Upgrade Batteries Or Alternator?

[066]

Hi, my name is Dylan. Thanks for looking at my thread.

Im trying to make sure I take the right next step with my electrical system.

First, the truck is a Powerstroke diesel. Stock dual (lead acid) batteries and a 130a alternator. Big 3 already done with 1/0 welding cable.

Im powering 2 CT Sounds 1500.1 (strapped at 2ohm ~1700 watts) and a JL 600/6 (4 and 2 ohm loads ~500 watts)

At full power, voltage is dropping like a hammer (<13). At my normal-high listening level, voltage is fine but my lights still dim.

Batteries are fairly new so I’d prefer to do the alt first.

Which one will give me the best result though?

 

[HardofWhoring]

View attachment 46355
This is the sheet on my alternator. I would guess if I wanted a different output than 14.8 I could have it. True, it may only make peak power under limited circumstances but the proof is in the pudding. Or rather it’s on the spec sheet.
This one was hand made in AZ.

Why is idle rpm 217 amps, and 217 amps is clearly not until 2250 rpm? They don't even test it below 1600 rpm?? I'll have to see if I can find mine, but my Mechman does about that, but shift the curve about 800 rpm lower.

 

[HardofWhoring]

Thanks for all the replies, everyone. I ended up with the 370a Mechman. Showtime ftw.

I just installed the alt and got a smoke show. Melted a wire when I turned the key. I don’t suppose anyone has an idea what the problem is?

That pigtail doesn't make sense to me. Is that the way it came? One should have been a low voltage power/switch wire, and there needs to be a ground wire. I'm really puzzled why the pigtail wire would go to the same bolt as your charging cable.

My mechman came with a pigtail. That wire that goes to the charging bolt, did you cut that and add the terminal ring to it? Was it about 5 feet longer, and you just cut it short?

Where is your alternator grounded? Did that just become your only ground? (I don't even see a grounding cable for your alternator).

 

[2023 LTZ]

3:1 so 1000 on my tach is 3000 alternator rpm.

 

[2023 LTZ]

Based on the burn pattern I’d say there’s something amiss in that plug that the pigtail connects to. If it’s not the alternator.

 

[066]

That pigtail doesn't make sense to me. Is that the way it came? One should have been a low voltage power/switch wire, and there needs to be a ground wire. I'm really puzzled why the pigtail wire would go to the same bolt as your charging cable.

My mechman came with a pigtail. That wire that goes to the charging bolt, did you cut that and add the terminal ring to it? Was it about 5 feet longer, and you just cut it short?

Where is your alternator grounded? Did that just become your only ground? (I don't even see a grounding cable for your alternator).

Not sure why I didn’t get notifications to this thread. Anyway, that harness is exactly how I received it and the directions said to hook that wire to alt charge post. I guess it’s a voltage sensing wire.

The problem with my install was on a 6.0 Powerstroke, the alternator to battery cable feeds the glow plug circuit so when I removed that cable, somehow my glow plugs (>200a) tried to charge through that 16ga wire

The alternator is working great now with the original alt cable reconnected.

Im seeing a steady 14.4v until I really crank the volume, I can still drop to 12s at idle. At higher RPM, no problems. Actually, at 2000RPM (engine) when I crank it, my voltage went UP to 15.3v

 

[066]

Also, the alt is grounded to battery and cab. You can see the cables at the rear left mounting bolt.