[ltp] Running with line power and no battery

[Henrique de Moraes Holschuh]

On Thu, 28 Feb 2008, Joerg Bruehe wrote:
> What I would like to have for this is a dummy battery cover, to prevent  
> any dirt from reaching the contacts. But I haven't yet started any work  
> for this.

Cleaning those contacts is not too troublesome, and if you use it as an
excuse to clean up the laptop itself, it is benefitial :-)

> I work from my home office, so any loss of power would affect running  
> machines, but I did not get any kind of UPS - that's my assessment of  
> the risk (for me !). I have heard from colleagues that short outages are  
> frequent for them, because they are supplied via overhead wires which  
> are affected by wind, rain, ice, car accidents, ...

Lack of power is not exactly the problem.  The issue is that when you power
up a heavy load in an uncontrolled manner (i.e. when power returns to the
feeding branch that reaches your home), you get nasty variations on the
power feed (it is a n-degree system, where n > 2.  If you're lucky, you get
a single overshoot, but usually you get the full "ringing" effect that looks
a lot like the one of a 2nd-degree undercompensated system).

That can kill electronics and high in-rush current devices like your
refrigerator quite easily.  Especially with the kind of under-protected crap
we get for PSUs nowadays.

If you're at home, when the power goes out you should open all circuit
breakers.  When it comes back, wait a small while for the power grid to
stabilize (I use 5 minutes), make sure electronics are unplugged, close
breakers one by one with at least one second between them, and after that is
done, replug the electronics.

Yes, where I live we have a lot of "power events".  I don't dare leave home
with the computers plugged without a good UPS in the way.

> IMO, everybody has to assess that risk for themselves.

Yes.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh