High Amperage Reading

[hogie]

I recently upgraded to an 83 280zx alternator and added relays to my headlights and fuel pump. I also picked up the MSA Dual fan kit.

Yesterday I replaced some wire and redid the connections for the main power wires (white/red, solid white) at the fuse block and by the accessory relay.

I have read that once you start to power items with relays it bypasses the amp meter so that it will read higher than it really is. With the lights and fan on my meter is right in the middle of 0 and +45 and it doesn't follow engine rpm. Is this too high? I connected my multimeter to the radio power wire and it showed 14.36 volts so I don't think I am over charging.

I just want to make sure that I am not about to blow up the battery or toast the wiring (which so far is much cooler than it was)

[Shade133]

adding those relays change the circuit for those specific accessories but i dont see how they would effect the overall electrical system of the car. if you didnt add in a relay in the charging circuit i dont see how it would bypass the regulator, which would stop regulating the amp/volts to be put to the battery and over charge it.

and im not to sure about this as im super tires right now and not thinking straight but i doubt any relays would bypass the regulator for any accessories and damage them as well.

as for the amp gauge, my opinion is ive never really liked them, the volt gauge is more helpful to me. but the relays i guess could effect how the amp gauge is reading when those certain accessories are on and off.

[mlc240z]

Seem to remember reading somewhere here on the site that the conversion to relays drawing power directly from the battery will cause the meter to show charging more than stock alternator/wiring setup. Don't know why (Dave jump in here). Better performance, less strain on the switches and fuse box, but higher charging shown when running thru relays.

[Shade133]

Seem to remember reading somewhere here on the site that the conversion to relays drawing power directly from the battery will cause the meter to show charging more than stock alternator/wiring setup. Don't know why (Dave jump in here). Better performance, less strain on the switches and fuse box, but higher charging shown when running thru relays.

that seems to be because the alt simply has to provide more power to the battery to generally supply it with juice for the relays running straight from the battery?

if i understand it right it would be the same as if you installed a huge bass sound system and when the bass hits hard the amp gauge or volt gauge will go up because if the system is hooked directly to the battery it would pull juice from the battery and the alt will then provide more power to the battery to charge it.

am i correct?

[hogie]

Ok, sounds like i was fine after all. Unfortunealy, today the amperage was following my RPM. The odd part is the sensing wire was showing right around 14 volts at idle so I wouldnt think it would keep ramping up with revs.

I guess it must be time to drop it off at autozoo for some testing.

[Zs-ondabrain]

Think of the Ammeter as a Pointer. It sits between the battery and the fusebox. Think of the needle on the meter as a pointer that is showing you where the power is being drawn from.

If you step on the brakes or use the turn signals, the needle will switng back toward the (-) Your system is working just fine. I would suggest that you reinforce or enlarge your alternator wire. You're pumping another 20+ amps thru an old wire that was designed or installed for a 40 amp alternator.

I personally use an 8ga wire from the alternator to the starter for better power transfer.

Though doing this will basically Bypass your ammeter and it won't show much swing after that. Leave the stock alternator and starter power wires installed and connected, but add the 8ga to it.

In the picture below, you can make out the silver 8ga wire that goes from the starter to the frame rail, then it goes over to the alternators output bolt.

Dave

[hogie]

Sounds like a plan to me...I am already running 4 gauge straight to the starter from the battery so more wire isn't going to hurt anything.

After that all I have to do is figure out my intermittant miss and replace my five speed and then I will have a decent driver.

Thanks