Charger with only 14.0 V?

Hello,

There's a signature on the Superb.
Valeo 120A alternator with a 14V voltage regulator.

He's doing a rather poor job.
Regardless of the engine speed, I get 14.0 V with a low electrical load, and 13.6 V to 13.8 V with many consumers connected.

In my opinion, that's not enough!
But maybe Skoda had a reason for doing that? At the very least, the battery will never fail due to gas buildup.

I'm having trouble determining whether the battery is charging properly. In any case, the battery voltage, when the engine is off and after the various control units have powered down, is 12.6 - 12.7 volts. During the preheating phase, the voltage drops to 11 volts.

What do you think? Should I replace the voltage regulator? Lima already has 160,000 kilometers (or miles) on the odometer.


Hi Georg,

Why, if it's already lasted 160,000 km?! Is the battery still the original equipment? If so, how old?

I replaced the battery last year in the winter.

The first battery only lasted 3 years and failed on me during the winter while the auxiliary heating was running.

I'm asking about the 13.6 - 13.8 volts because all the other cars I've ever owned have had a board voltage of around 14 - 14.4 volts.


Best regards,
Georg.

The Passat in question originally had a Valeo 120A alternator from the factory. I recently replaced it after 275,000 km because the charging voltage at the battery terminals, without any consumers running, was 13.68V. It's also a vehicle with a standing heater, and I sometimes charge my batteries with a CTEK charger. This charger visualizes the charging process with colored LEDs, and the Passat battery always took a particularly long time to reach full charge, even though I drive the car about 70 km daily. It was therefore likely that the battery was never fully charged by the alternator.
"First, I replaced the voltage regulator, but that didn't make any difference. Then I replaced the alternator. I installed a Delco Remy (remanufactured Valeo) unit, and its charging voltage was significantly above 14V, specifically 14.21V right after installation. Two days later, I took my laptop with me in the morning, and it showed a reading of 14.44V. The difference was also clearly visible in the brightness of the lights, even without using any measuring devices. Unfortunately, this alternator was defective, and I had to replace it again. Now, a Bosch 140A alternator is installed, and its charging voltage varies between 14.0 and 14.52V. Immediately after starting, it reads approximately 14V, and after 1-2 km, it gradually increases to 14.44V. The value of 14.52V was also briefly displayed. It stays at that level for a while, and then the voltage..." It dropped back down to 14.0V. I don't know if the Delco did the same thing, because I didn't log that data as extensively.
The Sharan also has a Bosch alternator and a voltmeter in the instrument cluster. The charging behavior is similar. It always regulates between 14V and 14.5V, but never below that. This is true even with the headlights, heater, and seat heaters all on.
Modern Bosch multi-function controllers, among other things, take the temperature (unfortunately, the temperature of the controller itself, not the battery) into account when regulating the voltage. I don't have that information for Valeo controllers because I don't yet have any documentation for their controllers.
See also here:
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"With the older hybrid controllers, there were some specifically designed for short-distance operation with a higher charging voltage, manufactured by Bosch. However, I haven't found such a controller in the generation of multifunction controllers."
/viewtopic.php?t=25924
Or, to put it another way: 13.6V is too low. Even the best batteries won't last long with that voltage. This is especially true in the winter and for cars with auxiliary heaters.
Replace the voltage regulator or alternator. Alternatively, you can regularly charge the battery externally if you're willing to do that. Without any electrical loads, you should see significantly more than 14 volts at the battery terminals. Ideally, it should be 14.4V.http://aa.bosch.de/aa/de/berufsschulinfo/media/2003_2.pdf{MARKER}

Thank you for your reply, Steffen.


I've also done it the way you did, for now.
I've connected the charger to the battery and am now waiting for it to be fully charged. This way, I can get a rough idea of how discharged the battery is.

Otherwise, your post doesn't exactly fill me with hope. I could just buy a Bosch alternator and save myself the cost of the Valeo regulator.


Best regards, Georg.

