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#278302 - 27/03/2006 02:55 Low battery icon adjustment???
farmtech
journeyman

Registered: 22/08/2003
Posts: 59
Hello,

Just wondering if there was any way to disable or change the low voltage icon threshold? Every time I turn my engine off with the system on the player mutes and the icon shows up within 10 - 15 seconds. It seems to me like the voltage threshold is a little too high. I wish there was a way to disable it completely.

Thanks for any help.

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#278303 - 27/03/2006 03:41 Re: Low battery icon adjustment??? [Re: farmtech]
matthew_k
pooh-bah

Registered: 12/02/2002
Posts: 2296
Loc: Berkeley, California
Have you tried a new battery in the car? I've never heard of it behaving like that for anyone. Do you have large amps installed?

Matthew

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#278304 - 27/03/2006 04:04 Re: Low battery icon adjustment??? [Re: farmtech]
n2toh
journeyman

Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
Quote:
Hello,

Just wondering if there was any way to disable or change the low voltage icon threshold? Every time I turn my engine off with the system on the player mutes and the icon shows up within 10 - 15 seconds. It seems to me like the voltage threshold is a little too high. I wish there was a way to disable it completely.

Thanks for any help.


I had a similar problem when I had my empeg installed in my Jeep, in my case the problem was a bad ground connection.
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#278305 - 27/03/2006 05:40 Re: Low battery icon adjustment??? [Re: farmtech]
Robotic
pooh-bah

Registered: 06/04/2005
Posts: 2026
Loc: Seattle transplant
I get the battery icon to come up when I'm driving with my headlights on and then step on the brake or switch on the turn signal.
It's annoying, to say the least, but I haven't yet exhausted my possible problem areas- such as grounding issues (as mentioned above).
I also have a nasty 'alternator whine', which usually points directly to grounding issues.

It makes me wonder, though... would a capacitor in the power circuit smooth out such voltage fluctuations?
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#278306 - 27/03/2006 06:00 Re: Low battery icon adjustment??? [Re: Robotic]
n2toh
journeyman

Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
Quote:
I get the battery icon to come up when I'm driving with my headlights on and then step on the brake or switch on the turn signal.
It's annoying, to say the least, but I haven't yet exhausted my possible problem areas- such as grounding issues (as mentioned above).
I also have a nasty 'alternator whine', which usually points directly to grounding issues.

It makes me wonder, though... would a capacitor in the power circuit smooth out such voltage fluctuations?


I should have been more specific before, I cheated when doing my Jeep install and used the grounding bolt for the door switch. I later attached the black wire for the player power to the steel dash sub frame. (as a side note in my VW it has a cool star thing for quick connects in the same basic location as the Jeeps ground bolt for the same thing plus about 20 other things, but without the battery warning issues.) On the subject of alternator whine, I have a strange digital squealing on startup most times that eventualy goes away.

Alternator whine can also be caused by a leaky or bad rectifier diode in the alternator.
_________________________
The only difference between science fiction and reality is about 60 years.
100GB MK2 Green 080000171 + OEM tuner
v3.00a11 hijack v450 jEmpload v70

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#278307 - 27/03/2006 09:15 Re: Low battery icon adjustment??? [Re: Robotic]
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2992
Loc: Wareham, Dorset, UK
Errr... a battery, built of many parallel plates with an electrolyte - is effectively a capacitor.
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One of the few remaining Mk1 owners... #00015

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#278308 - 27/03/2006 09:19 Re: Low battery icon adjustment??? [Re: farmtech]
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2992
Loc: Wareham, Dorset, UK
I would suspect stuff other than the player:

- is the battery good?
- is the charging system good?
- what is the local temperature?
- what voltage is arriving at the sled through your wiring?
- what is the gauge of the wire (end to end) supplying, and earthing your sled?
- is the gauge of the wire on the sled earth the same or larger than the power feed?
- how many hard disks in your player?

Why does having this icon come on irritate you? It does have a useful function.
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#278309 - 27/03/2006 09:24 Re: Low battery icon adjustment??? [Re: Robotic]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5588
Loc: London, UK
Quote:
I get the battery icon to come up when I'm driving with my headlights on and then step on the brake or switch on the turn signal.


