Voltage of festool batteries?

[bryan1982]

Hi guys 

Have any of you actually tested the he volts coming out of your batteries ?

I'm getting 20.6v very from my 18v 4.2 ah festool batteries.

And 17.6v out of a 5.2 ah 15v  festool 

I have no idea what it means or if it matters but thought it was interesting on what others thought.

Cheers

Bryan

 

[sae]

That's about right.

4.2v/cell is the peak voltage most li-ions should be charged to. Any more is an explosion hazard.

3.7v is nominal, which is how most derive the 18v rating.

Lowest it should ever go is 2.5v for most chemistries, though manufacturers usually cut it off higher (a) because the tool performs like crap when the voltage dips that low, and (b) for a larger safety margin when you discharge a battery completely and don't have time/forget to get to a charger immediately. If it drops below, it's also a hazard to charge them unless you very tightly control the charging output.

 

[Holmz]

What does your 12V car battery measure?

 

[Locks14]

What does your 12V car battery measure?

Nothing, it hasn't got any hands or a tape measure! ;D

 

[yetihunter]

Well, now you know the story about Dewalt's "20v Max" batteries.
Any and all lithium ion 18 v battery stacks should come off the charger
at around around 20 v. 

They are 18650's:  3.7 v batteries. 
However,  they'll read as 4 to 4.2 v when fresh off the charger.