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Alternator output?

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fras
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Alternator output?

Postby fras » February 9th, 2021, 9:27 am

On a vehicle with a 140 amp alternator, approximately how many amps would be available for audio at idle?
Vehicle is diesel btw!

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Re: Alternator output?

Postby SR » February 13th, 2021, 6:47 am

28

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Re: Alternator output?

Postby altec » February 13th, 2021, 7:06 am

Depends on the current draw, which depends on how much electrical stuff you have running eg headlights. Electrician can measure that for you easy.

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Re: Alternator output?

Postby fras » February 16th, 2021, 3:42 pm

SR wrote:28
:lol: ur joking right?

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Re: Alternator output?

Postby fras » February 16th, 2021, 3:42 pm

altec wrote:Depends on the current draw, which depends on how much electrical stuff you have running eg headlights. Electrician can measure that for you easy.

ok cool

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Re: Alternator output?

Postby 88sins » February 16th, 2021, 5:16 pm

Depends on what you have adding load to the electrical system as altec mentioned. Lights, ac, even your radiator fans will draw and reduce the total power available to your amp. Get a clamp meter that can read DC amps, and check the power being delivered at the amp power input for a better idea of what's going on.

Also, for maximum power, you could have the run the amplifier power cable connected directly to the alternator, but that may cause a bit less power to get to your battery, engine and other accessories whiletl the systemis is playing on full blast. Not something I advise you do on your own or on a daily driver, but it can be done.

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Re: Alternator output?

Postby fras » February 19th, 2021, 9:41 am

88sins wrote:Depends on what you have adding load to the electrical system as altec mentioned. Lights, ac, even your radiator fans will draw and reduce the total power available to your amp. Get a clamp meter that can read DC amps, and check the power being delivered at the amp power input for a better idea of what's going on.

Also, for maximum power, you could have the run the amplifier power cable connected directly to the alternator, but that may cause a bit less power to get to your battery, engine and other accessories whiletl the systemis is playing on full blast. Not something I advise you do on your own or on a daily driver, but it can be done.

No lights or ac... Just audio in use! Also the fan is driven by the engine (clutch fan)

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Re: Alternator output?

Postby adnj » February 19th, 2021, 3:22 pm

There is no simple answer on alternator output unless the alternator output curve is known. All things being equal, a lower maximum output current alternator may have a higher output at idle. Larger, heavier alternators produce more current at lower RPMs, also.

This chart shows alternator shaft speed versusus output. Most alternator pulley designs try to use sizes that are 2:1 to 3:1. Most OEM automotive design requirements leave about 10 amps of vehicle power for the Vehicle Navigation & Entertainment system - sometimes you may see up to about 30 amps.
Image

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Re: Alternator output?

Postby SR » February 20th, 2021, 6:46 pm

An oem alternator is designed to provide what the vehicles needs with a small reserve capacity. No oem manufacturer will put a alternator with a high reserve capacity as it will send the cost of the vehicle up. Aftermarket alternators are designed to provide high amperage to run aftermarket accessories such as sound systems etc.
This is why your lights dip at night when the bass kicks in as the alternator cannot provide the additional current and the battery cannot provide it quickly enough plus when under load the battery itself also becomes another load for the alternator

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Re: Alternator output?

Postby sMASH » February 20th, 2021, 9:01 pm

fras wrote:On a vehicle with a 140 amp alternator, approximately how many amps would be available for audio at idle?
Vehicle is diesel btw!


What vehicle u put the tiida alternator in?

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Re: Alternator output?

Postby Ted_v2 » February 22nd, 2021, 9:11 pm

sounding like a WL, td27, qd32 boi

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Re: Alternator output?

Postby fras » March 4th, 2021, 11:38 am

sMASH wrote:
fras wrote:On a vehicle with a 140 amp alternator, approximately how many amps would be available for audio at idle?
Vehicle is diesel btw!


What vehicle u put the tiida alternator in?

It's a 2018 hilux, I was told the alternator is 140 amps!

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Re: Alternator output?

Postby fras » March 4th, 2021, 1:01 pm

Here is what's really up...
I have a small 5ch system (600 rms) and was looking to upgrade to a 2000 rms system. But I don't want to go over my budget, which doesn't include an additional battery!

Currently have the factory alternator (140 amp?) and an optima yellow top battery (55 amp hour). Would also do a big 3 upgrade in the near future!

If I would need an additional battery, I would either opt for a smaller system (1200 rms), or consider extending budget! I would love to know what I'm getting into before I begin!

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Re: Alternator output?

Postby sMASH » March 4th, 2021, 2:17 pm

i really cant say. is if u could link up wiht some one with a clip on ammeter, to directly check current draw, while all ur typical current drawers are on, i.e. headlight, ac(the fan comes on).
i thought was an older vehicle and would guestimate a 40a was used by the vehicle. the newer ones, i cant say.

the best option is to change out to an after market alternater which is over 2k extra starting. the second best option is to add a second/third battery to just to hold out for the lil 5mins ur going to jam full tilt every so often, and allow a lil recharge time before u switch off.

the more experienced installers would better guide, but imo, a 2krms system woudl be easier on the batteries and alternators with more capacity than that 55ah. the less u cycle ur battery the longer it will last, and the less strain on ur alternator too, which can also damage if u keep making it recharge a very low voltage battery.

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Re: Alternator output?

Postby SR » March 4th, 2021, 10:58 pm

What are the fuse rating on the new amp and what load will each channel see?

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Re: Alternator output?