I also get the battery icon when I press the brake pedal. On the other hand, I have to have the A/C, the headlights, the heated front and rear screens and the heater on.

Get a newer battery?
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-- roger

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#278310 - 27/03/2006 12:59 Re: Low battery icon adjustment??? [Re: schofiel]
farmtech
journeyman

Registered: 22/08/2003
Posts: 59
Hello,
My install is just fine, I have this in a Chevy Tahoe and it is a 2 year old factory battery. The battery is not great and I think the voltage drops quite a bit when the key is on, engine off. It always starts good so I don't want to buy a new one just yet. The problem that bothers me is the fact the Empeg cuts out for 2-3 seconds before coming back up with the icon. It is kind of like a reboot. I know the Empeg should be able to safely run down to 9 volts or so, that is why I wish I could change the sensitivity level. When I shut my engine off the factory radio and Empeg stay on until I open a door, I love this feature but it always cuts out within 10 seconds of doing so. Sometimes it will do it more than once also.

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#278311 - 27/03/2006 14:36 Re: Low battery icon adjustment??? [Re: farmtech]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31223
Loc: Seattle, WA
Agreed that Farmtech needs to check and see what's wrong with his car's electrical system, BUT...

I'd still like to know the answer to his specific question: Is the low voltage threshold controlled in the player software or the kernel? Or is it hard-coded into a PIC somewhere?
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Tony Fabris

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#278312 - 27/03/2006 15:07 Re: Low battery icon adjustment??? [Re: Roger]
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2992
Loc: Wareham, Dorset, UK
If the battery is older than about 3-4 years, then It May Be Time.

However, first, do the usual - check the connectors are clean and greased, that the cells are topped up (assuming you can). If you have not got one of the no-discharge types, you could try the total discharge trick (H4 bulb wired across the terminals, outside the car, discharge till flat, re-charge). However, not all batteries will allow this. Mike Tempsch is our battery man. Mike?
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#278313 - 27/03/2006 15:17 Re: Low battery icon adjustment??? [Re: tfabris]
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2992
Loc: Wareham, Dorset, UK
There's an op-amp driving a GPIO pin on the CPU. The actual voltage at which it flips is measured relative to the processor's 3V supply line: this is set to be roughly 3/5 of your car battery voltage.

Assuming your battery is healthy and being charged, it's voltage should be about 14.4V. Off charge, it should be about 12.6V.

Hence, if your engine is off and your battery is good, you should only see the icon come on if the battery is loaded (fan? amplifier?) sufficiently to bring the voltage down to 7.6V. I would say, if you can do that to a battery then either the battery is sick, your wiring between the battery is causing too big a voltage drop or your amp is TOO B***** BIG
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#278314 - 27/03/2006 16:16 Re: Low battery icon adjustment??? [Re: schofiel]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31223
Loc: Seattle, WA
Quote:
There's an op-amp driving a GPIO pin on the CPU. The actual voltage at which it flips is measured relative to the processor's 3V supply line: this is set to be roughly 3/5 of your car battery voltage.

In other words: It's set in hardware and cannot be altered by a software modification. Thanks!

Too bad, but, thanks!

In my case, I get the battery icon because my amp is too f'ing big. Only when the car is idling and there's lots of bass thumping does the problem occur for me. I had once solved the problem by putting some capacitors on the power line to the empeg. But once when troubleshooting some noise issues, I removed the capacitors so I no longer have that advantage.
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Tony Fabris

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#278315 - 27/03/2006 16:20 Re: Low battery icon adjustment??? [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I could be wrong, but it seems like capacitors on the amp would solve that problem, too.
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Bitt Faulk

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#278316 - 27/03/2006 16:56 Re: Low battery icon adjustment??? [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31223
Loc: Seattle, WA
Quote:
I could be wrong, but it seems like capacitors on the amp would solve that problem, too.

