knots Posted July 25, 2011 Share Posted July 25, 2011 The last replacement batteries that I purchase for my battery drill lasted about one half the time that the original batteries furnished when my drill was new. I suspect that the batteries had been on the shelf for an extended period of time and were therefore timed/aged out to some degree. I now need to replace them again and want to understand (be informed of )the age of the product and understand what the aging criteria means. I examined the failed battery casing but have found no obvious date of manufacture. My question is - How does one determine when power tool replacement batteries have been manufactured, and what should the sell by date be, if indeed the date can be determined ? I assume that the last part of the question should be measured in maximum months between manufacture and sale. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 26, 2011 Share Posted July 26, 2011 Depends on brand, some of my DeWalts have date stickers. As an aside, I have seen ads for companies-one was a community college-that will rebuild your old battery for around $30, or sell you a kit to do it yourself or around $20. Think RC car power cells bundled to get the voltage needed. A lot of batteries, especially NiCad are killed by improper charging practices. Those need to be fully drained before recharging, or they will take a set, and only charge so much. Li-Ions are better, but I always run my batteries down till they are totally dead, then I drain them some more :D Quote Link to comment Share on other sites More sharing options...
knots Posted July 26, 2011 Author Share Posted July 26, 2011 My current battery sets are mostly Ni-Mh and I do discharge them before recharging. That is good advice to follow. I have considered rebuilding my own but decided that the time spent rebuilding is not time well spent for me. I don't mind paying the going price it the replacement battery provides service life equal to the original battery sets. During my research into rebuilding I found a good discussion of rebuilding procedures with tips and observations of those who have rebuilt batteries before. Rebuilding/building batteries is apparently a common practice among model enthusiasts http://www.instructables.com/id/Hot-Rodding-a-Power-Drill-Battery/ I guess that my next move is to contact the manufacturer and find a sure source of fresh batteries. Seems like I end up buying most stuff like this off of internet anyway. Quote Link to comment Share on other sites More sharing options...
son_of_bluegrass Posted July 26, 2011 Share Posted July 26, 2011 SNIP A lot of batteries, especially NiCad are killed by improper charging practices. Those need to be fully drained before recharging, or they will take a set, and only charge so much. SNIP I've heard and read that largely depends on the charger with newer / more sophisticated chargers not creating a memory. I had one set of batteries that I discharged all the way and they didn't last as long as a set I just charged when needed without ensuring they were completely dead. From my research, heat kills batteries faster than anything else (including storing someplace hot, using hot and charging hot). ron, by NO means a battery expert. Quote Link to comment Share on other sites More sharing options...
wshelley Posted August 5, 2011 Share Posted August 5, 2011 If you guys are interested, I'll write up some info on battery life based on usage and charging. There is a tremendous amount of mis-information circulating about this topic. I've been involved in electric radio control airplanes for a long time and have picked up a few things. On the high performance side, I routinely pulled over 100 amps from sub c ni-cads just like what they use in cordless power tools. I used nickle metal hydride cells too and these days mostly LiPoly. Let me know if you are interested. Ward not a battery expert but I play one in more than one industry ;-) Quote Link to comment Share on other sites More sharing options...
Fosterob Posted August 5, 2011 Share Posted August 5, 2011 I for one would like to know more about this, I have a 36v Hilti concrete drill that needs to have a battery rebuild. I think it's ni-cad but need to check. Rob Quote Link to comment Share on other sites More sharing options...
son_of_bluegrass Posted August 6, 2011 Share Posted August 6, 2011 I too am interested. I'll have to have rebuilt a couple 18 volt batteries for my cordless kit and would prefer to have as much knowledge as possible when I get it done. Thank you for the offer. ron Quote Link to comment Share on other sites More sharing options...
knots Posted August 6, 2011 Author Share Posted August 6, 2011 I would love to be taken to school on this topic. Quote Link to comment Share on other sites More sharing options...
Glenn Posted August 6, 2011 Share Posted August 6, 2011 Sounds like a blueprint to me (grin) Quote Link to comment Share on other sites More sharing options...