Postby fras » March 5th, 2021, 6:47 am

sMASH wrote:i really cant say. is if u could link up wiht some one with a clip on ammeter, to directly check current draw, while all ur typical current drawers are on, i.e. headlight, ac(the fan comes on).
i thought was an older vehicle and would guestimate a 40a was used by the vehicle. the newer ones, i cant say.

the best option is to change out to an after market alternater which is over 2k extra starting. the second best option is to add a second/third battery to just to hold out for the lil 5mins ur going to jam full tilt every so often, and allow a lil recharge time before u switch off.

the more experienced installers would better guide, but imo, a 2krms system woudl be easier on the batteries and alternators with more capacity than that 55ah. the less u cycle ur battery the longer it will last, and the less strain on ur alternator too, which can also damage if u keep making it recharge a very low voltage battery.

I spoke with a popular installer and he has done 2000rms systems in same hilux, using optima redtop, with a small voltage drop!

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Re: Alternator output?

Postby fras » March 5th, 2021, 6:51 am

SR wrote:What are the fuse rating on the new amp and what load will each channel see?

Mono amp is 100 amp, would be playing at 1 ohm (1400x1)
4ch amp is 80 amp, would be playing at 4 ohm bridge (300x2)
These are the manufacturer fuse rating

I forget to mention, I'm also using an epicenter!

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Re: Alternator output?

Postby Rovin » March 5th, 2021, 12:09 pm

jes for a reference , i use a yellow with 80A alt & 1k mono , normal voltage after engine running not cold start voltage is 13.8

i dont play music long never constant full tilt for maybe a hr or 2 max but very low bass & averages 13-3-13.5v never goes below 13 , never did d big 3 for my fielder - too lazy or never got around to it

u can average\calculate all u want but true test is when u install everything & run it ...

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Re: Alternator output?

Postby fras » March 6th, 2021, 11:47 pm

Rovin wrote:u can average\calculate all u want but true test is when u install everything & run it ...

Unfortunately lol

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Re: Alternator output?

Postby Jerry84 » March 27th, 2022, 11:29 am

My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?

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Re: Alternator output?

Postby timelapse » March 27th, 2022, 3:56 pm

Jerry84 wrote:My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?
Had that issue.Turned out to be an ac fan sensor.These issues can be weird af

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Re: Alternator output?

Postby Jerry84 » March 27th, 2022, 7:56 pm

timelapse wrote:
Jerry84 wrote:My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?
Had that issue.Turned out to be an ac fan sensor.These issues can be weird af
Could it also be that I should check another reputable electrician to recheck the alternator? Reason I ask this is because I put a multimeter on the discharge line to the battery and only getting 12.6 volts at idle when in theory I'm supposed to be getting 14volts proper

Suggestions welcomed

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Re: Alternator output?

Postby timelapse » March 27th, 2022, 8:17 pm

Jerry84 wrote:
timelapse wrote:
Jerry84 wrote:My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?
Had that issue.Turned out to be an ac fan sensor.These issues can be weird af
Could it also be that I should check another reputable electrician to recheck the alternator? Reason I ask this is because I put a multimeter on the discharge line to the battery and only getting 12.6 volts at idle when in theory I'm supposed to be getting 14volts proper

Suggestions welcomed
Check Voltage regulator

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Re: Alternator output?

Postby Jeremy09 » March 28th, 2022, 9:45 am

I think with that 140amp alt,a good agm bat and a big 3 upgrade ur safe to handle about 1500-1600 real rms.

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Re: Alternator output?

Postby Jerry84 » March 28th, 2022, 6:57 pm

Check Voltage regulator[/quote]


Where is this regulator located in the car? Is it easily accessible and easy to change?

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Re: Alternator output?

Postby Jerry84 » March 28th, 2022, 6:57 pm

Jeremy09 wrote:I think with that 140amp alt,a good agm bat and a big 3 upgrade ur safe to handle about 1500-1600 real rms.
Did this already bro.

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Re: Alternator output?

Postby speedmelter » March 29th, 2022, 1:17 pm

Jerry84 wrote:My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?


The battery most likely is bad. Check grounds from engine to battery and engine to chassis as well.

But that battery is pure failure, especially if from price M.

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Re: Alternator output?

Postby speedmelter » March 29th, 2022, 1:18 pm

speedmelter wrote:
Jerry84 wrote:My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?


The battery most likely is bad. Check grounds from engine to battery and engine to chassis as well.

But that battery is pure failure, especially if from price M.


Do a load test on the battery as well

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Re: Alternator output?

Postby SR » March 29th, 2022, 1:42 pm

I have 2 vehicles with the red top from pricesmart with no issues whatsoever.

Keep in mind the battery model that pm sells and your application

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Re: Alternator output?

Postby adnj » March 30th, 2022, 12:09 am

speedmelter wrote:
speedmelter wrote:
Jerry84 wrote:My 140 amp alternator is charging my red top Optima but on accelerating I'm noticing a drop in voltage for 13.8 to 12.4 and sometimes 11.8, no music being played. Also noticed that my battery light is blinking when accelerating. Serviced the alternator and same issue. Battery is less than a year old. What could be the possible causes?


The battery most likely is bad. Check grounds from engine to battery and engine to chassis as well.

But that battery is pure failure, especially if from price M.


Do a load test on the battery as well
A faulty battery will not change the output of the alternator at increasing RPMs.

A switched load can change the output voltage. The AC sensor was mentioned earlier, that is common problem. Faulty diodes, a faulty regulator or a slipping belt can also cause output decrease with RPM increase.

The voltage regulator is typically integral to the alternator and screwed into the rear of the alternator housing.

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