Simple question, just want to know roughly what size amplifier I could run upto without putting too much load on my alternator and battery. (approximate current drain or power rating.....just working figures).

Ordinarily I'd not have much concern in a mini (I've run 200 wrms no probs) but with the EFI engine I'm wondering if I should be a little more conservative?

Thanks.

I ran a 4x100w in my Rover SPi. Never had any problems - even at night with it cranked to keep me awake (also running H4's and 4 x 100w spots). Lets face it, that rating is only the peak, and with an amp that size you never get it up to full power inside a Mini for a long time anyway (unless you like bleeding ears ).

I was running the standard Rover alternator.

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My van has 3 amps with a collective 2000w peak, with a 63A bosch alternator it could pull the volts down to 12.8v with revvs, so i put in an 85A unit, no problemo

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Dean Hutton's first car was a Mini.

ran 2400 peak, 1500 rms with no problems with the standard alternator, just have to use it conservatively

your battery just wont last real long

that said i didn't and upgrade my alt to 90amp

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1962 850,Frog

I've just upgraded to a pair of pioneer amps, I still have the standard alternator for my van but i seriously need to upgrade it as the sub amp shuts off from the lack of power from my battery and alternator.
I've been researching Capacitors for a temporary solution, but for the cost of a decent 1 or 2 farad capacitor (there is some junk out there) it's just as expensive to get a bigger output alternator like the one's convertible mini (tony) on here sells.

With a bigger alternator everything gets more volts/amps as needed.
With a capacitor (voltage stiffener) only the amp(s) get stable volts while the car can keep up with the demand put on the charging system as the cap is only a temporary storge device for fast delivery.

Oh and I also have halogen headlights and 2 x 100w driving lights as well.

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Would a voltage or amperage gauge be recommended to be installed?
Which one is the one you'd actually be looking at?

you'd be looking at a voltage gauge, so you know if your altenator is keeping up with your power requirements....

the purpose of a capacitor is to reduce the instaneous drain on the battery. the cap will drain voltage at a set rate but discharge it all at once when its needed. so its perfect for big bass systems. thats why headlights dim on the bass hits. with a cap they wont (or less anyway)

Nav thats why your sub cuts out. the bigger alternator will help but a cap will help more

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1962 850,Frog

At what sort of system RMS value should I start to look at capacitors?
500? 1000? Is it 12 volt times 65 amp alternator output or anything clever?

Yes I know but in terms of overall bang (pardon the pun ) for your buck the bigger alternator is the way to go for me, my stereo doesn't get loud enough to cut out very often, generally only when showing it off. but with the lights on it is approaching it's limits already.

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True Nav. thats why i installed a bigger alt rather than a cap as well. my peak power wasnt huge but it was constant so the alt is a better option in this case


its not RMS that decides when you need a cap.

its the problem nav was having of the sub amp turning off.

its trying to draw more than the battery can supply at that point in time. the cap acts as a reserve for it.

if your running a big system i would go a 65amp alternator as it will charge/maintain the battery quicker

as for when you get the cap the higher volume and power you go the more current you will draw, then you'll need the cap. basically turn all your systems on at once with the car running and if you amp cuts out on the bass hits you need a cap.


heares a rough over view i found for you

• Audio capacitors accumulate power whenever it is not required. This power is released when the demand for power exceeds the supply capacity of the power system of the car.

• Audio capacitors are necessary to supplement the regular power supply of the car in order to ensure the smooth functioning of the amplifier. Car audio capacitors usually range from 0.5 farads to 3 farads.

• You have to install a car audio capacitor that complements your amplifier. It is also necessary to place the capacitor as near as possible to the amplifier. For 500 RMS of power output, it is necessary to have an audio capacitor of 0.5 farads.... (note this is not absolutely needed but is a good guide)

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1962 850,Frog

I put a 1 farad cap in my stereo as i noticed heavy bass would take the power from the front speakers, and it has a volt readout which has been helpful.

Another cap bonus is they soak up any electrical noise fron the alt or dizzy.

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Dean Hutton's first car was a Mini.

When I turn my ignition on, the amp makes the speakers give a thump.
Is there a way of stopping this or is it just normal.

Sorry for the thread hi-jack Harley.

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'72 English Van...'72 Export Moke ...63' 850...KZ 750E1...'74 P76

Not making assumptions on your system Damian, but every time I've heard that thump on startup or shutdown it's because the car has a cheap amp powering it. Most good units have a soft start / stop that eliminates this. Some head units have this feature too.

Now I think about it my system doesn't do that anymore
I just found the model and peak power for these amps I bought
my sub amp is a GM-7300M mono 500w
and the 4 speakers are powered by a GM-6300F 4ch x 120w
and for just over $500 for the pair I'm very very happy with them. They're far more power hungry than the old 4x 150 amps I had. Well I still have one. The other let it's smoke out a while ago. Anybody need an amp?

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