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leverhead 08-20-2012 08:55 AM

CS Alt/sense wire/batt in trunk w accessories
Hello all. Trying to decide about where to run alt sense wire. The battery is in the trunk and the distribution block is up front under the dash. A 4 awg cable connects the block to the battery (thru a cutoff switch). The block distributes to the fuse block and rest of car. However, an EFI ECU and MSD go direct to the battery, and possibly an air ride system later on. Possible solutions are:

To the battery (hot side of switch) -
Pros - full voltage at battery for battery, ECU, MSD and anything running off the battery.
Cons - long wire run (12 awg) & possible voltage drop at sense wire?, maybe too many volts at block up front as alt compensates at rear of car?

To the block -
Pros - Full voltage at block and everything up front
Cons - possible voltage drop at battery combined with drain on battery from ECU, MSD etc running directly off of it?

Jumper to alt 'BAT' terminal -
Pros - easy & no wire run to deal with
Cons - no alt compensation

Any experience or suggestions are appreciated. Thanks.

vicrod 08-20-2012 03:34 PM

My choice is the fuse block because the alternator powers the loads and maintains battery voltage. The load on the #4 wire running to the battery is only battery maintain current whereas the larger loads are at the fuse block.
This assumes that the battery is in good condition.
FYI- The alt. sense wire has no load to speak of thus no voltage drop. It is only used as a reference for regulation of the alt. output.


EOD Guy 08-20-2012 04:44 PM

I spliced mine in at the battery 8 gauge wire via a 6 foot run of wire..... basiclly from the alt, over to the radiator support, started across the support then looped back to my 70 amp Maxi-fuse then to the pos post on the battery..... works very well for me. I tried to mimick GM's original wire length etc....

leverhead 08-20-2012 08:02 PM

My first thought was also the distribution point/fuse block up front. My concern is maintaining the battery in the trunk when I have a fairly descent size load running directly off of it.

Not much of a voltage loss in a #4 cable though .....I presume a little resistance would keep the battery from charging too fast. This may have to be one of those things I'll have to figure out by experimentation.

Thanks for the replies.

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