Recently, I had the alternator (90 amperes) in my Montero rebuilt as a temporary fix. I'm considering an upgrade, and was wondering if a 110 ampere unit would be a direct replacement. Would I need to make any modifications to the electrical system to accommodate to the additional 20 amperes, or is it pretty much plug and play? Thank you.
Alternator upgrade
- Thread starter Falcon_LS
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that's the capacity. for example ur house is connected to the grid, which has a huge capacity. if the grid is upgraded and there is more capacity, your house still continues to draw the same. but if you wanted to add more cities onto the grid, the grid can now service it. so if u want to put more current drawing things into ur car, the alternator can do it. pretty much plug and play, as long as the hardware fastens the same.
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An alternator with larger capacity will rob the engine of more horsepower. Choose an alternator that has a charging capacity (A) of 25 to 40 percent of the total capacity (Ah) of your batteries.
I would think that even in 2000, and even on a SUV the vehicle would be equiped with an electrical load detector which will vary the output from the alternator anyway. So your upgrade might be useful sometimes, but the majority of the time it won't be significantly different from stock.
I'm no expert on this, but all the Honda's I've owned except the '86 have had an ELD.
I'm no expert on this, but all the Honda's I've owned except the '86 have had an ELD.
mori...
Am I correct in recalling typical car batts around 45-50AH (excluding deep cycle, marine, etc)? That suggests a 15-20A alt, ??? I think you want the 25-40% charge rate *in addition to* vehicle loads (20amp daytime, 35amp night, 50amps with wipers, defrost, etc...)
And actually, the reverse *can* be true for daily driving. A larger capacity alt can actually waste less hp, given it's the same case/structure/design: A larger capacity alt typically has thicker copper in the windings. Provided the electrical load remains the same, the larger alt will not lose *as much* energy in resistance while loaded, yielding more efficient operation. Also, some cars will raise idle speed if the voltage is low to boost alt output (Chrysler/Dodge did this until ~2001 when the upsized alts in the minivans, per allpar artciles) which uses more fuel.
Really 90A is a pretty good size. 60-ish was a standard for a while. I don't think an extra 20amps is going to improve your daily drive. Apply the extra $ to the one with lifetime warranty b/c in my experience a lot of the remans last a year or so. :-(
M
Am I correct in recalling typical car batts around 45-50AH (excluding deep cycle, marine, etc)? That suggests a 15-20A alt, ??? I think you want the 25-40% charge rate *in addition to* vehicle loads (20amp daytime, 35amp night, 50amps with wipers, defrost, etc...)
And actually, the reverse *can* be true for daily driving. A larger capacity alt can actually waste less hp, given it's the same case/structure/design: A larger capacity alt typically has thicker copper in the windings. Provided the electrical load remains the same, the larger alt will not lose *as much* energy in resistance while loaded, yielding more efficient operation. Also, some cars will raise idle speed if the voltage is low to boost alt output (Chrysler/Dodge did this until ~2001 when the upsized alts in the minivans, per allpar artciles) which uses more fuel.
Really 90A is a pretty good size. 60-ish was a standard for a while. I don't think an extra 20amps is going to improve your daily drive. Apply the extra $ to the one with lifetime warranty b/c in my experience a lot of the remans last a year or so. :-(
M
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Originally Posted By: moribundman
An alternator with larger capacity will rob the engine of more horsepower. Choose an alternator that has a charging capacity (A) of 25 to 40 percent of the total capacity (Ah) of your batteries.
Practically no production vehicle comes with an alternator that small.
Alternators need to be sized for the load. The majority of the load in a car is NOT recharging the battery, but powering other electrical loads, so basing the alternator size on the battery capacity is not the way to size an alternator for a vehicle.
An alternator with larger capacity will rob the engine of more horsepower. Choose an alternator that has a charging capacity (A) of 25 to 40 percent of the total capacity (Ah) of your batteries.
Practically no production vehicle comes with an alternator that small.
Alternators need to be sized for the load. The majority of the load in a car is NOT recharging the battery, but powering other electrical loads, so basing the alternator size on the battery capacity is not the way to size an alternator for a vehicle.
Originally Posted By: meep
mori...
Am I correct in recalling typical car batts around 45-50AH (excluding deep cycle, marine, etc)?
A group 48 battery is 75 amp-hours and that's fairly large as far as car batteries go. For comparison, a group 24 deep-cycle marine is about 85 amp-hours, and a group 27 deep-cycle marine about 110 amp-hours.
mori...
