ERA 289FIA alternator replacement

[Dangerous Doug]

Bob, I take it that fuse#4 is the recommended placement fit the driving lights power draw line? DD

[patrickt]

I think Bob thinks you blew that fuse and that's wire you're showing a heavy discharge all the time....

[RICK LAKE]

Dangerous Doug. Doug first off what pulleys are you running on the motor?
Is the crank shaft pulley small? This is an underdriven setup. The Alt will not spin fast enought to charge the battery and handle the load on the electrical system. Should run a 65 -75 amp alt in the car to start with extra electrical draws on the system like lights, radio., ac system, etc. Get a cheap volt meter. Hook it up to the car, turn on what you normally run and check the voltage reading at idle. Any thing less than 12.5 volts means the battery is nto being recharged and is slowly draining the battery at idle. Run the motor up to 1,500 rpm and repeat the test. Alt should be running 13.7-14.2 volts with the same curcfuits on. If it is less your alt will not FULLY charge the battery. Cobras had basic charging systems. Some came with a 38 amp output Alt others got in the 60-70's in ampage output. Here's the other thing. If you run a charging system in the 70 amps or higher it will over time burnt out the insolators on the terminals for the amp meter. All the power goes through here. This is the reason to convert to a volt meter for the dash and hook the (2) white 10 gauge wires to each other and tape Hook 1 wire there for the volt meter, use the light from the volt meter and you just need a ground. My system runs a 95 amp setup. 5 fans, MSD ignition, ECU, fuel injector, heater blower motor, lights, wipers and 2 fuel pumps. I also ran under size pulleys and would kill the battery if the car idled for 10-15 minutes before. With 95 amp setup I have 40 amps at idle and 13.8 volts at idle and 78 amps with 14.2 volts at 2,000 rpms with all power ideas on and running. Alt is still charging the battery. Most cars today have from 100 amp to 220amps on highbreds. I think you will find that if you turn on your, head lights, wipers, electric fuel pump, and coolant fans running you will see a draw larger than the charging system can supply at idle. It doesn't matter where you power those lights from, they still drain the system with anywhere from 8-20 amps. Again tyoo much at idle for your charging system. Rick L. you have p-m.

[xb-60]

Doug, IMO, you need to go back to what you know works. So that means first up, disconnect the wiring and the relay for the new lights, then fix the turn signal problem and then make sure everything is then working the way it should be.
Only then should you wire in the lights and relay, remembering that if you take power for the relay directly from the battery, it won’t show up correctly on the ammeter. If you wire it this way, then just accept that your ammeter won’t read correctly ONLY when the big lights are on, but that’s OK. So consider changing to, or adding, a voltmeter.
If you take power from the ‘non-battery’ side of the ammeter, it will show correctly, but you will be putting an extra 16amps (if the lights are 100W each) through your ammeter wiring, and I wouldn’t do that.
Taking power for the relay direct from the battery is the most efficient way to do it.
Incidentally, I have run two 100W Super Oscars on a car with a Lucas generator (22 amp rated output). That worked OK (just) but I eventually replaced the gen. with a 35 amp alternator which was more than adequate. That car didn’t however have significant other electrical loads other than ignition, normal lights and radio.
Fix the turn signals first.
Cheers,
Glen

[patrickt]

Maybe he doesn't have any problems at all. Maybe he just bumped the voltage regulator fuse and it blew and he didn't notice it. Then, if that happened, he effectively has no charging at all. And maybe those new lights only draw 15 amps and his existing alternator is plenty good enough and he could move the source over to the hot side of the #1 fuse holder and everything will work perfectly and he won't have to do much of anything....