Got a FIA Battery cut off switch off the T-Car team at work.
At the moment I have a standard cut off switch, how do I need to wire up the alternator so it wont blow when I cut the switch with the engine
running.
The new switch I have has a small block on the bottom with 4 spade connectors on it. The electrics guy at work said I will need a ballast resistor
(which I can get off him). Does anyone have a wiring diagram for the switch and resistor?
Thanks
just searched google and came up with this as the top entry...
http://www.dazecoop.co.uk/15-06-2006/wiring-battery-cut-off-switch
hth
Steve
I think this has the answer
http://www.websitetoolbox.com/tool/post/viatron/vpost?id=1896001
quote:
Originally posted by worX
just searched google and came up with this as the top entry...
http://www.dazecoop.co.uk/15-06-2006/wiring-battery-cut-off-switch
hth
Steve
Thanks for the links. Still a bit confused though. At the moment the alternator has the main output going to the starter which is then connected to
the battery. It has the 12v 'exciter' feed coming from a switched live via a warning lamp.
Do I need to wire the exciter feed across the N/O terminals on the cut off switch so that when I turn the switch off the feed is killed to the
alternator?
Where does the ballast resistor come into it? I can see the resistor in your diagram Chris, but it doesnt mention the alternator.
Sorry if its stupidly obvious!
Just went back and re-read the piston heads topic. Think I have my head around it now! I can also see why the alternator wasnt mentioned.
Maybe I should search google more before asking!
Just disconnecting the battery won't stop the engine as the alternator will supply the juice. Because the alternator can supply over 50amps you
don't just put the alternator output through one of the smaller switches, it's normal to put something like the ignition coil 12V feed
through so the engine will stop but there's not so many amps it will tater the switch. Now when you hit the big red switch there's no drive
or load on the 12V so it 'could' float around for a while causing general embarrassment - so the 'ballast resistor' circuit is
there to pull it down to deck.
Bob
in other words, if you don't use the pull down resistor some alternators will then put up to 80volt's on the system because it can't
see the battery anymore and thinks the Battery is flat, thus going into rappid charge, with no load, hence voltage goes up.
prepare to replace everything that's turned on at that exact moment.
grtz Thomas
learned the hard way once! had 81volts on the laptop multimeter interface.