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nexus7
05-11-2005, 02:58 PM
To begin, it's my first post here so i say hello to all people here :D

I've just bought a Loox 720 and i want to get the best of what it can do for me. Especialy for autonomy and intensive usage.
I need help to clarify some points about best practices for batteries..
(I'd read a lot about this on the net, 'googling' around, and i must admit that i can't have a clear opinion on that subject since advices are very contradictory!)

- is it necessary to overcharge it (about 12 hours) before the first use ?
- is it good to make 3 full charge/discharge before using it on AC ?
- does using it intensively reduce the number of charging cycle possible ?
(In other words, I now that there is a limited number of charges (around 1000?) . If i use my PDA with max power saving or at full speed/services, is it better/worse/doesn't change anything ?)

Every advices/warnings will be very appreciated !
Thx for your answers !

Kowalski
05-11-2005, 03:41 PM
First of all you cant overcharge the battery by simply plugging it to the wall. The batteries have a circuit built in which is responsible to cut the current when the output voltage reaches to a limit. When the battery cuts the current it doesnt matter how long you keep the device plugged.

It will be a good practice to charge and discharge the battery fully for about a couple of times, because batteries reach to their maximum capacity after a couple of charge cycles.

It is also adviced to totally discharge battery once every month or a couple of months.

If you wont use your device for a long time, make sure that the battery is not fully discharged or fully charged. Optimum level will be 40%. Keeping a battery in a cool place will be good but batteries dont like moisture.

Finally all li-ion batteries have a lifespan, and no matter how well you care about your battery, it will die when it reaches a limit. There is also a charge/discharge limit, but you will hardly achive this limit. Say that you charge your device daily, 1000 charge cycles will last for 3 years! My device is nearly 2 years old, and the battery still performs like it is new. Using the device in max speed will drain more current from the battery, but i dont think that this will effect the lifespan of your battery significantly, it will only reduce its runtime per charge.

emuelle1
05-11-2005, 03:43 PM
You'll find varying opinions. Some people say that you must charge it for the full time that the manufacturer recommends. Others will say that you can start playing with it almost right away as long as it's on the charger.

Once you get it fully charged, L-ion batteries love to be trickle charged. Fully discharging them will hurt them over the long run. I put my Pocket PC on a charger every chance I get.

When I got my first cell phone, I would let it fully discharge before charging it back up again. I had to replace the battery within a year. Since then, I try to charge my devices when it's convenient, and I haven't noticed a loss of battery time on any Lithium ion battery powered device I own.

Menneisyys
05-11-2005, 03:58 PM
Please read http://batteryuniversity.com/partone-12.htm :

"Lithium-ion is a very clean system and does not need priming as nickel-based batteries do. The 1st charge is no different to the 5th or the 50th charge. Stickers instructing to charge the battery for 8 hours or more for the first time may be a leftover from the nickel battery days. " - that is, you don't need to stick to the initial 12 hours.

"No trickle charge is applied because lithium-ion is unable to absorb overcharge." - this means that, unlike with Nickel-based batteries, the charging completely stops after reaching the 100% charge level in some 1.5-2 hours.

"Much attention is focused to avoid over-charging and over-discharging." - this also refers to the fact that Lithium-based batteries should not be discharged (depleted flat).

My experiences: I have several backup batteries. I've charged some of them 12 hours initially, and, for a test, only for waiting for the 100% charge rate with another one. These two batteries deliver equally well after 1.5 years. Therefore, I'd personally say it's not necessary to leave your PDA on the charger for 12+ hours at the first charge, no matter what some sources say.

nexus7
05-11-2005, 04:14 PM
Ok, thanks you all, i'll make a mix of all that advices ! :wink:

- no 12 hours first charge
- 2 full charge/use for the begining
- no full discharge after that..

applejosh
05-11-2005, 05:27 PM
Well, no problem with the charging/discharging, but try to avoid completely discharging a Lithium ion battery. When they are fully discharged, they degrade (at least I've heard that certain chemical reactions take place which cause some sort of crystallization inside the cells to occur). From a personal experience, I noticed this on my Zaurus, which I let sit uncharged for months. It holds a charge for about 15 minutes now, rather than the hours I used to get from it.

