Can a stock 60amp alternator handle 120 amp load

3VZRUNNA · 09-19-2009, 10:43 AM

I currently have a 500watt rockford fosgate amplifier that uses 60amps. Will my charging system be able to handle another 60amp Amplifier? because I plan to add a 2channel amplifier to power my rear speakers.
Will there be any harm done?

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**aviator** · 09-20-2009, 01:43 PM

Well by definition the answer is in effect no it cannot. Now you may not be pulling peak output from the amps all the time but any time you try for more then the 60A available from the alt. the electrical system will make up the shortfall by pulling the extra amps out of the battery. This will stress the charging system and reduce the batt. life considerably. The sound sys. is not the only electrical draw in the vehicle either consider starter/ignition/fuel pumps/fans/wipers/lights/ecu all of these draw juice from the same well as the entertainment system. The alt. does not put out the full 60A at idle either so anytime you are not at hwy cruise rpm [say 1800+] you're going to be getting a lot less then 60A.
If you want to add another amp you will need to go to a larger alt. to keep up. The factory 60A can be rebuilt to put out 90A or a little better fairly easily by any competent alt. repair shop. You can also get alts. of up to 200A output from online shops.
Hope this helps a little... anybody else got some input?

Pigman · 09-20-2009, 02:42 PM

General rule of thumb is never exceed 2/3rds of your alternator output, as stated you'll drain the battery or burn up your alternator, I run linear amps for 2-way radio's and have got myself in the same dilemma from time to time. Get a bigger alternator and a darn good battery, then enjoy and forget about it!
Pigman

desertcamper67 · 09-20-2009, 08:49 PM

I think you should look into capacitors.

Merlin · 09-21-2009, 12:31 PM

you may want to look into upgrading your battery to a deep cycle battery.

you may also want to look into alt. upgrades, i considered having one rewound but it will only increase output to around 80-90 amps. also, you will only get those amps at higher rpms. idle rpms may actually decrease with rewound alts. also, if you try to get too many amps out of a stock case rewound alt, you will also get more heat, which can shorten the life of the alt.

you *could* try underdrive pullies, but while they'd give you more amps at idle, your alt would be spinning REALLY fast at highway speeds, or if you rev up the motor to up the output at a stop.

a cheap solution would be adapting a GM h/o large case alt to fit, might need to mod or fab up a bracket and maybe change your belts, but if you can get a junkyard h/o alt in good condition, it might be just enough for your needs. these can also be rebuilt for more output, and these are often the basis of specialty h/o alt rebuilds for comp vehicles, db drags, and keydown vehicles.

anything more than that, and you're getting into the ohio generator or leece-neville range, which involves multiple batteries, LARGE ga. wiring, etc... and ridiculous current draw. these would be more for comp or keydown vehicles - with your current system, you're not there yet.

Merlin · 09-21-2009, 12:33 PM

Quote:

Originally Posted by Pigman

General rule of thumb is never exceed 2/3rds of your alternator output, as stated you'll drain the battery or burn up your alternator, I run linear amps for 2-way radio's and have got myself in the same dilemma from time to time. Get a bigger alternator and a darn good battery, then enjoy and forget about it!
Pigman

oh, good point - one option i forgot about is dual alts. some people replace the a/c compressor with another alt, or fab up brackets to mount dual alts.

of course, they are running LOTS of wattage, so this is probably more than overkill for your application.

a modded alt and a yellow top has served me fairly well with a 6 pill, provided i keep the rpms up and don't run high gear and ratchet jaw.

milehigheric · 10-10-2009, 09:55 PM

Quote:

Originally Posted by desertcamper67

I think you should look into capacitors.

Say no to capacitors !

In reality your setup will be fine. The amp will never ever draw 60A, averaging more like 1/6th of that...Run some current draw tests if you don't believe me. Nearly every sound system out there will exceed alternator output, that is where a good battery comes in to fill the gap.

Upgrade the big 3 cables (alternator to battery positive, battery to ground negative and engine to ground negative) to prevent voltage drop across the charge circuit. If you are still having issues look into a battery upgrade.

Best of luck

Jeremy11 · 11-09-2009, 04:26 PM

I have a stock 60 Amp alternator in my runner. I put in 2 12" Jackhammers and a 600WATT rms 1200WATT peak Infinity amp to support it. Had it wired to the battery like you would anything else and my truck starterd to slowly die. Took the battery to get checked and was told it was fine, that i needed a new alternator.. Turns out luckily i didnt fry my alternator yet. But the ground going to the alternator was fried. I had to resplice it and get another clip for it and got a .5 capacitor for my amp and no trouble since. If you are going to run more than one amp i would get a cap. Helps alot and improves sound

olharleyman · 11-09-2009, 04:53 PM

Dual battery's with a battery isolator that's what I did and run the entire stereo system to the extra battery and you will never have any issues with it at all because it only has to run the system and it is really easy to set up and the isolator is not very expensive at all 3 wires to the whole set up and your jammin down the road with no worries.

