Re: Can a power supply have too much current?

[Anthony Lawther <alawtherNOSPAM@westnet.SPAMMENOT.com.au>]

In article <dPOdnZN60-vuGXrYnZ2dnUVZ_rWnnZ2d@comcast.com>,
 "Michael J. Mahon" <mjmahon@aol.com> wrote:

> Mike Spurgeon wrote:
> > Michael J. Mahon wrote:
> > 
> >> And a shorted 500A battery will make a fire *much* faster than a
> >> 200A battery.  ;-)
> > 
> > 
> > If you've never seen the 1.5 volt wet cells the phone company used for 
> > battery backup in the 1970s, they were pretty impressive.
> > 
> > They could melt most wire you think would work...
> 
> I've seen them--actually a whole *room* full of them!
> 
> Nickel-iron cells are very reliable and very low impedance (high
> current capability).  AFAIK, the phone company was the only big
> user of them.
> 
> -michael
> 
> NadaNet networking for Apple II computers!
> Home page:  http://members.aol.com/MJMahon/
> 
> "The wastebasket is our most important design
> tool--and it's seriously underused."


Diesel Electric Submarines use some nice big batteries. Something like 
95 kg (about 210 pounds) per cell when wet. Capacity in the tens of 
thousands of Amp Hours.


I've seen the end result of an unsheathed torque wrench having been 
shorted across a number of cells.
It vapourised the end and completely fused the joint. Eye opening 
evidence to support the rule "no metal in the battery compartments".

Regards,
Anthony.