924Board.org

924aussie · Posted: Mon Sep 22, 2008 11:05 pm Post subject: negative post on battery

No this is not a negative forum post on a battery.

What I would like to know is it good or BAD practice to connect a earth connection from a device direct to the (-) terminal on a battery.

I know some high performance speakers need to be connected direct to the positive terminal but I am wondering about the negative.

alan
_________________
green 924 .. 1980 rego 924PSH
1998 Mopar Neon ... sick
2003 Challenger / Montery 4WD
1995 Hyundai Scoupe ... sold
1998 Nissan Silvia ... sons back from OS he has taken it
BIG BLOODY MOTORHOME 300zx Sold
1980 Fire truck Sold

datatrain · Posted: Tue Sep 23, 2008 2:32 am Post subject: Negative term

I think it depends on what your connecting. In order to complete a high current curcuit all parts of the wiring must be capable of carrying the load.

Usually a connection to the chassis is sufficient. However if you splice into a small ground wire, there could be a problem with capacity.

You'll note the battery ground wire to chassis is quite large. So a chassis ground connection will carry any load.

The reason some items want to be connected to the + of the battery is to ensure the wire size is adequate for the device and often it has a separate fuse for protection..
_________________
'78 924 NA with Collector plate
33 year old car, with me for 21 yrs
Mint '92 318i BMW
Near mint '98 Buick LeSabre
VE7HFR

wombat · Posted: Tue Sep 23, 2008 6:44 pm Post subject:

I dont think that it would matter all that much for most things. The main problem I can see with - straight to the battery is that it may confuse people working on the car later, I usually assume most things running to engine bay to be not earth (ground) and it could be a royal waste of good copper, Man with copper prices the way they are I wouldnt waste it.
_________________
1977 924 2.0 Auto