Hi Amp Alternator

[psea17]

Recently had 2 air compressors die on me. Ea different brands. I think it's my alternator's voltage output. it's output is 14.8-14.9v. i noticed the label on one of the air compressors said it needed 13.8v. Hence, my hunch it's voltage related. What's kind if crazy is that i get the same voltage at my rear bumper via 2awg wire. zero voltage drop.

i have no big lights and no lithium. im running lead acid. I believe the oem alternator voltage is 14.4v.

first, any thoughts on how to address this other than buying another alternator? any way to down regulate the voltage externally fr the alternator?

if not, can anyone recommend an alternator that outputs oem voltages but w/ higher amps?

thanks guys!

ps. im not going down the cs144 path again.

 

[phattyduck]

Power through a resistor (DC motors basically work like a resistor except when starting and stopping) goes by the square of the ratio of voltages. The difference between 14.4V and 14.9V works out to 7% extra power to the compressor motor. That shouldn't be enough to kill it...

That said, you really shouldn't be running over 14.6V unless it is REALLY cold, otherwise it can overcharge and damage lead-acid batteries. Maybe the alternator company tweaked it for gel-cell batteries (even though they only need 0.1-0.2V more)?

-Charlie

 

[psea17]

hi charlie,

thanks for the response. the manufacturer claims it was set at 14.8v and ive been using my old compressor for a few years... but i was connecting it using battery clips. i think that helped slow it's death. the second one used an anderson plug. it was getting the full 14.9 and failed after a few tire inflation tests.

i think ive found 2 companies that offer oem voltage and high amp output: tucson alternator and power bastards.

going to get one from tucson.

 

[det107]

No CS144 alternator again..?

I believe you can run a Suzuki Vitara? If my CS144 dies, prolly will go this route.

 

[pluton]

As phattyduck wrote, it is unlikely that the higher voltage killed the air pump motor itself, however, it could have killed some controlling circuitry, especially if it involves digital stuff (microprocessors, displays, etc). Perhaps you could relate what make and models of compressors were killed [presumably] by your alternator's high voltage? Maybe the alt was set for folks who use AGM batteries, although 14.9 is at the upper end of that spec also.
BTW, the OEM alts start at about 14.4VDC when cold, but the voltage lowers as the engine compartment heats up. Expect about 13.2VDC from an OEM alt on a hot day.

 

[phattyduck]

BTW, the OEM alts start at about 14.4VDC when cold, but the voltage lowers as the engine compartment heats up. Expect about 13.2VDC from an OEM alt on a hot day.

As it should - no need to try to charge a full battery...

I run the Denso alternator from the Grand Vitara, seems to work just fine. 105A rated, only very minor mods to fit, along with upgraded charge/ground wiring (4 gauge). I kept my old stock application one as a spare (was working when removed).

-Charlie

 

[Ripper238]

As phattyduck wrote, it is unlikely that the higher voltage killed the air pump motor itself, however, it could have killed some controlling circuitry, especially if it involves digital stuff (microprocessors, displays, etc). Perhaps you could relate what make and models of compressors were killed [presumably] by your alternator's high voltage? Maybe the alt was set for folks who use AGM batteries, although 14.9 is at the upper end of that spec also.
BTW, the OEM alts start at about 14.4VDC when cold, but the voltage lowers as the engine compartment heats up. Expect about 13.2VDC from an OEM alt on a hot day.

I added a voltage booster for my 5th gen and wouldn't expect the little extra voltage to matter for an air pump, or really any of my electronic addons. I would think running the pump too long would more likely be the reason.

 

[3bears]

As it should - no need to try to charge a full battery...

I run the Denso alternator from the Grand Vitara, seems to work just fine. 105A rated, only very minor mods to fit, along with upgraded charge/ground wiring (4 gauge). I kept my old stock application one as a spare (was working when removed).

-Charlie

I too am running the suzuki denso

 

[psea17]

As phattyduck wrote, it is unlikely that the higher voltage killed the air pump motor itself, however, it could have killed some controlling circuitry, especially if it involves digital stuff (microprocessors, displays, etc). Perhaps you could relate what make and models of compressors were killed [presumably] by your alternator's high voltage? Maybe the alt was set for folks who use AGM batteries, although 14.9 is at the upper end of that spec also.
BTW, the OEM alts start at about 14.4VDC when cold, but the voltage lowers as the engine compartment heats up. Expect about 13.2VDC from an OEM alt on a hot day.

first compressor was an air armor. second was a napa. neither had circuitry (i removed it fr the napa instead choosing a relay and air pressure switch). both displayed similar behaviors prior to dying (uneven motor operation and stuttering).

i simply dont need 14.9v. it's too much for lead acid. agm is out for me. they dont perform as well in heat imo. really, the only reason for wanting more amps is the winch.

i built my own lifepo battery box w a dcdc charger to take care of it.

new alternator ordered from Tucson. should be here next week. then need to get another compressor.

appreciate the input guys!