Battery Is Not Charging

[GC427]

The battery is not getting charged. With the engine running or not running the battery voltage reading at the battery is 12.5 volts. If it were being charged, I believe it should read approximately 14.5 volts. The voltage at the alternator (Powermaster 18050505, 17294RR, WC) indicates it’s producing approximately 17.5 to 18 volts. While the engine is running the ammeter (Lucas, AM1640 070, Ammeter 50/50, 45 Amps) reads slightly negative. When I turn on the radiator cooling fans, lights, or heater fan, the ammeter accordingly goes further negative as the load is increased. Thinking the ammeter might be the problem, since it does not show a positive reading indicating the battery is being charged, I took the ammeter out of the circuit and placed a jumper in its place. The battery still does not show a 14.5 volt reading. The voltage regulator is a Motorcraft Electronic Regulator FOPU-10316-AA NEG, Short Circuit Protected. The battery (Optima) was checked out and found to be working properly. Is there a fuse somewhere between the voltage regulator and the battery, or ammeter and the battery I’m not aware of? Is there a way to check the voltage regulator to find out if it’s working properly?

[lovehamr]

Yes there is a large 30 amp fuse in-line in the harnes under the passenger side fender. It's in the large red wire that runs to the alt. Guess how I know that? LOL

[DSM351]

On an SPF the main fuse is in the drop down electical tray and may look like an old wire, its 80 amps if I remember correctly. Depending on your serial number the main fuse is just 2 studs glued to the electrical tray with a metal stip between them which is the fuse. The glue on these can come lose and the stud can contact frame grounded parts ;-(

more info:
Main Fuse in Early Mark III

Good luck!

[Wbulk]

You could just check the hot wire to the alternator with a voltmeter without the engine running. You should get battery voltage. If you have power and it is not charging take it out and take it to an auto parts store. Most will test them for free.

[Blas]

Contact me tonight...See below for my email

[jhv48]

When that happened to my SPF, I found that the wire that connects to the bottom of the alternator had broken at the connector. All parts were working fine, but charge was not getting to the battery.
Check yours out just to make sure.

[Murky781]

I had this problem after assembling my ERA. hunted forever and finally took it in to the mechanic. Did I feel stupid when he told me the belt wasn't tight enough. I thought i had really pushed the alt. back enough, but..... look for the simple first. IMHO

[mattpatt]

I've just done a bit of work on my new (SP3033) SPF Cobra's electrical system trying to trace out what might/might not be a problem. What I've learned is: The alternator output voltage should show up at the battery - so you definitely have a disconnect between the alternator and the battery. The Optima (red top) battery can only handle 15.0 volts max charging voltage - make sure, when you get the charging circuit fixed, the voltage at the alternator is 15.0 volts or less (not the 17.5-18.0 you mentioned) - maybe under load it will drop into range.

As for fuses, I found that my car is wired different than Blas' wiring diagram (a real good investment, by the way). On my drop down fuse panel the unfused post ONLY has one wire which is connected to the amp meter. The alternator is wired to the fused post (6 wires to this post - post has an 80 amp fuse between it and the unfused post)) which, I think, is a factory miswire (do you know, Blas?). If yours is wired like mine and that 80 amp fuse is blown you will have an open charging circuit. Note that if your ignition is powered from the unfused post circuit you'd probably have trouble on a long ride because you'd be using the battery to power your ignition.

Blas - I added a 60 amp fuse between the amp meter and the battery supply - I assume my alternator should be re-wired to the unfused post to protect the alt/battery circuit from a short on the fused side. The 60 amp fuse just adds protection between the alt and the battery. What do you think? By the way - I'll post where I am with the Optima "problem" under the thread I originally started after I get the battery tested later this week.

Gil - good luck. Let us know what you learn.

Matt

[Blas]

Send me a photo if possible

[GC427]

I checked the voltage at the alternator positive post to ground with the engine not running. It's 12.7 volts, the same as the battery across the positive and negative posts. My Cobra is SP02047. Like SP03033, it has the 80 amp fuse between the two posts as you described. I'm going to check that fuse now to see if it's blown. I have Blas' wiring diagram, which is very helpful. Yes, on a long ride is where I had the problem. The car ran well until the battery finally did not have enough charge to keep the fuel pump going. I had the battery charged at a gas station and easily made it home. I drove about 550 miles before the battery output could not support the fuel pump. Going to check the fuse...

