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I know the Smart has a pretty hefty battery draw. I've been procrastination about connecting an amp gauge inline to the battery to just see how many amps or milliamps it is drawing out of the battery when not running. Now I am guilty of a few things. I added a barrage of LED's to the dome light circuit. I put a 9 LED bulb in the dome light, 4 in the cargo area, 6 outside under the car(more on that in another story), two on the doors, one on the ignition switch and 2 in each footwell. I figured that's alot, but comparing how much the original bulb draws compared to the tiny bit each LED draws I thought it was okay. 26 LEDs total is probably over what the incadescent bulb draws. I live in the country and when it gets dark it's dark, and where I park "Max" when he is outside it is dark. I walk with a cane and it sure is nice to hit the unlock button and have the area "around" the car light up to get to and from it. But I was concerned with the phantom glow of the LED's since they glow with the 4 or 5 volts that the SAM allows in the dome light circuit even when it's off. But we talked about this in another post. The incadescent bulb recieves the same voltage, but 4 or 5 volts isn't enough to light the bulb, but it will light the led's slightly. Then of course the SAM itself draws power always listening for a signal from your FOB.I'm sure the radio draws a little because it will turn on for a period of time without the key being on. Then I added a rear view mirror backup up camera (yes it's crazy on a smart, but I can't turn around enough to see to back up properly) and it is connected to power all the time which I presume is miniscule. Then the pod clock runs all the time and draws a little. But I have loaded on the options and I need to go down and check the total draw. Even if it totals 2 or 3 amps total the battery should last a couple of days without running the battery dead. I could see it going dead in a month of sitting or even maybe 3 weeks but I really think the battery is losing capacity because even after I drive it to town it still turns over slowly and struggles. It just a case of me checking battery voltages to pinpoint whether it's my negligence of too much battery draw (LEDS and phantom glow) or a failing battery. You will notice that if you try to start your Smart with a low battery and you have the door open, the SAM instantly turns your dome light off to try and help the situation. But you know Max smiles whether his battery is dead or not and the computer stores a code when the battery dies. There's no escape from technology!
Wow, I just "fixed" my wife's computer and even though I've read through this thread on my phone, this is the first time I've come across this post. Long story short, make sure you see your anti-virus scanner in the lower right corner of your computer screen. (Rootkits look just like Windows!) And check your Android for Stagefright! Not sure if that's related to not seeing this post, but....

It wasn't really clear, but do all 26 LEDs glow? I wouldn't worry about this leak current, at least not at first review of this...

That back up camera is my concern: "is connected to power all the time"! Woah, I'm kind of surprised Rusted Wrench didn't comment on this, or maybe I just missed it, or something special about it?!?!?!

An interesting test/experiment would be to line up a LED in series with an incandescent bulb, and then turn on the circuit. In my humbly little experience with LEDs, I GUESS that the incandescent bulb will not light. Because LEDs do not draw much current, it will not support the flow necessary for the incandescent bulb to light, and IF THIS LITTLE MIND EXPERIMENT PROVES TRUE that the incandescent bulb does not light, can quell at least some concern over the LEDs. You can have all the voltage you want across a circuit, but if no current flows, you're not draining your battery.

(But I'll wait to hear/read about the backup camera...)
 

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Rusted Wrench my assumption of there being 4 to 5 volts active in the dome light circuit comes from an SCOA post. It says:

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Jim - I made some measurements myself and I think I now know what your measurements were:
Off voltage at lamp terminals with lamp removed: 12V.
Off voltage at lamp terminals with lamp in place: 4.94V.
Off current with lamp removed: 0.16mA.

I'm guessing you measured the on current by turning the light off and putting your current probes (low resistance shunt) on the center switch contact and one of the outside conductors on the dome frame.

In the case of the incandescent bulb, the off current I measure is close to yours at 0.143mA; the on current is beyond the 200mA scale of my cheap multimeter.


And this other post on the dome light circuit from a later SCOA post:
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solder a 20 ohm 5W resistor across the socket to load the leakage and it'll go out. stuff it up in there somewhere but don't let it short to ground, of course.

The LEDs are a virtual open until there's about 2.1V across them. Any leakage over that will make them glow. Obviously, our series switching transistor has the wrong bias or is so cheap it leaks....


It wasn't my intent to mislead anybody. I haven't checked it out for myself yet, but I intend to because I'm curious. My take on it is that you can wire a resistor acrossed the circuit and stop the glow, but the voltage leak is still gonna be there because it is from the electronic switching of the SAM which is triggered by the door switches which do ground out the circuit if I understand it right. Like this post.........

