hi all, 

 

been reading the FAQ on upgrading the stock alternator to a golf 90amp one.

 

i am running a 10" re-audio sub powered by an alpine 1000w (m1000) amp and the system seems to be struggling.

i have upgraded the big 3 and added in a bosch s5 battery.

 

i was thinking of changing system to 2x SWR10 alpine subs powered by PDX M12 amp.

 

regardless of changing system, am i better off helping the set up by upgrading the alternator to the 90amp one and leaving out the power cap or is the power cap essential.

 

i'm thinking upgrading the alternator will help my electrical system in whole as my head lights (HID) pulls a lot of power too.

 

can anyone advise me please?

all help appreciated!

 

thank you.

A healthy alternator is always desirable.

 

Use a simple analog volt meter at the power connections to your amplifier. If this reads over 13v all the time then a bigger alternator will not help. If this reads less than 13v, check the reading at the back of the alternator - if that reads over 13v then improve the wiring between the alternator and the amplifier until the voltage at the amp remains over 13v.

 

As you have probably worked out - if your amp was actually producing anything near 1000w - you would need fantastically large cables to power it and to connect the speakers. Whilst its possible the amp may produce large very short bursts of power (<1ms) it is unlikley to get near 10% of its rating in 'real' use. For this reason, fitting cabling capable of 1kw (~80 Amps @12-13v assuming the amp is 100% efficent!!) would be very expensive (3 meter length would require a CSA approaching 125mm(sq) [12mm diameter]) and unbeneficial. A capacitor on a very short lead to the amp would be more use but many of these are just bullshit items taking advantage of the un-sceptical.

 

You may find this hard to beleive and there are bound to be many who 'swear' that fitting Max-Oh-Boom cable and shiny connectors allowed them to pass enough power to supply a small town. They are either liars or have not understood the basics of physics.

 

A quick way of proving such things for your self is to locate one amplifier under one speaker on a very short cable and then power the amp from a local battery also on a very short cable. If the amp now sounds the way you like it - you'll know its possible and you'll be able to decide on how much of a compromise you are prepared to accept as you extend the cables.

 

If you get the cable length to a minimum you can use sensibly sized cables - if you're running the cable from the bonnet to the boot then you can't (regardless of the ebay sellers or clueless Halfrauds burger flippers who happily re-invent the laws of physics through ignorance or the chance of a sale).

 

Have a play and see for yourself.

 

 

if I&#39;m honest iv tried power caps, they work well for the first second of a continuous bass note but drop off after that second. just add some more batteries in the boot and youll be sorted