Cordless Battery Life

[twertsy]

So I've always been told that you shouldn't plug in/charge your cell phone until it's almost completely depleted/dead. Does this philosophy hold true for our cordless tools? I've noticed that waiting until they are completely drained and then charging seems to make them last longer.

A second question, a friend told me to hit old worn out LI batteries with a zap from an arc welder, supposedly blasts the crystallized elements of the battery and refreshes it. Any truth to that? I'm assuming there must be a specific technique for doing this.

EDIT: Did some research and the welder trick only appears to work on NiCad. How-to Video

 

[kf4zht]

I wouldn't do anything with lithium based batteries except use the official chargers until you study how they work pretty extensively. They have the tendency to explode/burn/etc depending on chemistry if mistreated

 

[Will S.]

Keep the welder away from any batteries, as that is a formula for disaster. As far as when to charge batteries; Ni-cads should go through complete charge/discharge cycles in order to retain their capacity. e.g. let them run down almost completely before charging, as ni-cads have "memory", and if repeatedly charged at say, half run down, then they will lose the ability to deliver more than half the normal run-time.

Ni-Mh and lithium do not have "memory", and can be recharged at any state of discharge, without ruining them But all batteries do have a finite life; good for "x" number of charge/discharge cycles. I don't remember the "typical" number, but 1000 comes to mind, so that would be years of use.

 

[kc-steve]

Yeah, the old NiCad batteries are different from the new Lith-Ion batteries. I've also read that Lith-Ion have a charge number limit, but have ALSO read that heat is bad for them. In other words, don't wait to recharge when they are discharged. That causes heat and is likely worse for wear.

Steve

 

[gworrel]

The idea that you should fully discharge a lithium ion battery is completely false. More frequent charging and avoiding full discharge will give longer life. They do lose capacity over time if you use them at all. The useful life number of discharge/ recharge cycles is 300-500 if fully discharged before charging. That goes up to 1200-1500 if only discharged 50% before recharging.

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

 

[kc-steve]

The idea that you should fully discharge a lithium ion battery is completely false. More frequent charging and avoiding full discharge will give longer life. They do lose capacity over time if you use them at all. The useful life number of discharge/ recharge cycles is 300-500 if fully discharged before charging. That goes up to 1200-1500 if only discharged 50% before recharging.

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

That's an excellent article, thanks for posting that. It spells out the number of charges and life cycles at different rates of discharge. I should get about 2000+ before they **** out, but I think they will likely just get old before that happens in my case.

Steve