When to upgrade alts/batteries?

[osmith 10+ year member]

So, I am relatively new to all this and I am wondering at what point you would need to start adding extra batteries and ho alternators to your system?

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[Pickler 10+ year member]

asap

 

[Crownvicon28s 10+ year member]

It depends on how strong your stock electrical system is. How many amps is your current alternator? How much power do you plan on running?

 

[rumple4skin 10+ year member]

It depends on how strong your stock electrical system is. How many amps is your current alternator? How much power do you plan on running?

what is your cars make and model, what is the amp make and model and subs. if you know your alternators amperage out put that will help with your question.

 

[Wildbillpb 10+ year member]

At the point where your amp is not getting a steady flow of volts.. Dmm your terminals if it is dropping or something like that I would upgrade... Do big 3 before anything else it's cheaper and even if you get more batteries and a better alt they are restricted by factory wiring.

 

[helotaxi 5,000+ posts]

The rating of the stock alternator doesn't mean anything since you don't know what the basic functions of the car draw or how much headroom was designed into the system. Put it this way which car is better off for adding a system, one with a 100A alt where the car uses 80A or one with a 63A alt where the car uses 25A?

 

[osmith 10+ year member]

The car is a 1990 toyota camry. I am in the process of putting together a complete system in it. I havent purchased the subs or amp yet. I am going to be going with a soundstream xxx 18, but I am not sure what amp yet. Obviously one that would power that sub decently, but not sure exactly which one.

 

[CHEMMINS 10+ year member]

Yes you will need an upgrade with those plans.

 

[osmith 10+ year member]

Exactly what would that require do you think? How many extra batteries? How many alt or what amp?

 

[emilimo701 10+ year member]

Exactly what would that require do you think? How many extra batteries? How many alt or what amp?

When you get up there in wattage (typically >2000 on a class D amp) you may be approaching the limits of your electrical system, the heart of which is your alternator.

The general rule I have come up with is, take the fuse rating of whatever amp you'll be using, multiply it by .75 (you have to be skilled to run your amp at 99% power and not have the fuse blow). If that number is greater than the residual amperage (what wouldn't be used without subwoofer system), then you might want to run some tests (some are obvious, such as checking headlights) to see if your voltage is dropping.

For the Soundstream XXX... yes you are definitely going to need a high output alternator. Otherwise it wouldn't make sense to spend money on a sub with that kind of power handling.

And extra batteries are generally installed for playing music with the engine off.

 

[Sarthos 10+ year member]

Extra batteries can also be used as the equivalent of running a GIANT capacitor. To make your system not dim running off the alternator without enough backup from batteries isn't gonna work too well all the time.

 

[osmith 10+ year member]

So, as long as I wont be playing music with the engine off I wont need the extra batteries?

 

[Sarthos 10+ year member]

Extra, no, upgraded, yes. We really need to know what amps you're gonna run first.

 

[osmith 10+ year member]

I wish I knew myself, haha. What is a good amp that would be recommended for that sub?

 

[helotaxi 5,000+ posts]

You're going to want an extra battery even with the upgraded alt. The inductance of the alt keeps it from delivering instant power. Transient demands are handled by the batteries and the alt just recharges the batteries once it catches up. The bigger the system and the more dynamic the music, the more batteries you want to absorb the transient demand without dropping the voltage.