Putting in a 90 amp alternator, do you have to change your battery

[ShannonFoster69]

I was just curious if I had to change my battery, I have a duralast Gold battery in it now if I put in a 90 amp alternator on my 89 Honda GL 1500

[Rambozo]

As long as your battery tests good, no need to replace. You do have to replace your main dogbone fuse. Usually, you just double them up to deal with the higher current.

[blupupher]

If your current battery is good, no need to change it.

I did not "upgrade" my dogbone fuse.
My view is the dogbone is meant to protect the wiring of the bike, which is rated to 55 amps. Just because it is a "90 amp" alternator does not mean it is putting out 90 amps.

I put on a 95 amp LActrical because I was tired of having only 12.4v at < 1300 rpm's and dealing with dimming lights when sitting at a stoplight with the turn signal on.
Plus the LActrical was a good price with decent reliability compared to any other 40 amp unit.

[DenverWinger]

My view is the dogbone is meant to protect the wiring of the bike, which is rated to 55 amps. Just because it is a "90 amp" alternator does not mean it is putting out 90 amps.

+1 on that. I too have high output alt. Just because the alternator CAN output 90 amps doesn't mean it WILL output 90 amps. The alternator (controlled by the regulator) will only output as much as the bike asks for to hold the correct charging voltage, on my bike it has never exceeded the capacity of the 55 amp dogbone.

[Nlmman47]

is it real hard to change the alternator i might want to change mine

[Rambozo]

Pretty easy job. Some of the aftermarket ones like Compufire are a bit larger so it can be tricky to get them positioned to fit in the space. Plenty of people have done it on the side of the road.

[blupupher]

is it real hard to change the alternator i might want to change mine

Really not that hard. Several youtube videos and I think there is a how to with pics here on the site.

The biggest pain is having to take off most of the plastic on the left side to get to the wire from the alternator to the main harness.
The rest is pretty simple. Take off both side panels on both sides, disconnect battery, 3 bolts on the alternator, 1 nut for the power, and the above mentioned plastics to disconnect 1 wire (some just clip and splice the wire).
It is recommended to use new isolators (the "bushings" that cushion the alternator from the engine).
Installing a 40 amp is super easy, my 95 amp was not that much harder (just try to remember the angle that allowed you to remove it, installation is just the opposite, and my 95 amp was really not that much bigger). Getting the splines lined up was a bit of a pain, but not that hard.
The rest is just the opposite of removal.
I was maybe 2 hours total time, and I took my time.

[newday777]

I was just curious if I had to change my battery, I have a duralast Gold battery in it now if I put in a 90 amp alternator on my 89 Honda GL 1500

As long as it is an AGM battery that is still good, you'll be fine.

[Limpy45]

The only thing you have to change is possibly the battery when it expires by itself. Just check it frequently to add water if it is not a sealed
battery. AGM is recommended with a higher amp alternator. The fuses will be just fine as they are. I have a Dodge Caravan with a 110 amp alternator and all the fuses are the same value as on my old VW diesel I used to have. The fuses are to protect the vehicle wiring from a fault, not to limit amperage in the charging system. Sorry if I offend anyone by this, but study some books on automotive charging systems. That is basically what our motorcycles have, except for 4 cylinders and HD's.