Trying to fault find a recurring flat battery problem on a Cavvie.
Its drawing 0.2A with nothing on except the car stereo on standby. Head unit is a Sony..whats a rough figure for its standby current? Suspect a dodgy stereo install because the guy who fixed it was a knob who cut off the all the wires to the standard connectors at the same time with a pair of scissors - you know...the ones that would've fitted straight into the stereo?
Less than 0.01 Amp just for the memory.
Has it by any chance got a separate power amp which is permanently powered? 0.2A sounds more likely as a quiescent consumption for this. If so, it needs a relay switched from the head amp.
Even ar 0.2 amp currenr draw it should still take some time to flatten the battery. I.E 100amp hour batt = 1 amp for 100hrs (ok the voltage drops) etc. But how long does it take for your battery to go flat.
I dunno what you've got with a 100 amp/hr battery - my 3.5 litre has only a 70 amp/hr one. 50 is more likely an average.
Also, at this time of year, many batteries aren't fully charged - especially with short journeys etc. And with the holidays, a second car may not be used for several days. Many modern cars will flatten their battery if left for two weeks or so even in the summer.
Check which of the feeds is drawing the current - I fitted an aftermarket radio to my Cav and had the same problem (not fun when you fly back from business to where you left your car on a secure site in the evening to find your battery dead); In my case the memory line was drawing the current; easily fixed by inserting a 10k resistor in series (prompted by a more expensive radio having the same, however that got nicked). Worth looking into.
(0.2A is way too high, as others have said)
No seperate amp. I figured 0.2A was a bit on the high side.
Sis-in-laws car. Takes a few days from a full charge with a battery charger. Changed the battery anyway and it turns out the same tit who fitted the stereo decided to use a battery for a Mini on a 2L Cavvy. Anyway, its got the right one now.
Very much so. Sure it is 0.2A and not 0.02 (20 mA)? 'Cause that's nearer what I'd expect.
However, can you pull the fuses feeding the radio and check again? There might be as many as four circuits - main, memory, dial lights, electric aerial.
What do you mean by "standby" exactly? The last Sony I had an "off" button that used to just turn off the audio, leaving a clock on the display with the backlight still on. 0.2A would, at a guess, be about right for that mode. To turn it off completely, the "off" button needed holding in for a couple of seconds. It was a right pain in the arse, since the car had no "acc" position on the ignition switch, and I ended up making a gadget so it worked properly.
In fact I was so proud of it, I even included it on my, now derelict, website...
Colin.
[snip]
A lot of Sony head units have a silly off-but-not-really-off mode, with the clock and the backlight still on. If it's in that mode then
0.2A is pretty plausible.Cheers,
Colin.
Not unfeasibly so. I used to have an old Kenwood that took 145mA on standby with no separate power amp.
That sounds an awful lot for simply maintaining a memory of some sort. Early BBC Acorn computers, for example, managed it with a couple of zinc carbon AA cells - which lasted for years. Did the panel remain illuminated or something?
I'm not entirely sure why. There was no visible illumination and I doubt it was anything like a class A amp inside. It could just about have needed that to run a tuner if it didn't switch that circuit off but even so that seems high.
I eventually just wired it to the ACC switched live from the ignition rather than a permanant live and that solved it of course.
Sounds like that is how its wired.
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