ok guys...my car is a 70 charger pro touring all aluminum hemi equipped with many items that will be connected to battery....like holley hp efi,msd 6a,spaghetti menders 3 terminal relay that will control a1000 fuel pump and 2 spal fans....i have 160 amp alt and optima yellow top..i will have volt gauge on my tablet display..will i be able to run nacho's parallel or will this be to much draw for amp gauge and bypass it all together ...i would love to have both...ok guys...lets hear it..ty

Short answer: With all your stuff I would relay em all directly to the alt not to the battery. This lets your high powered alt power all the extra high powered draws & keeps the ammeter honest & keeps the rest of the electrical system out of the picture except for the minor current needed to trigger the relays. I would definitely still do Nacho's parallel bypass on the 2 main in/out wires at/thru the bulkhead. EDIT The Madd bypass is excellent IF you are OK with giving up your ammeter function. I'm old school & I like it (plus an added voltmeter to switched 12V)

I had a long, long talk with Mark from Mad Elec about six months ago and have since then really studied this issue. The best possible spot to connect is the positive stud on the starter relay. The idea is to establish a power point that is between both power sources. The attached drawing Mark asked me to draw explains it a little better than my text here. Power moves in the direction of the draw. When the alternator is running power goes TO the battery, when the power is off, it comes from the battery, etc. Basic stuff I know.

In short, the primary power distribution point right now is the welded wires under the dash. The idea is to move that point inside the engine compartment so the primary power does not have to cross the bulkhead connectors. Unless you establish a new "central" point, the best default one is the positive stud on the starter relay.

This new power point should then be the primary tap for things like headlight relays, fans, etc. If you look at the arrows in the drawing you will see that when the alternator is running, ALL power to this point will be pulled from the new central point. However, this only reduces risk if you run a jumper between the ALT and the positive stud. One or the other won't help you much.

To really make a difference, you need to:

1) Run a Bypass wire
2) Move the "central" power point from the weld to something like the positive stud on the starter relay.
3) Begin placing relays in the engine compartment for lights, fans, etc.

I have done this and it looks invisible and made a huge difference to my power. I can send plenty of photos but they are all from an E-Body.

-Steve

With your setup I'd ditch the Ammeter in a nano second and just run a voltmeter.
The Ammeter was a good thing in the 30's 40's 50's 60's and 70's. But the generator was also good until the alternator came along.
Trying to run an ammeter on a system like your describing is opening the door for trouble with no real benefit.
HMMM how many vehicles made in the last 20 years have ammeters?????
There is a reason

my relay from spaghetti menders....will having this hooked up to battery give me activity on amp gauge....

The only way I would keep an amp gauge is if you run a shunt type amp gauge. Mopar started using them on the bigger cars around 1973 I believe. The shunt carries 90 % of the load so that way not much current goes thru the amp gauge. But the amp gauge is not as accurate since it dont move much with most of the current bypassing it and you still have to run the wires up to the amp gauge in the dash and the alt output has to go on the load side of the gauge for it to work right. Myself I would just eliminate the amp gauge and go with the voltmeter as then you can run the alt output right to the battery or whereever you want. Ron

Do I need really to writte up everything again, this time on a new thread about that ? LOL

being you have read my replies is hepfull to make this.

how I would do?

if you have a powerfull alt able to feed everything iddling, you won't have any problem to keep the ammeter working, even if is still the stock 40 amps alt.

A low charge alt won't ever suck enough power to get a full load charge reading at regular RPMs. And if does, will be for a minute or so.

but if your source everything from batt side keeping the ammeter, you'll have mostly sure a "ghosty" charge reading wich is not really a charge job, but really a sourcing job for the newer accesories. Is then, an unnecesary stress and load for the charge system, meaning this, wiring, terminals, ammeter.

The ONLY moment you should worried keeping the ammeter and sourcing everything from alt side is if alternator says byebye, or if you turn off the engine and keeps sourcing the devices/accesories somehow... i.e. fans relay being sourced from a constant power source instead keyed, but if this is the case, these will turn off by itself once engine gets cold, which should be more less quick.

the question is... do you want to keep the ammeter or not ?

myself, I wouldn't get worried as in fact really do. I have 6 relays sourcing my car with stock in everything but just halogen headlights, my 40 amps stock ammeter working, and stock 80's mopar replacement alt. All relays sourced from alt side straight from ammeter stud ( all relays inside the cab to be hidden making a cleaner engine bay view without splices anywhere ). Well of course, these 6 relays will be never working together, just 3 max, but normally 2, if I turn A/C in low speed and headlights. If turn on A/C on mid or high, 3 relays, since low speed is allways activated no matter the speed when you trun on the A/C( factory design on 70s Mopars ), but still just 2 getting the load.

next question... have you calculated how many amperes you'll need to source everything, and how much amps gives the alt iddling ?

THIS is the main to be answered... after this, you can decide which way to go.

I've seen plenty of charred Mopar instrument panels or firewall connectors over the years. The original design might have been okay in the 60's, but it doesn't hold up to modern electrical demands. The firewall connector is probably the weak link rather than the ammeter, but the ammeter will melt if you send enough current to it.

The Mopar engineers started to figure it out in the 70's. They ran heavy gauge thru the firewall on some vehicles and they started to shunt around the ammeter.

Actually I'd say mostly of ammeter and bulkhead fails are related to 3 BIG stupidities!!!

1-hook every existant newer accesory to batt
2-upgrade the batt with a more powerfull one, keeping SAME FACTORY underrated alternator
3-the factory guilt misconception ammeter is an alternator gauge where really is a batt gauge

and these three are proportionally related electricity ignorance

every body is worried about some electricity burn around, but our car works with EXTREMELLY DANGEROUS GASOLINE ACTIVATED WITH A SPARK INTO A CILINDER!!! and quite often with backfires trhough carb due whichever reason.

If we use gasoline to make work our cars and everything takes care correctly about it, why not we do the same about electricity ? without any hack up job needed for that!!! just knwoledgement.

mantenience and knolwedgement will save you.

would be great ppl begins to understand about electricity, the same than takes cares about understand a camshaft!

My brother's 77 Dodge truck had a melted Amp meter that caught fire and damaged his dash. A voltmeter also will show you immediately when your alt. can't keep up.