Capacitor stay always on

[AMG]

Hello everybody and sorry for my english i am from Europe. I buy a new car with an audio installation in. There is in the trunk a capacitor, an amplifier and a sub. I notice that the light of the capacitor stay always on. There is 2 lights and a voltage indicator who stay at 0v. The capacitor is a crunch cr 1000 cap. I notice that there is a sort of box at the end of the wire of the capacitor and the amplifier. I don't understand what's in. My probleme is that do you know if the light on in my capacitor can broke my battery ? I close the car and let my phone filming inside. The lights stay always on even with the trunk and the car closed. Do you know how i can disconnect this capacitor ?

Thanks you all for your help

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[dragon.breath 10+ year member]

Those types of capacitors are pretty much a gimmick in car audio almost completely useless. I would remove it and trash it. The 2 wires are power and ground. Run the power wire directly to the positive on the amplifier. If the amplifier ground is going to the capacitor , do the same thing. If the amplifier is grounded separately, leave it alone and just remove the capacitor ground wire.

 

[RobGMN 5,000+ posts]

Those types of capacitors are pretty much a gimmick in car audio almost completely useless. I would remove it and trash it. The 2 wires are power and ground. Run the power wire directly to the positive on the amplifier. If the amplifier ground is going to the capacitor , do the same thing. If the amplifier is grounded separately, leave it alone and just remove the capacitor ground wire.

Is it the capacitance that's a gimmick? I know in home audio, mega caps are used to smooth the power out and to maintain voltage for surge needs. One amp I had would continue to play for about 30 seconds after power was cut, as the capacitor bank bled off.

Are the car audio ones just too low in capacitance to be effective?

 

[dragon.breath 10+ year member]

The idea of extra capacitance is good. But 1 farad of capacitance is not enough to be very useful in a 12v environment. I run an ultra cap ( around 500 farads ) and it makes a huge difference.

 

[AMG]

Ok so the best is to diconnect this capacitor right.

I send you some picture of the installation.

 

[AMG]

More pics

 

[ThxOne Premium Member]

Be mindful of the cables as you disconnect that capacitor. That power is coming from the battery so if there is a fuse up there, disconnect the battery fuse on that power cable. Then be careful removing the capacitor. Dispose of properly. Connect that power cable to that distribution block where the wire was coming from the capacitor... go back under the boot and reinstall the fuse. Happy Days.

 

[RobGMN 5,000+ posts]

Be careful of that capacitor too. Could get a nice wake-up jolt.

 

[hispls 5,000+ posts]

caps are used to smooth the power out and to maintain voltage for surge needs.

This is what the amp's power supply does, and yes, the energy storage of those big can style ones sold by dubious car audio brands isn't a squirt of piss in the bucket even to supply energy needs of a modest aftermarket system.

 

[RobGMN 5,000+ posts]

This is what the amp's power supply does, and yes, the energy storage of those big can style ones sold by dubious car audio brands isn't a squirt of piss in the bucket even to supply energy needs of a modest aftermarket system.

Disregarding advertising hyperbole, what is the recommended ratio of farads/watts?
It seems most of the answers out there just follow what's in advertising (1/2:1,000 or 1:1,000).

 

[dragon.breath 10+ year member]

We used to hear 1 farad per 1000 watts. But that was mostly advertising. I would aim for 50 to 100 farads per 1000 watts.

 

[hispls 5,000+ posts]

Disregarding advertising hyperbole, what is the recommended ratio of farads/watts?
It seems most of the answers out there just follow what's in advertising (1/2:1,000 or 1:1,000).

What "problem" are you trying to get the capacitor to solve? As far as I know, even the lowest cost amps these days have enough R&D behind them that the power supply would have adequate capacitance built in, and capacitors aren't really a great way to store a lot of reserve energy.

Energy is 1/2 the capacitance times the voltage squared. 1 watt is 1 joule per second.

Figure out how much energy you're attempting to provide and you the calculator built in to whatever device you're posting this from should be able to give you an idea of what sort of capacitor bank you would need. Do take into account how quickly you will be able to recharge the capacitors as well.

By my math, a 500f bank would store enough energy to feed a 1000W amp for a few seconds. That size Maxwell bank sells for around 350$. I suspect 350$ worth of battery would hold a bit more energy reserve but do what you like. The whole thing seems rather impractical for most situations, particularly with the current state of lithium options.

 

[RobGMN 5,000+ posts]

What "problem" are you trying to get the capacitor to solve? As far as I know, even the lowest cost amps these days have enough R&D behind them that the power supply would have adequate capacitance built in, and capacitors aren't really a great way to store a lot of reserve energy.

Energy is 1/2 the capacitance times the voltage squared. 1 watt is 1 joule per second.

Figure out how much energy you're attempting to provide and you the calculator built in to whatever device you're posting this from should be able to give you an idea of what sort of capacitor bank you would need. Do take into account how quickly you will be able to recharge the capacitors as well.

By my math, a 500f bank would store enough energy to feed a 1000W amp for a few seconds. That size Maxwell bank sells for around 350$. I suspect 350$ worth of battery would hold a bit more energy reserve but do what you like. The whole thing seems rather impractical for most situations, particularly with the current state of lithium options.

It’s more a matter of learning and understanding at this point.

If 500F would only power an amp for a few seconds for that kind of money, wouldn’t it make much more sense to run another battery?
Or are there other benefits to a cap (weight, voltage sag, safety)?

In home audio it’s always “more is better”, but I assumed it had to do with the 15 amp limitations at a power outlet (ignoring of course that it’s 10x the voltage of a car system), and relying on capacitors for surge power.

 

[ThxOne Premium Member]

It’s more a matter of learning and understanding at this point.

If 500F would only power an amp for a few seconds for that kind of money, wouldn’t it make much more sense to run another battery?
Or are there other benefits to a cap (weight, voltage sag, safety)?

In home audio it’s always “more is better”, but I assumed it had to do with the 15 amp limitations at a power outlet (ignoring of course that it’s 10x the voltage of a car system), and relying on capacitors for surge power.

It depends... are you trying to support the power over a long time (sustained listening) or Just loud demo's (burps of bass) quickly?

Quickly, use the caps.
Sustained music, use additional batteries.

 

[RobGMN 5,000+ posts]

It depends... are you trying to support the power over a long time (sustained listening) or Just loud demo's (burps of bass) quickly?

Quickly, use the caps.
Sustained music, use additional batteries.

What is the science behind that? Faster power delivery in bursts from a cap over a battery?