Problem after adding alternator

[midgetll_busa]

Hi there,
I got problem for charging system after installing car alternator on hayabusa engine.

My setup as following:
- denso 75 amps
- 2" pulleys on both side, crank and alternator to get 1:1 rotation ratio
- 90 amp battery
- stock stator to the battery
- alternator wire to the battery
- the car has allot of electrical stuff

So i made the pulleys ratio to avoid any problem at red line which will be about 12k , the problem is battery drained while idling today for about 2 hours to check for any abnormal issue since its 2nd time starting this engine after changing its pistons. Offcourse i know the reason which is the alternator didn't charge the battery, i need some hints to keep the battery charging while idling without increase the rpm from the accelerator cable.

Any input will be highly appreciated

Thanks

[plkracer]

Single wire alternator? They drain up to 4 amps until they come up past 1200-1500 rpm. They start to draw current to feed the field coil as they rotate. You might change your ratio slightly, or up your idle.

I have a powermaster single wire, and they touted some of the lowest rpm to come alive. Im not sure when the denso alternator pick up, but you should be able to tell with a voltmeter and playing with the idle speed.

[midgetll_busa]

Thanks allot dear, i checked the out put voltage from the alternator today, i raised the rpm up to 2500 till i got 13volts, i did the calculation for pulley ratio and finalized with 1.3:1
Existing pulleys are 6.3 cm both so i will change the crank driven pulley to 8.2 cm to keep the alternator in safe region at top end rpms, so thank you very much for your input and hints