Replies

1. 
   DanH | Sep 22, 2007 03:37pm | #1

   Not specific to Millwaukee, but I don't recall that anyone has mentioned a fact about LiIon batteries: They lose 20-30% of capacity per year. (This from a recent IEEE Spectrum article by a battery expert.) Folks might want to consider this before buying a LiIon unit when they don't expect to use it heavily enough to wear out the batteries in 3 years or so.

   If your view never changes you're following the wrong leader
1. 
   junkhound | Sep 22, 2007 03:53pm | #2

   They lose 20-30% of capacity per year

   Maybe the cheap chinese tool batteries, have had a set of spacecraft batteries both in the lab and in space on continuous charge discharge cycles (40% dod) with near zero degradation in 8 years.

1. 
   DanH | Sep 22, 2007 04:29pm | #4

   This was a statement about all commercial LiIon batteries, including those used in cars, etc. Don't know about the spacecraft batteries that you speak of.
   If your view never changes you're following the wrong leader

1. 
   junkhound | Sep 22, 2007 04:45pm | #6

   Dan, you are correct in warning those here of limitations of portable power tool Li-ion batteries.

   To be sure I knew what was being discussed before any further comments, I just went and read the article, did not bother before as it looks to be written by an automotive editor for the benefit of 3 guys looking for venture capital money -  I gets lots of similar proposals (everything from nanocell solar and batteries to 'magic' motors) for evaluation across my desk every year. I read these generalized articles with more than a grain of salt.

   For better reference to those who do not have access to Spectrum, here is a quote from the article: page 31: It DOES NOT say to use these poorer type cells in cars.

   "Cobalt‑­based cells for portable electronics lose as much as 20 percent of their capacity each year, starting from the day of manufacture. That may be tolerable for cellphones and other portables that are replaced every three or four years, but not for a car, which is expected to last 15 years". (My bold typeface)

   Note that other type chemistries with very long lifetimes could be used for cars and are used for land based photovltaic, space, military, commercial air, etc. , my inference is that A123 only does DeWalt batteries now using the cobalt chemistry.

   Note on safety aspects:  I have been at 2 Lithium factories, both have burned down during operation (and rebuilt).

   Noter for other DIYers - building a Li-ion charger is approx 100X more complex than a simple Pb/H2SO4 or NiCd charger.

    

2. 
   highfigh | Sep 22, 2007 07:28pm | #8

   How does "spacecraft batteries both in the lab and in space" and consumer grade somehow become equal where you are? I don't think we get the good stuff, although I have never heard about a 20%-30% drop when I talked to someone I know at Milwaukee Electric Tool (Sr design engineer). NiCd, I can see losing capacity at about that rate, especially if used hard. I wonder if I can talk to someone at Johnson Control battery division- it's about 1/2 mile from here.Is the rate of decrease in capacity due to oxidation of the cobalt? Also, what does it say about hazards when working/burning down a lithium-ion battery plant? Johnson Control was recently awarded a contract for automotive Li-Ion batteries and another company, based in the US will be building a new facility here in MKE for making smaller Li-ion batteries, due to China increasing the duties on imported batteries. "I cut this piece four times and it's still too short."

   Edited 9/22/2007 12:35 pm by highfigh

2. 
   nailerman | Sep 22, 2007 04:05pm | #3

        I didn't buy the Mil. but did buy the Bosch 36 volt lithium. Have had it about 3 wks. Iinstalled set of maple cabinets using that drill to drill my screw holes, and used their pocket driver, which is lithium, to drive screws. Both used the same batery for 2 days.

    

                                                     Nailer

3. 
   emmetnee | Sep 22, 2007 04:41pm | #5

   Hi

   I bought the Lithium ion 36Volt Bosch back in november and am very dissapointed with it.

   The batteries dont seem to hold charge. I thought it was just me at first but when I started giving it to the rest of the crew to use they said the same thing. One day I was using the Bosch and another guy was using a 24V Nicad Hitatchi drill, the hitatchi way outlasted the 36V.

   I then decided to test how many 5/16 inch x  6" deep holes I could drill  in concrete blocks on a full charge. A very dissapointing 19 in total. I called  the rep to tell him that something was wrong with it so he took it & got the batteries and the circuts tested. He came back with it a week later and said that everything tested out fine & could not find a problem. He didn't offer any explaination why this was and basically it was my tuff luck!

1. 
   DanH | Sep 22, 2007 07:16pm | #7

   I understand that LiIon batteries need to go through several charge/discharge cycles to build up full capacity.
   If your view never changes you're following the wrong leader

1. 
   emmetnee | Sep 22, 2007 10:30pm | #9

   Im always very carefull with new batteries and making sure that they get the necessary charges they require but their put into operation.

    I'm really pi##ed off with the way the rep treated me. I've spent alot of money on tools  over the last few years while my company was growing & this is the first ever complaint I had with him. Its not good enough especially when he was happy to take all my money over the last few years!