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Old 12-16-2010, 05:45 PM   #1
kveroneau
Edge User
 
Question enTourage eDGE/Pocket eDGe battery care best practices

As a portable device enthusiast, I have read many different articles and manuals relating to proper care of a devices battery to extend it's overall life. The thing is, every device says something completely different...

My laptop, for example, says it is alright to keep it plugged in all the time, but at least once a month allow the battery to completely deplete and re-charge to extend the batteries life. In the Toshiba Satellite user guide. Since I really hate keeping a battery connected to an AC source for 8-10 hours a day, I disconnect the battery from the laptop if I plan on keeping it plugged in for extended periods of time.

My android cell phone, unfortunately will not boot up, if the internal battery is removed. It goes into the recovery mode screen telling me to insert the battery. So, in this effect, I never keep my cell phone connected to the AC once it's fully charged. I also never plug my phone in until the battery is less than 10%. I'm not completely sure if this is the right way of doing things, but the battery seems to be working the same as it did a few months ago when I received the phone.

Now, onto the eDGe. I did not see anything in the documentation on proper battery care best practices. After the eDGe's battery is fully charged, is it alright to keep it connected to an external source and continue using it like a normal laptop/netbook? Or after it reached 100% charge, to unplug the power adapter? Which of these would extend the batteries life time? Since I have the pocket edition, this is a rather crucial question, as the battery cannot be swapped out easily. Can I begin charging the eDGe at any point in it's depletion cycle? Or should I wait until the battery is below a specific percentage?

Currently, I unplug my eDGe as soon as it reaches 100%, and only begin to charge it when it hits about 12% or so. For the moment, the battery appears to be lasting just as long as it did when I first purchased the unit, but is this going to last?

How is everyone else's battery charging habits for their various portable devices and how well are those batteries lasting since you purchased your devices? From a scientific standpoint, what is the recommended way to treat portable device batteries? That is to say that people on these forums have worked or still work with a company which manufacturers portable device batteries.

Thank you all for any input you can provide that will help me and others save battery cells all around the world!
 
Old 12-16-2010, 06:00 PM   #2
borisb
Edge User
 
My experience with lithium ion batteries over the past 10 years indicates that using them wears them out. If you fully drain and discharge them daily, they'll last 1-2 years before they're down to 50% or less. If you rarely drain them (i.e., keep them plugged in all the time), they'll keep say about 80% of capacity for 5+ years. The discharge/recharge is effectively a destructive process.

This is based on my experience with Lithium Ion batteries on my Dell laptops. The Lithium Ion Polymer batteries used in the eDGe I believe is basically the same, merely lighter and more easily molded into custom shapes. If someone knows different regarding polymer, I'd be interested to hear from you

So, my recommendation is to keep it plugged in as much as you can and drain the battery as little as you can - without killing yourself with inconvenience of course.

EDIT: Based on some further digging I did in a post below, and being reminded by a post by dontpanic, it seems that it doesn't really matter how much or how little you run on battery, it will last at least 4 years. (The User Guide (click the Help app) has some battery care tips with regards to temperature, though.)

Last edited by borisb; 12-16-2010 at 11:27 PM.
 
Old 12-16-2010, 07:33 PM   #3
kveroneau
Edge User
 
Hmm, interesting. I'll keep this in mind, definitely. Hopefully this thread receives more replies. What is the mAh of the Pocket eDGe's battery? I do not see any information anywhere on this, and BatteryTime lite needs it for accurate battery usage display.
 
Old 12-16-2010, 10:49 PM   #4
Hopi
Edge User
 
The mAh is milli ampere hour, a unit of electric charge. Follow the link below for a short explanation:

http://whatis.techtarget.com/definition/0,,sid9_gci214359,00.html

As for battery life, here are sites that talk about ways to take care of your battery, plus the fact that Li-ion batteries do not suffer from memory effect:

http://www.friedbeef.com/top-15-ways-to-extend-your-laptop-battery-life/
http://www.wisegeek.com/what-is-a-li...on-battery.htm


Here's another site that has a different take on memory effect:

http://www.dansdata.com/gz011.htm

Eventually, you have to decide which point of view is correct. Or look for a more credible info source.
 
Old 12-16-2010, 11:16 PM   #5
borisb
Edge User
 
Some good info there, Hopi!

I'd like to clarify "memory effect" vs "wear out" as I use these terms.

"Memory effect", to me, means that if you regularly only drain your battery 50%, then the battery will think it has only 50% capacity, and you can no longer drain it further. Your 4 hour battery becomes a 2 hour battery. Repeatedly fully charging and discharging is good for this type as it maintains 100% capacity.

