Toyota FJ Cruiser Forum banner

New Alternator Recommendations?

23231 Views 18 Replies 11 Participants Last post by  norm356
Hi guys,

My battery light turned on today. Luckily the symptoms stop there but I'm planning for the worst as I do my research. My voltmeter looks fine and normal at this point and nothing is out of the ordinary so I'm hoping I don't have to replace the alternator although I'm about due (124k miles). I'm going to get my battery tested first and all that jazz that comes along with it.

If in fact I do have to replace my alternator is there any recommendation that you guys can provide? I don't do any offroading so I don't really need any upgrade. I've just seen some go for $150, others in the $350, and some up in the $450 range. I'd like to save some money but I don't want to buy the $150 one then have the same problem 6 months from now. Any opinions or suggestions are welcome.

1 - 4 of 19 Posts
Have you or anyone else used this alternator? That's an awesome price for a 200 amp alternator. That same seller also has a 250 amp for only $20 more! I think I'll send them a message and see if they can provide more specs like an amps vs. engine speed chart.
asked them at what RPM do you get 200 amps ...100% feedback I'm sure its a good one
I just sent them a message and post the results when I get them. I'm more interested in the 250 amp version for just $20 more...seems like a steal to me.

This was the vendor's response:
Our bench shows 125 amps at idle and 250 amps at 1200 rpm.
Just remember that when fitting a higher output alternator, and if you have actually added significant additional power consuming items to use that added power output, to also upgauge the ground wire from the battery to the body, and the power wire from the alternator to the battery, and to make sure those high current items which you've added which are higher than what your vehicle's system was designed with, have their own, dedicated power wires, from the battery.

This way you don't let the smoke out of any of your wires.

On the other hand, if you have not added anything of significant additional power draw, then fitting a higher output alternator won't really do anything for you (they only put out what is used). There's no down side, as long as it physically fits.

Good reminder about doing the "big 3" upgrade, definitely on my list when I do the alternator. I don't have anything that draws a lot all at once, but I've added a lot of additional smaller items. Main thing is the ARB fridge. Higher output alternator will more quickly charge the battery out on the trails so that the fridge continues to run at night. Also since I have a deep cycle high capacity battery once depleted you run the risk of never getting it fully recharged since it can take so long to charge off the stock alternator.
Just wanted to add my 2 cents on the topic of a "better" alternator. I am a firm believer of certain things that you should not do to your truck. One of which is get a higher output alternator. These vehicles are tested extensively and in some cases corresponding components are spec'd to handle certain tolerances.
For example you can't just throw a supercharger in without upgrading certain components like fuel injectors, likewise with the alternator... who knows what the cap of the limit is on the fuses, wiring and stock oem battery is. Whether it will trip the ECU for an error code.

Toyota in this case has chosen components with the design and intention of harmonious balance and if the output... whether that be horsepower or electrical current is too high it can cause undue stress on other "stuff"

This is the world according to me, the youtube mechanic. Please feel free to educate me if I am way off here.

Also this happened when I changed my sparkplugs and alternator. And they were all stock components. After I checked my work and cleared the codes TWICE! There have been no further issues. See pic.
While I agree to an extent, you can add a supercharger if you also add new injectors (which the kits come with). So you can add a higher output alternator if you also upgrade the wiring and fuses and battery. I wouldn't throw a high-output alternator on an otherwise stock truck, agreed. But for those with high capacity batteries and extra power draw, we've exceeded the Toyota design limits already and are trying to make the rest of the system (alternator) match.

Definitely a strange error to get when using stock replacement parts.
  • Like
Reactions: 1
1 - 4 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.