From: datakoll on
how to wire a two prong DELL Inverter for 9400/1705 laptops ? Need the
DC plug for the 1705E and the two prong AC plug for Optima 700Ah's
from a defunct inverter.
The DC plug has 3 operative contacts: inside sheath, outside sheath
and pin. The DC plug cord carries 3 wires.

ON the DC cord: what is ground, what is power, is the ???? inside
sheath for neutral circuit breaker use.

How to wire ? care is required given the unit's costs and possible
tricky computer circuitry with the 3rd wire.
From: Joel Koltner on
"datakoll" <datakoll(a)yahoo.com> wrote in message
news:7da5eac6-545a-4ff6-9855-cf18119fd67b(a)o8g2000yqo.googlegroups.com...
> how to wire a two prong DELL Inverter for 9400/1705 laptops ? Need the
> DC plug for the 1705E and the two prong AC plug for Optima 700Ah's
> from a defunct inverter.
> The DC plug has 3 operative contacts: inside sheath, outside sheath
> and pin. The DC plug cord carries 3 wires.

You can find out what's ground and power with a multimeter easily enough. The
last pin is actually a "data" pin for a serial EEPROM that tells the PC what
the supply's voltage, current, etc. are -- some BIOSes will refuse to, e.g.,
charge the battery if you don't provide this data, so it's important to have
if you're going to make your own inverter here.

I'm fuzzy on the details, but Google can help... see, e.g.,
http://www.laptop-junction.com/toast/content/dell-ac-power-adapter-power-plug
-- there's plenty more out there.