40amp versus 90 amp.

[purchelli]

Hi all, I've had a couple of major let downs due to my apparently dying factory alternator. I had the brushes replaced after the first let down. After the brushes were replaced I rode it another 450 miles and it stopped charging again but this time apparently due to the alternator rotor which has a broken coil. SO OUT SHE GOES !! A compufire is the obvious replacement choice however I'm concerned that they put out far more power than my bike needs. It also means my brand new liquid cell battery will need to be replaced with a sealed battery. I run pretty much standard lights front and rear. Our climate means I'll never require any aftermarket electrical heating. I do however use the cassette deck continuously and like the stereo system up loud. Stereo system is factory. I'm interested in any feedback you may have on 40 amp versus 90 amp replacement. Any recommendations and warnings. Thanks all

[NVSB4]

The 1500 is notorious for not charging the battery if under around 2000 rpm, so your driving environment may be the issue.
Many here have replaced the stock alternator with a higher amperage one.
I replaced mine with a 95 amp from Lactircal (off Amazon, but don't know the availability in NZ) instead of the Compufire, as it is almost 1/3 the price.
Yes, you will need to replace the battery with an AGM, but it's a small price to pay for peace of mind.

[Bluewaterhooker0]

I replaced mine for exactly the same problems and reason. I used a Lactrical 85A version. Works great, and charges the battery MUCH better than the stock 40A. I already had an AGM battery, and believe that's the only way to fly, in general. Replace the rubber dampeners when you install the new alternator, and you're good to go. As was stated, the Lactricals go for about $150, far cheaper than the Comp-U-Fire. Reliability seems to be about the same.

[Fiberthree]

I replaced my stock unit with the Compufire in November of 2005. With the Compufire and the stock lighting I never had a problem of overcharging the battery. Since "05 I have replaced 99% of the lights with LEDs and still no electrical problems. If the cost is not much higher, I don't think you will harm anything with the 90 amp unit.

[hugger-4641]

If you aren't running a bunch of extra lights and other gadgets and you aren't idling around a lot, then 40amp is sufficient and they run quieter than the larger amp replacements. The problem is ,you don't want an OEM Hitachi 40amp because of the faulty rotor issues. Unless you get a rebuilt unit from Ken Hemlin or some other specialist shop that has addressed the rotor problem, there's not much way to tell a "good" OEM unit from the ones prone to rotor failure. Some people just go ahead and upgrade to an 80 or 90 amp because that is the easiest way to get away from the stock 40 amp. You should upgrade that battery anyway, but unless you are adding a bunch of extra gizmos, there is no requirement to go with a $400 Compufire when an Lalectrical or Dbelectric will do just as well.
I don't know what the availability is like in New Zealand, but if you don't have any other options, you might be able to locate a junked mid '90s model Saturn car or the alternator from one. Some of them had the same alternator as the Goldwing except that the Saturn unit had a 60amp or larger rating. You just have to swap the housings out since the Saturn runs off a belt drive.

If you happen to be the type that likes to tinker, there is a How-To article here that shows how to repair that bad coil in the rotor. I've done it successfully a few times now for myself and some other folks. If you lived close to me, I'd do it for you, but it's not rocket science.

[lamasue]

ken hemming says bike runs at 35 amp so go ahead and spend the money I got a 85 amp from ken at good price and it was bench tested

[purchelli]

thanks all for the comments and advice. This is just an awesome forum !!!

[Davek80514]

The 1500 is notorious for not charging the battery if under around 2000 rpm, so your driving environment may be the issue.
Many here have replaced the stock alternator with a higher amperage one.
I replaced mine with a 95 amp from Lactircal (off Amazon, but don't know the availability in NZ) instead of the Compufire, as it is almost 1/3 the price.
Yes, you will need to replace the battery with an AGM, but it's a small price to pay for peace of mind.

My brother got both of us the same alternator that you have. But can someone explain why we need to get AGM batteries when we install them

[NVSB4]

My brother got both of us the same alternator that you have. But can someone explain why we need to get AGM batteries when we install them

The AGM batteries are sealed. The higher amp alternators can/will boil the others.