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TarheelTerp 11-18-2013 02:51 PM

quick chargers
 
Do they really work and/or
does working come with other problems like premature failure?

I have some B&D yard tools all of which work great and meet my need except for charge time under extended use time (like blowing leaves in the fall).

Waiting 8hrs to do more work suits me just fine...
but the boss gives me the hairy eyeball if I come back in too soon.

Wally's has this thing for $45...
http://www.blackanddecker.com/attach...L2AFC-OPE.aspx

It says 40 minutes which beats the pants off the current 8 hours let alone having to remember to do the midnight cassette juggle.

Is it worth it?

raylo32 11-18-2013 04:09 PM

My Makita lith ion quick charger works great. 15 minutes for the small 30 minutes for the large battery. I am not in a commercial setting so don't charge every day but I've had the set for a year and so far so good. I could never go back to the slow chargers myself...

Oso954 11-18-2013 04:17 PM

What they do is bring the battery to about a 70% state of charge and let you get back to work.

They will not provide the same run time as a battery that has been fully charged.

Unlike some other batteries, partial charging does not hurt lithium ion batteries.

ddawg16 11-18-2013 04:35 PM

Quote:

Originally Posted by Oso954 (Post 1268299)
What they do is bring the battery to about a 70% state of charge and let you get back to work.

They will not provide the same run time as a battery that has been fully charged.

Unlike some other batteries, partial charging does not hurt lithium ion batteries.

Not quite true.....if it's a good charger...it will bring it to 100%.

Battery charging for the new LI stuff is a lot different than an old car battery.

In the old days, NiCad chargers shut just applied a known current and sat there....once the battery was charged, it won't accept any more current. Pretty much self regulating.

One of the issues with charging a battery is heat. A pulse charger can reduce that while charging it faster.

Quote:

Some chargers use pulse technology in which a series of voltage or current pulses is fed to the battery. The DC pulses have a strictly controlled rise time, pulse width, pulse repetition rate (frequency) and amplitude. This technology is said to work with any size, voltage, capacity or chemistry of batteries, including automotive and valve-regulated batteries.[4] With pulse charging, high instantaneous voltages can be applied without overheating the battery. In a Leadľacid battery, this breaks down lead-sulfate crystals, thus greatly extending the battery service life.[5]
Several kinds of pulse charging are patented.[6][7][8] Others are open source hardware.[9]
Some chargers use pulses to check the current battery state when the charger is first connected, then use constant current charging during fast charging, then use pulse charging as a kind of trickle charging to maintain the charge.[10]
Some chargers use "negative pulse charging", also called "reflex charging" or "burp charging".[11] Such chargers use both positive and brief negative current pulses. There is no significant evidence, however, that negative pulse charging is more effective than ordinary pulse charging.[12][13]

Oso954 11-18-2013 05:32 PM

Quote:

Not quite true.....if it's a good charger...it will bring it to 100%.
100% what ? Voltage or charge saturation ?

How much would you like to bet that a $50 lithium ion fast charger from B&D is not just wacking the saturation charge based on the battery reaching 100% voltage (end of stage 1 charge).

Edit: And possibly using a slightly higher charge voltage during stage 1

woodworkbykirk 11-19-2013 04:30 PM

fast chargers can also shorten the service life of a battery as well. dewalts xrp line of batteries were notorious for this when used on the fast charger.. i know a few guys that swore by them however they had to buy new batteries prety much yearly

ddawg16 11-21-2013 07:10 AM

Quote:

Originally Posted by woodworkbykirk (Post 1268790)
fast chargers can also shorten the service life of a battery as well. dewalts xrp line of batteries were notorious for this when used on the fast charger.. i know a few guys that swore by them however they had to buy new batteries prety much yearly

There is a difference between cheap fast chargers and pulse chargers.

The XRP battery is NiCad....NiCad's do not like heat...a 'fast' charger typically just tosses a lot of current at the battery....that causes a considerable heat rise...most of those chargers have a temp sensor that when the temp of the battery (typically the neck) reaches a certain point...it shuts off.

My older Ryobi's are like that....if fact, if I was doing some heavy use stuff with it, like drilling holes with the angle drill...the battery would be warm enough that when I put it in the charger, it would not charge because of the heat...I had to let it sit for awhile to cool off.

NiCads do not like heat....they also do not like being left charged or not run down all the way. A typical NiCad has a service life of 300-1000 charges....so, if your charging that battery 2-3 times a day (not unusual) and using it 200 days a year....your going to have 400 plus cycles on it the first year....so....yea, 1-2 years life out of a high use NiCad is about right. Toss in reduced life due to not fully discharging and/or leaving it on a charger over the weekend....less life.

But a Pulse charger is not going to reduce the life.

To get the most life out of a NiCad, pulse or slow charge. Once charged, remove from charger....use it until dead. Re-charge. Also note that NiCad's have a self discharge rate of about 10%/month. So...just sitting there....they will loose charge. They also have a finite life....8-10 years....left unused, the life will be shorter (some people try to call it 'memorie').

With the current flavor of Li....the market is dumping all the NiCad's....it's best to check the manuf date on the battery....I've seen some that were 3 years old and still on the shelf....that is a battery that is not going to give you full service from the start.


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