Menneisyys
05-11-2005, 05:43 PM
Ok, thanks you all, i'll make a mix of all that advices ! :wink:

- no 12 hours first charge

You won't do anything bad if you leave your PDA on the charger for 12 hours - it's just not necessary because there's absolutely no charging current after 2-3 hours.


- 2 full charge/use for the begining

I woulnd't say that it's necessary either... some people say "formatting" a battery is neceesary. With my spare lithium batteries, I didn't experience the same.

- no full discharge after that..

At least try to avoid it and, particularly, never do it on your own will.

Dyvim
05-11-2005, 05:54 PM
Menneisyys,
So you're saying that the 24 hr initial charge recommended for the Mugen Power batteries (e.g. 5800 mA battery for Toshiba e8xx) is probably not true? I should just charge it to full and that should be good enough?

Great link on Li ion batteries.

Thanks,
Dyvim

Menneisyys
05-11-2005, 06:05 PM
Menneisyys,
So you're saying that the 24 hr initial charge recommended for the Mugen Power batteries (e.g. 5800 mA battery for Toshiba e8xx) is probably not true? I should just charge it to full and that should be good enough?


I can't give you a definite answer. According to the article I've linked and also according to my experience, it doesn't / didn't cause any problem for me in the past when I "only" kept my new PDA's / new spare batteries on charger for 3-4 hours.

For example, I've done a lot of battery life tests (how many hours an MP3 recorder is able to work with one charge) with a Li-Ion 2210 battery that I didn't 'format' / kept on charger for much time either. I got exactly the same results than with a "properly" "formatted" and, initially, long-charged battery.

Other users may report exactly the opposite experiences - I don't know.

So, again, I'm not sure.

MulesRockorz
05-12-2005, 06:06 AM
Well to start It depends on your battery type. I don't know of any Ni-Mh or Ni-Cd powered PDA's and I'm pretty sure all PDA's use one type of lithium batteries, But there a are hand full of lithium variants.. Time for a quick lesson on battery basics..

When ever you see 1000 mAh or 1400 mAh Or anything with mAh that tells you how much the battery holds. mAh stands for milli-Ampere-hours, so the proper way (but people want the battery to seem huge to full idiots) is after it gets over 1000 mAh to put it as 1 Ah because milli is the prefix for thousandth so it takes 1000 mAh to make 1 Ah.

What that means is that if its a 1 Ah battery you can draw 1 ampere from that battery for an hour, after that the battery is dead.

Cycle life - The cycle life of a battery is how many times you can completely discharge the battery and recharge it and it will Still have over 80% its original capacity. Honestly I don't know the Average cycle life for lithium's, but because lithium is such a extremely reactive metal and they DO use pure lithium on the batteries you shouldn't expect your battery to last over 3 years and still have 80% its original capacity. Please note that the battery will still be useable even though its below 80% like it might drop below 80% in 3 years but depending on how much you abuse the battery it might last 6 years before its capacity is so little it has become useless, Lithium's I think are kind of new to be able to tell accurately what their cycle life is. The science of battery chemistry has literally exploded in the last few years. "Back in the day" you had 2 types of mainly used batteries Ni-Cd and Lead Acid, don't get me wrong the Lead Acid is pretty damn good but its heavy.

Go to http://www.powerstream.com/ and find your way to the Battery Chemistry page, or just click here [ http://www.powerstream.com/batfaqint.htm ] Power has a VERY good site that explains it very well, even if your not good with chemistry you will understand a good part of it, if you look around you can find a page on how to care for your batteries and what not to do.

As far as battery saving goes Remember this... As your battery Dies the voltage starts dropping to where its almost straight down, meaning as the battery dies it starts dying faster under the given load. To make the battery last a lot longer turn the brightness on the screen down, this can boost your battery run time to over 7 hours even 9, 10 and maybe 12 hours. (considering you have a good sized battery and you don't use the PDA that much)

Menneisyys
10-16-2005, 04:42 PM
Whie writing a battery-related post (http://www.pocketpcmag.com/forum/topic.asp?TOPIC_ID=18761) (worth reading!), I've run into another, very good chapter in the book of Battery University (http://batteryuniversity.com/partone-19.htm) on initial charging:

Lithium-ion batteries deliver full power after the initial charge. Manufacturers of lithium-ion cells insist that no priming is required. However, priming is beneficial as an initial start and to verify battery performance. Excessive cycling should be avoided because of wear-down effect.