What have you learned from the Battery University?

[theilluminati]

They have a great web site but probably Way Too Much Information! (At least for me, perhaps not for all on this forum.) Basically what they have is a book which you can read online, buy on Kindle or in paperback and learn all about batteries. sounds interesting but perhaps the average user or folks like me don't need that much.

Is there a good summary of what you should know perhaps in one article, blog post or even essay, but one definitely shorter than a full book? It's just net realistic everyone uses batteries will read that through, right?

 

[Russel]

I see it as very realistic that battery consumers would, and should, read the whole book. But, if you aren't interested in the whole thing you can just read the sections that you are interested in. Battery University covers many different battery chemistries, if there is one in particular that you are interested in, that is the section that you should read.

What types of batteries do you use? What types of batteries interest you?

 

[donn_]

It's one of my favorite reference sites on the web. I have a prominently placed shortcut on my desktop, and visit at least once a day...sometimes more often. I've read it all at least once, and frequently use it as a jump-off point to more information through Google.

 

[reppans]

I run Eneloops for most of my portable electronic gadgets and some Li-ions for my flashlights. The Eneloops are tough cells and flashlight batts are cheap and easily replaced, so I don't worry too much about these. I do, however, try and care for the Li-ions in smartphones and tablets, esp. Apple stuff which tends to use non-removable batts. So I like the "How to prolong Li-ion batts" section on Battery University, and this military study of different charging habits w/18650s backs it up.

In summary, I try to minimize the average voltage (and temp) of my Li-ion devices, while still maintaining a reason level of back-up charge, and minimizing hassle for myself. For example, I typically use 40% per day, and so I will:

- cycle on 30-70-30 basis
- use a light timer to charge nightly between 5-7am, ie, just before I need the device
- don't use cases which insulate warmth, and "heat sink" the device on a marble countertop while charging

 

[yoyoman]

I learned that I needed a voltage meter. The key rules for Li-ions are don't over-charge and don't over discharge. How can you know if you don't have a voltage meter?

 

[vicv]

I've also learned to use a DMM to check batteries from that site. I had a box of random alkalines that I went through to see which were good and which were bad. Cleared out a lot of crap. Also seeing how my devices are discharging my Imedions. I also learned a lot about li-ion batteries so I felt comfortable buying and using them since now I know the associated risks. Plus this site helped a lot!

 

[theilluminati]

What types of batteries do you use? What types of batteries interest you?

I use phone, camera and laptop batteries. Not really interested in learning all I can about batteries only using them properly.

And this is the shortest - most useful article I found I could use: http://lifehacker.com/5875162/how-often-should-i-charge-my-gadgets-battery-to-prolong-its-lifespan

Do you agree with it's main points? Keep your batteries between 50-90% I think it's more reasonable to read this one article for the average user (think females and other nontechies) than 300+ pages of Battery University.

 

[theilluminati]

I run Eneloops for most of my portable electronic gadgets and some Li-ions for my flashlights. The Eneloops are tough cells and flashlight batts are cheap and easily replaced, so I don't worry too much about these. I do, however, try and care for the Li-ions in smartphones and tablets, esp. Apple stuff which tends to use non-removable batts. So I like the "How to prolong Li-ion batts" section on Battery University, and this military study of different charging habits w/18650s backs it up.

In summary, I try to minimize the average voltage (and temp) of my Li-ion devices, while still maintaining a reason level of back-up charge, and minimizing hassle for myself. For example, I typically use 40% per day, and so I will:

- cycle on 30-70-30 basis
- use a light timer to charge nightly between 5-7am, ie, just before I need the device
- don't use cases which insulate warmth, and "heat sink" the device on a marble countertop while charging

Might be interesting what you have to say. If you could also put it in an easy language like the Lifehacker article, I could even understand. I much appreciate you.

 

[SilverFox]

Hello Theilluminati,

The basics are that different battery chemistries behave differently.

With Li-Ion chemistry there is internal oxidation of the chemicals that takes place at both extremes of charge. They are "most neutral" at 50% charge. If you look at about 1 standard deviation around this you come up with close to 20 - 80% and that eliminates both extremes of under and over (or full) charge.

Nickel chemistry has problems when kept constantly at 100% charge.

Lead Acid chemistry has problems when the charge drops below 100%.

All chemical reactions in batteries degrade when exposed to high temperatures.