wshelley Posted August 9, 2011 Share Posted August 9, 2011 Well, I hadn't planned on writing a book but I'll cover the basics and answer questions from there. #1 memory in most battery technologies is a myth, simple as that. It did happen in the early days of the space program when the batteries were monitored and charged by computers but it isn't anything to worry about these days. Charge when convenient. Don't worry about completely discharging them unless your charger has a special function to do it for you. If you run it down past where you see a drop off in performance you will reduce the life of the pack. In other words, don't wait until the battery is completely drained to charge. #2 if you are going to abuse your batteries, stick with NiCd cells. They can handle amazing amounts of current and come back for more. NiMH cells are pretty robust but will offer a shorter service life when abused. The lithium cells are great because they hold a charge for a long time when not being used and are lighter (greater energy density). #3 Charging. In the context here, portable power tools, I will assume you are using the charger supplied with your tool and designed to work with your batteries. Follow the instructions that came with the charger and you should be golden. One caveat, if the battery pack is warm to the touch while still in the charger more than an hour after a complete charge (charger indicates done) you should adopt the habit of removing the battery from the charger after the charge completes. The reason is the charger is still performing a trickle charge (only supposed to put in enough to counter the self discharge rate). On some chargers (one of my older Dewalts for example) the trickle charge is too high and it results in the cells being overcharged which results in shorter service life. My point is, don't store the battery in the charger if it stays warm after the charge is complete and it should have cooled to room temperature. #4 Rebuilding packs - if you can solder well and are handy you can rebuild your own packs. Lots of info on the web about how. When I build mine I use a high power soldering iron, 75 watts, clean everything well, use rosin flux (not acid flux like used in plumbing), tin the cell and the wire/bars used for interconnects (I use heavy duty braided copper), and solder quickly. If you overheat the cells, especially the positive button you will degrade or melt the seal leading to, yep you guessed, decreased service life. If you are not comfortable soldering, get someone to help or use a battery re-builder. As for the cells, there is huge range of quality. This is a place where you get what you pay for. Buy good cells or plan on re-building more often. The last time I did a pack, the cells were around $2.65 each but they were bought in bulk, about 200 cells I think. They were about $4.50 in small quantities. That was a few years back. The packs can be built with any capacity cell you choose as long as they are all the same. The higher capacity cells will be able to provide a higher current because thier internal resistance will be less. They will also run cooler for the same reason and last longer. 2400 mAh cells are a good choice in NiCd. Lets start there and see what questions you have. Ward Quote Link to comment Share on other sites More sharing options...
knots Posted August 9, 2011 Author Share Posted August 9, 2011 How does extended periods of storage and non use affect battery life ? Quote Link to comment Share on other sites More sharing options...
wshelley Posted August 9, 2011 Share Posted August 9, 2011 Depends on the battery chemistry: #1 For NiCd and NiMH it is best to discharge them and store them someplace cool and dry. With good quality cells they should be fine for a long time. I've had new, unused cells, stored for years and built packs that worked great. The downside is that NiCds are suceptable to growing dendrites or wiskers that short out the cells. They can often be blasted away with a high current pulse but damage has been done to the seals and then cells will fail fairly soon so it is at best a short term fix. The dendrites tend to form more rapidly in cells with a partial charge that sees infrequent use. NiCds are happier when used regularly and recharged soon after use. The manufactures quote 500-1000 cycles as typical. Power tool use is a bit more sever but hundreds of cycles should be normal. #2 For lithium cells it is best to discharge to around 60% and then store them cool and dry. They should be checked occasionally (I look at mine every few months). They should not be allowed to self discharge to 0. They usually won't come back from that allthough there are some techniques that work sometimes. Ward Quote Link to comment Share on other sites More sharing options...
Borntoolate Posted August 29, 2011 Share Posted August 29, 2011 I was going to rebuild my Dewalt 14.4 batteries. I could not seem to buy batteries in the quantity I needed in order to do this cheaper than I could have them rebuilt for. I did not want to buy 200 batteries. I think I needed like 11 batteries. Then there was the quick soldering issue without overheating concern. In the end I paid to have them done for me. The result has been OK. My belief is that they use the weaker cheaper batteries in these. The dewalts are also the most expensive. So buying new is a tough pill to swallow. What brands of batteries do you folks use and how do they perform. I am happy with the dewalts except the price. Then there are the Harbour Freight ones that I am afraid to use. Does anyone have epxerience with these. Others? Online Rebuild companies? Quote Link to comment Share on other sites More sharing options...
wshelley Posted September 2, 2011 Share Posted September 2, 2011 @Borntoolate - a 14.4v pack would require 12 NiCd cells at 1.2 volts each (nominal). You make a good observation, good cells cost real $$. To be honest, I'm not sure what cells the pack re-builders are using but it probably falls under the "you get what you pay for" advise. It sounds like you made a decent informed decision, I hope it works well for you. I know the Dewalt packs I've purchased have been good buys. They are not cheap but they use quality cells and are built well. I've used and abused my Dewalt packs and they give very good service. I priced some good quality 2400 mAh cells recently and they were over $6 each so a rebuild is nearly full price of a replacement direct from Dewalt. I'd probably pay for the convenience factor in that case even though I have the tools and techniques to rebuild it myself. If I had a dozen good cells in my parts bin it would be a different story. Ward Quote Link to comment Share on other sites More sharing options...
knots Posted September 3, 2011 Author Share Posted September 3, 2011 Is there any reason, other than marketing, that the battery packs should not be designed to be able to open them up, dump the batteries, and slide new ones in just like a flashlight or camera ? Quote Link to comment Share on other sites More sharing options...
Unforgivun Posted September 4, 2011 Share Posted September 4, 2011 Might look in the yellow pages under battery and see what you find. There are a few places around here that rebuild rechargeable batteries for tools, laptops, phones etc. They're generally much cheaper than buying a new battery. Quote Link to comment Share on other sites More sharing options...
Borntoolate Posted December 13, 2011 Share Posted December 13, 2011 Unforgivin, I was thinking the same thing. I took my battery apart and was pondering how to make them easily replaceable by puting some springy metal clips in there that would make contact in the right areas. Then all that would be needed is to open up, replace and screw back together. I did not do that though. I bet someone could invent a kit that changes a given battery pack over to this kind of set up. I should invent that. I mean we already have that in flashlights. There isn't a lot of extra space though in these battery packs. Quote Link to comment Share on other sites More sharing options...
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