Battery discharging

[afterglow]

I have a 69 Mach 1 w/ 351W/C6 and PS & A/C. Alternator is rated at 90 amperes. The battery has been draining quickly lately and it died on me in traffic the other day.

I brought it to an electrical place today and they said that the alt is charging the battery fine (13+ volts) without any accessories. It drops to ~11 volts at idle though with the lights and A/C on. Goes up to ~13 volts when I step on the accelerator a bit. Their diagnosis is that the kickup doesn't kick the RPM's high enough when the accessories switch on.

My mechanic says that there must be another solution since the RPM's are pretty high already (can't tell since my tach is wonky). He'll take a look at the car next week but feels that a new alternator might do the trick.

Whaddya think???

 

[cusp]

I have a 69 Mach 1 w/ 351W/C6 and PS & A/C. Alternator is rated at 90 amperes. The battery has been draining quickly lately and it died on me in traffic the other day.

I brought it to an electrical place today and they said that the alt is charging the battery fine (13+ volts) without any accessories. It drops to ~11 volts at idle though with the lights and A/C on. Goes up to ~13 volts when I step on the accelerator a bit. Their diagnosis is that the kickup doesn't kick the RPM's high enough when the accessories switch on.

My mechanic says that there must be another solution since the RPM's are pretty high already (can't tell since my tach is wonky). He'll take a look at the car next week but feels that a new alternator might do the trick.

Whaddya think???

Stock pulley sizes?
Alts regulate their output by adjusting the field current. Is there enough field current? But they do need a minimum RPM to do their thing also. Smaller pulley on the alt perhaps? Larger pulley on the balancer?

 

[afterglow]

Stock pulley sizes so going with a smaller alternator pulley might work. Trouble is finding the damn thing (I'm based in the Philippines).

I've spoken to a few mechanic friends of mine and we're all doubting the RPM angle. The alternator should charge even as low as ~700 RPM and I'm certainly above that.

I'm thinking of biting the bullet and just buying a new alternator. Peace of mind and all that.

What should I go for though?? Powermaster?? Ford 3G? One-wire?? And where should I get it?? Summit/Jegs? Ebay? Or a stock one?? Sorry....no access to pick-and-pulls from here.......