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Big amp alternators, plug and play?

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Big amp alternators, plug and play?

Post by -Nemesis- »

My 1UZ alternator clapped out. Looking them up on US sites you can get remanufactured units in varied amperage upgrades.

A stock Lexus pumps out 100 amps, but if i'm getting a new one anyway I'm thinking of getting more grunt. You can get anything from 140, 180 (I was thinking of this one) right up to 300 amp if you have the cash.

So I was wondering, is it as simple as bolting in a 180amp alternator and off I go? Or do you have to upgrade/add anything to compensate for the extra amps?
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Post by PBBIZ2 »

I think you only have to ensure your cables to the battery are upgraded in size to handle a 180 amp surge. Thats all I did when I went from 90a to 200a in my GQ. I had two cables made up using 600a welding lead cables - I was running to two isolators though. I am assuming the control wiring is the same - sounds like a direct swap. Maybe the control voltage wire needs to be bigger also - others may know - my set-up is a bit different to standard and was a direct kit fitment.
Hope this helps
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Post by -Nemesis- »

Yeah thanks to the Lexus masses in the US there's heaps of mobs selling remanufactured OEM alternators claimed to have these amps. I'm not expecting much as I can't afford the ones by the mob with the 300 amp option. Even their 200 amp version is $500US, where as the 180 amp one I found is $250 delivered with 12months warranty (which they honour OS)
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Post by bugshifter »

-Nemesis- wrote:Yeah thanks to the Lexus masses in the US there's heaps of mobs selling remanufactured OEM alternators claimed to have these amps. I'm not expecting much as I can't afford the ones by the mob with the 300 amp option. Even their 200 amp version is $500US, where as the 180 amp one I found is $250 delivered with 12months warranty (which they honour OS)

Do you have a link to the site please
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Post by -Nemesis- »

I just searched US ebay for LS400 alternator, there's a few pages of options!
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Post by tj81 »

PBBIZ2 wrote:I think you only have to ensure your cables to the battery are upgraded in size to handle a 180 amp surge. Thats all I did when I went from 90a to 200a in my GQ. I had two cables made up using 600a welding lead cables - I was running to two isolators though. I am assuming the control wiring is the same - sounds like a direct swap. Maybe the control voltage wire needs to be bigger also - others may know - my set-up is a bit different to standard and was a direct kit fitment.
Hope this helps
Um direct kit fit, 200a alternator for a GQ, please tell. :)
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Post by PBBIZ2 »

The wiring kit was a direct fit, the alternator wasn't. I bought a Uni-power MAX AMP 200, 200amp alternator from Uni Power in WA. It is 'cross marketed' as both a H/D welder alternator and as a vehicle replacement alternator. It is rated at 100% duty cycle 200A. Cost is around the $1700 mark new. I matched it to a Sterling Power Advanced Alternator regulator(think this cost in the order of $1000 with the isolators). You have to modify the Unipower with some additional cables to convert the internal regulation to external - easy job - then the controller changes the charge profile depending on the state of discharge of the battery being sensed.

I ran this set up for about 8 yrs. No problems, but when I did have a problem, suspect the alternator got too hot, and in turn it damaged the controller, lost both items - burnt out the alternator and also the main chip on the controller. So, a fairly expensive set-up, worked well then cost a fortune when it crapped out.

The Max Amp 200 has a crappy voltage curve as a stand alone unit. It develops 200a at 10000rpm, and at idle you get around 13V, 14.3 at 2500rpm. With the right pulley combination you can easily get the speed right under normal driving conditions, but if you like to 'valve bounce' all day, the alternator will see some excessive speeds.

Without the controller, which boosts the output voltage and changes the charge curve, the alternator is really not that satisfactory for normal applications. I have repaired the alternator and replaced the controller with a newer version, but not re-installed the big alternator. I went for a 90a Bosch standard unit and this is operating well. The bigger alternator was put in for winching, but have a hydraulic winch now, only fridge and camping lights off aux battery, so no need for the bigger unit. It also gave me more room at the rear of the alternator and allowed better cooling. I also installed a seperate 'bilge blower' to keep the alternator cooler when sitting stationary.

Size wise, the max amp is about 40mm longer than a standard bosch 90 a alternator, but same dia. It doesn't have a vacuum pump attached either.

In hindsight, I would not buy the Maxamp. It was reliable, but did need the additional controller to make it a practical alternative. It is smaller than comparable 200A units, so that is attractive. It will happily perform as a suitable charge device that can deliver high current all day if required, but you just need to be aware of the operating limits.
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