U60 Battery Life

[Marcus Durham]

One of my U60's has suddenly only started holding half a charge (and showing 180 mins left). It dates from 2009 but has only had 52 cycles.

Is that part of the course? It's sister battery purchased at the same time which is on roughly the same amount of cycles is fine and is holding full charge with only a slight drop in minutes compared to a year old battery.

Just one of those things?

[Andy Wilkinson]

It's not just cycles but also age, heat they might have been exposed to, number of complete discharges, how you store them when not in use (not fully charged I hope) and full charges compared to just topping up etc.

I have 3 Sony batteries for my EX3 dating from the summer of 2008 and, to be honest, I am still amazed that I am getting decent use out of them even now - and they still last for hours.

Modern battery technology is all about dealing with very unstable chemistry and mostly they get it right. So I would say just one of those things - but we would both be interested to know how others are getting on with these batteries!

[Chris Medico]

Several factors come into play with LiON batteries.

If you store them charged you reduce their life (over 3.7v/cell or about 14.8v on a U60).
If you charge them hot you reduce their life.
If you get them over 140 degrees at any time you reduce their life significantly. One hot day in a car can cut their life IN HALF.
Running them down below 30% charge reduces their life significantly.

The chemistry in a LiON battery degrades over time whether you use them or not. Storing them at 3.7v/cell and as cool as possible will extend that life. 3-4 years use is normal for users that don't work to get long life out of their batteries.

The best way to maximize the life of a LiON battery is to charge them just before use. If you are going to store them charge them to 50%. Don't run them down below 25% if you can help it. Keep them as cool as practical between uses.

[Warren Kawamoto]

One of the biggest mistakes I see people do is to completely drain their li-ion batteries. I hope you didn't.

[Marcus Durham]

Originally Posted by Chris Medico

Several factors come into play with LiON batteries.

If you store them charged you reduce their life (over 3.7v/cell or about 14.8v on a U60).
If you charge them hot you reduce their life.
If you get them over 140 degrees at any time you reduce their life significantly. One hot day in a car can cut their life IN HALF.
Running them down below 30% charge reduces their life significantly.

The chemistry in a LiON battery degrades over time whether you use them or not. Storing them at 3.7v/cell and as cool as possible will extend that life. 3-4 years use is normal for users that don't work to get long life out of their batteries.

The best way to maximize the life of a LiON battery is to charge them just before use. If you are going to store them charge them to 50%. Don't run them down below 25% if you can help it. Keep them as cool as practical between uses.

Which is literally how they have been used. They always get charged before a job. Although obviously it is always perfectly possible to charge a battery that then isn't used. But it would never be more than a couple of weeks before it was used. No long term storage.

No heat and rarely run down either.

[Alex Dolgin]

Originally Posted by Marcus Durham

One of my U60's has suddenly only started holding half a charge (and showing 180 mins left). It dates from 2009 but has only had 52 cycles.

Is that part of the course? It's sister battery purchased at the same time which is on roughly the same amount of cycles is fine and is holding full charge with only a slight drop in minutes compared to a year old battery.

Just one of those things?

Yes, just one of those things. The recommendations here are all good, but they have relatively minor effect on the Li-Ion battery (say for the sake of the argument 10% in overall, except that heat can really kill it). The U60 consists of either 4 cells or 4 pairs for the total of 8. While assembling a new pack, a manufacturer always uses similar cells, from the same lot, same date, etc, to make sure they match each other as close as possible. If at some point during service life one cell starts falling off - loses some capacity sooner than the others, the end result is the whole pack goes south pretty rapidly.