Testing simulates a particular usage pattern. If your actual use comes close to the testing pattern you can expect similar results. If your use differs you end up with different results.

Another thing to keep in mind is that everything is in a constant state of change. Some of the information that seemed correct a few years ago may not apply to current chemistry changes.

While some of us are very interested in every detail of how batteries work, we all complain when they fail and it doesn't matter if we have been using them for a year or 10 years.

If you get interested in the details of batteries you may be able to make some adjustments and stretch your laptop's battery life from 3 years to 5 years. The problem is that the time required to learn what is going on, to test various schemes, and to keep track of your actual results may not justify the simple replacement of the battery pack when it wears out.

Tom

 

[theilluminati]

Thank you Tom/SilverFox to your detailed answer.

So, ideally I should keep Li-Ion (Li-Polymer as well) between 50 and 80%? Okay. But why one standard deviation? And how did your calculation worked? That little piece of math might be of my interest.

Chart from the LifeHacker article:

It would be also interesting to know if your can properly plot these data on a graph will the ideal point be exactly at 50% not 45 or 55%? Just interested.

4 bonus questions:

- To properly use a Lithium battery:
-- no formatting is needed
-- never charge to 100%, only to 80% maximum
-- discharge to 0% once a month for the "smart"part to be calibrated
Correct?

- I have a Kindle which does not say how much the battery is charged in %, just an approximate graph. If I understand correctly, I would need a multimeter if I want to know proper charge.

- How can I calculate timing how long I should charge in a casual way? When they reach 80%? (First by watching constantly, then by setting a stop watch for the same time?)

- The proper care of Eneloop batteries in brief? Haven't really found info on BatteryUniverrsity as well. No special care needed?

Thanks for your insights.

 

[SilverFox]

Hello Theilluminati,

The standard deviation comment is simply a way to avoid the extremes. 1 standard deviation is around 68%. If you take 100% charge and want to avoid the extremes at either end, you can visualize this as taking 68% out of the middle.

There is no math model associated with this. It was just my attempt to help visualize the concept.

Plotting the data on a graph would be interesting but there is variability between manufacturers so it could become quite involved. My experience has been that if you avoid extended time in the extremes the cells seem to perform better and last a reasonable length of time. I try to keep my cells somewhere in the 20 - 80% charged range when they are stored for more than a day or so. In use I charge them to about 95% and use them until they run out.

My laptop has a Li-Ion battery pack. I charge it to 100% (especially if I am flying cross country and need the run time). I watch the meter that gives me expected remaining run time and if it seems off I will do a full discharge, but I don't do this every month. In "normal" use by me at least it gets run down to near empty about once every 3 - 4 months and it may be that is enough to keep things calibrated. When I am at home I unplug the charger and let it run a few minutes before I shut it down. The next time I go to use it I plug it back in and let it charge back up. While not "ideal" it is very practical and easy to do. Usually the battery pack lasts long enough to render the laptop obsolete so I just replace the laptop with a new one.

I also have a Kindle. I charge it fully then read a few pages to take the top part of the charge off. When it gets below 50% I charge it back up again. A voltmeter would give you a better indication of where you are but I have never checked that out. I just go by the gauge built in.

Your idea on using a timer to limit the charge is good on the surface, but if the cell has a partial charge on it you would need to determine the current state of charge of the cell before figuring out how long it will take to charge. This can be difficult to do. It is more practical to just charge to 100% then use the device a little to drop the state of charge down.

Eneloop and other low self discharge cells should be charged up and used. If you have a surplus and want to put them into storage they should be good if you follow the manufacturing procedure. This means charging them to 70 - 80% of full charge and keep them away from excess heat. It seems that after extended storage (a few years) it takes a full charge/discharge cycle or two to restore them to full capacity but after that you just use them normally.

The LSD chemistry is still somewhat new and we are still trying to figure out the best ways to get the most from it. The problem is that they work so well that there is little incentive to try to improve how they work.

Tom

 

[bbb74]

Nickel chemistry has problems when kept constantly at 100% charge.

Hi Silverfox, do you have some references for this I can read up on? I've seen you mention this before, but every other source I've seen either says it doesn't matter, or that if stored at low charge, more cycles will be required to bring the nimh cell back up to capacity.

 

[Etsu]

Hi Silverfox, do you have some references for this I can read up on? I've seen you mention this before, but every other source I've seen either says it doesn't matter, or that if stored at low charge, more cycles will be required to bring the nimh cell back up to capacity.

