Could the MSD module be fed from different sources?

[CB]

MSD advises in their instructions to run the power lines - and + wires of the ignition module to the  - and + terminals of the battery.
see 'HEAVY RED' and 'HEAVY BLACK'




Now Nacho and I are rebuilding the electrical circuits.
Upgrading the whole mess , running a high output ALT etc

The question: is it safe and possible if we use the alt post instead of the battery to keep a right and accurate Ammeter reading?
And also, how can you 'ground' it correctly?

Thanks!

CB and Nacho

(running the MSD 6AL module)

[John_Kunkel]

MSD wants the heavy red and black wires hooked directly to the battery for a reason, no voltage loss through extended wires.

The ammeter will still read correctly with the wires hooked directly to the battery, why wouldn't it? The ammeter will still show whether or not the alternator is keeping up with the draw.

[Nacho-RT74]

The ammeter will still read correctly with the wires hooked directly to the battery, why wouldn't it? The ammeter will still show whether or not the alternator is keeping up with the draw.

No John, is a wrong statement the ammeter is an alt status when really is a batt status, since shows when batt is being charged or discharged... an alt never is discharged because is not an acumulator.

with a fully charged batt and when you have good power coming from alt, you won't have an ammeter reading because the splice to feed the car demand is just right before the ammeter on the power coming from alt. That means batt is not being discharged because you have enough alt power

conecting ANY device to batt side of the ammeter, will convert the reading like the batt is sucking power to be charged back ( so a needle fluctuation to C side of amm ), so on that moment you get a missread. Maybe an important fluctuation on reading, maybe not, but is a fact

If we talk about a 100 amps alt, theorically being a fully powered source, you shouldn't register any power decay and in fact a constant 13.5 to 14 volts, like it was at batt.

if MSD the demand for power strictly directly from batt is completely true then... HOW the ppl with batts on trunks run the power with the long distance ?... in fact on that situation, the alt is closer so will save the power decay if gets from alt by the shorter distance.

[John_Kunkel]

No John, is a wrong statement the ammeter is an alt status when really is a batt status, since shows when batt is being charged or discharged... an alt never is discharged because is not an acumulator.

You're reading my comment wrong, I said "The ammeter will still show whether or not the alternator is keeping up with the draw." You're right that a high current draw directly from the battery that the alternator can't keep up with won't show on the ammeter as a discharge but it will center the ammeter needle which isn't normal, the needle usually shows a slight charge if the system isn't overwhelmed by the current draw.

OTOH, if a device hooked directly to the battery is drawing a high current and the alternator can keep up with it, the ammeter will show a high charge rate so the ammeter is "showing it".

if MSD the demand for power strictly directly from batt is completely true then... HOW the ppl with batts on trunks run the power with the long distance ?...

They don't, they run it to the battery connection at the starter just as most people with front-mounted batteries do. Directly to the battery is preferred but the starter is an acceptable alternative because the battery cable is large enough to prevent any significant voltage drop over its length.

[Nacho-RT74]

OTOH, if a device hooked directly to the battery is drawing a high current and the alternator can keep up with it, the ammeter will show a high charge rate so the ammeter is "showing it".

yes that right, well, we where just asking for the right reading, not just show a reading. Beside that, no need for "stress" unnecesarilly the ammeter.

They don't, they run it to the battery connection at the starter just as most people with front-mounted batteries do. Directly to the battery is preferred but the starter is an acceptable alternative because the battery cable is large enough to prevent any significant voltage drop over its length.

well, but then still they are not saving the large wire up to trunk and still having a decay, what will be opposed to the MSD advice maybe ...

anyway posting just opinions and learning