I am wondering if anyone has ever run a 14v battery in a polo 6n2 charging at 15.9 or above? I am in the process of getting custom made high out put alternator with an external regulator, that let me charge high enough for a 14 volt system. I don't want to just go and do it with seeing if any one else has and if there are any major issues they had with it. I know a lot of components on some vehicles do not like the higher voltage

Gotta ask the question, why 14 volts?

better for car audio, higher voltage is more efficient.

I would run that on a seperate system .ie split charge system. That way there is plenty of juice for the sound system and the car can run on its normal battery.

I would run that on a seperate system .ie split charge system. That way there is plenty of juice for the sound system and the car can run on its normal battery.

how would i run a second charging system for that, to the best of my knowledge no one has ever had a high output alternator made for one of these, let alone ran dual alternators. the stock 90a alternator is not plenty of juice for the the system i am running. i am not going to be running your every day little boom boom system but a 12k rms one, already have i XS Power s3400 under the hood and 4 d3400s in the hatch.

the only way i would know how to do a split charging system would be to run a voltage step down like this one click here but that can only do 25 amps continously and there not cheap and i don't even know how many i would need for the car.

Google split charging, from memory they are used in 4x4 off roaders a lot, but may not have enough juice as you say.

Iirc they use a controller that monitors the batteries and alternator and keeps them topped up, I don't think it beads an exta alternator.

It is the Zenor diode part of the voltage regulator that sets the output voltage, so providing that an alternator has a high enough CURRENT output, you can make it charge at what voltage you like, by building the appropriate value Zenor into an external regulator.

However, that does not solve your split system problem.

I am a little sceptical about using a higher than normal voltage on semi-conductor devices, as these tend to be VERY voltage sensitive, there are exceptions and it may be that your system is one of these.

Regards.

Problems of doing this practically aside, I can't see the advantage of feeding an extra couple of volts to an audio amp?

OK you'll need a reduced current to get the same power but as power amps don't run off the raw 12 volts rails anyway a small hike in input voltage will have negligeable affect on output power.

If you went for a 60 volt system I can start to see advantages, current is reduced by 1/5 and cable resistance starts to have significantly less effect in terms of losses and efficiency improvements start to look worth having.

If you're having a custom alternator made, why not go for a dual output? Leave the car's systems at 12 volts (14 volts charging) and go for a significantly higher voltage on the audio system. 60 volts might be over ambitious but 24 volts should be within reach. 24 volt alternators are common in commercial vehicles so regulators should be available.

A couple of other points, this is a Polo you're putting 12,000 watts of audio into? Has the engine got 10 hp plus to spare?

Why not go for the Alternators the rally service barges use, they put out 240 vac @ 3kva but I doubt your little engine would handle the power drain!! Be realistic and adapt your audio system to the power your motor can supply or have an external genny to make up the power requirements

When running the alternator is giving 14.7volts anyway so what is the benefit overall?

Wouldn't higher ampage be better over voltage? Even then you need to take into account the parasitic losses a higher amp output alternator causes on an engine.

Any car with white towing plug will have a split charge relay system as it supplies the caravan battery on the move.

I have the wires in my car for one to charge the leisure battery we use in the tent. (Need to refit before show season).

Problems of doing this practically aside, I can't see the advantage of feeding an extra couple of volts to an audio amp?

OK you'll need a reduced current to get the same power but as power amps don't run off the raw 12 volts rails anyway a small hike in input voltage will have negligeable affect on output power.

If you went for a 60 volt system I can start to see advantages, current is reduced by 1/5 and cable resistance starts to have significantly less effect in terms of losses and efficiency improvements start to look worth having.

If you're having a custom alternator made, why not go for a dual output? Leave the car's systems at 12 volts (14 volts charging) and go for a significantly higher voltage on the audio system. 60 volts might be over ambitious but 24 volts should be within reach. 24 volt alternators are common in commercial vehicles so regulators should be available.

A couple of other points, this is a Polo you're putting 12,000 watts of audio into? Has the engine got 10 hp plus to spare?

how is it impratical, most competition amps run up to 18v. and the advantage of feeding an amp a few more volts can be a couple thousand watts. i am really not sure you know what your talking about when it comes to car audio because you would know the advantages to a higher voltage system. i'd be charging at 15.9 volts and and running 5 xs power d1400s if i went to a 14v system.

i am thinking about getting a couple batts and doing a trial run to see how the car handles it.

very few amps are 24v capable let alone most car electronics wont take that much voltage.

the polo wouldn't be a daily driver so i don't mind the loss of power. its not a race car .

most competition amps run up to 18v. and the advantage of feeding an amp a few more volts can be a couple thousand watts. i am really not sure you know what your talking about when it comes to car audio because you would know the advantages to a higher voltage system. i'd be charging at 15.9 volts and and running 5 xs power d1400s if i went to a 14v system.

I'm quite clear on the advantages of a higher voltage system, BUT, to make a significant difference the voltage has to be significantly higher. Power amps use switch mode power supplies to generate a higher voltage for the output stages, these can be designed to work over a range of input voltages. The input DC voltage is switched to give pseudo AC which is then stepped up to the final voltage before being smoothed and filtered. To work over a voltage range, the input circuit is regulated, the circuit won't generate higher output because you put a higher voltage in, (if it does, the amp isn't very good, to perform well you must have well regulated supply rails) all that will happen is you'll use less current to produce the same wattage, which has the nominal effect of less power loss in supply cables. Different output stages do things in slightly different ways, but even the digital or 'class D' outputs need that higher generated output voltage to produce high power levels. At the end of the day, Ohm's law still applies.

With audio amps, output power is one of the biggest sources of fantasy on the planet. Quoted figures, even for true rms wattage are very rarely achievable in the real world. Testing is done with a single frequency source into a resistive load, real world loads are reactive and signals are complex. I've always gone with the approach that sound quality is whats important, if it sounds good and plays at the levels you want then its spot on! A well spec'd 100 watt amp with good current reserves can sound as good as a 1KW amp with little or nothing in reserve.