Black and Decker Electric Screwdriver - fixed - Page 1
Forum section: electronics / projects

author: tom66
author_rank: Super Contributor
timestamp: July 03, 2012, 11:49:27 pm
content: Got this from work. Wouldn't do anything after charging except turn very, very slowly.Classic dead NiCd pack (3x1.2V), dead short on two of the cells, one was still okay, measured about 1.3V open circuit.So I took my bench power supply and 3x 3300µF 10V caps, charged up to 10V. Pulsed the battery about 20-30 times in all (shorted). Initially the battery will just act like a short to the pulses but after some time it starts accumulating and holding a charge. When it's at 1V/cell I slapped it on my RC aircraft battery charger (does NiCd as well as LiPolys) at a fast 1C/1.2A charge. Guessed a 1200mAh capacity (same size as similar drill battery cells), but actual capacity not written on the cells so I can't be sure.Anyway, the result being it held a charge at 4.45V (3.6V nom) and now works perfectly.So, I've now got a fully working electric screwdriver. I only bought a cheapie (2.4V) Tesco junk one a couple of days ago from fleabay for 3 squids... This one does have much more torque though and stubborn screws come out quicker.Got two power drills with the same problem to look at as well.

author: IanB
author_rank: Super Contributor
timestamp: July 04, 2012, 01:41:33 am
content: Quote from: tom66 on July 03, 2012, 11:49:27 pmThe trouble is the fix may be temporary. Once NiCd cells have grown whiskers they apparently have a tendency to grow back again (at a guess I imagine the remains of the old whisker acts as a nucleus for new growth). You could get a more long lasting fix by replacing the old cells with new ones. (If they banned NiCd cells in the EU maybe you can get some from China or HK? Or you could use high power NiMH cells such as used for RC stuff and charge them carefully.)

author: SeanB
author_rank: Super Contributor
timestamp: July 04, 2012, 05:13:14 am
content: I made a fixer, using a 100uF photoflash capacitor, charged up to 310V via a diode and a big current limiting resistor from the mains. Used a big switch to discharge it across the cells, and it worked quite well to revive dead cells. Lethal voltages of course, and the bang on closing was pretty bad for the switch, so it was a frequent candidate for surgery and cleaning/replacement.

author: tom66
author_rank: Super Contributor
timestamp: July 04, 2012, 05:37:12 am
content: Quote from: IanB on July 04, 2012, 01:41:33 amTime will tell, but I can always shock it again to remove the growth. If not I got it for free, I lose nothing. I'll harvest the one good cell and use that in one of the drills.Under RoHS, NiCd is still allowed in power tools, for some silly reason. Don't ask me why they would ban cadmium in small things like light sensors, but then allow big drill batteries to use it. It's just like banning lead in electronics, yet we still had lead acid batteries, the biggest user of lead...

author: T4P
author_rank: Super Contributor
timestamp: July 04, 2012, 09:02:10 am
content: Not lead acid, but military artillery are the biggest users of lead.Imagine 60% of the world's lead in the air

author: amyk
author_rank: Super Contributor
timestamp: July 04, 2012, 09:12:22 am
content: Quote from: tom66 on July 04, 2012, 05:37:12 amNiCd has high current capability, low self-discharge, and is more robust than Lion. The "small things" are also far more likely to be thrown out and more often than power tool batteries.

author: SeanB
author_rank: Super Contributor
timestamp: July 04, 2012, 03:30:15 pm
content: As well there is a very long and established recycling for lead containing batteries. You generally cannot get a car battery without giving in an old one in it's place, and most scrap yards take SLA batteries with no problems.

author: FenderBender
author_rank: Super Contributor
timestamp: July 04, 2012, 06:17:19 pm
content: I've owned a few Black & Decker battery powered tools. Dustbuster, 2 electric trimmers, and a drill. Apparently I don't learn my lesson.Every single one of those tools has nearly become useless due to dead NiCad packs. If you have the option to get lithium powered equipment, they're not perfect, but they're a helluva lot better than NiCad.To be honest, I think what the problem is sometimes, especially with cheap battery powered tools, is the lack of proper charging circuit. My electric trimmer's charger is just a constant voltage wallwart. There's nothing advanced about their charging methods. Now NiCd is a pretty forgiving chemistry, but jeez, I would think that a somewhat more advanced charging method could be advantageous. But I'm no battery expert.

author: IanB
author_rank: Super Contributor
timestamp: July 04, 2012, 07:14:39 pm
content: Quote from: FenderBender on July 04, 2012, 06:17:19 pmYou are entirely right about this, but consumers don't get it. The device with the proper charging circuit would be more expensive and then consumers would leave it on the shelf and buy the cheaper one with the dumb charger instead. It's nearly impossible for most people to understand that something they can't see will add any value to the product.

