Alternator Charging

[KJoeZ61]

Ever since installing my Sniper, which is running great, my alternator is constantly heavily charging. I installed a new battery at the same time, which seems fine. Is the in-tank fuel pump using that much power? The battery is 800 amps and the car is a '71 Plymouth with a 360.

[Danny Cabral]

Ever since installing my Sniper, which is running great, my alternator is constantly heavily charging.

What do you mean by "constantly heavily charging"? The alternator is constantly charging the battery.

[KJoeZ61]

The needle on the gauge is really up on the positive side, all the time. Usually it's just a little above the middle.

[gregs69rs]

You can look up the specifics for your model fuel pump, but it probably added at least 10 amps of draw if you had a mechanical pump before. Are you still running a 1971 type alternator or have you upgraded to a more modern style over the years?

[Danny Cabral]

The needle on the gauge is really up on the positive side, all the time. Usually it's just a little above the middle.

If you mean overcharging, check the battery voltage with a multimeter and report back.

[Gaz64]

The needle on the gauge is really up on the positive side, all the time. Usually it's just a little above the middle.

You must have something wired incorrectly, since converting to EFI would draw more current than your carburetor fuel system. The charging system might work a fraction harder, but certainly not charge excessively. Gary

[djh61187]

Alternators in 1971 only put out around 50-60 amps on Mopars. I would at the very least have your alternator checked out and see what it's really putting out. Especially at idle. Probably 10-20 amps, which is not enough nowadays. And then when you are cruising at a higher RPM the alternator is working itself to death putting out everything it's got to recharge the battery.

[KJoeZ61]

And that appears to be what's happening. By hooking the fuel pump & Sniper directly to the battery, it's giving the old 60 amp alternator a workout. My main concern is that I'll blow the fuse link and be dead in the water. I need to figure out another way to get power. Bottom line is, I can't take power directly from the battery! That's not going to work.

[Danny Cabral]

Bottom line is, I can't take power directly from the battery!

Yes, you can. The main power harness should be connected directly onto the battery terminals.

That's not going to work.

No, it's your alternator that won't work.

[AndyF]

Sounds like your charging system (or your wiring harness) is screwed up. Not a big surprise, Mopar alternators from that era were terrible and the wiring harness is now almost 50 years old. I updated the wiring in my '65 Dodge Coronet and I use a modern Denso alternator. Zero problems for my Sniper system and fuel pump. Here's a link that will show you how to install a modern alternator on your old engine.
http://arengineering.com/products/de...-small-blocks/

[KJoeZ61]

Yes, you can. The main power harness should be connected directly onto the battery terminals.
The wiring harness for this car won't allow it! It will burn up the harness and by the way the harness is brand new from classic Industries.
No, it's your alternator that won't work.

The alternator is working as it should, it's just not intended for the load now being put on it.

[KJoeZ61]

Sounds like your charging system (or your wiring harness) is screwed up. Not a big surprise, Mopar alternators from that era were terrible and the wiring harness is now almost 50 years old. I updated the wiring in my '65 Dodge Coronet and I use a modern Denso alternator. Zero problems for my Sniper system and fuel pump. Here's a link that will show you how to install a modern alternator on your old engine.
http://arengineering.com/products/de...-small-blocks/

Actually the alternator and wiring harness are new. The entire car was rewired during its rebuild. I bought all OEM harnesses from Classic. Everything was fine before the Sniper electrical-wise. And the Sniper works great, the system just can't handle the load. Thanks for the above link. Does that give power directly from the alternator? I'm asking because if that ties into the factory harness I'll still have the fusible link issue.

[Danny Cabral]

The alternator is working as it should, it's just not intended for the load now being put on it.

Yes, that's why it needs to be replaced. EFI requires a stronger charging system. Andyf has you covered in post #10 with a better Denso alternator for Mopars.

[gregs69rs]

Yes, that's why it needs to be replaced. EFI requires a stronger charging system. Andyf has you covered in post #10 with a better Denso alternator for Mopars.

Please take this advice. You MUST attach the Sniper to the battery. No exceptions. So your thought process is not "where else can I get power from". Your thought process should be "How can I upgrade to a modern charging system to support my upgrade to a modern EFI system?"