Niles H.

I've heard a similar figure for lithium-ion batteries -- three or four years. But it depends on a number of factors, including the manufacturer and model, and the storage conditions. When stored at 40-60% charge and under refrigeration, IIRC, they can last much longer.

Apparently Toshiba and others have the ability to make longer lasting lithiums.

I have heard that some of the high-charge-rate lipo packs do not have terribly long cycle lives and shelf lives, but I haven't yet come across hard data on this, and some of these sorts of packs are fairly new on the market.

Sanyo NiMHs do have clear, multiple independent reports of surprising longevity. I wouldn't be too surprised to see these go twenty or thirty years, with proper care.

Laptop batteries are typically just lithium-ion 18650s connected in series and encased in plastic. I verified this with a couple of old packs I found for a dollar. Sometimes these are recycled by Chinese sellers of cheap 18650s. It's a crapshoot -- some are fine, others are DOA.

It would be interesting to survey a series of computer techs, or just ask a few of them how long they've seen laptop batteries last. They seem to do pretty well at times.

*******

If the shelf life of a particular battery model were so short that you would only use 10% of the available charge cycles, then you could fast charge even if fast charging shortened the cycle life considerably, and still not lose out. The shelf life would be the determining factor, whether slow charging or fast charging -- as long as the fast charging didn't shorten the cycle life too severely.

At the other end of the spectrum, there are some batteries that do seem to have the longer shelf lives.

Burton

Personally I've been using and working with NiCAD and NiMH rechargable batteries for about 30 years and Lipo and LiFeO4 batteries for about 6, and have had numerous discussion with reps on behalf of clients. The biggest issue NiCAD had was capacity, but it takes sophisticated chargers to avoid a memory effect in those. NiMH batteries actually lasted a lot longer before companies got into the capacity competition. My oldest batteries were made by Sony and are still going after 15 years - which really doesn't matter because they've been discontinued. The higher capacity replacements never lasted more than 4 years.

Same for Lipo and LiFeO4 chemisteries. It depends who makes them, how the battery management system controls charging, and how many cells are in the pack. Low charge rates still consistantly result in a longer life expectancy. Yeah - storing any battery at low temperature will improve life expectancy, but there's not a chance you can store any lithium ion lithium polymer chemistry battery at 40% capacity. The available capacity of those batteries is only a percentage of the total capacity and discharging or allowing it to discharge below typically 3.0V will result in what would appear to be a dead battery to most consumers.

Niles H.

40% of current capacity (not rated capacity, but current capacity) is the usually recommended way of estimating proper state-of-charge for storing lithium-ion batteries. 3.75 volts is used as an approximate guideline.

www.batteryuniversity.com has a section on battery storage.

There are various other technical points on all this, but I don't want the primary focus of the thread to get lost or swamped by too microscopic a focus on technical minutiae.

Some points do have clear practical applications, and are worth mentioning though -- one of them is that prolonged heat will dramaticaly shorten the lifespan of batteres.

On a long bike tour it would be best to keep them where the temperatures will not be too high.

Niles H.

I was wondering how great a trade off would be acceptable. Where would I draw the line?

I decided that a 90% loss would be acceptable.

At least for the Eneloops rated at 1500 charge cycles.

That would mean about 150 charge cycles, with a 90% loss.

This would last me around six or seven years. Which is enough. The batteries only cost about nine dollars or ten dollars per set (of four) on Amazon....

Then I realized that they will probably last substantialy longer than that, because they won't always be fast charged. Sometimes slow charging is just fine.

(Probably most of the time.)

So if I average about two charges per month per set (some months would be more, others would be less), and even if only half of them are slow charges, then it means more than eleven years of charging.

Or less than 25 cents per battery per year.

With more slow-charging (over half the time), the picture gets even better. And it was already more than good enough.

Niles H.

Then the question became, How great are the actual losses with a fifteen-minute charger -- using Eneloops?

And the next thought was that someone has probably tried this.

And I was able to find a few people.

The results of their tests: the Eneloops were good for about 100-150 cycles. One person reported 125-150 cycles.

(Using an Energizer fifteen-minute charger.)

Someone suggested removing the batteries after ten minutes to extend cycle life.

Not always necessary, but could be useful at times.

So it looks like a green-light situation.

I like it.

