MikeT

Voltage: how low can you go?

39 posts in this topic

28048568409_e40f4c75d3_b.jpg25954034338_a111bd1183_b.jpg

 

 

Fun! The smart was our only available car to head to Victoria to get some photos of Tim Bowles' Peugeot 404C wiring. I knew the voltage regulator in the smart was bad but it would usually hold about 13.2 volts - low, but not low enough to depreciate the battery too much on a single drive. I was milking it...

 

 

Well, at the last stoplight leaving Victoria in the heavy rain, the alternator stopped charging completely and voltage showed 11.8V. Oops!

 

 

As you probably know, the smart uses electricity for nearly everything! We drove towards home and by the summit of the Malahat it was showing 11.5V, then 11.0V in Duncan, 10.4V approaching Chemainus, and not much more than 9V as we rolled on the home stretch.

 

 

The battery warning light illuminates at 11.4V I found out, and the airbag, ABS and general warning lights come on in the high 9V range!

 

 

Lucky to make it home! This car will go to Mercedes Nanaimo for a new alternator, intercooler and intercooler holder ASAP.

 

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I had an ‘82 Cadillac that developed a sudden loose alternator belt that was not charging.  It only got me about 100 Kms before everything shut down and I coasted into a gas station for a belt tightening and a boost to restart.

 

Off topic, but do you know if the other Canada1s have the same dash plaque as you have ??

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#2 and #3 have the BRABUS plaque.  For some reason #4 has 4 of 10 on it, which is strange because by then it was certain that no more than 4 would be built!

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Mine looks like this.....

Canada1 No. 01/10 

Thanks for the info Mike.  Ain’t the Smart world strange.

 

Now, back to alternators, batteries and other electrical charging gremlins.

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Car goes under the knife Wednesday.  Hope my bank account doesn't hurt too much afterwards!  LOL!

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I'm predicting $500 for the alternator, $450 for the intercooler, $75 for the I/c bracket, and 5 hours labour.

My guesstimate - $1700 + tax

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Because it has a hole and has been leaking oil for over a year.

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Mainly it's the oil.  This happens to most cdis over time.  Maybe boost is a tad lower because of it but the car still has good power.  This car is from the last 5 months of production so the rumour that smart got their crap together and fixed the intercooler holder during production is just wrong.

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Driving something that's not charging, in the rain, is the worst. Wipers, headlights, blower motor... dispense your electrons wisely lol

No issues shifting as the power got low? I found the clutch actuator and shift motor started to misbehave in the 9-10V range.

 

With all the work at the dealer the car's going to be like new again! I'm due for some intercooler attention on mine as well, been noticing a drip which I thought was an axle seal at first but after replacing those and cleaning the area of all the splattered oil I was able to notice the "fresh" drips after a drive were in fact from the intercooler not the transaxle... 

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Got it back and the intercooler and new holder are in.  That's the good news.  Fired her up and ScanGauge said 14.1V after 10 seconds.  Good, turning onto the main road, blower fan sounds slow; V is 12.0.  Uh oh.  Then it starts vacillating up and down between 14.x and 12-11-10 and eventually 9 when I got home.  I couldn't take it back right away because I needed a ride.  Ugh.

 

I put my "better" battery in at home, quick test.  Starts up, 14.3V.  Good.  Drive 500 metres, down to 12.0.  Parked it at home with 12.4V showing at rest (when the car is running on battery power alone, the V gets a lot lower than static V).

 

Car goes back tonight, my son is home in the B 200 so there's my ride.

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Original alternator was most likely fine. Problem caused by something else. Glow plug relay or perhaps wiring. 

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It is back at the shop and I will call them shortly about this.  I don't do electrical work on this sort of thing.  So either they fix it or the car will be scrapped.  The original alternator was OK until last weekend when it ceased charging entirely.  Now the voltage regulator is dead, at a minimum.

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Mike, it is both sad and bad just to scrap the wee car for such an elementary problem.  Looking at the diagram I see connector X26 is also a possible culprit as is the continuation of this wire where it connects to SAM.  From memory, X26 is inside cabin under carpet near fire wall but I could be wrong there.

 

About alternator terminals:

 

D+ is what traditionally would go to a charge lamp and then to ignition switched +.

DF on this Bosch provides a voltage signal typically between 0 and 11 volt.  Gives glow plug controller an idea of how much electrical power is being generated.  Glow plug controller then sends the excess energy to the electric cabin heater elements.

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I'll run a test on my 450.  Will disconnect existing  lead to D+ on alternator and connect a charge lamp in series with switched plus and see what happens.  it would be good to have a traditional charge light.  Better being advised of lack of charge instantly instead of when battery has nearly gone flat.

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I'm confused? Did the dealer install a new alternator?

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An expensive procedure no doubt. Mike said in a previous post:

 

This car will go to Mercedes Nanaimo for a new alternator, intercooler and intercooler holder ASAP.

 

Lucky I get mine done at the nearby cheap and friendly Banchory Smart Centre. 

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On 1/21/2018 at 5:51 PM, MikeT said:

28048568409_e40f4c75d3_b.jpg

Your interior is really nice. It makes me want to change mine.

 

Hopefully the problem will be fixed.

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4 hours ago, smart142 said:

I'm confused? Did the dealer install a new alternator?

Yes.  It charges but it randomly stops charging and voltage goes to battery V.  Then it picks up again, lights wobble in brightness for a while and it stabilizes.

 

Brisk acceleration (and the car is faster with a proper non-holy intercooler) makes it stop charging as does putting additional load on the electrical system.  This is what makes me suspect a ground strap because as the engine moves on its mountings it presumably stretches the ground.

 

The workshop STAR was down today so they will resume work tomorrow.  Mercedes-Benz Canada wants them to check all the modules in the car first on STAR.  We will see.

 

Worst case scenario, I will have to store it at the back of the garage indefinitely.  I won't really scrap it. 

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OK. But the alternator they installed could be defective, that's what I would check first.

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Il y a 19 heures, tolsen a dit :

I'll run a test on my 450.  Will disconnect existing  lead to D+ on alternator and connect a charge lamp in series with switched plus and see what happens.  it would be good to have a traditional charge light.  Better being advised of lack of charge instantly instead of when battery has nearly gone flat.

Test done.  Connected a Fluke multimeter to battery terminals to read out voltage.  Disconnected existing lead to D+ and connected D+ in series to a 12 volt/ 3 watt test lamp connected to switched plus.  Test lamp lit up when turning ignition on and extinguished when engine started just like a good old traditional charge lamp.  I also tried to get the dash charge lamp to turn on whilst driving by leaving D+ disconnected.  Gave up after a 30 minute drive.  The charge lamp on these cars is no more than a joke.

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Good info presented by Mike in post 1:

The battery warning light illuminates at 11.4V I found out, and the airbag, ABS and general warning lights come on in the high 9V range!

 

My battery never dropped that low hence reason why I had no battery warning light.

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No.  The old alternator ceased charging entirely a week ago (I have a voltmeter in the car).  The newly installed one worked well, but only intermittently. The old one was shot.  But there is a reason why it was shot, and that's what they're after now.

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Slip rings and carbon brushes are dead cheap and easily replaceable for those that are sufficiently smart and skilled. Regulator assembly is also cheap and replacable even by fools.  Too late now since your original alternator is gone although most likely nothing was wrong with it. Must be an external cause since both have failed. 

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6 hours ago, tolsen said:

Regulator assembly is also cheap and replacable (sic) even by fools.

That's a great testimonial! :lol:

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