Firstly, I don't work for Halfords, I don't work for Motorworld or any of the other, "You need a power cap", brigade....
A few basics....
A cars power supply is DC, (Direct Current), so cable resistance plays a large part in supply voltage....
Supply voltage directly affects current being delivered....
A cars stock electrical loom is designed with safety & cost in mind....
On 90% of cars a simple test can be performed to evaluate your stock loom, simply turn on your interior light, now operate your hazard lights, does the interior light dim in time to the hazards???
Operate the windows, again does the interior light momentarily dim???
If you were to rewire your entire car with only electrical performance in mind, then the costs would spiral as would the overall weight of the loom itself....
General claims....
1, Makes system louder.....
Utter unfounded crap....
2, Improves sound quality.....
Debatable, caps are usually used on the bass side of systems, if the bass side is particularly heavy then the cap will become discharged quite quickly, (you need to remember a cap will supply as well as draw from both directions depending on point of lowest resistance), so in some cases a cap can actually harm overall quality....
3, Very fast discharge/recharge cycle.....
True, caps do indeed discharge/recharge very quickly, but you need to remember this cycle is dependant on draw, (if the relevant charge circuit is lacking in any way, then cap performance will suffer)....
4, Will sort 'dimming lights' syndrome.....
If your charge circuit is capable of supporting a power cap, then chances are fitting one won't alter the 'dimming effect' one bit....The only way to rectify the issue in this case would be rewiring the light circuit with performance in mind....
Avoiding Dimming Lights.....
The most common cause of 'dimming' lights is incorrect wiring practices....
YOU CAN'T TAKE OUT WHAT YOU CAN'T PUT BACK IN
A circuit is just that, an outward path & a return path, current will only flow as fast as it can at its weakest/narrowest point....
Lets revert to a basic pic, makes it easier to explain & hopefully easier to follow;
As current is drawn, voltage will dip, (blue level line), if return path is restricted then voltage will remain low, if return path is similar or larger then current will flow easier, (quicker), so maintaining higher voltage level....
By 'NOT ADDING' a new battery to chassis earth to MATCH the new power supply, your simply creating a dam that will restrict voltage throughout the whole car....
A power cap can supply the initial high transients that are required on big bass hits, but if the charge circuit is restricted elsewhere then its usefulness over anything more than a few seconds is very doubtful....
In short, a power caps usefulness is limited to your actual charge circuit, if the charge circuit is adequate, then you simply don't need one....If your charge circuit isn't adequate, then fitting one is pretty much pointless....
Nothing stopping you from using one on the supply to your head unit though
A few basics....
A cars power supply is DC, (Direct Current), so cable resistance plays a large part in supply voltage....
Supply voltage directly affects current being delivered....
A cars stock electrical loom is designed with safety & cost in mind....
On 90% of cars a simple test can be performed to evaluate your stock loom, simply turn on your interior light, now operate your hazard lights, does the interior light dim in time to the hazards???
Operate the windows, again does the interior light momentarily dim???
If you were to rewire your entire car with only electrical performance in mind, then the costs would spiral as would the overall weight of the loom itself....
General claims....
1, Makes system louder.....
Utter unfounded crap....
2, Improves sound quality.....
Debatable, caps are usually used on the bass side of systems, if the bass side is particularly heavy then the cap will become discharged quite quickly, (you need to remember a cap will supply as well as draw from both directions depending on point of lowest resistance), so in some cases a cap can actually harm overall quality....
3, Very fast discharge/recharge cycle.....
True, caps do indeed discharge/recharge very quickly, but you need to remember this cycle is dependant on draw, (if the relevant charge circuit is lacking in any way, then cap performance will suffer)....
4, Will sort 'dimming lights' syndrome.....
If your charge circuit is capable of supporting a power cap, then chances are fitting one won't alter the 'dimming effect' one bit....The only way to rectify the issue in this case would be rewiring the light circuit with performance in mind....
Avoiding Dimming Lights.....
The most common cause of 'dimming' lights is incorrect wiring practices....
YOU CAN'T TAKE OUT WHAT YOU CAN'T PUT BACK IN
A circuit is just that, an outward path & a return path, current will only flow as fast as it can at its weakest/narrowest point....
Lets revert to a basic pic, makes it easier to explain & hopefully easier to follow;
As current is drawn, voltage will dip, (blue level line), if return path is restricted then voltage will remain low, if return path is similar or larger then current will flow easier, (quicker), so maintaining higher voltage level....
By 'NOT ADDING' a new battery to chassis earth to MATCH the new power supply, your simply creating a dam that will restrict voltage throughout the whole car....
A power cap can supply the initial high transients that are required on big bass hits, but if the charge circuit is restricted elsewhere then its usefulness over anything more than a few seconds is very doubtful....
In short, a power caps usefulness is limited to your actual charge circuit, if the charge circuit is adequate, then you simply don't need one....If your charge circuit isn't adequate, then fitting one is pretty much pointless....
Nothing stopping you from using one on the supply to your head unit though