Burton

So my experience with 30 Imedians and doing nothing but controlled charges with a MAHA smart charger has been a bit of a crap shoot. After 2 years the capacities of 10 of those is about 30% lower than the rest, and none are above 80% of original capacity. Since a battery pack is no better than the weakest link, my suggestion would be to take NEW batteries on a tour, and to bring spares.

Niles H.

Good point. Some brands are definitely more consistent and reliably consistent than others. Eneloops seem to be about as good as they get, according to experiences on CPF. Also, there is an engineer who posts some excellent reviews on various AA batteries and chargers over on amazon.com (N Lee). He has found these batteries (Eneloops) to be the most consistent and reliable and lasting. Both he and the CPF crew give them their highest marks.

Someone recommended marking each set with month and year purchased, plus a letter if multple sets were purchased during the same month. Then a number (1-4).

This way, if you had multiple sets, you might be able to reserve one set for the fast charging, and allow for better monitoring.

And just put a dot of paint somewhere on the battery, where it would last. -- Red dots for a hot (fast charge) set. Blue dots for a cool set. Etc.

The date system would also help in keeping track of the ages of different sets. And it would help in keeping a set of similarly performing batteries together. And help as well with testing and record keeping.

wbuttry

well the turnigy 2200 lipo packs 11.1 are like 8 to 10 apiece and you can get a balance charger for 10 to 20 bucks
https://www.hobbyking.com/hobbyking/s...Lipo_Pack.html https://www.hobbyking.com/hobbyking/s...30w_2s_4s.html https://www.headsuphobby.com/Parallel...?categoryId=-1 here is every thing you need to setup a charging system and a bag on ebay https://www.ebay.com/itm/2012-Cycling...item43ba1da1be and cig adapter WITH USB CHARGE PORT https://www.ebay.com/itm/12V-Car-Ciga...item5aef2a5262 aand if you need a little bigger bag there is plenty to choose from..

Niles H.

Great stuff -- thanks for that.

tdister

Some good info here. I had terrible luck with chargers a few years ago and have been gun shy of rechargeable AA 's since. I'm pretty well converted to dynamo and Li-ion at this point but the eneloops might be in my future now that they've been battle tested. Lithiums are getting expensive for a helmet/headlamp that uses AAA's

KirkBeiser

What kind of batteries did you have bad luck with? It would kind of reinforce my suspicions if they were the fast recharging type.

Niles H.

Some chargers are very tough on batteries.

I have one hour and also fifteen minute chargers that kill most batteries quickly. You can find reviews of the fifteen minute chargers (at amazon.com for example) that call these chargers 'battery killers.'

Good term for them.

But some batteries live through the torture; and this fact is lost on most reviewers.

Some batteries can take quite a bit of it.

*******

I now have the Turnigy Accucel 6 charger. It is amazingly versatile. And it's an unusually good value at 22.99.

There are some reviews over at youtube.com that give a good idea of what it is like.

tdister

I know some were Energizers, just whatever department stores had as a set, but I went through 3 chargers. I never had a chance to kill a set of batteries, the chargers kept on dying within a few charges.

Pretty sure 2 were energizer chargers, not sure on the other. They were not the super-fast type. It's been several years and hopefully the quality control has improved.

Thinking about it, I went through 12 AAA lithiums (use the headlamp at work too) this fall/winter which was <$30. They work great when cold, hold their voltage strong til the end, don't drain in standby and have the full 1.5 volts. I remember spending $100 in chargers and rechargeable batteries in well under a year for a bunch of frustration. I actually probably won't be trying rechargeables again.

I'll probably buy a li-ion headlamp next time and be done with it.

Niles H.

Thanks for sharing those experiences.

If you buy chargers that get a large number and percentage of top reviews it helps to weed out the less reliable ones. Good warranties from reliable companies are also helpful.

I've had great luck with Eneloops. Most reviewers have had same.

If anyone wants a great charger for AAs, the Maha chargers are worth a look.

For lithiums, Pila and Xtar have excellent models.

If you don't mind spending the money, there are the high end hobby chargers like the iChargers.

And there are the Turnigy chargers that probably won't be as durable but cost much less.

Some of the hobby chargers can be set for anything from a slow trickle charge to a very strong fast charge, and everything in between.

For reliable lithiums avoid Chinese and go with Japanese made (eg the best of the Panasonics, Redilasts from EDCPlus, Callie's -- all great batteries, and worth the extra money, especially in the long run -- for better performance, greater reliability and longevity).

Best of all have been Eneloop and Eneloop XX.