In contrast, "wear out" means that the cells in the battery will slowly die, one by one, and no longer be able to hold a charge. If a battery comprises 5 cells, the most used one (the first cell, lets say) will die first, not being able to be charged any more. At this point, a 5 hour battery now will only last 4 hours no matter what you do. This shifts the most charge/discharge cycles to the second cell, which will then die, too. Now you're down to 3 hours. Likewise, the remaining cells will in turn die (actually somewhat more quickly since they get used more frequently being the only ones left). Eventually the last cell dies and your battery will show something like a red light (meaning it's failed), or it just won't show anything any more. For these, while they don't care how much you charge/discharge them, the more you charge & discharge the faster they wear out, and conversely, discharging them as little as possible greatly extends their lifetime while maintaining near 100% capacity even after years.

The old NiCad (nickel cadmium) batteries were really bad for the memory effect. If you faithfully fully charged and discharged them, they would last quite a while, and keep close to 100% capacity.

The subsequent NiMH (nickel metal hydride) were less susceptible to the memory effect, but still had it. They also showed more evidence of wearing out over time. Better capacity and recharge rates, too.

LI (lithium ion) batteries eliminated the memory effect, but are very susceptible to usage, which is why these I recommend keeping charged by keeping the device on AC as much as convenient.

The latest LI polymer batteries are even better, having no memory effect, and greatly reducing the wear out rate. These ones (used in the eDGe) you don't have to worry about wearing out as much, but if they're kept plugged in, they'll last that much longer. Also, draining these below 5-10% requires a "deep recharge cycle", which I suspect is probably harder on the battery, so it's best not to let the eDGe run out completely.

For reference, look at http://en.wikipedia.org/wiki/Lithium_ion_battery. Note the right side bar indicates 400-1200 charge/discharge cycles. It also states the following (corresponding to my "wears out" term):
Quote:
Charging forms deposits inside the electrolyte that inhibit ion transport. Over time, the cell's capacity diminishes. The increase in internal resistance reduces the cell's ability to deliver current. This problem is more pronounced in high-current applications. The decrease means that older batteries do not charge as much as new ones (charging time required decreases proportionally).
Lithium ion polymer batteries (http://en.wikipedia.org/wiki/Lithium...olymer_battery) are better having more than 1000 charge/discharge cycles (but not infinite ) It supports the statement by enTourage that the eDGe batteries will last quite a while at near-full capacity:

Quote:
Originally Posted by dontpanic
The battery in the product is a very advanced design and should last more than four years before performance begins to degrade. At that point, the Pocket eDGe may be returned to enTourage systems to have the battery replaced for $85, not including shipping. There should be no concern about the need to replace the battery on the Pocket eDGe.
The following article gives another detailed comparison of rechargeable batteries with the pros/cons/characteristics: http://en.wikipedia.org/wiki/Battery_cycle.
 
Old 12-16-2010, 11:19 PM   #6
borisb
Edge User
 
Quote:
Originally Posted by kveroneau View Post
What is the mAh of the Pocket eDGe's battery? I do not see any information anywhere on this, and BatteryTime lite needs it for accurate battery usage display.
You'll have to ask Tech Support as this information hasn't been published anywhere, and since the battery is internal, we can't read the label.
 
Old 12-17-2010, 02:35 AM   #7
kveroneau
Edge User
 
Thank you very much, this is very helpful information. For some reason I've always thought that "constantly charging a battery" would have a negative effect on the battery itself. I notice that if my phone is constantly plugged in, the battery becomes very hot at times, like it's overcharging or something. Is there a special charging circuit in the eDGe which routes DC power directly to the motherboard bypassing the battery if the battery is full? I just hate the idea of power flowing in from the battery constantly, while the DC re-charges what was just used. Like how FIFO(First-in First-out) works.

Or am I just completely uneducated in new battery circuits? When DC is connected, does it even touch a fully charged battery, or just supply power to the main board?
 
Old 12-17-2010, 10:13 AM   #8
borisb
Edge User
 
You'd have to ask the electrical engineer at enTourage
 
Old 12-22-2010, 12:23 AM   #9
jimates
Edge User
 
A lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges.
Battery University

For example if you use 25% of the battery and recharge it on 4 occasions, that resulted in 1 cycle of the battery. Using 75% one time and 50% another time would count as 1.25 cycles. This means that lithium batteries start to wear out as soon as you begin to use them. Keeping them plugged in all the time does not count toward the cycles because the circuitry in the charging system bypasses the battery completely when it is fully charged and on AC power.
 
Old 12-22-2010, 10:00 AM   #10
borisb
Edge User
 
Welcome to the forums, jimates Thanks for the extra info!

The eDGe uses Lithium-ion "polymer" batteries, which apparently are more advanced than the older lithium-ion (in providing more cycles).
 
 

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