Lima regulator voltage. Which one is correct?

Volvo V70/2 with an AEL clone alternator and a 120A Bosch alternator.

Problem: The battery is not charging fully and sometimes only reaches a voltage of 12.1-3 volts.
The battery generates approximately 14.1-2 volts when cold (after starting), and then gradually decreases to 13.6-8 volts.
Measured at the 12V output, there is approximately a 0.1-volt drop to the battery terminals.

exchanged; swapped; traded.
2 x Battery, now Varta Blue 95Ah/800A.

1 x Bosch regulator (original) versus the corresponding one from Hella (which, oddly enough, has "14V" printed on it).

The pole/cable connections looked good everywhere.
The quiescent current (below 0.5A) is within acceptable limits.

As far as I know, the regulator has a temperature compensation feature to reduce the charging voltage at high temperatures, but 13.7V seems awfully low, doesn't it?

The controller replacement made no difference.
A mechanic who specializes in alternator rebuilds (where I wanted to have my alternator refurbished) told me that he uses the same regulators and that nothing would likely change.

I'm quite at a loss and I don't want to sacrifice another battery or have to ask other people for jump starts.

Is there anything else that could be directly defective with the alternator (given it has 400,000 km) that might be causing this error?
I'm a bit lost and would appreciate any further ideas!

cumminsracer wrote:

The quiescent current (below 0.5A) is OK.

It depends on whether all the ECUs were truly idle. If so, 0.5A is far too high. I would only accept a value of less than 50mA at most.

Quote:

The battery generates approximately 14.1-2 volts when cold (after starting), and then decreases to 13.6-8 volts.

I would consider that to be within the normal range.

Roger wrote:

If so, 0.5A is far too high.

That's the way it is.
How long does it take to wait before measurements are taken? For example, my Golf needs over 30 minutes for all ECUs to "go to sleep" and for the idle current to be okay.

Sure, thanks in advance.
"14.2 volts maximum might be a bit low, but after 5-10 minutes, we'll reach 13.8 volts, and later it will stabilize at a constant 13.6 volts."
I suspect that's far too little power to charge the battery.
Can someone please measure this (if necessary, using a multimeter plugged into the 12V socket)?

Normally, I would say the regulator has an incorrect characteristic curve, but this is already the second regulator where this is happening.
Actually, the battery is doing really well; it can handle long distances of 2-3 hours at a time. However, it's slowly but surely losing its capacity.

"0.5A seems a bit high to me, but there are quite a few control units/accessories connected to the bus, and it's likely that not all of them had fully shut down after 20 minutes."
I was told that it's a lot, but it's acceptable for the bus/car.

Hi there,


It is borderline at 13.6V.

Regards,
A.

For lead-acid batteries, the charging voltage is between 2.3-2.35 V per cell. So, everything is within the normal range.

"Switch on some of the larger power consumers; this should cause the onboard voltage to increase slightly if the generator is working correctly."

jarobaldu wrote:

It is therefore borderline with 13.6 V

.

Don't forget where the measurement was taken. The previously mentioned voltage drop of 0.1V may become even larger if the vehicle's electrical system is under stress due to afterglow or other factors.

Okay, thanks. I'll turn something on and measure it again; I think I remember that it didn't really have much of an effect before.
Looks like there's another long drive ahead, plenty of time to mess around.

I'm just curious to know if other LIMA devices also experience a significant drop in voltage, below 14V, after a few minutes.

Because if everything is alright, then a battery that isn't fully charged definitely isn't ideal, right?
That's what I'm talking about.

The Euro2 (Model 2001!) AEL probably doesn't have a very good afterglow; it's more like "modern-day devilry."

It appears the alternator has one or more faulty diodes (alternators typically have 9 diodes), and a damaged coil. It's supplying power, but it can't generate more than 14 volts. Take it to a workshop with a Bosch alternator/battery tester to check the alternator; it only takes about 5 minutes. The device measures the ripple voltage of the alternator.

My two battery boxes produce 14.2-14.8V in the low load state, and with all major consumers connected, they output 13.3V in the low load state.
When I apply throttle to 2000 RPM with the accessories on, the voltage is 14.2V. Both have a 120A alternator.
For me, the values are almost the same whether I set it to "cold" or "warm."
I also don't like the 0.5A quiescent current; a maximum of 150mA is acceptable.

