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Old 25th November 2021, 18:10   #1
VVC-Geeza
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Default DAB and battery drain.

Does DAB radio have a higher drain on the battery than AM/FM stations if the engine isn't running? I know DAB eats batteries in household radio's.


Same question about watching TV on a DD without the engine running.


If you were parked up (engine off) for 1-2 hours while listening to DAB or watching TV would it flatten a healthy battery?I would have no fear of listening to AM/FM radio for a similar period with engine off.
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Old 25th November 2021, 19:49   #2
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Does DAB radio have a higher drain on the battery than AM/FM stations if the engine isn't running? I know DAB eats batteries in household radio's.
Hi Mick,

I very much doubt that the radio signal transmission system has a significant effect upon radio receiver current consumption.
From where did you get the information that DAB radios "eat batteries"?

Few batteries in cars are "healthy" if the definition of that is fully charged. Therefore it is risky to draw conclusions after listening to the radio or watching TV for a particular length of time.

The answer to your question Mick lies in measuring the current consumption of an analogue radio, a DAB radio and a TV receiver powered by the same car battery.

Simon
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Old 25th November 2021, 22:09   #3
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Hi Mick,
From where did you get the information that DAB radios "eat batteries"?
I was talking about in portable transistor radio's Simon.It's my personal experience that batteries last no time at all. I was wondering if this also meant extra power draw on a car battery.And also in the case of watching TV.
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Old 25th November 2021, 22:54   #4
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I was talking about in portable transistor radio's Simon.
Yes I know Mick, because you specifically said "household radios". Sorry if my reply suggested otherwise.

What does the manufacturer quote for your portable DAB radio's current consumption? Are you using alkaline batteries? Are you listening at high volume levels (because the power output stages of the radio will be the highest current consumers)?

It's not an easy question to answer really.

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Old 25th November 2021, 23:23   #5
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Yes I know Mick, because you specifically said "household radios". Sorry if my reply suggested otherwise.

What does the manufacturer quote for your portable DAB radio's current consumption? Are you using alkaline batteries? Are you listening at high volume levels (because the power output stages of the radio will be the highest current consumers)?

It's not an easy question to answer really.

Simon

I'll see if I can find the manual for my present DAB home radio Simon.I've always used the mains lead for this one as I distictly remember the previous one consuming batteries very quickly under 'normal' use.
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Old 27th November 2021, 15:27   #6
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DAB radios do consume a lot more power than am/fm - it can be a factor of 3+.

DAB requires a lot of signal processing to decode the digital signal and the early radios used quite power hungry general purpose DSP chips which were programmed to perform the processing. Most major radio chip manufacturers, other than those producing cheap Chinese radios, are working on reducing the power consumtion to perhaps 25 to 50% more for DAB using dedicated signal processors. I believe the UK radio manufacturer Roberts Radio is leading in this field.

Of course the difference may be overshadowed by the power being injected into the speakers at high volume.
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Old 27th November 2021, 15:50   #7
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I'm with Maninder on speaker volume, although DSP chips, as Manuel would have said, I know nothing lol. I had a nice transistor radio with a big speaker many moons ago at uni when battery tech was inferior and rechargeables were pretty poor. I'd play it fairly quiet, but my room mate would wack up the volume when I wasn't there and flatten the battery in no time. I'm sure it would have run for days though on a fully charged car battery.
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Old 27th November 2021, 16:34   #8
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DAB radios do consume a lot more power than am/fm - it can be a factor of 3+.

DAB requires a lot of signal processing to decode the digital signal and the early radios used quite power hungry general purpose DSP chips which were programmed to perform the processing. Most major radio chip manufacturers, other than those producing cheap Chinese radios, are working on reducing the power consumtion to perhaps 25 to 50% more for DAB using dedicated signal processors. I believe the UK radio manufacturer Roberts Radio is leading in this field.

Of course the difference may be overshadowed by the power being injected into the speakers at high volume.

Thanks Maninder

I've noticed that when changing from FM to DAB in both the car and house radio's I need to turn the volume up a reasonable amount to achieve the same volume on DAB as when on FM.It would be interesting to know if this extra power consumption of DAB would also cause a much higher drain on a healthy car battery without the engine running.
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Old 27th November 2021, 18:17   #9
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Mick,

It al depends on how old or poor the design of the DAB section is in a specific radio. It's reasonable to assume that an old design would consume 500mW more in DAB mode than FM. At 12V, this is only .042 Amp of extra current drain from say a capacity of 40Ah for a car battery that is a few years old. The difference equates to over one moth of 24/7 use. So in practice the difference should be negligible as the average current pumped into the speakers will be much higher.

Modern car radios by quality manufacturers such as Philips should not display any difference between DAB and FM as power efficient dedicated signal processors have been developed by these companies during the past 10-12 years.

Martin - the difference in the signal processors here is very similar to digital cameras. Early cameras used general purpose DSP chips and chewed through batteries e.g. my Kodak DC290 digital camera (which I still have and is a beast for using battery power) compared with a modern digital camera which sips power despite performing far more sophisticated image processing.

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Old 27th November 2021, 20:08   #10
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Mick,

It al depends on how old or poor the design of the DAB section is in a specific radio. It's reasonable to assume that an old design would consume 500mW more in DAB mode than FM. At 12V, this is only .042 Amp of extra current drain from say a capacity of 40Ah for a car battery that is a few years old. The difference equates to over one moth of 24/7 use. So in practice the difference should be negligible as the average current pumped into the speakers will be much higher.

Hi Maninder


For reference my DAB car radio is incorporated into an Xtrons (Chinese) DD and the car battery is a 77Ah Exide Premium - 18 months old.


As previously mentioned I'd also be interested to know what drain watching TV on the DD has on the battery without the engine running.


So, I can safely park up for 1-2 hours using either mode (DAB/TV) without fear of battery failure?
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