High output alternator (250+ Amps)

[RWD4ever]

I've spoken with the staff from JS Alternators and they have the following available:

• 250amps - $359US
• 320amps - $459US
• 370amps - $559US

I've also heard the brand Singer being mentioned so will look into them too.

Do those have bigger pulleys? When I worked in geophysics, we had 300 Amp alternator on the equipment truck, and it needed a big pulley
(otherwise the drive belt would slip at full load) but then with the engine idling, the dash discharge light came on...

 

[Banjo79]

So how does one embarking on such a substantial audio upgrade calculate the alternator size required? Golden rule, stab in the dark, educated guess or all three?

 

[KLoNe]

I use the dart throw method haha.

Nah, quick maths is the key.

 

[Banjo79]

So a Commy is making a couple of thousand watts. Very roughly half chewed by the car. So a 1000wrms sub with a 4 x 150wrms amp or thereabouts would be safe at normal to loud volume but totally battery draining at full tilt? "God my stereo sounds bitchin, but why the hell is my steering so damn heavy said the VF driver to the VE passenger!"

 

[Banjo79]

Oversight. I failed to take into account at what RPM those couple o thousand watts are being made. So a 140amp alt is rated at what RPM to make those amps?