refreshing Dewalt batteries

[cckw]

I am new here and have gotten the C9000 to maximize my Eneloop experience.

I want to take this extra attention to my power tools. I have a home use 9.6v Craftsman that is getting weak, but more importantly want to keep the health in my 6pc Dewalt 18v work tools. How are you techie types refreshing and/or maintain your power tool NiCad batts?

 

[SilverFox]

Hello Cckw,

Like all other NiMh and NiCd batteries, the power tool battery packs can benefit from a Break-In cycle, and a few charge/discharge cycles from time to time.

I use a hobby charger for the Break-In charge, and build something to cycle the packs.

Tom

 

[cckw]

Hello Cckw,

Like all other NiMh and NiCd batteries, the power tool battery packs can benefit from a Break-In cycle, and a few charge/discharge cycles from time to time.

I use a hobby charger for the Break-In charge, and build something to cycle the packs.

Tom

I am new to all of this. so forgive me.

What about just using the flashlight to cycle the cells? If yes, how often and how many cycles back to back?

can you point me towards one or more hobbie chargers that would do what you recommend?

 

[SilverFox]

Hello Cckw,

Battery packs will remain vibrant if they are cycled at least once a month. Your flashlight would work fine for that.

You will have to do a search on hobby chargers. I happen to have and use a Schulze charger, but there are some less expensive options available that work "almost" as well as the Schulze...

Tom

 

[cckw]

Using the flashlight to cycle, I assume charge to full then immediately put on light? how low should I run it? then recharge immediately, or let sit overnight first?

I don't have a 9.6v flashlight. advise on that one?

 

[SilverFox]

Hello Cckw,

My standard advice to keep cells vibrant is to store them discharged and to subject them to a charge/discharge cycle every 30 days. This is for NiCd and NiMh chemistry.

Keeping this in mind you would charge the battery pack then use the light. You could even use the light over a few nights and have some fun with it. I was thinking that you may have a DeWalt light that the battery pack would simply plug into.

Tom

 

[cckw]

My 9.6v Craftsman has a dumb charger that is a wall wart 11v to an empty shell. With a pretty dead cell what would you guess the ideal charging time is? the instructions gave several answers, ranging from 5-17 as I recall.

Part #2: to discharge a 9.6 is it a good plan to take a spare bulb for the 18v Dewalt and solder leads on the bulb then use a plastic clamp to put it to the terminals on the 9.6 batt?

 

[Closet_Flashaholic]

Not sure about your DeWalt charger, but I just bought a new 18V hammer drill and the owner's manual for it says that the charger has a "battery reconditioning" mode built into it. Just leave a battery on the charger for more than 8 hours and it will automatically start a reconditioning cycle on it. The cycle will run for 24 hours.

 

[SilverFox]

Hello Cckw,

16 hours is a good maximum charge time.

Your idea of using a bulb for discharging will work fine.

Tom

 

[SilverFox]

Hello Closet Flashaholic,

I have one of those battery chargers, but I have not been able to determine what it does during the conditioning cycle. It may be more of a balancing effort than providing a charge/discharge/ balance cycle.

Tom

 

[TakeTheActive]

What About 'Cell Reversal'?

I am new to all of this. so forgive me.

What about just using the flashlight to cycle the cells? If yes, how often and how many cycles back to back?

...Battery packs will remain vibrant if they are cycled at least once a month. Your flashlight would work fine for that...

Using the flashlight to cycle, I assume charge to full then immediately put on light? how low should I run it? then recharge immediately, or let sit overnight first?

...Keeping this in mind you would charge the battery pack then use the light. You could even use the light over a few nights and have some fun with it. I was thinking that you may have a DeWalt light that the battery pack would simply plug into...

...to discharge a 9.6 is it a good plan to take a spare bulb for the 18v Dewalt and solder leads on the bulb then use a plastic clamp to put it to the terminals on the 9.6 batt?

...Your idea of using a bulb for discharging will work fine...

