Nicad vs Nimh

[festooltim]

I picked up my new C-12 yesterday  [big grin] I got the 2.4 battery . I was looking at the charger and it said it worked with the Ni-cad And the Nimhd battery so i looked in the catalogue and saw that the 3.0 comes with a Nimhd battery. What is the advantage and disadvantage between the two.

 

[PeterK]

I had both batteries with my C12 along with the little one - 1.2ah?. Same power but longer run time with the 3.0. I found I used the smallest battery most of the time as it saw primarily shop use so run time was not an issue. Outdoors doing fence work or such, the larger batteries are great so don't have to recharge as often - but they sure are heavier!! I found no real advantage of the NiMhd over the NiCad as Festool has the best NiCad batteries I have ever used. I outfitted my electricians with the 2.4 volt NiCads and they held up to hard use for 4 years before requiring replacement batteries. Festool is supposedly coming out with a new version of the C series drill with LiIon and I think I read that those batteries will be backwards compatible with the C12 drill - not in the US for quite a while. Don't know if will need a new charger though. I would not be concerned at all with what you purchased as it is a FANTASTIC drill and to me has the best all-around battery in the 2.4 ah. Enjoy  [smile]

 

[Brice Burrell]

....Festool is supposedly coming out with a new version of the C series drill with LiIon and I think I read that those batteries will be backwards compatible with the C12 drill - not in the US for quite a while. Don't know if will need a new charger though.....

The new Li Ion batteries are not compatible with the older model drills. However, the older nickel based batteries are compatible with the new Li Ion model drills and chargers. 

 

[Administrator_JSVN]

Tim, Wikipedia has a good section comparing the advantages and disadvantages of NiCad to other battery technologies, including NiMH. 

Based on my understanding of battery technologies, NiMH is usually used for higher capacity battery, hence its use in the 3.0Ah battery.  Ampere hour (Ah) is essentially a measurement of how long it takes to discharge a battery (or battery capacity in simpler terms).  Unlike NiCad, NiMH batteries do not have a memory effect meaning that partial discharge before recharging doesn't have an effect on the battery's ability to fully recharge over time.  However, NiCad does have a memory effect and should be fully discharged and full recharged to optimize battery life.

If any part of that is incorrect, please feel free to correct me.

 

[ajones]

Tim, Wikipedia has a good section comparing the advantages and disadvantages of NiCad to other battery technologies, including NiMH. 

Based on my understanding of battery technologies, NiMH is usually used for higher capacity battery, hence its use in the 3.0Ah battery.  Ampere hour (Ah) is essentially a measurement of how long it takes to discharge a battery (or battery capacity in simpler terms).  Unlike NiCad, NiMH batteries do not have a memory effect meaning that partial discharge before recharging doesn't have an effect on the battery's ability to fully recharge over time.  However, NiCad does have a memory effect and should be fully discharged and full recharged to optimize battery life.

If any part of that is incorrect, please feel free to correct me.

Hello Shane  I do not agree,with the last part of your statement  nicads should be discharged to the point that performance starts to fade and then fully charged,I have seen many guys on site holding the tool in the on position until it stops completely, before recharging.It is my understanding that this practice will damage the battery.

 

[slb]

Tim, Wikipedia has a good section comparing the advantages and disadvantages of NiCad to other battery technologies, including NiMH.  

Based on my understanding of battery technologies, NiMH is usually used for higher capacity battery, hence its use in the 3.0Ah battery.  Ampere hour (Ah) is essentially a measurement of how long it takes to discharge a battery (or battery capacity in simpler terms).  Unlike NiCad, NiMH batteries do not have a memory effect meaning that partial discharge before recharging doesn't have an effect on the battery's ability to fully recharge over time.  However, NiCad does have a memory effect and should be fully discharged and full recharged to optimize battery life.

If any part of that is incorrect, please feel free to correct me.

Hello Shane  I do not agree,with the last part of your statement  nicads should be discharged to the point that performance starts to fade and then fully charged,I have seen many guys on site holding the tool in the on position until it stops completely, before recharging.It is my understanding that this practice will damage the battery.

You are correct.  Regardless of battery type, you should recharge as soon as you detect a drop in power.  The reason is that the cells in a battery are never all perfectly equal.  The drop in power occurs when the weakest one is discharged.  If you continue past that point, you actually reverse the reactions in the weak cell and risk damaging it permanently.  This is a different issue than the memory effect, which decreases the capacity of many NiCd cells if you recharge them from a partly discharged state.  NiMH and Li-ion cells don't have this problem.  Some makers claim they have figured out the cause of the memory effect and their NiCd cells don't suffer from it.

Steve

 

[slb]

By the way, the right way to think about AmpHours is like the capacity in gallons of a gas tank.  It is a measure of the amount of charge the battery can store.  And, just like the capacity of a gas tank, it doesn't tell you how much power the engine (electric motor) will provide.  Within quibble, all batteries of the same voltage will provide the same oomph to the tool, but a larger amp-hour battery will let it run longer.

 

[Rick Christopherson]

What two of the posters are referring to is called cell reversal, and it is bad for the batteries. However, I do not believe cell reversal is an issue with the C12 drill because the MMC electronics shut the motor down when the voltage drops and will not operate. I don't believe you will cause any problems with the batteries if you run them down to the point of the electronics shutting down.

On the other hand, the rapid charging rate on the C12 (and more so on the CDD12/TDK12) does reduce the effects of cell memory in the first place.

 

[ajones]

I guess that with the field leaders building electronic monitoring of battery state and auto cut off into their tools to protect both tool and battery, the issue of over discharge remains pertinent only to users of cheaper or older brands [thumbs up]

 

[Groggy]

I was reading through this thread as I am replacing some well-worn NiCd BPS15.6, BPH9.6T and BPH9.6C with NiMh spares. What was not discussed in this thread is if there is any difference with the chargers for these units?

Can I still safely use the NiCd chargers?

 

[TomE]

Replaced the NiCd batteries that came with my old C12 with new NiMh.
Still using the same charger supplied with the drill.

 

[Maximus]

A helpful free resource I can highly recommend to anyone wanting to learn more about batteries is The Battery University.

>>>http://batteryuniversity.com/learn/