Yes, exactly like yours, that's what I would like! Something with a voltage of around 14V, suitable for both summer and winter.
And always having a full battery... ah, that would be wonderful.
No joke, I don't trust that battery at 12.3V, and I wouldn't even charge my phone with it for the whole day...

I forgot to mention that the battery seller has a load tester connected (it checks the battery at idle and then with 1-2 consumers running), and everything was fine according to that test.
However, even after just 2 kilometers of driving, the car was already cold.
It also seems to be relatively insensitive to consumer feedback (or "cold" about it).

I should probably get it checked out by a Bosch specialist soon, maybe with a new alternator (13.8V), and have them redo the heating system installation.

We also measured the quiescent current at that time; it was initially 3.8A, then dropped to 0.5A after 10 minutes, and remained at that level for the next 15 minutes.
But they should have measured it for a longer period to ensure that the "Sandman" (Sleepy Hollow) feature works correctly on all types of set-top boxes.

Hi there,

"12.3V directly at the battery isn't necessarily a cause for alarm. That roughly indicates over 50% charge. Furthermore, when you open the hood to measure the battery voltage, you're already activating several control units, so you're essentially measuring under some load."
Please refer to the table (in the lower third) in http://batteryuniversity.com/partone-13-german.htm.

Was has been modified or added to the car?
So, is it the radio, the navigation system, or some other electrical device?

Yesterday, I went on another trip with my measuring device.
It started at 14.1 and then dropped to around 13.7 (probably 13.8V at the battery).
It was interesting that the voltage quickly dropped to 13.3V as soon as you switched on high-power consumers, such as two rear defrosters and the air conditioning.
The voltages are surprisingly constant, regardless of the speed (3000 RPM = 800 RPM = 13.3V).

Actually, I would tend to say it's a problem with the regulator, but then the regulator would always be trying to maintain its 14V, so an increase in speed would lead to an increase in voltage.
As mentioned before, the Lima test yielded no results, so everything seems to be fine.

The battery is probably not charged that way.
And a charge of 50% already indicates that it is being permanently sulfated.

Here's how the story continues:
- Last idea: There must be something wrong with the engine (400,000 km).
So, it's disassembled (a quick look showed the slip rings were still in good condition), and now it's off to the alternator repair specialist.
The problem was described, and the LiMa system underwent testing.
20 minutes later ("be careful, it's hot"), she came back, and everything was fine; it even drew up to 127 amps.
Due to my disbelieving facial expression, another brand new alternator was tested on the dynamometer, which also only produced 122 amps; otherwise, everything was the same.

So, now all the positive and negative contact points have been tightened, sanded, and cleaned.
I also noticed a voltage drop of 0.2V from the alternator to the first positive cable distribution point (approximately 1.5 meters) in the engine compartment.
Subsequently, a second cable was run parallel to the first one.
Voltage drop is now only 0.07V, which is better.

Result: A slightly higher voltage was initially measurable, but it decreases over time to approximately 13.7V. However, the battery is still not being charged properly (12.3V after 5 hours of driving the previous day, and today even only 12.15V, resulting in an "ABS+DSC undervoltage" warning).

Conclusion: The power supply is working, the cable connections are fine, and the battery is okay... but it still doesn't work.
Does anyone else have a crazy idea? I'm out of them...
I dread the winter .

Check all grounding points involved in the battery charging process, and given the age of the vehicle, also inspect the ground strap from the battery to the chassis and the one from the engine block to the chassis. As a test, try installing a direct ground strap between the engine and the negative terminal of the battery. Even though the car's body is generally used as a common grounding point throughout the vehicle, it may not always be the connection with the lowest resistance and losses.

In my desperation, I did the same thing; I exposed all the positive (+) terminals (the one has two cables because it's the central jump-start terminal) and all the ground points, even the ones way down below in the dirt near the transmission, cleaned them up with a grinder, and reattached them.
The voltage difference is no longer significant (only 0.1V to the cigarette lighter).

I'm at a loss. The alternator is producing over 120 amps, and the voltage is around +/- 14 volts... it should work.

What else needs to happen before you start taking the issue of quiescent current seriously?
Sometimes, a faulty thermostat switch is all it takes.