author: SeanB
author_rank: Super Contributor
timestamp: July 04, 2012, 07:31:16 pm
content: Cheep n cooking charger will mostly get the unit out of warranty period before killing the battery. I have a nice collection of Ryobi cordless screwdrivers that all work, but i am careful in charging them. I most likely will make a dedicated better constant current charger for them, as the wall melter they comes with leaves a lot to be desired. Voltage regulation and current limit by the winding resistance, and they are very capable of melting the battery. I charge then for 1 hour only with the original unit. Must make a better one, even if it is a constant current source that provides 50mA only.

author: G7PSK
author_rank: Super Contributor
timestamp: July 04, 2012, 07:58:43 pm
content: Quote from: DaveXRT on July 04, 2012, 09:02:10 amI read that there are ten rounds of AK 47 ammunition for every person on the planet, most of it floating around in Africa and middle east, totally crazy world.

author: SeanB
author_rank: Super Contributor
timestamp: July 04, 2012, 08:10:15 pm
content: But the only good thing is that a lot of it has been stored in improper conditions. It might fire, or it might not. Worst is a partial misfire where the projectile does not clear the barrel, but there was enough gas to run the piston back and recock. The next round hits the first and either blows back or bursts the barrel.

author: tom66
author_rank: Super Contributor
timestamp: July 04, 2012, 09:27:20 pm
content: The Black and Decker charger (integral to the screwdriver, using a wall-wart) is genuinely a cheap 'n' cooking charger - a diode and resistor.Black and Decker win 10 tom66 points for WORST human interface design ever. Spent 30 minutes trying to figure out how to get the thing to turn. Read the manual. "Press the DIRECTION switch to drive." I wouldn't have guessed that unless I pressed it accidentally.One of the drill battery chargers does not work. The resistor has got so hot it has toasted the PCB right through, and the resistor is open circuit. One works, but shows signs of significant heat damage. Though it's kind of obvious why; the resistor drops about 7V when charging at a 600mA charge current - I guess they figure that no one leaves batteries on to charge and there is a warning on it "This charger does not stop charging when the battery is full - do not leave on charge continuously."...of course it doesn't, it's just a frigging diode and resistor!

author: ee851
author_rank: Regular Contributor
timestamp: July 05, 2012, 02:49:10 pm
content: "Black and Decker" means total junk.If you try to do a job using a tool with this label, you're wasting your time.

author: SeanB
author_rank: Super Contributor
timestamp: July 05, 2012, 03:12:52 pm
content: Yours came with the resistor! My Ryobi ( aka as OHL rebrands) came with the only limiting being the transformer winding resistances and the cheap diode forward resistance..

author: T4P
author_rank: Super Contributor
timestamp: July 05, 2012, 03:13:13 pm
content: Quote from: ee851 on July 05, 2012, 02:49:10 pmEven WWP drills last longer and work better than "B&D"

author: SeanB
author_rank: Super Contributor
timestamp: July 05, 2012, 04:08:07 pm
content: I have had a Clack and breaker angle grinder and a few drills that are from the 1980's, and they all work fine. Of course they come with an accessory if you want to borrow them, me. Big, and likely to break you if you break it.The current crop is junk yes, but then again I like Bosch, and use the cheap OHL branded stuff with care, so that I get a good life out of them.

author: G7PSK
author_rank: Super Contributor
timestamp: July 05, 2012, 05:45:27 pm
content: Quote from: SeanB on July 04, 2012, 08:10:15 pmTo my mind that is the best result for any one pulling the trigger on an AK 47 especially if it was pointed in my direction.

author: G7PSK
author_rank: Super Contributor
timestamp: July 05, 2012, 05:52:34 pm
content: Quote from: SeanB on July 05, 2012, 04:08:07 pmI have a Wolf 16 mm 5/8 inch spade handle drill that I purchased new in 1975 it is still going strong today the only thing I have had to replace is the trigger switch which failed a few months ago, the only place I could find a replacement was from an Australian supplier. The drill has now outlasted the manufacturer.

author: SeanB
author_rank: Super Contributor
timestamp: July 05, 2012, 06:47:42 pm
content: I have a Miller Falls drill, quite old, still works, though I do not use it much, as i suspect the motor needs servicing.

author: nukie
author_rank: Frequent Contributor
timestamp: July 06, 2012, 03:50:59 am
content: If you can find US made Energizer NiCd then buy them for replacing your Chinese cells, the cells last forever and they are happy with deep discharge, overcharging etc. I abused a pack I built for many years, I hooked it up to my hobby charger it still has 93% capacity left very impressive! The Chinese cells rusted and some die of negative discharge.I wanted to replace with Eneloop but they the Energizers just refuse to give up, maybe ill build another pack.tapatalk

author: G7PSK
author_rank: Super Contributor
timestamp: July 07, 2012, 09:26:38 pm
content: I have a set of Japanese made NiMh that I put into a 5 watt two way radio in 1996 after the original NiCd died after a year They are still good today and the radio still puts out a bit over 5 watts. The other pack of Nicd that came with the radio are now dead as a Dodo so I will have to do the same to that pack some day but as the NiMh are still good I wont rush.