"Dave Liquorice" wrote in message
ll.com...
On Sun, 6 Feb 2005 23:36:23 -0000, Mike wrote:

I was going to use some of those gold coloured power resistors.

The colour isn't important but their wattage rating is...

Yes :-) Just gave the colour so that people would recognise them. The
green ones cannot take such a high load and are slightly inductive.


Any idea what voltage drop at what current shows a car battery is or
isn't worth using ?

Take a look through http://www.batteryuniversity.com. Everything you
wanted to know about rechargeable batteries but where to afraid to
ask. Open circuit anything less than 2v/cell is doubtful. IMHO under a
load of 10 to 20A for 10s or so the terminal voltage shouldn't drop
below 12v and preferably remain above 12.6v. Note 15A @ 12.6v is 189W
so take heed of the wattage rating of your less than 1 ohm resistor...

Just what I was after. I'll wire this lot up into a small box with two
leads. Just hope our local scappy doesn't mind a few sparks while I test
what he's got.