Am I correct in recalling typical car batts around 45-50AH (excluding deep cycle, marine, etc)?
A group 48 battery is 75 amp-hours and that's fairly large as far as car batteries go. For comparison, a group 24 deep-cycle marine is about 85 amp-hours, and a group 27 deep-cycle marine about 110 amp-hours.
Originally Posted By: bepperb
I would think that even in 2000, and even on a SUV the vehicle would be equiped with an electrical load detector
Is that more conventionally known as a voltage regulator?
I would think that even in 2000, and even on a SUV the vehicle would be equiped with an electrical load detector
Is that more conventionally known as a voltage regulator?
Originally Posted By: meep
yea, seems like the "ubiquitous" gp 34 is around 50. 48 is a big daddy. Would love to shoehorn one of those into the jeep...
The formula for figuring AH according to Johnson Controls is to multiply reserve capacity in minutes by 0.6, the answer is the capacity in AH.
yea, seems like the "ubiquitous" gp 34 is around 50. 48 is a big daddy. Would love to shoehorn one of those into the jeep...
The formula for figuring AH according to Johnson Controls is to multiply reserve capacity in minutes by 0.6, the answer is the capacity in AH.
I recently upgraded (in a Pontiac) from a 105 amp to a 140amp. I noticed less light dimming at idle. Maybe the original alt was shot, but it always did this, especially if I was running other accessories like the AC, headlights and rear defrogger.
There's sort of two kinds of higher capacities- there's the total capacity of the alt when it's at speed. Any factory alternator should be able to easily power all the accessories when you're cruising down the highway.
But there's also the shape of the output curve. I upgraded because the output curve of the new one is flatter, meaning it can provide more power at idle.
There's sort of two kinds of higher capacities- there's the total capacity of the alt when it's at speed. Any factory alternator should be able to easily power all the accessories when you're cruising down the highway.
But there's also the shape of the output curve. I upgraded because the output curve of the new one is flatter, meaning it can provide more power at idle.
Quote:
I would think that even in 2000, and even on a SUV the vehicle would be equiped with an electrical load detector which will vary the output from the alternator anyway.
?!?!? There's no such thing as an "electrical load detector."
But there is a voltage regulator, and EVERY vehicle with a generator or alternator made since at least the 1930's has a voltage regulator. If they didn't the battery would boil dry at high engine speeds and go dead at low speeds. The VR increases the output of the alternator whenever it senses a drop in system voltage, whether caused by an electrical load turning on or simply because the vehicle was just started after sitting for a long time and the battery was discharged.
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An alternator with larger capacity will rob the engine of more horsepower.
Not true in the general sense. Because the output of the alternator is regulated, it will only put out enough current to match the electrical load at any given instant (electrical devices plus any required battery charge current). So in other words if the battery is fully charged and the electrical load is 15 amps at any given time, an 80-amp alternator and a 140-amp alternator would *BOTH* only put out the required 15 amps and would thus put exactly the same load on the engine. The 140-amp alternator would only make a difference at those times when more than 80 amps are required, and yes at THOSE times it would put a bigger load on the engine. But those times are few and far between.
I would think that even in 2000, and even on a SUV the vehicle would be equiped with an electrical load detector which will vary the output from the alternator anyway.
?!?!? There's no such thing as an "electrical load detector."
But there is a voltage regulator, and EVERY vehicle with a generator or alternator made since at least the 1930's has a voltage regulator. If they didn't the battery would boil dry at high engine speeds and go dead at low speeds. The VR increases the output of the alternator whenever it senses a drop in system voltage, whether caused by an electrical load turning on or simply because the vehicle was just started after sitting for a long time and the battery was discharged.
Quote:
An alternator with larger capacity will rob the engine of more horsepower.
Not true in the general sense. Because the output of the alternator is regulated, it will only put out enough current to match the electrical load at any given instant (electrical devices plus any required battery charge current). So in other words if the battery is fully charged and the electrical load is 15 amps at any given time, an 80-amp alternator and a 140-amp alternator would *BOTH* only put out the required 15 amps and would thus put exactly the same load on the engine. The 140-amp alternator would only make a difference at those times when more than 80 amps are required, and yes at THOSE times it would put a bigger load on the engine. But those times are few and far between.
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Originally Posted By: meep
mori...
[snip] I think you want the 25-40% charge rate *in addition to* vehicle loads (20amp daytime, 35amp night, 50amps with wipers, defrost, etc...)
