Managed charge level -- 95% lithium Ion

[jef144]

Just got a new laptop - Thinkpad T60 -- and it has an option to charge the Lithium Ion to LESS than 100%. Claims are that the battery pack will last twice as long. They don't explictly say, but it appears that charging will start when the capacity goes below 91%, and stop when the capacity goes above 95%. The 4% differenential is enforced when you select the option to pick your own level - I'm now using 85%/ 89%.

Dell has similar capability. After all the battery recalls, I can only speculate whether this approach also reduces explosions -- the laptop makers haven't made that assertion!

Toyota's Prius (Nimh chemistry) also manges the traction battery charge level to about 80% for battery longevity. Their design point is 150k miles.

So, my question is, are there chargers out there for flashlight batteries, especially Lion, that can do the same?

 

[wasBlinded]

The DuraTrax ICE, and I think the Triton let you choose either LiPoly (4.2v) or Li-ion (4.1v). 4.1v would correspond to about 90% charge level.

I think you can also have the Duratrax ICE input charge to a percentage of maximum input capacity, which will give you some more control. I'm not home right now to confirm that, though.

 

[SilverFox]

Hello Jef,

Welcome to CPF

Interesting information... I believe the cell phone manufacturers did a study where they found that you could get a drastic improvement in cycle life by limiting the ending voltage while charging Li-Ion cells. If memory serves me correctly, charging to 4.200 volts yields around 500 cycles, where charging to 4.100 volts increases that yield to around 1500 cycles.

The Schulze also offers a charging algorithm that ends at 4.100 volts, as does charging with a regulated adjustable power supply such as those available from Mastech.

Tom

 

[KonradC]

Regards the Prius battery: as far as I know the main reason battery charging terminates at 80% is to provide a degree of headroom to accept more charge during regenerative braking and not to increase battery life.

 

[koala]

Current Prius runs on gas and NiMH, the 2008 models will come with gas+Lithium. Whether it make Michael Bay style explosions is still unknown .

 

[65535]

Undercharging is highly beneficial to non memory type batteries, NICDs will just lose capacity even faster than normal, but NIMHs and lithiums seem to like it.

 

[2xTrinity]

Current Prius runs on gas and NiMH, the 2008 models will come with gas+Lithium. Whether it make Michael Bay style explosions is still unknown

Yeah, I can't believe people would put such a dangerous, volatile technology into their cars without considering the potentially explosive consequences! Sure, it has great energy density and all, but I've heard that even the slightest spark can caues this so-called "gasoline" to "vent with flame".

 

[LEDite]

The Real Electric Car is...

Lithium Ion or Lithium Polymer Batteries

I've blown a lead acid battery apart, but never had a lithium ion even vent.

Larry Cobb