Alternator shot....or just underpowered?

[antichrist]

Assuming 100amps for a 3' run (to allow for routing) #10 would be fine. I'd probably use #8 to get the volt drop even lower, but would be comfortable with #10 if it was already there.
For reference, #12 would reduce the voltage to the battery by 0.5v.

[knac1234]

Mark & Tom,

Agreed on your electrical thoughts. I think I did a pretty good job of it when I was working on the Rover's electrics late last year. The new fuse box was wired as follows:

-8 gauge wire from solenoid live to very large fuse (forget amperage, but it matches the new fuse panel's rating!)
-large fuse via 8 gauge wire to new fuse panel
-each circuit stands alone and is fused according to the rating of the device powered
-each circuit with a high amp draw item (all heated glass, fog lamps, rear work lamp) has a separate relay
-wiring to each of these high amp items runs the right gauge wire (I think 10 or 12 gauge depending on the item)

So, that, in conjunction with a stock clean system, I think is pretty darn safe, and so the alternator recommended should be safe.

No problems again this morning.....one turn of the key and she fired up instantly even after sitting all night outside in the cold wind and more snow!!! Think the Lucas is fine right now.

Julian

[SafeAirOne]

I think is pretty darn safe, and so the alternator recommended should be safe.

Yeah, you'll be fine with that setup.

[LR Max]

Test the alternator first. Grab your volt meter and put the black on the negative of your battery and the red on the positive of your battery. With your engine running, measure the voltage across the battery terminals. If it is a ~12v or less, your alternator is toast.

Also make sure you increase the RPMs of your engine while testing. Your alternator might not provide optimum voltage at idle. But at ~2k, it might be putting out 13.5~14v which means it is good.

As for the light. My low voltage light is all messed up. As I increase RPMs of the engine, the light goes from a dim to full glow. Then back at idle it is dim . However I don't have any electrical issues (it has been doing this for months and I haven't had to put a battery charger on it).

[I Leak Oil]

Just curious, on a SIII what's the path from the alternator output to the battery? What does the current go through(switches, connectors, etc.)? Might want to look at it and ask if you want the increased amperage going through that stuff.

[SafeAirOne]

Just curious, on a SIII what's the path from the alternator output to the battery? What does the current go through(switches, connectors, etc.)? Might want to look at it and ask if you want the increased amperage going through that stuff.

Only going by my 2.5 and the SIII schematic, but the internally-regulated alternator output goes directly to the big stud on the starter with nothing in between.

[I Leak Oil]

You mean Rover made some attempt to wire something correctly?!

[LR Max]

Only going by my 2.5 and the SIII schematic, but the internally-regulated alternator output goes directly to the big stud on the starter with nothing in between.

X2. There are other wires that go to the wiring harness to control it but the important wire is pretty much wired to the battery via the starter solenoid stud.