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I have a Black & Decker EPC128 12V cordless drill. It has two batteries. Since the recharger has no light or indicator on it, I never surely understand whether the battery is partly/fully charged or overcharged. How long exactly should I recharge the batteries? The tool is something like this:

bd_drill

Mehper C. Palavuzlar
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    Does it not say in the instruction leaflet? – ChrisF Mar 02 '12 at 22:22
  • I have lost the instruction leaflet. – Mehper C. Palavuzlar Mar 02 '12 at 22:23
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    A search for the model number might turn up the instructions online. – ChrisF Mar 02 '12 at 22:24
  • @ChrisF: Thanks to your advise, I've found the answer. – Mehper C. Palavuzlar Mar 02 '12 at 22:33
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    Wow, that's a major design flaw - no blinky light! – Doresoom Mar 02 '12 at 22:47
  • @Doresoom: That's right. I should've noticed while I was buying it. A small but crucial detail. – Mehper C. Palavuzlar Mar 03 '12 at 08:07
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    Yeah, I would have issues with no blinky light, especially as some batteries (NiMH) can be overcharged which will shorten their lifespan. My Ryobi ONE+ NiMH charger has TWO blinky lights (!) and it's a smart charger that'll go into trickle-charge mode to protect a battery that's left in it overnight (or longer). – KeithS Mar 05 '12 at 16:06
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    Pretty sad as overcharging kills NiCad and NiMH batteries. There are many specialized chips that understand the charge cycle of both these battery chemistries and can sense when the maximum charge is reached and the cycle is complete for termination. Even cheap Chinese knockoff stuff includes smart charging. It's one of the reasons I've moved away from Black & Decker tools, they've gone too damn cheap. Overcharging also lights LiPoly batteries on fire, so if you don't have a smart balance charge system with that battery chemistry, you'll eventually pay for the cheapness. – Fiasco Labs Jan 19 '13 at 19:32
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    Honestly, this drill looks like one of those things that should never be bought by anyone, even someone who only needs a cordless drill once a month. an 8-10 hour full-charge time is ridiculous and indicates inferior quality parts, in both the battery and the charger. My Ridgid 18v lithium ion batteries go from dead to full charge in about 25 minutes. If you can, return this drill to the store and get a better model. – William S. Jan 02 '15 at 07:01
  • 'No light' does not necessarily mean the charger is so dumb it will keep charging even when the battery is full. – Hobbes Oct 10 '16 at 11:01
  • @cathode: an 8-10 hour charge time likely leads to an increased lifespan for the battery, and is a good choice for tools that are only used occasionally. Rapid charge cycles can reduce a battery's lifespan through overheating. – Hobbes Oct 10 '16 at 11:03
  • A competent battery charger should not be overcharging the battery at all, and it should be safe to leave it on 24x7, and it doesn't need a light for that. However, you said this was Black & Decker, they love to shortcut on quality, having torn down a few pieces of B&D equipment in a hopeless attempt to repair a bad design... – Harper - Reinstate Monica Jan 04 '17 at 20:28

3 Answers3

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I have found the original instructions on this page.

After approx. 3 hours of charging, the battery will be sufficiently charged for use in regular applications. After approx. 8-10 hours of charging, the battery will be fully charged.

After a few lines, it says:

After normal use, a charging time of 3 hours will provide sufficient power for most applications. However, further charging for up to 6 hours could significantly increase the use time, depending on the battery and charging conditions.

Mehper C. Palavuzlar
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  • I have the EPC 18 volt and my instructions says the same, up to 8- 10 hours the battery will be fully charged. –  Dec 30 '14 at 18:35
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From the manual... Instructions for jack plug chargers:

  1. Place the battery pack into the tool until it “clicks” into place.
  2. Insert the charger plug into the connector as shown in figure B.
  3. Plug the charger (6) into any standard 120 Volt 60 Hz electrical outlet and let the battery pack charge initially for 12 hours. After the initial charge, under normal usage, your power pack should be fully charged in 6 to 12 hours.
wallyk
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boscher
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    If you found the instructions online, a link to it as part of your answer would be most welcome. – wallyk Jan 16 '15 at 19:40
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If the battery is fully discharged, the formula is: Time(t) = Battery Capacity(q) / Charging Current(i) Units can be hours, amp hours and amps or seconds, coulumbs and amps

For Example, If The battery your charging is 1Ah and the charger output is 100mA(0.100 amps), charge for 10 hours. If the same battery is charged with a supplied charger output of 250mA(0.250 amps), charge for 4 hours.

These equations assume a charger efficiency of 100% which is impossible in real life, charge times may be longer depending on charger efficiency...

Mitchell Spanheimer
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wayne of welling.
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