Hi Georg,

"As the saying goes, 'If you measure, you measure manure.' So, I'm curious about the measuring device used. Is it a high-quality one, or a cheaper model? If it's the latter, you might want to take measurements on a different vehicle to confirm the results." It wouldn't be surprising if the cheap device's batteries are simply drained, which would explain why it's giving inaccurate readings.


If your voltage is indeed that low, the question is whether the regulator is designed to operate at that level, or if the regulator itself is faulty. Let's take a look at the regulator data then.

Georg_G wrote:

I could just buy a Bosch alternator and save myself the cost of the Valeo regulator.

According to my understanding, Steffen replaced the regulator with an identical one that also had a low voltage. That's why there was no change. You could check if there's a regulator with the same dimensions but a higher rated voltage.

Greetings.
Guste.

My Golf and Passat represent significantly different voltage levels.

Lima is the same.
However, I'm still in the early stages of research - please see the battery and heater threads for more information.

The factory-installed regulator was replaced with a Hüco 130731. Its parameters are specified as a nominal voltage of 14V and a regulation voltage of 14.5V, which is how it should be. And that's how I wanted it to be without having to replace the alternator.
Unfortunately, the campaign was not particularly successful at the time.
But that doesn't necessarily have to be the case here. Maybe you'll have more luck and be able to fix it with the regulator.
The carbon brushes on the old regulator were very worn down at the back, while the front ones were at the wear limit. That's why I immediately replaced the regulator at that time. There's also a picture of it on page 2 of the thread.
/viewtopic.php?t=24534
Unfortunately, the range of models with different parameters within the same design for Valeo regulators is not as extensive. Bosch, on the other hand, provides catalogs with tables listing regulators for all Bosch types, categorized by type and parameters. I am not aware of any information source for Valeo regulators that offers such a comprehensive selection.

Hi Guste,

I have (retrospectively) measured consistent nonsense with...
a) my cheap multimeter
b) a casual encounter with a former colleague.
c) via OBD.

Thank you for the thought-provoking suggestion.


Steffen,

I once estimated the battery charging time using an external charger. It's a cheap device that provides a maximum of 3.8 amps. It indicated that the battery was fully charged after approximately 5 hours, with a charging voltage of 14.4 V.
In this case, I'm not assuming a loss of approximately 20 Ah based on 5 hours * 3.8 Amps. The charging current of such inexpensive chargers is usually significantly lower than the specified maximum value, especially above 13V.
According to the charger, the battery was almost fully charged...
A rather crude piece of cast iron.


I've also looked into alternative charging algorithms, but I haven't found anything yet. I'll try swapping it out with the same one, but only after inspecting the one that's currently installed.


Thank you for your opinions!

Georg.

Connect VCDS and monitor the supply voltage while driving. If the battery isn't fully charged, for example, after preheating. Perhaps the Valeo regulator adjusts the charging voltage in a similar way to the multi-function regulators from Bosch. So, you've probably been taking your measurements just when it was reducing the voltage.
While that would explain the good battery charge level, it still leaves the question of why the original equipment (OE) batteries failed after only 3 years.
Otherwise, I would suggest starting with the regulator as well. Maybe you already have one lying around. If you need to buy one, the regulator with 14.5V of this type is called either Hüco 130731 or Valeo 593522.

Here's something to look at.

It was actually about whether the auxiliary heaters would turn on, but both of them are working.

The Golf still delivers a significant amount of voltage to the engine control unit (ECU), while the Passat shows a more noticeable drop.

Okay, so, I've now replaced the original Valeo regulator with a cheaper aftermarket unit from Alanko.

Initially, I was very hesitant because Alanko often receives negative reviews online. However, it was the only affordable source for a regulator: 31 euros including shipping, compared to over 50 euros for the original Valeo regulator.
After a phone conversation and incredibly fast shipping, I now have a very positive opinion of Alanko.

Anyway: The quality doesn't seem too bad. The regulator works, and it's better than the old one. Now I'm getting 14.1 volts with the lights and air conditioning on, and 14.2 volts with the air conditioning off.

Here are the front and rear views of the old and new controllers.

Ouch.

The original Valeos for cost over 80 EUR.

I'm not replacing mine .