SilverFox,

What prevents a Dewalt flashlight (on the Dewalt pack), or the 'spare bulb' (on the Craftsman pack), from causing cell reversal?

The more I read and learn, the more I dislike packs (*ALL* packs - power tools, Dust Busters, Roombas, even 9VDC batteries!). If you can't get 'Balancing Taps' into EACH cell, forgetaboutit.

IIRC, previous advice given in the CPF 'Batteries Included' Archives stated to STOP using the power tool at the first indication of speed decrease. NOW, (as opposed to my pre-CPF days), I can clearly see that when the speed drops, ONE CELL JUST DIED and continued use of the tool will only serve to reverse-charge / damage that cell - effectively ruining the pack.

NOTE TO SELF: It appears that vBulletin can't handle over 5 Multi-Quotes.

 

[SilverFox]

Re: What About 'Cell Reversal'?

Hello TakeTheActive,

There is nothing to prevent over discharge of a battery pack when you use a lamp for discharging. In some cases, over discharge will result in cell reversal and the pack will be ruined.

However, if one attends to the discharge, the light can be disconnected at the first signs dimming avoiding the problem with over discharging.

Balance taps only apply to Li-Ion technology. NiMh and NiCd cells in battery packs are balanced by an over charge at a 0.1C, or lower, charge rate after the initial charge has been completed, or by simply using a 0.1C charge for 16 hours.

Tom

Note to TakeTheActive: Since your question was directed to me, I can say that I would have completely understood your question without the use of any of the quotes... :nana:

 

[TakeTheActive]

Re: What About 'Cell Reversal'?

...There is nothing to prevent over discharge of a battery pack when you use a lamp for discharging. In some cases, over discharge will result in cell reversal and the pack will be ruined.

However, if one attends to the discharge, the light can be disconnected at the first signs dimming avoiding the problem with over discharging...

Since you were replying to a Newbie concerning packs, I wanted to be sure to get 'Cell Reversal' into the conversation. I was very surprised that you didn't mention it at all. You're usually very thorough.

...Note to TakeTheActive: Since your question was directed to me, I can say that I would have completely understood your question without the use of any of the quotes... :nana:

Again, looking forward to future Newbie SEARCHes hitting this thread, I wanted to get the point across by presenting my interpretation of the logical path of the thread. You can't just hook up a load to a pack and walk away. And, to your :nana:, I say...

 

[n3eg]

I'll add a question to this thread:

What battery analyzers will handle 18 volt batteries?

At work here, neither the Cadex or the JaBRO/Telepower will go over 15 volts, so we're stuck opening packs (if possible!) and analyzing halves.

 

[SilverFox]

Hello N3eg,

The CBA goes up to 55 volts.

Tom

 

[cckw]

I see TakeTheActive's point with all the quotes and seemingly over the top point. It really made an impression on me, the noob OP, so perhaps saved a pack.

 

[clintb]

I'll add a question to this thread:

What battery analyzers will handle 18 volt batteries?

At work here, neither the Cadex or the JaBRO/Telepower will go over 15 volts, so we're stuck opening packs (if possible!) and analyzing halves.

Check out the new FMA CellPro PowerLab 8. 1000W charging, 100W direct discharge, or 1000W regenerative discharge, two way PC communication...all at a price that's not much more than a CBA III.

 

[Bright+]

It's a bad idea to discharge using a resistor (like a light bulb) since you can discharge the pack to the ground.

The pack is made of multiple cells and just like everything, there's a variation. Unlike single cell use applications, packs are built using reasonably matched cells, but there's a +/- 5% or so tolerance

so, lets say they're 2Ah rated. Range could be 1.8 to 2.2Ah.

By heavily discharging, the lowest battery will drop to 0v, but remainder continues to work, then charge the weakest cell backward. Overtime, that cell becomes so weak that it becomes a resistor or an obstruction in a string of batteries causing the entire pack to not work well. Recharging at 20-30% charge remaining on regular basis is not going to cause memory effect.