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Research Topic: Which Battery Will Do?

Last updated:	Overview & Terms 8 March 2012		Single Use 7 January 2016		Rechargeable 10 November 2019		Battery Analyser 23 April 2021		Battery/Charger Shopping 24 April 2021		Recommended Batteries for Particular Uses 16 May 2014
Original article by Ian Mander, 22 July 2002			Single Use Test 6 November 2007		Rechargeable Test 21 September 2023		Test Procedure 4 June 2011		Button and Coin Cell Shopping 31 July 2021		More Info & Links 29 February 2012
					LSD Shootout 7 January 2016		When Battery Testing Goes Bad – Consumer Magazine 20 June 2023		Battery Holder Shopping 28 July 2022

On this page: Testing Procedure | Start/Finish Times Chart

Rechargeable (Secondary) Battery Test Procedure

Proposed testing procedure is as follows, designed to produce reasonably relevant results for real-world uses such as digital cameras.

1. New cells only: Discharge at 0.2C to determine maximum off-the-shelf capacity (for Eneloop cells) and prepare all cells for breaking in. The 0.2C rate is used here because it will provide a direct comparison with the 0.2C discharge used in the break in (step 3).
    
2. Used cells only: Fast charge (0.5C rounded up to nearest 100mA), then discharge at 0.2C to determine initial condition.
    
3. Both new and used cells are broken in (or "formed"), using the claimed capacity entered into the MH-C9000 for it to determine charge and discharge rates. As per the MH-C9000 regime (from an IEC specification, apparently), cells are charged at 0.1C for 16 hours, rested for one hour, discharged at 0.2C, rested for one hour, charged at 0.1C for another 16 hours.
    
4. Rest then discharge AA cells at 1 amp, AAA cells at 400mA.
    
5. Fast charge (0.5C rounded up to nearest 100mA), rest, then discharge at 1 amp (AA) or 400mA (AAA).
    
6. For Eneloop AA cells: Charge at 2 amp for 1.1 hour, rest, discharge at 1 amp.
   For Eneloop AAA cells: Charge at 800mA for 1.1 hour, rest, discharge at 400mA.

All charge and discharge rates are nominal; the MH-C9000 integrates the total mAh based on the actual current. It terminates discharge at 0.90V, avoiding a possibly damaging deep discharge. 500mA is the analyser's default discharge rate but at present it seems like too much work to include it in the test regime, and it's the same as the 0.2C test for 2500mAh cells anyway. 1 amp is a very common discharge test, since digital cameras often use about that much current.

Resting the cells after charging gives more realistic capacities than using them "hot off the charger".

All testing done at room temperature, whatever that may have been at the time.

Break-in Start/Finish Completion Times Chart

The whole break in process takes at least 39 hours - more than a day and a half. See the table below for start and finish times.

Light grey for the day after commencing, darker grey for the day after that.

A few battery shoot-outs are mentioned on the More Info & Links page, or get information on the charger/analyser I use.

Read on for suitable uses for particular battery types.

Last updated:	Overview & Terms 8 March 2012		Single Use 7 January 2016		Rechargeable 10 November 2019		Battery Analyser 23 April 2021		Battery/Charger Shopping 24 April 2021		Recommended Batteries for Particular Uses 16 May 2014
Original article by Ian Mander, 22 July 2002			Single Use Test 6 November 2007		Rechargeable Test 21 September 2023		Test Procedure 4 June 2011		Button and Coin Cell Shopping 31 July 2021		More Info & Links 29 February 2012
					LSD Shootout 7 January 2016		When Battery Testing Goes Bad – Consumer Magazine 20 June 2023		Battery Holder Shopping 28 July 2022

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