Yeah, but I'd need bigger capacitors for the amp than for the empeg.
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Tony Fabris

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#278317 - 27/03/2006 17:04 Re: Low battery icon adjustment??? [Re: schofiel]
farmtech
journeyman

Registered: 22/08/2003
Posts: 59
Is this the same op-amp that senses absolute low voltage and tells the Empeg to write to flash and shut off? I am the guy that had that weird broken resistor problem that did not let my Empeg save on power down. I was losing all my settings when power was removed because that op-amp circuit did not work correctly and was not able to signal the processor upon power loss. This problem seems to me more code related, does the Empeg read battery voltage through an A/D anywhere? I thought the low battery icon was activated in the 10V - 11V range through software? My battery is not the greatest but I know I am well above the 8V range with the key on, probably in the 11V range. I will hook it up to a lab supply tonight and figure out the exact voltage where this "icon" condition occurs.

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#278318 - 27/03/2006 18:03 Re: Low battery icon adjustment??? [Re: farmtech]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5588
Loc: London, UK
Quote:
Is this the same op-amp that senses absolute low voltage and tells the Empeg to write to flash and shut off?


Rob's explained the hardware side; here's how it works in the software:

Every now and then, the player writes the contents of the flash area to kernel space. Rather than write it to flash immediately (which would wear out the flash too quickly), it's cached in kernel space.

When the op-amp sees the voltage drop, it signals the CPU, which prompts the kernel to write this cached data into the real flash device. There's usually enough juice in the on-board capacitors that this succeeds before the power drops out completely. This is why the display is turned off at this point -- it leaves more runtime from the juice in the caps.

In case it doesn't succeed, the block written to the flash has a checksum in it. This means that when the player starts up, it can avoid loading a half-written flash block.

The player cycles through several flash blocks, which means that it can always get a 'last known good' block, even if the last one was corrupt.

If, after flushing to flash memory, the power comes back, and the player is still running, then the player displays the low battery icon. Thus, it's not actually telling you that the voltage is low at that point. It's telling you that the voltage dropped out just now, and you should maybe check your installation.

It doesn't actually tell the empeg to 'shut off'. The power going away is all the 'off' that the player needs.
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-- roger

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#278319 - 27/03/2006 19:11 Re: Low battery icon adjustment??? [Re: Roger]
schofiel
carpal tunnel

Registered: 25/06/1999
Posts: 2992
Loc: Wareham, Dorset, UK
This, and the hardware explanation, really should go into the FAQ. Tony? You up for that?
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#278320 - 27/03/2006 20:02 Re: Low battery icon adjustment??? [Re: schofiel]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31223
Loc: Seattle, WA
done.
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Tony Fabris

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#278321 - 27/03/2006 20:19 Re: Low battery icon adjustment??? [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
FAQ update ported to Wiki FAQ copy.
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Bitt Faulk

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#278322 - 28/03/2006 01:01 Re: Low battery icon adjustment??? [Re: Roger]
farmtech
journeyman

Registered: 22/08/2003
Posts: 59
Guys,

Thanks for the explanations. I thought the op amp that Rob talked about was just for low power dropout set to around 7.6V or so. I checked the output of my op amp and it drives high (thus signaling the processor) at 10.51V or less. At the same time the player resets and then shows the low battery icon. I will now monitor my battery voltage at the sled and see if it is in fact 10.51V I still wish the voltage threshold was less, I may (at my own risk) change the reference voltage divider so the threshold is closer to 10.0V. I'm sure if I had a big new battery this problem would not be as bad though. The player seems to run happily down to less than 7.0V so I would not think the op amp would have to be 10.51V.

Thanks for eveyone's help.

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#278323 - 02/04/2006 13:07 Re: Low battery icon adjustment??? [Re: farmtech]
altman
carpal tunnel

Registered: 19/05/1999
Posts: 3452
Loc: Palo Alto, CA
ISTR 10.5v is about what we set it to. It's annoying for me too, as when the Noble's cooling fans (hovercraft impersonators, more like) kick in I get the screen off/etc behaviour.

The switch-mode PSUs in the player running the HDDs, CPU, etc will run down much lower, 7v would be fine. The only issue is that the 9v (?) analogue linear regulators will also drop out - however, these will only cause - at the worst - momentary distortion, not any sort of CPU upset.

You can change the resistive divider split to set the threshold lower if you want - or just disable the behaviour in the kernel (Mark? )...

