Hello,

I've a 96 LS400. I am having some voltage drop issue with my car. I have recently changed the alternator, and the battery is also 6months old only..
I replaced the alternator with a donor 2002 celsior which is LS430.. since it owns a high amp alternator, i thought just to buy that one so it wont fail easily...

I checked with the multimeter, Im getting 12.7volts without engine being started, which tells that the battery is fine.

As soon I turn on the engine, without accessories, I got 13.9volts to 14.1volts.

I got a constant 13.9volts with all the accessories being in use, e.g. wipers, hazard lights, windows motors, AC blower, Fm Radio, head lights, taillights..

I want to know that if its okay? since i dont own a manual, to check if its throughing out a proper voltage.

As I use accessories like using hazard lights windows motor for rolling windows up and down, the voltage drops, causing interior lights and side lights to go dim..
RPM also goes down slidely.. about 50-70rpms
Any help on this?

 

Anything over 13 volts and you're charging/maintaining the battery. So I wouldn't worry about it especially if it's only idle. If it dips below 13 volts then I would be worried.

 

So, was it a direct swap with the 02 alternator? Notice a change in drain at all? Was anything else needed other than the alternator? Someone mentioned a third bolt of some kind.

 

It's been a year and a half since you have reported and questioned. It may be a bit late to inform you the reason why you get more generating power at the lower engine RPM. I tell you a secret.

Other than the improved design, there is a very important issue which is the difference of the pulley. The one you picked up from a donor 2002 Celsior has about 10% smaller pulley in diameter. This simply means that you get 10% more power when the saturation is not yet occurred. See the photo and you can see the difference. The left side is for a UCF20(p/n 27060-50230) and the right UCF30(p/n 27060-50280). The actual measurement: 66mm vs 61mm. Other than the pulley's diameter, the generator itself is a bit smaller due to the improved design.

 

I just tried to add the figures and letters to the original photo above but it din't work well. So let me post a photo with them here.
I wish a moderator would help me to switch the photo.

 

Posts looks fine Yamae.