[Paragon1]

So after my powered sub install my woefully underpowered stock alternator cant keep up. Elected to get DC power alternator, and as luck would have it, I discovered antigravity batteries after making the purchase. So after a bit of scotch, one purchase became two. Alternator is here, still waiting on the battery.

I have two questions for you electronically inclined individuals out there.

First, I've only seen a single install thread for the alternator, is it really necessary to upgrade the cables to/from the alternator & battery?

Second, does anyone have experience with high output alternators charging Lithium Ion batteries?

Worse case i can imagine is that i'll have to sell the alternator since Lithium batteries charge better. And the reason i went with AG is because they never deplete to the point you cant start the vehicle, you can monitor their health via phone app, and their also extremely light (45lbs lighter than the stock battery in my RS5).

I've sent inquiries to both vendors but the holidays have delayed their responses past my ability to wait so i'm putting myself at the mercy of the forum. Any info would be appreciated. - Cheers

[fkheath]

Why not get one of those really large capacitors for car power amplifiers? A quick look on Amazon shows that you can get them up to 10 Farads. Be sure to mount as close to the amp as possible and use the largest wire that will fit in the receptacles. That should solve your problem.

[Captain Planet]

Originally Posted by fkheath

Why not get one of those really large capacitors for car power amplifiers? A quick look on Amazon shows that you can get them up to 10 Farads. Be sure to mount as close to the amp as possible and use the largest wire that will fit in the receptacles. That should solve your problem.

Mounting an actual 10f capacitor under the hood sounds like a good way to die.

[Nobody Special]

OP, don't rip out the OEM stuff, Just augment it with 4AWG.
You can follow the route of OEM cables and secure to OEM in some manner.

How many amps is the alternator rated for at idle and speed?
How many watts is/are your amp/s?

[Nobody Special]

Originally Posted by fkheath

Why not get one of those really large capacitors for car power amplifiers? A quick look on Amazon shows that you can get them up to 10 Farads. Be sure to mount as close to the amp as possible and use the largest wire that will fit in the receptacles. That should solve your problem.

People still use caps?

[jhguth]

caps are how you protect against voltage drops during hard hits, i don't see a reason how/why that would have changed

[Nobody Special]

Originally Posted by jhguth

caps are how you protect against voltage drops during hard hits, i don't see a reason how/why that would have changed

I am well aware. But mostly I see a second battery, usually Lithium, these days.

A cap stores power to an extent, but it does not function in the same way as a battery.
They are usually band-aids to "failing" electrical systems which also has an effect on the main battery, shortening its life.

Since capacitors have to charge, discharge and then charge again, they will supply uneven voltage to your amps which is not a good thing.
Amp life is also shortened.

[Paragon1]

Originally Posted by Nobody Special

OP, don't rip out the OEM stuff, Just augment it with 4AWG.
You can follow the route of OEM cables and secure to OEM in some manner.

How many amps is the alternator rated for at idle and speed?
How many watts is/are your amp/s?

Cant remember the wattage on the main amp but I think it’s 200, the powered sub specs are: 32Hz-150Hz frequency response, Power Rating: 120W RMS. RCA (0.1-4V) / Speaker Input (1.5-30V/auto sensing).

Here’s the DC Power alternator output, I don’t know how this compares to stock:

[Nobody Special]

Dude, you have less than 1,500 watts total, right? No typos there?
Something does not seem right. Like a bad ground somewhere.
Did you ever have your old batt/alt tested?

Just a ROUGH estimate as power is dynamic, not static, a single 1,500 watt amp/system would need 65 amps for music. (You are not pulling all 1500 from the amp every minute)
If you are listening at SPL comp levels drawing all 1,500 watts, that increases to say ~215 amps.

Do you have your amp model numbers?

[Nobody Special]

FYI, I am going to be installing some larger amps, and the FIRST thing I am doing is "The Big Three". Actually, I would be doing it regardless of audio system.
IF IF IF I push current limits, then I will upgrade the alt/battery.


Toyota is going to use the bare minimum they can get away with.
They are not building cars like they used to, where everything was beefy.
They build with the average user in mind.

I am pretty sure the stock alts are either 100 or 130 depending on model/options.

[fkheath]

Originally Posted by Captain Planet

Mounting an actual 10f capacitor under the hood sounds like a good way to die.

I said to mount the cap as close to the amp as possible, Amps are never mounted in the engine compartment, but usually under a seat or in the cargo/trunk area.

The reason Paragon1 thinks he needs a bigger alternator is because when the hard bass hits (drums, bass guitar, etc), the amp draws a huge current for a short period of time. The large cap provides that current, as long as you use a large, short wire (near the amp) to connect them.

A good battery can also provide that current, but due to the long distance from the car battery to the amp, there is inevitably a voltage drop, causing lights to dim and other associated electrical problems (same reason the lights dim when you start the engine).

[rayofsi]

i don't know if i'm reading right. but Antigravity batteries have like half the reserves, maybe even less then you have in an agm battery like odyssey?

[Paragon1]

Originally Posted by Nobody Special

Dude, you have less than 1,500 watts total, right? No typos there?
Something does not seem right. Like a bad ground somewhere.
Did you ever have your old batt/alt tested?

Just a ROUGH estimate as power is dynamic, not static, a single 1,500 watt amp/system would need 65 amps for music. (You are not pulling all 1500 from the amp every minute)
If you are listening at SPL comp levels drawing all 1,500 watts, that increases to say ~215 amps.

Do you have your amp model numbers?

I replaced the stock battery with an optima last year, and I had to use my jump starter this morning actually. It was only 38 last night, and my 4R lives in the garage. Pretty sure it’s the alternator as I can’t even run music for more than 30min (not full volume) without killing it. Amp is an alpine S-A32F 55 watts RMS x 4 at 4 ohms (80 watts RMS x 4 at 2 ohms)

[fkheath]

Originally Posted by Paragon1

I replaced the stock battery with an optima last year, and I had to use my jump starter this morning actually. It was only 38 last night, and my 4R lives in the garage. Pretty sure it’s the alternator as I can’t even run music for more than 30min (not full volume) without killing it. Amp is an alpine S-A32F 55 watts RMS x 4 at 4 ohms (80 watts RMS x 4 at 2 ohms)

Easy to test the alternator. Just measure the voltage across the battery with the engine running. If it is about 14 volts the alternator is good. Thus you may have a battery (or connection) problem.

[Bumbo]

Originally Posted by jhguth

caps are how you protect against voltage drops during hard hits, i don't see a reason how/why that would have changed

The trends have changed... these days its better to just use LiFePO4 cells.

Headway is a good cheap alternate that gets you a lot more value and capacity than caps. Benefits of a battery with the low resistance discharge potential of caps.

Melting metal with Batteries - YouTube

USED HEADWAY 38120 HP 3.2V 8AH LIFEPO4 BATTERY – Battery Hookup