Hugo

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#278324 - 02/04/2006 14:11 Re: Low battery icon adjustment??? [Re: altman]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 13961
Loc: Canada
Quote:

You can change the resistive divider split to set the threshold lower if you want - or just disable the behaviour in the kernel (Mark? )...


It's just the little battery icon that we're discussing here, right? Not much point in disabling *that* (what would it accomplish?).

Cheers

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#278325 - 03/04/2006 06:01 Re: Low battery icon adjustment??? [Re: mlord]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 1966
Loc: Brisbane, Australia
Quote:
Quote:

You can change the resistive divider split to set the threshold lower if you want - or just disable the behaviour in the kernel (Mark? )...


It's just the little battery icon that we're discussing here, right? Not much point in disabling *that* (what would it accomplish?).

Cheers


I assume the player accesses the interface through the kernel. i.e. Hugo is saying if Hijack intercepted it in kernel space, it could easily disable it or at least provide a bit of a delay before it passes it through to the player. A delay would provide a solution to the majority of peoples problems since it's the initial spike that causes the temporary dropout from what I've seen.
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#278326 - 03/04/2006 09:15 Re: Low battery icon adjustment??? [Re: Shonky]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 13961
Loc: Canada
Quote:
Quote:

It's just the little battery icon that we're discussing here, right? Not much point in disabling *that* (what would it accomplish?).


A delay would provide a solution to the majority of peoples problems since it's the initial spike that causes the temporary dropout from what I've seen.


Again, my original question stands.. what would that accomplish, other than not displaying the little battery icon?

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#278327 - 03/04/2006 11:02 Re: Low battery icon adjustment??? [Re: mlord]
peter
carpal tunnel

Registered: 13/07/2000
Posts: 4151
Loc: Cambridge, England
Quote:
Again, my original question stands.. what would that accomplish, other than not displaying the little battery icon?

Yeah, quite; the thing that would need changing is the hardware component. Any delay on the software side would stop it working properly in the cases where it does need to happen.

Peter

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#278328 - 03/04/2006 20:41 Re: Low battery icon adjustment??? [Re: mlord]
Robotic
pooh-bah

Registered: 06/04/2005
Posts: 2026
Loc: Seattle transplant
Quote:
Again, my original question stands.. what would that accomplish, other than not displaying the little battery icon?

When the problem occurs for me, the screen goes blank and all sounds stops for a couple of seconds. When the player comes back, the battery icon is displayed.
It's not the icon that's a worry, it's the interruption in the playback.
It's very similar to normal cut-out for radios and accessories during cranking of the motor, for example; just that it occurs with combination of lighter loads (headlight and blinker/brakes).
I've got to sort out a better grounding strategy on my installation, though, and perhaps that will solve my individual problem.

Hmm- maybe my amp is powering down for that interval...?
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10101466 (2x60GB, Eutronix/GreenLights Blue) (Stolen!)

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#278329 - 03/04/2006 23:10 Re: Low battery icon adjustment??? [Re: Robotic]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 13961
Loc: Canada
Quote:

When the problem occurs for me, the screen goes blank and all sounds stops for a couple of seconds. When the player comes back, the battery icon is displayed.
It's not the icon that's a worry, it's the interruption in the playback.


Well, not much to do about that. The blanking etc.. are quite necessary for proper operation. Go for the hardware tweak instead.

Cheers

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#278330 - 04/04/2006 07:59 Re: Low battery icon adjustment??? [Re: Robotic]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5588
Loc: London, UK
Quote:
Hmm- maybe my amp is powering down for that interval...?


Yes, it is. The amp remote line is directly connected to the empeg display. When the display is turned off, the amp is turned off.

As Mark says, the display/amp off behaviour is the correct behaviour -- otherwise the empeg won't be able to save the flash area when you pull it out.

If you want to adjust the voltage at which it happens, it'll have to be done in hardware.
_________________________
-- roger

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#278331 - 04/04/2006 12:15 Re: Low battery icon adjustment??? [Re: Roger]
Robotic
pooh-bah

Registered: 06/04/2005
Posts: 2026
Loc: Seattle transplant
Thanks Mark and Roger!
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10101466 (2x60GB, Eutronix/GreenLights Blue) (Stolen!)

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