Alternators - battery sense wire

[savage1987]

Why, in VN Commodores at least, did they run the battery sense wire all the way back across the whole engine bay to the battery? Is there any advantage to this over running it straight to the alternator's 12V post? (which has a direct connection to the battery)

vrollin and I recently redid / hid a bunch of wiring in my LS1 VN and I shot that wire straight around from the alternator plug to the alternator's 12V post, on the advice of the bloke who built my engine harness, and I'm having no problems with it so far.

I'm wondering if I can get away with doing the same thing on my 5 litre or if there's any reason I should leave well enough alone.

Thanks,
Sam

 

[drewVHSS]

looping it back to the the 12v post is what i do to retro fit one into an early commodore. I haven't bothered to check where the s wire actually ends up but it's working on your 5.0l as is, i'd leave it be.
If you felt the need to move it, i'd be hooking it to the junction point of where it can sense load levels the best (main fuse power feed etc) then again, common sense tells me that's where it it's probably hooked up to anyways!

 

[savage1987]

It's hooked up direct to the positive battery terminal at the moment. Might leave it alone if it is working well. It's just a pathetically thin wire so I thought about buggering it off altogether with a little loop

 

[bcw61]

It's hooked up direct to the positive battery terminal at the moment. Might leave it alone if it is working well. It's just a pathetically thin wire so I thought about buggering it off altogether with a little loop

This wire senses the voltage directly at the battery rather than at the alternator itself. This ensures the battery receives the correct voltage for charging purposes, by compensating for voltage drops across the output distribution wiring from the alternator output. It only needs to be a very thin gauge wire, as it is only used for voltage sensing, with very little current flow.

I would tend to leave it connected, as it will ensure your battery receives the correct voltage for charging.

 

[savage1987]

yeah that's very similar to info I got from other forums as well. General concensus is it's better to leave it at the battery, but if it's moved to the alternator charge post it will still work fine, especially with decent cabling from the alt to the battery.