Lithium-ion/NiMH Batteries - How to care for

[glenyoshida]

It's been bothering me that some manufacturers, right in the owner's manual, state that brand new mobile phone batteries should be charged, then fully depleted, then charged again before using the phone for the first time. Some even state to leave the phone charging for 24 hours before using it. So I thought I would take a little time to find out what the heck.

Here's the scoop as of Dec '07

1. No, you don't need to charge your battery for 24 hours before using it. Three hours is quite sufficient, after that you are wasting time.
2. Don't buy old lithium batteries even if they are cheap. Lithium batteries lose life at about 20% per year whether they are being used or not.
3. Don't leave your cell phone in a hot place such as a car. Heat is not good for lithium ion batteries. You lose about 6%/ year of it's life at near 0 °F and 40% at 140 °F. If the outdoor temp is in the upper 90s it's not uncommon for a car dash to reach 180 °F
4. Conversely if you have a spare battery storing it in a cool place like your refrigerator (not freezer) will prolong it's life.
5. Keeping the battery topped off (frequent charging) will make it last longer than letting the battery go dead before recharging.

Laptop side notes:

1. Consider removing the laptop battery when plugged in to keep the heat from the laptops CPU off the battery.
2. Laptops monitor the battery and have a kind of "fuel gauge". On most laptops it might be a good idea to let the laptop run down on it's batteries every 30 charges so the laptop can recalibrate it's gauge. This may help keep the laptop accurate on it's battery condition.

[glenyoshida]

As long as I'm talking about batteries and going off into geek land it's worth it to mention a good battery charger and tester for NiMH batteries. (Nickel metal hydride NiMH batteries are the rechargeable batteries that don't need to be drained before recharging them unlike the Nickel Cadmiums NiCD). In fact, like Lithium-ion batteries they last longer and perform better if you keep them topped off. This

La Crosse Technology BC-900 AA and AAA charger (http://www.amazon.com/gp/product/B00077AA5Q/ref=wl_it_dp?ie=UTF8&coliid=I1U7LQIZF96FPP&colid=3H0TFMW7G9R91) is the best charger you can get IMHO. Well, unless money is no object that is. It's also not very expensive at about $40 shipped.


http://ecx.images-amazon.com/images/I/51VR9QN2XGL._AA280_.jpg

If you use rechargeables I'm sure you've come upon a time that you are not sure just how good a battery still is. So without a way to test them you just charge them all up and then hope you have a good set. I found out a couple of times, in the middle of a photo shoot, that at least one of the batteries was bad and missed shots while switching out the batteries.

This charger has a couple things that are very useful and worth the extra $20 that a craptastic charger can't do. It also has quite a few other nice features but these are the most valuable. With this charger you can test the battery's capacity. So you'll be able to tell the battery's ability to take a charge. You can also refresh batteries and often improve the battery's capacity and ability to deliver juice.

[slosurfer]

Wow, thanks for the good info. This is stuff I always wondered about. I'll have to make sure the wife reads this one.

[BruceTS]

I still like ni-cad batteries, even thought they don't last as long, charge wise, they do last longer as in battery life, if maintained properly. Years ago I used to do plenty of testing with making ni-cads perform to their fullest. Here are some of my finding.......

If you slow charge the batteries, they have a tendency to release the charge slower
When you fast charge them, keeping them in ice will help get maximum capacity
After a while the batteries build resistance from constant use, this shortens the life, but you can erase this "memory" so they can regain full capacity. The simplest way I used to do this was with a 12v car battery. Short a wire from the positive to positive on the nicad and negative to negative.(this was done to the sub c size) Only do this for a second.... This method can also be used to bring back a dead battery that has been sitting for a few years. I've been 90% sucessful in recovering a dead battery.

Unfortunately the NiMH and LI-ion batteries can't be recovered one they die......