Old 06-16-2011, 08:23 AM
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Garage
Smartdigger is correct. The interior light on the smart is negative switched. Since it is controlled by the SAM, there isn't a physical "switch" or relay to turn it off, it's done via a solid state circuit. There is a slight amount of voltage bleed across the circuit. This is what is causing your LED to glow. I had this trouble with the original LED I used in mine I switched to one here: Super Bright LEDs ? Festoon Light Bulbs . Look for part number 3710-CWHP6. It is a festoon type light mounted to a circuit board that prevents this from happening. Been using mine for almost 3 years, and it never glows.
Hope this helps.


I've tried to research the heck out of this because I know it's an issue with Smart dome lights and the LED's. I'm sure that you are correct that the systems go to sleep after a few minutes, but my dome circuit glows all night long and that current will still be flowing whether I have an incadescent bulb in there or LED's. And I would guess that it doesn't matter if I have 1 LED or 100 LED's that current is still there flowing. So my bottom line was that it was draining the battery in the dome circuit since the car was new and I added LED's and ran it for months with no problem and now that the weather has gotten cold I suspect the battery is failing.
And by the way thanks for alerting me to thise wires rubbing on my horn bracket. I will certainly fix that, I never even caught that. I must be getting OLD and CARELESS ! Thanks Rusted Wrench
You can calculate the current draw of the incandescent by measuring the voltage across. (I'm assuming you might already know this). Then measure the resistance across the festoon bulb separated from the circuit. I=V/R. It should be more or less accurate I hope...

It's more complicated with a LED/you'd have to measure milliamps in series I guess...
 

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Wow, I just "fixed" my wife's computer and even though I've read through this thread on my phone, this is the first time I've come across this post. Long story short, make sure you see your anti-virus scanner in the lower right corner of your computer screen. (Rootkits look just like Windows!) And check your Android for Stagefright! Not sure if that's related to not seeing this post, but....

It wasn't really clear, but do all 26 LEDs glow? I wouldn't worry about this leak current, at least not at first review of this...

That back up camera is my concern: "is connected to power all the time"! Woah, I'm kind of surprised Rusted Wrench didn't comment on this, or maybe I just missed it, or something special about it?!?!?!

An interesting test/experiment would be to line up a LED in series with an incandescent bulb, and then turn on the circuit. In my humbly little experience with LEDs, I GUESS that the incandescent bulb will not light. Because LEDs do not draw much current, it will not support the flow necessary for the incandescent bulb to light, and IF THIS LITTLE MIND EXPERIMENT PROVES TRUE that the incandescent bulb does not light, can quell at least some concern over the LEDs. You can have all the voltage you want across a circuit, but if no current flows, you're not draining your battery.

(But I'll wait to hear/read about the backup camera...)
I bought one of those cheap rear view mirror MP5 players from Ebay that also has the backup camera input on it. It has a red wire, black wire and a yellow wire in the power department. Black is ground and yellow connects to the back up lamps so that it knows when to turn on the backup camera. Now most people would probably connect the red power wire to a power source that is only on when the key is on. But I elected to connect it to power all the time so that I wouldn't need the switch turned on to watch the MP5 player. You aren't supposed to watch it when the car is being driven, I like to watch old shows like American Hot Rod when I am waiting on the wife somewhere or have an occasion to be waiting in the car for any length of time. I surmized that the radio can be played for a preset amount of time without the key, why not the player? So I connected the red wire to the SAM on one of the "edge connectors" for power all the time. But in hind sight I should have connected it "switched on power". I thought if it was "off" there was no draw, but sometimes the USB pen drive that connects to the side of it to play lights up even when it's off. I suspect that sometime it may draw a little too much. But I used it this way for months and then when the weather turned colder the battery showed signs of "draining". So I now put the Smart in the garage where it's warm and it sat for 5 days and started right up. It probably see's the new battery I bought for it sitting over in the corner. I would suspect that the POD clock draws a little bit because it runs a stepper motor that is crystal controlled to advance the hands. At any rate I'm set to drop the engine down and pull the head for burned valves so I'll change the battery just for good measure. Now if I can just get the energy to get this project started !
 

