Charging system close to max?

[Canadian1968]

I just went to a 2 electric fan setup . I belive the fans are only rated for 7.5 amps each.

I do have a newer alternator bought it 5 years ago now... I forget the specs . The car is using mopar electronic ignition, with 0 problems . I am running a piggy back wire upgrade from the alternator to ammeter and back to battery eleminating the bulkhead .

Testing out the new fan setup , threw my test leads on the battery it's reads steady 12.7 V . The ammeter is reading is just below the first mark (20). Not so worried about the 20 amps .... more so the 12.7 V . I guess it's not discharging but it's right on the line.

I read in a couple other post about running a wire from the alternator directly to the fans ?

 

[Canadian1968]

So I just went out and started the car . Fans were not running . Battery was charing 13.7V . The fans kicked on and voltage slowly started to drop. Seemed to be holding a bit at 13.04 V . The only other extra electrical is AEM wideband. I guess I should test it with my headlights on to......

 

[kiwigtx]

Are you using relays to switch the fans?

 

[Photon440]

Also, how much are the fans on? As you noted, they aren't on before the engine warmed up. Chances are they're also not running at highway speeds, and if they are the air rushing past them will reduce the load on the fan motors. And both fans need not turn on at the same time; if only one is needed when lightly loaded, only one should be on.

 

[Canadian1968]

Yes, I have both fans wired to a single relay. 12v turn on source is radio fuse ( don't actually have a radio) . Thermal switch for grouding. Power directly to battery with inline 30A fuse . And finally power out to fans.

When driving the fans will turn off . At least in this weather . Today was probably 75 out not a true test . But I will figure that out later .

Also note: The motor seems to run with a noticeable "quiver" when the fans kick in. I don't think the ignition system likes the lower voltage

 

[MoparLeo]

Why a 30amp fuse when both fans are only rated at 7.5 amp each ? The purpose of the fuse it to protect the accessories. With a 30 amp fuse you are really using the fans as the fuse to protect the circuit if they melt before you get to a 30 amp load.

 

[72RoadrunnerGTX]

All loads need to be on the alternator side of the ammeter when an ammeter is in use, nothing should be connected at the battery. Automotive fuses are to protect the wiring not the load. Twice the expected normal current draw is the accepted formula for fuse sizing.

 

[Canadian1968]

All loads need to be on the alternator side of the ammeter when an ammeter is in use, nothing should be connected at the battery. Automotive fuses are to protect the wiring not the load. Twice the expected normal current draw is the accepted formula for fuse sizing.

So then I should run my wire to Alt stud instead of going to the battery.

I just ran the car again . Ita not a sharp drop to 12.7 , takes a few mins . But that is where it settles .

 

[oldbee]

You might also have a failed diode in the alternator. 12.7V at idle or revved up? At idle sounds low.

 

[72RoadrunnerGTX]

So then I should run my wire to Alt stud instead of going to the battery.

I just ran the car again . Ita not a sharp drop to 12.7 , takes a few mins . But that is where it settles .

I assume these observations are while at idle rpm. Sounds the like the alienator output (what ever it is) is not keeping up with your new total electrical loads at idle. May need an alternator upgrade to one with more output capacity at idle speeds.

 

[Canadian1968]

Yes everything is at idle . Approx 800 rpm
if I rev it up a bit was able to get 13.00 which doeant really mean to much because if I can't get what I need at idle it doesn't matter .

 

[72RoadrunnerGTX]

Needs to be around 14.2v at 1500-2000rpm, may have other issues to fix first, regulator or other alternator internal problem preventing full alternator output performance.

 

[bearman]

Yes everything is at idle . Approx 800 rpm
if I rev it up a bit was able to get 13.00 which doeant really mean to much because if I can't get what I need at idle it doesn't matter .[/QUOTE
you might want to change up pulley speeds instead of changing alt etc. just a thought

 

[Don Frelier]

It sounds about right to me.
The battery will charge up pretty quickly when driving and the fans turn off.
I wouldn't worry about 12.7 at idle for a couple minutes.

 

[oldbee]

It sounds about right to me.
The battery will charge up pretty quickly when driving and the fans turn off.
I wouldn't worry about 12.7 at idle for a couple minutes.

You're correct, but only short term. Should be closer to 14v anytime above idle. There's also the load from blower fan,lights,etc.

 

[Canadian1968]

So played some more today.

This is what I found.

There is .4v drop from the alternator to the battery . Not to concerned about that.

The longer the car runs the more the voltage drops . Directly from the alternator stud. Then .4v voltage drop remains constant no matter output of the alternator.

Fan running , headlights on i was getting 12.78 at the battery or 13.18 at the alternator @ idle . Lights are not dimming .

I'm looking at the alternator as the.problem .

 

[Don Frelier]

I don't think there is a problem.

 

[bm02tj]

You did rewire to the alt side away from battery

 

[Canadian1968]

You did rewire to the alt side away from battery

No have not done that yet. Question I had. If I hook right to then Bat. stud on thr alternator the load is not being picked up by the regulator is it? How will the alternator know to about the extra load

 

[bm02tj]

The reg takes the voltage from the ing switch
And the only time you will see the amp gauge show + or - is when not enough or it is recharging battery
good luck