Will my alt be ok?

[MrSkippyJ]

your logic isn't that great, so you should probably read up for a little longer before posting suggestions.

Well using physics, University Physics II to be exact... His first amp can put out 2600 watts plus the 400 watts of the second amp = 3000 Watts. Lets say 14.4 volts is desirable... Using P (watts) divided by E (volts) equals I (amps) or 3000/14.4 = 208 amps roughly and that's without the in efficiency of the amps or the cars draw... he is only charging with 160 amps, my logic doesn't add up??? Ok then...

Or

the since we are just going on assumptions, he is running the amp at 4 ohms, so 50x4. and the hifonics amp probably does around 2000. so more like 2200 instead of 3000 like you were assuming. that gives us 152 amps. In that case, adding a second battery would do a lot of good.

There, the facts are known.

[Brandon_4078]

Or

the since we are just going on assumptions, he is running the amp at 4 ohms, so 50x4. and the hifonics amp probably does around 2000. so more like 2200 instead of 3000 like you were assuming. that gives us 152 amps. In that case, adding a second battery would do a lot of good.

There, the facts are known.

All without car draw and amp inefficiencies, amps can be as inefficient as 25% or possibly more because of heat and circuits etc. That will add at least 500 watts with out the car considered... 187 amp... and a car does use a good chunk of the original alternator already, a battery that has been drained won't charge much on a short drive, also why you should top of all vehicles time to time with a bat charger.

Edited April 23, 2012 by Brandon4078

[MrSkippyJ]

yes, most of us know all of this. the whole point was it is pointless to throw out formulas showing what the amperage draw is, the best we can do is guess, too many variables.

adding batteries can help when an alt can't keep up. Then after that yes, you need to charge them back up. That is why Kranny said to watch the voltage. When it gets low, shut the system off and let the alt take it easy for a while. Let the batteries charge over night, rinse and repeat. Most of us don't have big enough systems OR we don't play them long enough that a high output alt is necessary.

That was the point you missed.

[BEEMDUB]

Everyones math is wrong, for 150 bucks for 2 of them they will only work in my truck so send them to me asap! LOL you will be fine just do as Kranny suggested and check the voltage you will want to toss them on a charger and top them off but I do that with all of my builds no matter what amp, alt or battery.

Thanks for the input everyone....As for topping them off, how exactly should I do that? Just hook up a charger to one of the batteries every night and let it trickle charge at 2 amps? and if so wouldn't that pose a fire hazard lol

[Brandon_4078]

he simply said he would be fine just to watch voltage... for what the op is doing is fine and the price hes getting the batts i would say go for the 2 batts setup. i am running more than 3000 watts in my car and its just fine and i have a stock 130amp alt

It might be ok to watch the voltage, and I have no problem with that at all... Earlier I was simply giving my opinion for an electronically sound system witch I prefer if I were going to be blasting music for a long duration of time with out having to let my alt catch up causing strain to the system... I just don't enjoy being called a liar when there are facts to be considered, and was simply liberating myself. Don't mean to be rude to you or any one else. I just want to make the facts known and not be bashed for it cause its not the "normal way". Again not trying to be rude.

yes, most of us know all of this. the whole point was it is pointless to throw out formulas showing what the amperage draw is, the best we can do is guess, too many variables.

adding batteries can help when an alt can't keep up. Then after that yes, you need to charge them back up. That is why Kranny said to watch the voltage. When it gets low, shut the system off and let the alt take it easy for a while. Let the batteries charge over night, rinse and repeat. Most of us don't have big enough systems OR we don't play them long enough that a high output alt is necessary.

That was the point you missed.

I didn't miss the point, and actually said it was FINE. The equation is not pointless to throw out, and it was to justify MY POINT of an electrically sound system, which IS CORRECT that is the point that EVERYONE HAS BEEN MISSING. Again I have no problem with watching the voltage, nor am I trying to be rude, just defending myself.

[Brandon_4078]

Everyones math is wrong, for 150 bucks for 2 of them they will only work in my truck so send them to me asap! LOL you will be fine just do as Kranny suggested and check the voltage you will want to toss them on a charger and top them off but I do that with all of my builds no matter what amp, alt or battery.

Thanks for the input everyone....As for topping them off, how exactly should I do that? Just hook up a charger to one of the batteries every night and let it trickle charge at 2 amps? and if so wouldn't that pose a fire hazard lol

That's the best way, we do that for everything (tractors, cars, lawn mowers etc.)

Edit: Its never been a problem for us, just don't put it on any thing more than 2 amps, that may not be good.

Edited April 23, 2012 by Brandon4078

[MrSkippyJ]

he simply said he would be fine just to watch voltage... for what the op is doing is fine and the price hes getting the batts i would say go for the 2 batts setup. i am running more than 3000 watts in my car and its just fine and i have a stock 130amp alt

It might be ok to watch the voltage, and I have no problem with that at all... Earlier I was simply giving my opinion for an electronically sound system witch I prefer if I were going to be blasting music for a long duration of time with out having to let my alt catch up causing strain to the system... I just don't enjoy being called a liar when there are facts to be considered, and was simply liberating myself. Don't mean to be rude to you or any one else. I just want to make the facts known and not be bashed for it cause its not the "normal way". Again not trying to be rude.

yes, most of us know all of this. the whole point was it is pointless to throw out formulas showing what the amperage draw is, the best we can do is guess, too many variables.

adding batteries can help when an alt can't keep up. Then after that yes, you need to charge them back up. That is why Kranny said to watch the voltage. When it gets low, shut the system off and let the alt take it easy for a while. Let the batteries charge over night, rinse and repeat. Most of us don't have big enough systems OR we don't play them long enough that a high output alt is necessary.

That was the point you missed.

I didn't miss the point, and actually said it was FINE. The equation is not pointless to throw out, and it was to justify MY POINT of an electrically sound system, which IS CORRECT that is the point that EVERYONE HAS BEEN MISSING. Again I have no problem with watching the voltage, nor am I trying to be rude, just defending myself.

fair enough

[Guest]

if OP has $500 to dump on a brand new alt to make sure he never ever gets voltage drop with his $300 amp, then that's his choice. otherwise, he'll be perfectly fine.

plus brandon, if you want to get technical, you must be insane to think that an amp will output its full power all the time. everyone is affected by impedance rise. so for example, 2000 watts will drop down to 1250 instantly while playing music because of the effects of box rise. granted it varies, but you will very very very rarely see the full 2000.

which explains why my 1200 watt sub amp and my 200 watt highs amp powered by a 2 year old walfart wet cell and a 70 amp alt, dont drop me down past 14 unless i dip into clipping.

i'll state this again, he will be PERFECTLY FINE with three batteries. everyone should monitor their voltage regardless of how strong or weak their electrical system is. it's just good practice

i didnt really read any of the above responses, so i'm just stating all of this on the fly.

Edited April 23, 2012 by Kranny

[Brandon_4078]

I never had any thing against 3 batteries other than it may be overkill (essentially). Yes, depending on music, and amp, and everything else your actual wattage may very, we covered that, but an amp is always going to use more watts than it putts out and your putting all this on top of what the vehicle already uses and is going to almost always exceed the factory alt. But you are correct that you can just watch you voltage and turn off the system and charge at night for a cheap alternative. I prefer to not have to deal with worrying about it but I do watch my voltage (plus I don't wanna have to stop on a good song lol). Anyway its getting too late for this... why don't we agree that we could go on and on for hours...

[BEEMDUB]

hah for the record too I'd like to say that the longest my subs have ever played consecutively is probably no longer than 2 minutes....and I never play songs back to back in between songs I always turn em off for a minute or so