Yes, I omitted "over" and stuck a misplaced "of" in there. Where's my coffee?
Choose an alternator that has a charging capacity (A) of 25 to 40 percent over the total capacity (Ah) of your battery.
mori...
[snip] I think you want the 25-40% charge rate *in addition to* vehicle loads (20amp daytime, 35amp night, 50amps with wipers, defrost, etc...)
Yes, I omitted "over" and stuck a misplaced "of" in there. Where's my coffee?
Choose an alternator that has a charging capacity (A) of 25 to 40 percent over the total capacity (Ah) of your battery.
With all the electronics big [high output] alternators are the norm. Falcon if you want to upgrade alt output a plug and play would be the way to go . You may have to shop around as I do not know the options available fot the Mitsubishis and which alternators would be a direct fit.
The only thing you could/should consider is the big positive wire between the alt and battery, sometimes it's got a fuse/fusible link in there.
Often it's a gauge or so thinner than it really should be.
You could leave the wire alone and move the headlight feed wire (with relays) to the alt output lug, that would take some load off the wire and make your headlights brighter too.
On my brother in law's MGB they added ~10 amps capacity to the alt so just added a ~14 ga wire parallel to the ~12 ga stocker and called it done! Lucas at work...
Often it's a gauge or so thinner than it really should be.
You could leave the wire alone and move the headlight feed wire (with relays) to the alt output lug, that would take some load off the wire and make your headlights brighter too.
On my brother in law's MGB they added ~10 amps capacity to the alt so just added a ~14 ga wire parallel to the ~12 ga stocker and called it done! Lucas at work...
"?!?!? There's no such thing as an "electrical load detector."
Why don't you google "Honda ELD" before you make such statements. Sorry if Honda's naming convention isn't the same as yours, you'll have to fly to Japan and let them know they're wrong. I'm sure they'll be quite interested in changing things.
But naming conventions aside, we agree that the ouput of the alternator will vary to load, so unless you're using the full load you probably won't see any advantage to this upgrade, nor will you see any loss in mileage.
Why don't you google "Honda ELD" before you make such statements. Sorry if Honda's naming convention isn't the same as yours, you'll have to fly to Japan and let them know they're wrong. I'm sure they'll be quite interested in changing things.
But naming conventions aside, we agree that the ouput of the alternator will vary to load, so unless you're using the full load you probably won't see any advantage to this upgrade, nor will you see any loss in mileage.
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Originally Posted By: bepperb
"?!?!? There's no such thing as an "electrical load detector."
Why don't you google "Honda ELD" before you make such statements. Sorry if Honda's naming convention isn't the same as yours, you'll have to fly to Japan and let them know they're wrong. I'm sure they'll be quite interested in changing things.
I doubt it, Honda takes a perverse pride in calling simple devices like electronic ignition modules "ignitors," so I'm sure they have an arcane name for what the rest of the world has called a "voltage regulator" since the dawn of the automobile. But its still FUNCTIONALLY a voltage regulator. An "electrical load detector" would have to function as a current sensor on the supply to the vehicle loads. They don't do it that way, they do it by sensing voltage just like everyone else.
"?!?!? There's no such thing as an "electrical load detector."
Why don't you google "Honda ELD" before you make such statements. Sorry if Honda's naming convention isn't the same as yours, you'll have to fly to Japan and let them know they're wrong. I'm sure they'll be quite interested in changing things.
I doubt it, Honda takes a perverse pride in calling simple devices like electronic ignition modules "ignitors," so I'm sure they have an arcane name for what the rest of the world has called a "voltage regulator" since the dawn of the automobile. But its still FUNCTIONALLY a voltage regulator. An "electrical load detector" would have to function as a current sensor on the supply to the vehicle loads. They don't do it that way, they do it by sensing voltage just like everyone else.
OK, I'll admit I was wrong. Honda actually does use a current transformer to sense vehicle load in addition to monitoring voltage, so even by "my" terminology, it is truly a load detector. Wierd, and (as evidenced by the web hits) more of an added point of failure than an added feature.
But aside from that, all vehicles achieve the same thing through one means or another.
But aside from that, all vehicles achieve the same thing through one means or another.
I do recall the civic high-mileage version in the mid 90s would decrease system voltage from 14.x to 13.x under cruise conditions to boost MPG. Maybe this load detector is a perverse part of the ECM programming?
I remember someone on here had a mechanic do work and was chagrined they used RTV instead of the honda shop manual equivalent with a really wierd name.
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