Boy racers

The TV/DVD/PS won't take that much but a beefy amp will. They'll probably be fine during the day (most alternators give out 70+ amps at the revs they'll be giving them), though if they also like to have their front fogs on, etc. then come winter they may well need to boost charge the battery each week. The alternator won't die from a high load unless it can't get enough cooling (because the battery will supply any extra current needed).

Darren

The message from "Krycek" contains these words:

Nah - even an elderly car can be expected to have a 70 amp alternator - those on modern cars are considerably more powerful. This allows the battery to be recharged very quickly after starting - having loads of gizmos just delays this slightly. Not by much though - and you rarely hear of people actually using more than the 1.2kW a 100A alternator could put out if it had to.

Dunno, but in the past I've seen some massive capacitors in Maplin for this thing. I think they were one Farad! Massive things with an LCD on top to indicate the charge level. It looks kinda cool, but I suppose a better use would be to wire it up to stop theives :-D. Of course, the alternator would still need to charge these, but with the revs they get it shouldn't be a problem.

It really doesn't make sense to me though, I never use my stereo!

The message from "G-Man" contains these words:

Of course - the chances of them actually drawing 2400 kW for more than a split second is minimal - and something the battery is well suited to serve anwyay.

It doesn't make any sense compared with a thicker feed from the battery but welcome to world of hifi.

Yes, I've seen those one Farad's at Maplin, but it's for slightly different usage. The has to be a capacitor between the Amp and the speaker to shield the speakers from DC current. But the larger capacitor, the more AC current burst can be transferred at bass notes. bim bom boom b0OOM BOOOM BOOOOOM!!!

I know it can't be considered a "standard" alternator, but as a sign of things to come the V10 Volkswagen Touareg has an alternator rated at 190 Amps continuous, 300 Amps short term. Oh, it's water cooled and driven via a 2-speed gearbox so that output can be boosted at low engine revs....

Chris

That's the guise they are sold under and with schoolboy electronic theory it may seem like it should work that way, however after much reading on the issue (in many long and well debated threads) I'm not convinced that at 1F, its anything but snake oil and a waste of money as far as operation goes (a bit like grounding kits, lolol).... however it looks techie and spinkee especially with the readout so if you've money to burn, get some for the looks alone but don't expect to hear the difference.

Ad

spinkee

Dunno, in electronics capactiors are quite often used to 'smooth' things, such as an unstable input. Having said that a few micro farads is usually enough lol. They probably are more for smoothing the current rather than maintaining the current though. It'd still be nice to see a Chav wired up to one though :-)

Even so it will probably be a 1200W PMPO amp which is only 400W rMS which is what the alterator measures things in.

Nah. Taking the Ka as an example, it either has a 70A or 90A alternator as standard.

The message from Chris Street contains these words:

Exactly. That's what I meant by "not for more than a split second".

I don't quite fancy being referred to as "schoolboy electronic theory", I think I've bit more experienced than that. If you buy an amp, the capacitor in the output stage is already in the amp. I think the large capacitor is intended for those who actually build the amp e.g. from a kit. It was some years ago since I did this, and then there was no such thing as 1.0 Farad; it was considered a ridiculous size and unobtainable. These days, however, kids can assemble a 1KW -2KW amp for less than a weeks salary. An oik about 5 houses away can make my walls move with his car stereo! However, I would be worried about frying the speaker coils.

Now that is ingenious. Next thing they'll announce an electrically-driven alternator.

theory", I

capacitor is

However,

I can't remember the exact description, but I got the impression that it was just for a normal amp. The 1 Farad capacitor was =A3100, which is a ridiculous amount of money!

In car screens don't take much power and the same can be said for PS2's/XBOXs and GameCubes even a lour radio can be run from a single decent amp (say 80W RMS per channel and 6 channels isn't going to put a strain on anything made in the last 20 years or so.) I may have some problems with a Type 2 camper should I stick a nice 20" flat panel or 2 in it as the alternators aren't up to much by today's standard.

Actually it's £39.99 from Maplin at the moment, but still money though.

Guy King wrote on Sat, 23 Apr 2005 14:42:44 +0100:

I'd pay to see someone with a 2.4MW amp. But only from a safe distance.

Nope. They aren't sold for that. You are meant to connect it straight across the power supply to the amp, supposedly to decrease the impedance and make up a bit for the resistance of the cables, battery, etc.

Car amps tend to either have bridged output stages, or split internal supply rails. neither of which have output capacitors.

Cheers,

Colin.