How much is too much alternator output?
- Thread starter coldtaco
- Start date
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Alternator was rebuilt in the last year or so.
14.8 is too high for a warm alternator. Don't trust cheap volt meters until you've checked it against a known voltage.
Cruiserdrew
On the way there
I think most recent voltage regulators are temperature compensated. So 14.8 cold is likely normal. What happens after you drive for 30 minutes? Normal driving should be 13.9-14.1 give or take.
And the needle on the dash board is meaningless. It is an idiot light that moves, not a trustworthy volt meter. You're going to need to bust out the DVM to figure this out.
And the needle on the dash board is meaningless. It is an idiot light that moves, not a trustworthy volt meter. You're going to need to bust out the DVM to figure this out.
I suspect you may be trying to fix something that is not broken.
According to Toyota, the (FJ60) alternator's voltage can be pretty much anything above 13.5 and be within "spec".
The FSM states, if the voltage is anything between 13.3 and 15 volts, a warm alternator is functioning properly. Wow!
That's clearly not right.
Sounds more to me like they just didn't want to deal with it.
The FSM states, if the voltage is anything between 13.3 and 15 volts, a warm alternator is functioning properly. Wow!
That's clearly not right.
Sounds more to me like they just didn't want to deal with it.
like he says,
unless the voltage output has changed since you've had it it it's probably always been putting out that voltage
Coldtaco nice ute mate it sounds like it's using a bit more fuel then it should what speeds are you cruising along at plus the rack and rear tarp wont help with the extra wind drag.
My 12ht/2h engine manual 13.8 to 14.8
My 12ht/2h engine manual 13.8 to 14.8
Cruiserdrew
On the way there
Regarding testing with the ammeter, the FSM left out a very important point. The battery must be fully charged or the alternator output could be much higher than 10 amps. Most ammeter settings on your average DVM max out at 10 and will blow the fuse or fry the meter if you go above that.
The worst case: the battery is 1/2 charged and the headlights are on. The alternator would go to full output, or close, and your meter would fry.
Regarding the original 14.8 volts-I'd be ok with that. It isn't like you run the truck 24/7/365. Most of the time the truck is off and an intermittent charge to 14.8v is more good than bad. It assures a deep full charge, and that prevents sulfation of the battery.
The worst case: the battery is 1/2 charged and the headlights are on. The alternator would go to full output, or close, and your meter would fry.
Regarding the original 14.8 volts-I'd be ok with that. It isn't like you run the truck 24/7/365. Most of the time the truck is off and an intermittent charge to 14.8v is more good than bad. It assures a deep full charge, and that prevents sulfation of the battery.
- Thread starter
- #13
Made it home tonight.
I remembered that my gps also indicates input power source voltage, so I used this to see what was going on. Basically came up with the following scenarios. I was told it is a 30 amp alternator, so don't know if this is a problem?
Basically at 62mph/2500rpm and no load indicates 14.3V
same with headlights on indicates 13.3V
same with headlights and high beam and lightforce lights on indicates 12.3V
Seems to me that the alternator is not able to adjust output to maintain a constant voltage irrespective of load? Is this because it is only a 30 amp unit?
Any insight would be appreciated.
I remembered that my gps also indicates input power source voltage, so I used this to see what was going on. Basically came up with the following scenarios. I was told it is a 30 amp alternator, so don't know if this is a problem?
Basically at 62mph/2500rpm and no load indicates 14.3V
same with headlights on indicates 13.3V
same with headlights and high beam and lightforce lights on indicates 12.3V
Seems to me that the alternator is not able to adjust output to maintain a constant voltage irrespective of load? Is this because it is only a 30 amp unit?
Any insight would be appreciated.
Hi mate the stock alternator is 55 amp.
Genuine Bosch Alternator for Toyota Landcruiser 4.0L 2H Diesel HJ47R HJ50R HJ60
Genuine Bosch Alternator for Toyota Landcruiser 4.0L 2H Diesel HJ47R HJ50R HJ60
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- Thread starter
- #15
Talked with a friend that is smarter than me when it comes to electric stuff and he says that he thinks one of the diode thingy went bad. So will have to find a alternator repair shop and have them do what they do.
If the current alternator in there really is only 30 amp you may want to consider an upgrade instead of repair.
At 30 amps you only have ~360 watts of power (P(W)=Voltage(V)*Current (amps)), so if you start adding everything up with the inefficient original head light plus the light force lights, all of the running lights and the GPS, radio, etc. I am guessing that you are getting pretty close to that number.
At 30 amps you only have ~360 watts of power (P(W)=Voltage(V)*Current (amps)), so if you start adding everything up with the inefficient original head light plus the light force lights, all of the running lights and the GPS, radio, etc. I am guessing that you are getting pretty close to that number.
- Thread starter
- #18
These observations where made over the last 2300mi of travel covering a minimum of at least 600mi a day so hopefully the battery was/is properly charged state each day. In Canada you are required to drive with headlights on during the day so I ran the led lights in the bumper as my daytime driving lights, which don't use much power.