Even if it's true (that NiMH shouldn't be stored at 100% capacity), I think it's mainly theoretical and marginal. I have NiMH cells that are well over 10 years old that still work fine. I always keep their charge near 100%. The only NiMH cells that have failed me are the very high capacity ones. I only buy Eneloops now, so that shouldn't be an issue.

If keeping my cells at 100% charge mean they only last 10 years instead of 11 years, I'm okay with that.

 

[ElectronGuru]

The problem is that they work so well that there is little incentive to try to improve how they work.

Definitely my quote of the day!

 

[SilverFox]

Hello Bbb74,

Sorry for any confusion in that.

When you charge a nickle based cell it reaches 100% then begins to self discharge when you remove it from the charger. I was pointing out that if you leave it on the charger and keep it at 100% you greatly shorten the life of the cell.

The Low Self Discharge chemistry is especially prone to failing when cells are left in the charger. I have a set of Eneloop cells that failed a few months after they first came out and it trying to figure out what happened I discovered that they were left on the charger for extended periods of time.

With nickel chemistry in high demanding applications the best storage is to discharge the cells down to 1.0 volt and store them discharged. Depending on how demanding your application is you do a charge/discharge cycle periodically to "stir things up." The periods range from 1 - 12 months.

The references for this come from testing, trial and error, and actual use. I strive to keep my cells and battery packs "vibrant" and this method seems to work very well.

Tom

 

[theilluminati]

- cycle on 30-70-30 basis

Sorry, why not 40-80-40? As here: http://lifehacker.com/5875162/how-often-should-i-charge-my-gadgets-battery-to-prolong-its-lifespan

Maybe I don't know yet everything there is to know.

 

[reppans]

Sorry, why not 40-80-40? As here: http://lifehacker.com/5875162/how-often-should-i-charge-my-gadgets-battery-to-prolong-its-lifespan

Maybe I don't know yet everything there is to know.

The military study I showed in the chart above indicates that the lower the average voltage, the lower the capacity loss (which is consistent with BU). I would charge 0-40-0 if I knew I would use exactly 40% per day.... it just depends on how much battery cushion you're comfortable with.

 

[theilluminati]

Sorry. Wrong title. Let's give this article a new title:

What's a comprehensive article or how-to guide which summarizes to a simple user how to best take care of portable batteries [as of the present moment]?

[ Hint: if no one else, someone feeling expert on this forum can write the constantly up to date wiki on the topic similar to - on another domain - http://lifehacker.com/5813990/the-always-up-to-date-guide-to-managing-your-facebook-privacy ]

I am especially interested in the following:

1. http://lifehacker.com/5875162/how-often-should-i-charge-my-gadgets-battery-to-prolong-its-lifespan
Previously I have learned the best practice of starting to charge the battery when it depletes to 50%, just up to 80%. ( @reppans contradicitng it at http://www.candlepowerforums.com/vb...y-University&p=4270555&viewfull=1#post4270555 ) Is there a viable (portable, lightweight, suitable for international travel) solution yet to the overnight charging problem? I mean, you can't take off the batteries from the charger when charge level hits 80% (or a little more) when you just fell asleep, right? Or, perhaps, technology made thinking of this problem obsolete?

2. http://arstechnica.com/gadgets/2014/04/ask-ars-the-best-way-to-use-a-lithium-ion-battery-redux/
The lead of this article suggest:

A little over three years ago, you, the readers, asked us, the Ars staff, about the best way to prolong the life of a lithium-ion battery. Now that time has passed, the gadget landscape has changed, and it's time for an update.

It's a continuously evolving art.

 

[TinderBox (UK)]

Any change of having an general battery question sticky, I have an simple question and making a thread for it seems a bit much.

OK, I have some old NiMh 5000mah C battery`s , they have sat for 7+ years and have had very little use, I did an charge discharge capacity test and only got 300mah, I dont know if this was the smart charger terminating prematurity due to the condition of the battery`s

I was thing of discharging the battery`s (how low 0.9v ???) and then doing an slow charge in an dumb charge, but it only has an 125ma and 250ma setting and it 250ma that is C/20, I read that trickle charge is bad for nimh battery`s

Does anybody have an advice, I have 10 of these battery`s and don't really want to have to recycle them.

Thanks

John.

 

[SilverFox]

Hello John,

I would charge them at 250 mA for 48 hours and then do a discharge and see if things have improved.

Tom