View Full Version : Long term storage of Lithium-ion batteries

29th September 2009, 01:03 PM
I've managed to accumulate 3 spare Olympus BLM-1 batteries, so I had a scout around to see the best way of storing them for the long term.

What I've gleaned is that their chemical clock ticks away and their capacity gradually and permanently reduces. This effect is at it's minimum when the battery is half-discharged, in the 40-60% region, so don't store fully charged. The effect is virtually non existent at low temperatures, so I store mine in the fridge, although at UK temperatures it doesn't make a huge difference.

This table shows how much effect on battery life this can have:

Temp .... 40% Charge ............ 100% Charge
0C ..... 2% loss after 1 year .. 6% loss after 1 year
25C .... 4% loss after 1 year .. 20% loss after 1 year
40C .... 15% loss after 1 year . 35% loss after 1 year
60C .... 25% loss after 1 year . 40% loss after 3 months
Source: BatteryUniversity.com (http://www.batteryuniversity.com/parttwo-34.htm)

29th September 2009, 02:35 PM
I have certainly read that you shouldn't store Li Ion batteries discharged.

I've said this before though, I have BLM-1s going back five years and I have no idea which are which and have no nasty surprises with charge life.