[GC427]

I checked the 80 amp fuse by taking it completely out of the circuit. The ohm meter reads 0.00 ohms. Therefore, not a blown fuse. Sorry for the poor photo, as you can see there are 5 red wires on the left side of the fuse and 2 red wires on the right side of the fuse. SP03033, you mentioned has 6 wires on one side and 1 on the other.

How would one verify the voltage regulator is working correctly?

If the alternator is producing 17.5 to 18 volts, was the wrong alternator installed, or is it now malfunctioning?

[Blas]

17.5-18v is pretty high and would toast a battery if it got to it. You would smell the battery boiling in the trunk when you opened it (off-gasing)
Easist thing to do is call me. I'll send my daytime/ evening phone numbers in a PM. Too early to type - no coffee yet.

Ok, I had coffee:
Short version: If all else is in order, (grounds, connectors, etc) replace the diode on the fuse panel - (radioshack)

Quote from my Wiring Diagram Note:
Diode function: (type IN5408)
The Diode allows power to the blue w/white tracer wire going to the regulator.
Symptoms:
The car just quits charging.
Testing: "A jumper wire can be used to test operation but disconnect the wire before shutting the car off or you could get a backfeed through the ignition switch and the car won't shut off."

As to the comment about rewiring your car.
This wiring has been done 2 ways.
The early design: The power came from the alternator via the voltage regulator via a 4mm red wire which connected to the hot side of the starter solenoid on firewall. This sent charging power on to the battery by way of the BIG red cable under the car connecting to the battery. Another 4mm red wire came from the hot side of the starter solenoid on firewall and went to the AMP meters input , all of which passed thru the AMP meter (so the meter can sense the cars amperage use) and then into the cars wiring harness - feeding the cars power users. Note: there is no fuse in this early design. This applies to cars up to chassis #1039.

Now a redesign of the wiring harness occurred (cars #1040+) and the addition of a drop down fuse panel (among other things) Now included on the new drop down panel is a post where the above mentioned alternator/voltage regulator power supply 4mm red wire connection was relocated to. (from the starter solenoid on firewall) From this new post, one 4mm red wire went back out to the starter solenoid on firewall, which sent charging power on to the battery like the earlier design, and a second 4mm red wire when on to feed the car thru the AMP meter as it did in the earlier design. But note the addition of a master 80 AMP fuse in the new design.

The difference being where the wire from the alternator/voltage regulator is connected. And this is what I believe to be the difference in your wiring and the wiring diagram is related to. I never saw the logic in coming into the car and then back out to the engine compartment with the charging wire. But both ways work.


Another person commented:
"...The ohm meter reads 0.00 ohms." Odd...that's an open circuit. No power would be going to feed cars harness thru that fuse???

Another person commented:
Great: 12.7v is a fully charged battery with engine NOT running. should have the same voltage at hot side of starter solenoid on firewall too. Now with the car running both of these voltages should go up to 13.8v-14v max at 2500rpm. Much less and the car won't charge properly - More and you'll toast the battery.

[mattpatt]

Thx, Blas, for the good info.

Still a bit confused though (sorry, haven't had MY coffee yet).

It sounds like you're saying that my wiring (alt to fused post on the left side of the 80 amp fuse) is wrong (not per your diagram). This means the fused loads, including the switched loads when the key is ON, aren't protected from alternator power in case of a short (alternator can supply 105 amps). Seems I should move the alternator wire to the amp meter/battery side of the fuse (i.e., the right side). Do you agree or is it my head that's mis-wired?

thx

Matt

[Blas]

Does your setup look like the photo posted below? Or if I understood you, you have 6 wires on the left and one on the right side of the fuse? Is the one wire on the right coming from the AMP meter or the charging system? All they factory looking end connectors on the wiring? Photo of fuse panel and starter solenoid on FW would helpful? Perhaps find where your charging wire from the alternator/voltage regulator is connected? Could be on starter solenoid on firewall, or if that was removed, on the starter itself. It should not be connected to the left post of the fuse, bypassing the fuse.