09-20-2009, 01:43 PM	#2 (permalink)
aviator Super Moderator Staff Join Date: Mar 2003 Location: COTKU,Ontario,Canada Posts: 7,469	Well by definition the answer is in effect no it cannot. Now you may not be pulling peak output from the amps all the time but any time you try for more then the 60A available from the alt. the electrical system will make up the shortfall by pulling the extra amps out of the battery. This will stress the charging system and reduce the batt. life considerably. The sound sys. is not the only electrical draw in the vehicle either consider starter/ignition/fuel pumps/fans/wipers/lights/ecu all of these draw juice from the same well as the entertainment system. The alt. does not put out the full 60A at idle either so anytime you are not at hwy cruise rpm [say 1800+] you're going to be getting a lot less then 60A. If you want to add another amp you will need to go to a larger alt. to keep up. The factory 60A can be rebuilt to put out 90A or a little better fairly easily by any competent alt. repair shop. You can also get alts. of up to 200A output from online shops. Hope this helps a little... anybody else got some input? __________________ Silver 1994 Hilux Xtra cab 4x4 3.0 K&N cone filter, ported MAF, advanced timing, oversize exhaust, free flow cat, "rumble" muffler custom covered SR5 seats, map lights, factory AC tv4184 style black interior conversion started mods to come... header, custom centre console, stereo upgrade tinted windows Founding member 1972TLC fan club - Get well soon Mary Toyota Hilux... Get in or Get out of the way. Last edited by aviator; 09-20-2009 at 01:45 PM.

11-09-2009, 04:26 PM	#8 (permalink)
Jeremy11 Registered User Join Date: Sep 2009 Location: Corpus Christi Texas Posts: 36	I have a stock 60 Amp alternator in my runner. I put in 2 12" Jackhammers and a 600WATT rms 1200WATT peak Infinity amp to support it. Had it wired to the battery like you would anything else and my truck starterd to slowly die. Took the battery to get checked and was told it was fine, that i needed a new alternator.. Turns out luckily i didnt fry my alternator yet. But the ground going to the alternator was fried. I had to resplice it and get another clip for it and got a .5 capacitor for my amp and no trouble since. If you are going to run more than one amp i would get a cap. Helps alot and improves sound __________________ "Stay far from timid, only make moves when your hearts in it, and live the phrase sky's the limit." -- Notorious B.I.G. http://s492.photobucket.com/albums/r...nt=gifs_21.gif

11-09-2009, 04:53 PM	#9 (permalink)
olharleyman Contributing Member Join Date: Dec 2006 Location: maryland Posts: 3,291	Dual battery's with a battery isolator that's what I did and run the entire stereo system to the extra battery and you will never have any issues with it at all because it only has to run the system and it is really easy to set up and the isolator is not very expensive at all 3 wires to the whole set up and your jammin down the road with no worries. __________________ 1990 4 runner 5 Speed Pro Comp Stage II 4" Lift 6" coils rear Aussie Locker front 5.29's Front And Rear 35 x 12.5 x 15 MT's Micky Thompson Classic II Wheels Super Charged 3.4 on the way 1993 SAS 4runner 22re 5 speed 4" front 5"rear 5.29's 35 x 12.5 BFG KM'S Dick cepek DC 1's 88 stock 4runner 3.0 auto for now 1955 Harley Davidson Springer Stock 1955 Hardtail Frame 4 Speed Kick Start Only 1998 Harley Custom Dresser 107 rwhp 139 ft.lbs.trq.

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09-20-2009, 02:42 PM	#3 (permalink)
Pigman Registered User Join Date: Aug 2009 Location: Central Oregon Posts: 24	General rule of thumb is never exceed 2/3rds of your alternator output, as stated you'll drain the battery or burn up your alternator, I run linear amps for 2-way radio's and have got myself in the same dilemma from time to time. Get a bigger alternator and a darn good battery, then enjoy and forget about it! Pigman

09-21-2009, 12:31 PM	#5 (permalink)
Merlin Registered User Join Date: May 2006 Posts: 160	you may want to look into upgrading your battery to a deep cycle battery. you may also want to look into alt. upgrades, i considered having one rewound but it will only increase output to around 80-90 amps. also, you will only get those amps at higher rpms. idle rpms may actually decrease with rewound alts. also, if you try to get too many amps out of a stock case rewound alt, you will also get more heat, which can shorten the life of the alt. you could try underdrive pullies, but while they'd give you more amps at idle, your alt would be spinning REALLY fast at highway speeds, or if you rev up the motor to up the output at a stop. a cheap solution would be adapting a GM h/o large case alt to fit, might need to mod or fab up a bracket and maybe change your belts, but if you can get a junkyard h/o alt in good condition, it might be just enough for your needs. these can also be rebuilt for more output, and these are often the basis of specialty h/o alt rebuilds for comp vehicles, db drags, and keydown vehicles. anything more than that, and you're getting into the ohio generator or leece-neville range, which involves multiple batteries, LARGE ga. wiring, etc... and ridiculous current draw. these would be more for comp or keydown vehicles - with your current system, you're not there yet.