Lithium-ion battery shelf life experience?

[michael osadchuk]

I'm considering buying a Makita combo pack BDF452 drill/driver and BTD142HW impact driver, which come with 18volt 1.5ah lithium-ion batteries.

One issue that I'm concerned about is the 'shelf life' of
rechargeable lithium ion batteries used in power tools, with the criticism from one allegedly authoritative source
being that they lose capacity over time to the point that after several years (three?) replacement is necessary.

http://www.batteryuniversity.com/parttwo-34.htm

...the online user written encylopedia, wikipedia (sp?) says the same thing, but its references on this point are the same above hypertexted source

.... the makita and dewalt website are silent on this point, with dewalt mentioning primarily lower weight/smaller size as advantages.....

.... I believe that some have had several years experience with lithium ion power tools and ask you to share your experience on this point

thanks

michael

[David Christopher]

Michael, I have 2 craftsman li on batteries for about 2 years and have had no trouble in fact I done a 6 month deployment and when I got home they were still charged. I want ever buy the nicad batteries again

[John Sanford]

All rechargeable batteries have limited lives. Whether lithium-ion, nickel-cadmium, lead acid gel cells, etc. I believe the Li-Ons have better life expectancies (based on cycles) than ni-cads, but not up to the levels of lead-acid batteries. Of course, they don't weigh anywhere near what lead-acid batteries do either!

The key shortcoming with Li-on batteries is that they do begin to degrade immediately after production. Degradation rate depends on two acknowledged factors (temperature and charge levels), and an unacknowledged factor, quality. Don't store fully charged batteries in your car during the summer in Arizona! This degradation takes place whether the battery is used or not.

[Paul Greathouse]

I've had my little 10.8V Bosch driver for a little over a year now. The batteries seem to last reasonably long. The driver, batteries and charger stay in my non-climate controlled shop most of the time. The charger stays plugged in 24-7 and the spare battery is always in the charger.

The only thing I have to compare the Bosch lithium to is a pair of 4 year old Dewalt 14.4 XRP Drill/Drivers and an even older Porter Cable 14.4 hammerdrill/driver which are all NiCad. These older tool do the job but require much more frequent charging, especially the PC. If I were using them on the job site instead of in a shop environment, I would definitly purchase a couple new sets.

I attened a tool show at a local lumberyard back in November. All the major brands were there along with reps to talk to. I was most impressed with the Milwaukee lithium 18V drill/driver. It just appeared to be the best made. The Makita looked good, but the Milwaukee looked more durable and just seemed better.

None of the new ones looked as strong and stout as my old XRP's but if I had to buy today, it would be the Milwaukee.

[John D Watson]

My experience with Lith-ion batteries comes from managing life rafts for the canadian navy. These batteries have been in use for more than 25 years. The main reason being that they hold a charge for a very long time. We changed them out of the rafts every 10 years, at which time they were checked, brought to a full charge and put back into service. Now I\m sure that like any other type of battery they will loose it after a certain number of charges.
I like the fact that you can pick up a tool thats sat on the shelf for six months and it's still fully charged. You sure can't get that with Ni-Cad.

[David Keller NC]

Michael - As John noted, all batteries will degrade to the point that they have to be replaced over a fairly short time frame (1-5 years). Some of the factors that go into how often you must replace them are:

1) The chemistry. In general, lead-acid batteries last the longest, followed by Ni-Cd, and it's about a tie for NimH and Li batteries. Much more important are 2,3, & 4, below

2) How many charge/discharge cycles they're put through. Obviously, the more you use them, the shorter their lifetime.

3) Whether you "short-cycle" the batteries. Charging any battery produces heat, and so-called "sealed" batteries are vented so they don't explode. The heat resulting from charging dries batteries out, so repeated short-cycling dehydrates them more than fewer, longer sycles.

4) Whether you store them in a hot place (same dehydration issue)

5) Whether you leave them on a "trickle-charger". Leaving a battery on a charger is bad news for the life of a battery.

6) Whether you totally discharge them before charging - total discharging is bad for multi-cell batteries. It's actually possible to reverse-charge a battery that's fully discharged. Doing so permanently reduces the voltage out of that battery pack, reducing its performance.

