Lithium Ion or NiMH power tool "systems": Which one?

[me]

I was originally looking to buy a Dust Buster type device but all the consumer ones have built in rechargeable batteries....such that once the battery dies you have to throw away the whole unit. Very wasteful!!

I recently came across many power tool "systems" where you buy the battery units separate and they can be slipped on various hand tools such as drill, chop saw, and hand vacs!

Curious which brand/model is the best value in terms of light weight, stamina, etc?

Is Li-Ion better than say NiMH?

Any brands to consider such as Black and Decker new GPX system? Milwaukee's?

I'm only buying the hand vac and battery system for now..... but since I have no other power tools "might" need the drill or saw at some point.

[ransley]

I bought a black and Decker hedge trimmer, probably the GPX, it did not cut at all it just chopped at branches. Then I decided to read Consumer Reports and it said the B&D did not cut well. B&D in my opinion is and has been junk for years, I returned it. Ryobi is better, Milwaukee, Bosch, Makita have always been tops.

[me]

Thanks

Will forget abt BnD then

[Dave Martindale]

Not necessarily. If you live in a decent-size city, there are probably several places that rebuild battery packs from cells. They weld the cells with straps in the same shape as the original pack. Just take apart the DustBuster, take the battery pack to the rebuilder, and pick up a new pack in a few days. I've replaced the battery pack in my DustBuster at least once this way.

(This works for NiCd and NiMH cells; I don't know if LiIon batteries can be rebuilt the same way. NiMH battery packs require more protective electronics, and the electronics are more closely matched to the cells).

However, the real problem with a battery-powered DustBuster is that you hardly ever use it. If you leave it charging forever in its wall bracket, this kills the batteries prematurely. If you don't keep it on charge, the batteries are always dead when you want to use it since it's been months since the last use. I've read about people using a timer to power the charger for an hour every day, but that seems like too much work for a DustBuster, which really won't pick up that much anyway.

So a vacuum that uses the same batteries as your portable drill is more likely to be useful (assuming you use the drill somewhat often).

Dave

[Jim Yanik]

[e-mail] wrote in news: [e-mail]:

I had the local DeWalt service center replace the built-in NiCd pack (after

10 years of use)in my B&D Dustbuster,it was cheaper than buying a new DB. I did NOT "have to throw the whole thing away". I still have it,still use it.

Yes. no self-discharge.You can store it for 6 months and have it ready to use without having to recharge it first or replace a failed battery pack.

Makita,other Name brands too. I'd not pick Black and Decker cordless power tools,myself.

A drill/driver is useful. Maybe a circ saw.

[Jim Yanik]

[e-mail] (Dave Martindale) wrote in news:ff6af2$kle$ [e-mail]:

Li-Ion are even worse,they use microprocessor ICs built into the packs to monitor and control charge.But I suspect the competent battery rebuilders will be able to rebuild those packs,too,once they become more commonplace.

WRONG.It's cells are the type expressly designed to be left on trickle charge when not in use.(at least the original DB,not the VersaPack models.) I believe it even says so in the DB manual.

BTW,DigiKey sells that type of NiCd cell,designed for continuous trickle charge.

[ransley]

Sure the manual says its ok to leave it in the charger, thats bs, you might get 5 yrs of life that way, I have 15 and 18 yr old Makita packs that work a bit, Heat ruins any cell eventualy as over charging generates heat

[Chris Lewis]

According to ransley :

then check out the "How to Charge Batteries" should help dispell a lot of myths.

[Chris Lewis]

Or, buy the cells and do the replacement yourself. While the strap welders are more convenient, you can do the same with a soldering gun, or a sufficiently heavy duty soldering iron. The one trick is to scrape/roughen the soldering points on the battery with a dremel or sand paper or emery stick before soldering, and don't take so long that the battery gets hot.

About 2 months ago, I rebuilt:

1) a dustbuster (3 cell) 2) 4.8v makita drill (quite old with an internal pack) 3) 2.4v electric screwdriver (2 cell)

Previously I had a battery rebuilder rebuild a 12v, 10 cell non-XRP DeWalt (DeWalt manufactured, rebranded device, 1.7AH) pack. I have at least one more to do over the next little while - this one I may do myself.

One of the advantages of doing this is that you can pick better batteries. All of these tools are running _better_ than new.

The cells I'm using are 2.2AH. The Dewalt was 1.7AH originally.

Note: while battery packs in things like Dewalts _look_ like C cells, they're actually not. "SubC" ("SC") seems to be the most common.

Things get confusing when you realize how many standards there are:

[ransley]

Chris I did look at that site, I still believe even from what they said heat is being generated, and damaging the cell, since the dustbuster is not being trickle charged

[Chris Lewis]

According to ransley :

Heat is always produced if current is going through it. The question is how much, and how much the cell can tolerate it.

Or, in other words, is a continuous .01C trickle charge when the place where it is at 20C going to do as much damage as letting the battery sit on a window sill at 35C? No.

That seems sarcastic, but it's not intended to be, just pointing out that the fact you do put a little heat in the battery via trickle charge, it's not going to be any different than the same amount of heat introduced any other way.

Unless the trickle charger makes the battery noticably warm, it's going to make relatively little difference. At least with Nicds.

Continuous trickle charge matters more with NiMH and Lithium (note the remarks about hydrogen generation on NiMH).

[Jim Yanik]

[e-mail] (Chris Lewis) wrote in news: [e-mail]:

yet 1-hour fast chargers make NiCd packs quite warm,and those packs last far longer than trickle charged packs. The heat only builds up in the last part of the charge,BTW.That is how many chargers decide when to cut off the charge.Other fast chargers use the "knee" voltage to detect a full charge for NiCds. NiMH fast chargers must use the deltaV/deltaT method of charge detection,there's no voltage "knee" in NiMH cells.

trickle chargers are just simple wallwart transformers and not IC charge controlled,simply X ma for Y time(usually at or less than 1/10C rate),allowing for under or over charging of the pack,shortening it's life.

[pheeh.zero]

One tip on DeWalt 9.6V drill packs. Wal-Mart sells the B&D packs for less than $25. You need to cut the "keys" to fit drill and charger, but they work fine.

[Chris Lewis]

According to :

Something similar but slightly with DW 12V and B&D "firestorm" 12V packs (in a rebadged product). The keying is identical. The difference is that the B&D packs exposes the shell of the battery in the "stem" of the pack, and the B&D charger has a sensor contact that makes contact with it. The DW doesn't have this.

The B&D charger won't charge the DW packs, but the DW charger will do both. It became a bit of a nuisance when I had one of the B&D packs rebuilt, and they didn't shave the cardboard off the shell for the B&D charger contact. I could shave it off myself, but so far I've not needed to.

[The B&D charger is _much_ heavier than the DW - the B&D has a big transformer. The DW has a switching power supply, so it's an itty-bitty toroid.]