big alt vs. smaller alt

[rickymac21 10+ year member]

alright guys.. i want a little input.. a debate if you want.. i just need to know so i dont waste a lot of money.... i know that most everyone with a reasonably sized audio system has a pretty high amperage alt... well does this really do you any good? i mean, the alt will get hotter faster wont it? and do all the h/o alts have lifetime warrenties??

i know that i can get a stock alt from autozone for $140 rather than spending $400 +.. yea its only 75 amps, but if i have 4 batteries laying around... all still have juice roughly around 550 cca's each... now my alternator will do just fine if i have that many batteries running say a 4k w system as long as when im done listening to the music, i turn off the amp and let the batteries charge for a minute or two... basically, if i have that many batteries the amp cant simply **** out all the power instantly or even enough to dent the batteries enough to make that little amperage alt kill itself.. am i right or am i missing something.. please go ahead and put in your input... i just need to know if i should go ahead and get the bigger alt or not.. either way im getting 3 more batteries...

Click to read more...

 

[skittlesRgood 10+ year member]

one thing is missing. the alt has to charge all that. normaly the alt is only on a small amount of time and wont get very hot. with more power and definatly more batts, the alt will be running constantly trying to charge everything. with the lower amperage it takes even longer to charge and thus is running more. this will make your stock alt burn up fairly quick. the HO alts are made to take the abuse and can charge the system faster and with less effort. thus lasting longer and actualy staying cooler.

yes the batts have 550amps but thats for what... 2 seconds or something? so yes you can drain them if you dont have an alt that can charge fast. its like trying to fill a water tower with a garden hose. and haveing a 10" pipe draining the tank

 

[jdawg 5,000+ posts]

if they are regular car batteries, forget it, deep cycle and you might get away with it, for a while anyways

 

[rickymac21 10+ year member]

well yea, both those make sense...i understand that but someone just explained to me this other theory and he is a mechanic and it sounds legit. like i said.. if you have all those batteries, there is no way the amp can run them dry or even close to it. because the amp is getting its power from all those batteries. ya know? so i guess a way to describe it would be me ( the amp . lol ) going around the world gettin a single $ from everyone, there is no real damage to any single person ( battery ).. really bad analogy but only thing i could think of at the moment.. too tired.... but yea, ill prolly end up spending the extra money... only thing about the cheaper alt too is that i can get a life time warrenty on it, so no matter how many times i do kill it , i get another free.

 

[jdawg 5,000+ posts]

you would kill the alt eventually. Atleast get a good one from like Napa, get an advanced one and you are gonna get tired of puttin a new one on after about the 5th time.

 

[rickymac21 10+ year member]

you would kill the alt eventually. Atleast get a good one from like Napa, get an advanced one and you are gonna get tired of puttin a new one on after about the 5th time.

thats true.. what about a dual alt kit with the 2 smaller amperage alts...? ahhaha now im just kinda throwin this shit out there but that would be alright wouldnt it? basically the same thing as 1 H/o alt... or do alternators not work like that??

 

[skittlesRgood 10+ year member]

garden hose filling a water tower with a 10" drain... itll run dry eventualy. oh and if the alt burns up it could create a short and burn your car down.

also i believe that you may void the warranty doing this. read up on that just in case. 4k watts is a lot of power and it needs to come from somewhere. the alt is the only thing making the power. you may not drain the batts fast but you can get bad voltage drop with just batts and no alt.

you have one mechanic saying one thing and a forum full of people saying another. and if it helps, my dad is a **** good comp. engioneer. he knows electricity like no ones buisness. i tried to just add batts and leave the alt and he told me that was stupid. in much nicer words =)

 

[bones22 5,000+ posts]

look for something that will give you 220-300amp

remember that even a 300amp alt wont give you 300amps until you hit a certain rpm which is usually over 2000rpm.

(example my 300amp EA did close to 300amp @ 2700rpm) in otherwards during a comp id never see it)

the idle amperage is a lot more important

i know MECHMAN alts all seem to give around 150amp @ idle

 

[rickymac21 10+ year member]

garden hose filling a water tower with a 10" drain... itll run dry eventualy. oh and if the alt burns up it could create a short and burn your car down.
also i believe that you may void the warranty doing this. read up on that just in case. 4k watts is a lot of power and it needs to come from somewhere. the alt is the only thing making the power. you may not drain the batts fast but you can get bad voltage drop with just batts and no alt.

you have one mechanic saying one thing and a forum full of people saying another. and if it helps, my dad is a **** good comp. engioneer. he knows electricity like no ones buisness. i tried to just add batts and leave the alt and he told me that was stupid. in much nicer words =)

hahaha.. thats funny... but yea.... i already knew i wanted to get the High out put alt.. i just wanted to see if this guy was right. i mean. it seems logical but in the end the batteries would have to die... voltage would drop and yea things go bad... that said is a 150 alt good enough to run a autotek mm4000 and 1 kinetik 600 and 2 kinetik 2400's???

 

[jdawg 5,000+ posts]

I guess depends on the car and how much it costs. 4k is ALOT. Dont skimp out or your amps go poof. Gotta fidure if its a 120amp alt you are gonna get half that at idle, so 2 alts and you get 120 at idle, or get like a Mechman that does 150amp at idle 300 past 2200 or something, bolt in up like stock and be done. Even with 2 factory alts, factory alts aernt made to take a beating like that.

 

[rickymac21 10+ year member]

I guess depends on the car and how much it costs. 4k is ALOT. Dont skimp out or your amps go poof. Gotta fidure if its a 120amp alt you are gonna get half that at idle, so 2 alts and you get 120 at idle, or get like a Mechman that does 150amp at idle 300 past 2200 or something, bolt in up like stock and be done. Even with 2 factory alts, factory alts aernt made to take a beating like that.

thats who i would be getting the alt from.. mechman.. he gave me a short list for my car... the one i looked at was like 150 max amperage. and it idled with like 100 - 120 amps... somthin like that.... there was another one for 180 amps and 140 or so at idle but it also is a significant amount of money more... lol

 

[skittlesRgood 10+ year member]

i dont think mechman is lifetime... though i should know since i have one. either way they are killer alts. with my electrical and system i get no voltage drop. and with more wire i could do even better. with 150amps and those batts you could be ok. just remember, the math says you need 285amps. 4000watts/14volts = 285amps. so... 150 x 14 = 2100. and at idle that alt will do even less. maybe 70amps.

you ever heard of bcae1.com? check that site out. its got a ton of great info.

 

[RAM_Designs 5,000+ posts]

Look into DC Power alts...I've seen nothing but good things from them.

 

[bones22 5,000+ posts]

i doubt matt (mechman) gives a lifetime.

just like all electronics in time it will crap out. in this case with added wear on it from the system he would lose a lot of $ if he offered it

although it would be great for the people who bought them

 

[skittlesRgood 10+ year member]

i doubt matt (mechman) gives a lifetime. just like all electronics in time it will crap out. in this case with added wear on it from the system he would lose a lot of $ if he offered it

although it would be great for the people who bought them

ya. matt knows what we do with these alts lol. just make sure you email matt, not that other guy. the other guy will NEVER get back to you. he emailed me like 2 months later about the alt i asked him for. matt had already taken care of me though.