(ET) Diodes

[Jeremy Gagliardi <jeremy gagliardi com>]

This is only slightly related to Elec-traks, but I don't know of any other 
forum that can answer my question.

I have a 12V battery pack that charges by plugging into any car-style 
power outlet.  The problem is, it allows voltage to go both ways.  If I 
forget it's plugged in, and I turn off power from the vehicle, the battery 
pack will immediately begin powering the vehicle.  I think this has 
damaged a relay on 2 separate occasions.

I want to prevent this behavior by putting 2 diodes on the line so power 
only goes 1 direction.  However, I don't know what kind of diode to buy.  
I went to Radio Shack and found some very puzzling codes on all of the 
diodes and a staff that was less than knowledgable.

Can someone on this list reply to this e-mail in private, and let me know 
what kind of diode to buy as well as what code to look for for a 12V, 5Amp 
system?

--
Jeremy Gagliardi
E20
Potomac, Md

 mailto:Jeremy Gagliardi com
 http://Jeremy.Gagliardi.com