In short: the charging wire could be connected before or after the AMP meter, which allows for the single wire on the right side of your fuse, (you'll need to chase it) But it should NOT be connected on the left side of the fuse. If it is, the amp meter would see no current draw; The cars electrical system would be unfused;

[GC427]

Blas,

I'll verify if the diode is working by trying the jumper wire mentioned. Do you think I should replace the alternator now since the voltage output is 17.5 to 18 volts, or wait until the problem is resolved by getting a charge voltage back to the battery (sealed red-top Optima)? Gil

[GC427]

Blas,

Brady at Powermaster Tech. Support said the alternator's internal voltage regulator is not working correctly if the voltage is 17.5 to 18 volts. It should be 14.5 volts per Brady. He said to send the alternator in for repair. If I can get a new one quicker, will do so... good whether is here now.

As discussed, I'll remove the voltage regulator and rewire.

Gil

[Blas]

Great....
For everyone else info...It appears Gil has a 1 wire alternator (w/internal voltage regulator) which was installed by the previous owner/installer, using the standard factory wiring harness AND with the factory voltage regulator still in service. So more than likely the alternator/internal regulator is now toasted...i.e. the 17v-18v output.

A tough one to type thru...but the phone call helped to get to the root of the problems I think.

P.S. Don't cut the wiring harness, just tape it so nothing shorts and tuck it up up in the fenderwell...

[mattpatt]

Hi, Blas

On my car (SP3033) there are 6 wires on the left side of the 80 amp fuse and 1 wire on the right side. The wire on the right side goes to the amp meter - the other side of the amp meter goes to the battery terminal on the starter. The alternator (1 wire) output is connected to the left side of the 80 amp fuse. All the wiring at the 80 amp terminals are the way I recieved the car from Hillbank (new car from Hi Tech).

Seems like the alternator wire on the left side of the 80 amp fuse should be on the right side so the 80 amp fuse protects all the other circuits from the battery/alternator circuit. Is that right?

thx

Matt

[Blas]

The latest routing (that I know of) is as follows:
Power from the 1 wire alternator gos directly to the AMP meter - then thru the AMP meter - and over to the right side of the fuse...then a wire goes from the same right side of the fuse back into the engine compartment and connects to the hot side of the starter solenoid on the firewall. If you have removed your firewall solenoid, connect to the starter hot side.. This wire routing is the power source "TO" all the cars electrical users and is used to charge the battery. Power can be drawn from the alternator and/or the battery as necessary.
Back to the fuse:
Power can now pass thru the fuses to the left post which is the source for all the power users on the car, switched or unstitched. If something you connect does not draw power from this wiring system, the AMP meter will not see it as a power user and won't react to its load.

Yours really seems to have a screwy routing...Sounds like you have 2 feeds from the alternator/battery. One to the AMP meter and one to the left side of the fuse. Was your car built on a Monday after a 3 day weekend? So yes, If you understand what I wrote, make the necessary modifications if not call.

NOTE: There is an alternate routing where power from the alternator goes to the hot side of the starter solenoid on the firewall first and then a jumper goes to the AMP meter; feeding the cars power users...but note that any users connected to the starter solenoid post (like the MSD box, DRIVING LIGHTS, ETC) will not be sensed by the AMP meter.

I waited for a call from you last night but it stormed here like all hell last night..phones may have been down.

[mattpatt]

Blas,

It looks like they changed the routing in my car. The wire from the 1-wire alternator went to the left side of the 80 amp fuse (the "fused" post where 5 other wires are attached - they all are routed per your diagram). I've moved this wire to the right side ("unfused" post). The original wire on the unfused post goes to the "+" side of the amp meter (reversed from your diagram). The "-" side of the amp meter goes to the Battery terminal on the starter motor (I removed the fire-wall solenoid). I think this wiring works just as your diagram intends it to work (now that I moved the alternator wire to the un-fused post - I think the factory mis-wired it). Also, since I have my MSD unit powered from the starter motor battery terminal the amp meter reads not only the charging current but also the MSD current - no biggie - just an observation.

Hopefully, this will be of use to others with newer cars. Seems to me that the mis-wire could have lead to extensive damage to the wiring harness in the event of a short.

BTW - I expect to be updating the Optima Battery Charging Current thread this weekend.

Thx for all your help!

Matt