[Mike Henderson]

It must be the charging and recharging that causes a Li ion battery to degrade. I have a bathroom scale that has a built in Li ion battery and I believe it is guaranteed for 10 years. On my car, I have the tire pressure monitors. They work by having a sensor, transmitter and Li ion battery in the valve stem (they transmit an alarm to the car when pressure is low) and the battery in that is guaranteed for 10 years, so I expect the actual life of the majority is more than 10 years.

See also, the comments of John Watson, above.

Mike

[David Keller NC]

Mike - Not all batteries, including Lithium ion, are created equal in the life department. You're indeed correct that low-amperage application batteries can last a very long time. But there's a design trade-off between battery replacement intervals and amperage discharge rate and long cycle time.

Typically, a deep cycle, high amperage rate battery doesn't last as long as a low amperage battery, though it provides obvious benefits in a power tool.

It's also possible to select properties and design choices for cold cycle, long cycle/high voltage/low amperage, very high discharge amperage, vibration tolerance, long charge retention on the shelf, and a whole bunch of other parameters. Reading technical papers on this sort of thing is a real eye-opener. It's no wonder there are so many types, chemistries, form factors, etc...

[Ronald Kellison]

I've had the Bosch 10.8V P20 driver for a couple of years now and have absolutely no complaints with battery life. I'm still waiting for someone to make a Li-ion 12V with enough capacity to drive my electric trolling motor!

[Ron Bontz]

I am looking at different Li ions my self and found they are putting 1.5 or 1.4amh batteries on the tools instead of 2.8-3.0amh batteries. I suppose that is to lighten the tool. I just sent a milwaukee set back for that reason. You are still going to have to charge that smaller battery more often than the larger one. All the batteries seem to be based on cycles (charges). So why go with a smaller battery you know will have to be charged more often? Aren't we wanting Li Ion batteries for the longer run time and life time? Just a thought.

[Dan Friedrichs]

While all secondary cell batteries will undergo certain chemical processes that cause them to wear out (without your use), Li-Ion doesn't suffer from this notably more than other chemistrys.

Li-Ion self-discharges at a rate much slower (2 or 3x slower) than Ni-MH and Ni-Cd batteries.

The reason you're seeing batteries rated at lower mAh's in these tools is because the manufacturers are trying to reduce weight. Li-Ion is more expensive per unit energy, but it has the highest energy density commerically available (most Wh/kg). HOWEVER - mAh is not a rating of energy storage, and alone will tell you nothing about the energy storage capacity of the battery. The average battery voltage times the Ah rating will give you the Watt-hour rating, which is what you'd be interested in if you're trying to compare the capacity of different batteries.

You probably don't need to be concerned about this (potentially) reduced capacity resulting in more charges, though - newer Li-Ion's are good for 500+ charge cycles before falling to below 80% inital capacity, and if you don't fully discharge them, that number increases.

So: Don't fully discharge your Li-Ion's, and don't worry about it.

[John Sanford]

Most of the toolmakers are building tools with both the 1.5 amph and the bigger 3.0 amph batteries. For some of them, the batteries are actually interchangeable. The extra run time really doesn't make as much difference as it used to, with the much quicker recharge times. So, lower cost, less weight, smaller tool, all reasons for a strong smaller battery presence.

[Ron Bontz]

Thanks for the info. The info. I had on duration 1.4 vs 2.8 was based on exactly what a rep told me when I e-mailed milwaukee with my question. ie; given the same work load the 1.4 will last half as long as the 2.8. I should have kept the e-mail. Not letting the batteries run all the way down is exactly what a Dewalt rep. told me about the newer Nicad batteries a couple of years ago.

[michael osadchuk]

Thanks everyone for the comments.

I went ahead and bought the black n white Makita combo 18 v. drill and impact driver, a reconditioned package for $230 Canadian.

michael

[Brook Wright]

I am a professional cabinet maker and use the makita drills you are looking at. I can usually go a full day without changing batteries. I have used the tools for over a year and do not see any decrease in battery life, but I do see a increase in time it takes to re-charge. I chose the makitas because I also purchased the larger 18v set (blue in color) that comes with the 3.0 amp hour battery. You can interchange the 1.5 and 3.0 amp batteries between drills. As far as I know no other company allows you to do that. I have experience with the Milwaukee and Panasonic Li-Ion tools and both are good choices also.