have a capacity of 1800 mah and when tested it can supply about 1650 mah. Overall this is not so bad and I generally get around 1400 shots from 1 charge.

I was given a Pisen battery for my 7D which claims 1450 mah capacity and when tested, it delivered 650 mah. Now that is rather poor and I have never used the battery.

Over time batteries loose capacity, thus I would not be surprised if my 7D batteries would only have a 1200 mah capacity after 500 recharges.

If you feel you are getting a shorter battery life than expected out of your battery, a capacity check is the only way to verify if the battery is having a problem or not. It is possible that there is a problem with your camera and that it uses a lot more power than normal, but that is unlikely.

There are many different battery dischargers on the market, needless to say, you would need one that tells you how much it discharged from the battery rather than one that just discharges and tells you nothing.

[Kym]

How to prolong lithium-based batteries http://www.batteryuniversity.com/parttwo-34.htm

@JorgD your comments are appropriate to NiMh batteries, not necessarily Li-ion

[JorgD]

@Kym I am not sure why my comments are not appropriate for Li-ion or Li-Po batteries, as any type of battery has a capacity and nearly every device has a cut-off voltage. Thus, IMO, it is perfectly reasonable to test the capacity of a battery to give you an indication of its expected performance in the field.

Depending on the application, I often test voltage drop under load of Li-Po batteries to compare which ones are a better battery for my needs.

[Kym]

All I'm getting at is Li-ion don't like full discharges. No drama.

[JorgD]

Ahh, ok. I agree with that one, so I would not test the battery every day. But even the link you provided on how to prolong the lithium battery life, they suggest a full discharge every 30 charges and don't seem to think that is a big problem.

So discharging them to the cut-off voltage of your device once a year or every second year (when you feel the performance is dropping off), should not do any harm.

[davros]

http://en.wikipedia.org/wiki/Lithium-ion_battery

Li-ion batteries have a limited life.
You need to measure their full cycle not just fully charged voltage to determine capacity.
As for voltage, a multi-meter will do that for you. You can get a cheap one from Jaycar or Dick Smith.

$10 http://www.jaycar.com.au/productView.asp?ID=QM1500&CATID=12&form=CAT&SUBCATID=546

$17 http://www.dse.com.au/cgi-bin/dse.storefront/4c0c59fb01e0b2702740c0a87e0106b1/Product/View/Q1467

While I agree with everything else you mentioned, checking the battery voltage with a multimeter will not work. In order to measure the voltage of a battery, the battery must be in a loaded state. For small batteries like this, a charge/discharge type unit should be used, as you typically cannot get a multimeter across the battery terminal while it is in circuit.

[arthurking83]

.....

Ive got one battery that came from my preivous camera, the D200, and then one each from my D700 and D300s, but haven't had a way of marking which was which.
any help, tips, comments or places i can go to get this (cheaply) tested would be much help!

I reckon this may be a good opportunity to see how effective the battery meter menu option is on your D300s(and I suspect your D700 too).

On your Menu, go to the Setup Menu(spanner icon). About half way down is the Battery info option. Press OK or click the joystick pad to the right and the battery info details will display.

I can't imagine the info to be 100% accurate nor as accurate as a dedicated battery testing device, but I'd be curious to know what the info is saying re the three different batteries? I only have the one single EN-EL3e battery and it works flawlessly.. with about 1500(est) images per charge, and charge levels never dipping below 25% according to the Bat. meter.

I have no idea on what the Pic. meter is on about, and I've yet to see the Charging life indicator move off the 0(zero) mark.. indicating a perfectly good battery even though it's 2.5yo, and has been the sole power source used for over 50K images.

0 = good battery, 4 = bad battery(I hope? :p)