power consumption of car radio

Sometimes I would like to leave my car radio playing while I am doing work on the car.

What sort of power consumption would a bog-standard car radio playing at "normal" volumes use?

Thanks for any info.

Simon G

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I have a position on the ignition switch which allows me to do that without running current through the coil, etc.

The radio is an oldish one with modest frequency response and plays through two ordinary speakers.

Reply to
Simon G
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You can ususally find the power consumption on the radio itself, or the instruction manual. The main factor I would say is what type of battery you have.

Reply to
CD

Shouldn't be a problem if your battery is good. Most radios are fused at 2 amps so it would use less than 1 amp at normal volume.

Reply to
John Egan

An ammeter would provide the answer you're looking for, although the current draw will vary depending on the type of audio you're listening to. i.e. Radio 3 with some rather long 'quiet' bits in the middle of a classical bits will draw less current than some hard techno tracks on Radio 1.

And if you're playing tape/cd then the current draw will be higher.

Reply to
F1LBY

The message from Simon G contains these words:

Be careful of what is also on at the same time. On my car the heated wing mirrors are also on - and a few other things. Flattens even a large battery quite quickly.

Reply to
Guy King

Don't try that at home! Most modern radios do 20W/channel x 4 or 80W. Even at 100% efficiency that would be nearly 6A. Most are fused at 10A; 2A wouldn't last very long once you get on the road!

However I would agree that listening whilst working should draw more than an amp or two. As the OP noted it was an older type with only two speakers, and such a radio might do 7W/chan, two amps is probably nearer the mark.

Reply to
Woody

Indeed - it's moving parts that sap power.

I wouldn't worry about power consumption of a car radio unless you're working on it for days and never driving it.

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Reply to
PeterE

Recently couldn't find a hotel in a trip 'oop north' so I slept in the car. From 2am to 7am the radio was on at 'home' volumes. Car started faultlessly in the cold misty morning.

This was the standard Renault 25 Radio.

Reply to
Paul Cummins

Wish that was all I had to worry about...

Reply to
jim.gm4dhj

A few amps. It can certainly flatten an older battery, as can leaving the interior light on for hours, but a new battery should have no issues for hours of work.

If you're going to do this day after day, take the battery home and recharge it overnight. Not good to leave a battery for long when it is discharged, it ages rapidly in those circumstances.

Reply to
Questions

Simon G wrote in news:954D79D214263471AE@127.0.0.1:

Fit a split charge relay and secondary battery - and power the system of that - no fear of ever being stuck with a flat car battery.

Leigh....

Reply to
Leigh

Or just don't worry about it, unless you've fitted more chav style amps than will let you get the shopping in the boot then if the battery goes flat from a few hours radio use it was time for a new one anyway.

Reply to
DuncanWood

Since that is all that will be on via an Auxilliary setting on the ignition switch - milliamps. No problems for hous on end, Simon. Probably even less than an interior light.

Peter C.

Reply to
cornelp

Depends what else is on the auxilliary. Not much use either if it's one of those cars which switch to "economy" mode after half an hour!

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Reply to
Jock.

: Don't try that at home! Most modern radios do 20W/channel x 4 or 80W

Well, that's what they claim, but that's peak only, and unless you are called "Wayne" or "Darren" you are very unlikely ever to be taking more than a watt per side out on average. So much less than an amp. Shouldn't flatten the battery at all, but if you have it on for ages you may polarise the battery: the plates get coated, the battery seems dead but a couple of minutes' charge is enough to revive it.

Ian

Reply to
Ian Johnston

Heh heh. The claimed power output isn't usually matched by the peak power consumption which tells you something about the claims, given that no amplifier is 100% efficient.

But car type amplifiers consume power according to the actual level they are giving out, so when used in a stationary car while working on it it's likely to be insignificant.

Reply to
Dave Plowman (News)

The confusion here is that someone is trying to compare output of sound in watts and DC input. RMS (root mean square) and all that. i.e. Apples and oranges.

Peter C.

Reply to
cornelp

The message from snipped-for-privacy@xtra.co.nz contains these words:

Or worse - PMPO - that wonderfully spurious measure which can rate a thing the size of a matchbox at 1000W.

Reply to
Guy King

A watt is a watt - a unit of energy. If an amplifier gives a genuine watt output it must consume *at least* a watt.

There is no such thing as 'RMS' power output despite what advertisers would have you believe.

Reply to
Dave Plowman (News)

The message from "Dave Plowman (News)" contains these words:

It's a better measure than PMPO!

Reply to
Guy King

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