Can a bad/failing battery cause an alternator not to keep up?

[Sephious 10+ year member]

The reason I ask this is I purchased a 200 amp high output alternator that apparently puts those 200 amps out at 1200RPM. I upgraded my wiring to 4 gauge, which should be more than enough for a system that, in the worst case scenario, can draw about 110 amps.

Now, the problem is my voltage still drops when my amp draws anything more than about 30 amps. It drops harshly when my subs are drawing the most power possible (about 80 amps, accounting for inefficiency of the amplifier). When the subs are maxed the voltage can drop as low as about 10.6V, and it keeps dropping the longer I play the tone.

Does this mean the high output alternator I bought isn't really high output, or could a bad battery cause the alternator not to be able to flow all of the needed amps through?

Thanks.

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[LosIsATool 5,000+ posts]

What amps?

 

[Sephious 10+ year member]

The two in my sig. At the moment the subs are using under 900 watts.

 

[silvercookie 5,000+ posts]

What amps?

Read his sig retard.

 

[silvercookie 5,000+ posts]

What gauge wire are you using?

And what brand alternator is it?

 

[Sephious 10+ year member]

What gauge wire are you using?And what brand alternator is it?

4 gauge with the stock still there, which looks to be about 8 gauge. It's a California Alternator and Starter alt. Figured with the fact that it has a one year warranty and that they actually list the engine RPM it's supposed to put 200 amps out at, I'd be okay with it.

I've still got a gut feeling it's the battery, unless that's not possible. Dropping to 10V seems like a lot, but then again I've never measured the voltage drop running off the battery alone on any car before. I'm pretty sure the battery is the stock one from when the car was new 5 years ago.

 

[grandam888 10+ year member]

also what size alternator? and a failing battery can cause alternator not to keep up. that is if you electrical system was beefed up enough to begin with.

when you exceed the alternators amperage for a brief period, it will draw from battery power. if said battery is failing, then you will be exceeding alternator amperage and have no where tol pull the extra power from.

what size is your alternator?

right now your pulling roughly 150-170 amps @ peak amperage draw from the amps, add the vehicles systems radio headlights A/C etc. your looking @ roughly 200-230 maybe a little more. this is why i run an alternator that amperage exceeds my demand, i really don't even need an extra battery.

so yes if the battery was saving your *** in terms of power availability and the battery is tanking, you will notice.

 

[Sephious 10+ year member]

also what size alternator? and a failing battery can cause alternator not to keep up. that is if you electrical system was beefed up enough to begin with.
when you exceed the alternators amperage for a brief period, it will draw from battery power. if said battery is failing, then you will be exceeding alternator amperage and have no where tol pull the extra power from.

what size is your alternator?

right now your pulling roughly 150-170 amps @ peak amperage draw from the amps, add the vehicles systems radio headlights A/C etc. your looking @ roughly 200-230 maybe a little more. this is why i run an alternator that amperage exceeds my demand, i really don't even need an extra battery.

so yes if the battery was saving your *** in terms of power availability and the battery is tanking, you will notice.

I'm not sure what size the alt is. I just know that it's supposed to put out 200 amps at 1200RPM. It's the same size as the stock one, but seems heavier.

The sub amp I'm using isn't even close to being maxed. It's only using about 900 watts, if not even a little less than that, so I'm nowhere near 150-170 amps. I'd be closer to that with everything running, including AC and brights. Even then that number is probably a little high. I've clamped my alternator wires and they seem to push no more than about 5 amps together, which seems a little odd to me.

EDIT: DEERRP. I have an AC clamp. I can't measure DC current, so I can't tell how many amps my alternator is actually pushing.

 

[LosIsATool 5,000+ posts]

Read his sig retard.

You can **** my sig..

 

[grandam888 10+ year member]

I'm not sure what size the alt is. I just know that it's supposed to put out 200 amps at 1200RPM. It's the same size as the stock one, but seems heavier.
The sub amp I'm using isn't even close to being maxed. It's only using about 900 watts, if not even a little less than that, so I'm nowhere near 150-170 amps. I'd be closer to that with everything running, including AC and brights. Even then that number is probably a little high. I've clamped my alternator wires and they seem to push no more than about 5 amps together, which seems a little odd to me.

EDIT: DEERRP. I have an AC clamp. I can't measure DC current, so I can't tell how many amps my alternator is actually pushing.

well what symptoms are you having that leads you to believe your having issues? and if the voltage is dropping below 13 @ idle and that's your issue, rev engine above 1000 rpm. most HO's don't really do worth a **** until 1200rpm

 

[Sephious 10+ year member]

well what symptoms are you having that leads you to believe your having issues? and if the voltage is dropping below 13 @ idle and that's your issue, rev engine above 1000 rpm. most HO's don't really do worth a **** until 1200rpm

Voltage drops to just above 10 volts during a 70Hz tone. This is at above 1200RPM.

I'm pretty sure the alternator is just garbage and does not do its rated output. I'm probably just going to buy a DC Power Engineering one, as they now list ones for the Mazda 3.

 

[grandam888 10+ year member]

if big three hasn't been done, that would be a major issue. if it has, sounds like the alternator is taking dump soon. personally i have a 250amp alt. from ebay and it stays @ 13.5-13.8 during all tones at full tilt when revvd to 1000rpm. i would say your battery being bad would be my last guess.

has big three been done? id so, get a new alt. soon. under voltage is REALLY BAD for an amplifier, eventually will fry it.

 

[Sephious 10+ year member]

Big 3 has been done. This is a new alt. It's a 200 amp alternator from eBay from California Alternator and Starter.

 

[grandam888 10+ year member]

i would say alternator is junk, send it back, i went with powermax on ebay. i couldn't be happier with my alternator does rated or super close, case is way bigger and heavier, unless you wanna run duals with your stock and this HO(so called HO) contact the seller and if he gives you ****, call paypal and say it was falsely advertised as a 200 amp alternator and it putting out less than 150 and isn't of any use to you.

what kind of car is it?

 

[mclerico83 5,000+ posts]

your running 4 guage to your amp, thats a problem 2, it needs 0 guage required