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I bought one of those cheap rear view mirror MP5 players from Ebay that also has the backup camera input on it. It has a red wire, black wire and a yellow wire in the power department. Black is ground and yellow connects to the back up lamps so that it knows when to turn on the backup camera. Now most people would probably connect the red power wire to a power source that is only on when the key is on. But I elected to connect it to power all the time so that I wouldn't need the switch turned on to watch the MP5 player. You aren't supposed to watch it when the car is being driven, I like to watch old shows like American Hot Rod when I am waiting on the wife somewhere or have an occasion to be waiting in the car for any length of time. I surmized that the radio can be played for a preset amount of time without the key, why not the player? So I connected the red wire to the SAM on one of the "edge connectors" for power all the time. But in hind sight I should have connected it "switched on power". I thought if it was "off" there was no draw, but sometimes the USB pen drive that connects to the side of it to play lights up even when it's off. I suspect that sometime it may draw a little too much. But I used it this way for months and then when the weather turned colder the battery showed signs of "draining". So I now put the Smart in the garage where it's warm and it sat for 5 days and started right up. It probably see's the new battery I bought for it sitting over in the corner. I would suspect that the POD clock draws a little bit because it runs a stepper motor that is crystal controlled to advance the hands. At any rate I'm set to drop the engine down and pull the head for burned valves so I'll change the battery just for good measure. Now if I can just get the energy to get this project started !
The good news, (I think,) is that I believe some of the open SAM connections are switched power, so if you decide to move it that should be somewhat simple enough. But since you explained how you watch while waiting, and assuming the engine is off while doing so, having the car in accessory mode would drain a lot more power than just the screen by itself... I'm afraid this is still my first suspect though.

I'm really sorry to read about your engine issues. I still have warranty left, until about the middle of October, on the 4 yr/50k miles. Mine has just above 10k miles on the ODO...

I'm assuming you already know about the smarttekinfo site. If you decide to try it and need help you can let me know, by PM if I'm floating around other forums or such....
 

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Discussion Starter #28 (Edited)
The good news, (I think,) is that I believe some of the open SAM connections are switched power, so if you decide to move it that should be somewhat simple enough. But since you explained how you watch while waiting, and assuming the engine is off while doing so, having the car in accessory mode would drain a lot more power than just the screen by itself... I'm afraid this is still my first suspect though.

I'm really sorry to read about your engine issues. I still have warranty left, until about the middle of October, on the 4 yr/50k miles. Mine has just above 10k miles on the ODO...

I'm assuming you already know about the smarttekinfo site. If you decide to try it and need help you can let me know, by PM if I'm floating around other forums or such....
Did a little investigation on the SAM and got some pics. The fuse index is what is in the owners manual as to what fuse goes to what circuit, but the one pic shows which of the "R" terminals are switched with the ignition and which ones are power all the time. Thought I would post it because maybe some people don't have this info.


This is the SAM with the fuses and their designation number as seen from underneath the dash.




This is the corresponding index.




This shows which ones are switched and unswitched.




Here is a pic of the fuses that are on the topside of the SAM. You can't get to them without dropping down the SAM.


And here are some other fuses that are located at your battery under the carpet in the passenger side wheelwell. not everyone knows there's fuses there too.
 

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Correction!!!

This image is incorrect for fuses 28 through 31. Fuse #28 should be at the bottom, and #31 at the top. Both the owner's manual and evilution.co.uk have the correct fuse panel layout.

Would someone who is a member of fq101.co.uk please notify them of this typo. I've been aware of this typo for some time, however they do not provide a contact method for non-members. :(

~toaster
 

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This image is incorrect for fuses 28 through 31. Fuse #28 should be at the bottom, and #31 at the top. Both the owner's manual and evilution.co.uk have the correct fuse panel layout.

Would someone who is a member of fq101.co.uk please notify them of this typo. I've been aware of this typo for some time, however they do not provide a contact method for non-members. :(

~toaster
Done :)
 

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Discussion Starter #31 (Edited)
This image is incorrect for fuses 28 through 31. Fuse #28 should be at the bottom, and #31 at the top. Both the owner's manual and evilution.co.uk have the correct fuse panel layout.

Would someone who is a member of fq101.co.uk please notify them of this typo. I've been aware of this typo for some time, however they do not provide a contact method for non-members. :(

~toaster
Thanks for the info Toaster. I never caught that. I will "modify" the pic I posted so that it is correct. Sorry for the oversight, it wasn't intentional. DreamCarOwner.

Image is modified per Toaster's instructions. I fixed it on my first post of it. I don't know if that will fix it where it is included in subsequent posts or not. DreamCarOwner
 
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