TDI mit zu kleiner Batterie: Probleme? | Posts 16+

t.klebi wrote:

In the case of a sealed battery, frequent charging up to the gassing level is often unhealthy because a certain amount of water loss must always be expected. Roger wrote: Is it not completely normal for frequent charging up to the clamping voltage of just under 14 volts? The smaller battery is not charged more often than the larger one, right? Yep, see above. Gassing (which is temperature-dependent) begins above approximately 14.4V and usually only occurs with common, unregulated home chargers.

If Ulf only drives long distances and the small battery, despite its small capacity, provides a high cold-cranking current, I wouldn't fear any problems.

Quote:

Although my daily commutes are only 2 x 20 km on country roads, the ~25 minutes per trip have so far been sufficient for recharging that even with the 10A home charger, hardly anything needs to be added back into the battery (after about 1 minute, the charging current is approximately 1 A).

My daily commutes are only 2 x 20 km on country roads,
I wouldn't have any reservations about it. Of course, the risk of running out of power is greater with a smaller battery; you just lack the reserves. Personally, I once completely drained my battery by leaving the interior lights on.
But if you pay attention to things like that, why not? And I'm sure there isn't a real winter in the Saarland either.

Regardless of that:
I personally place great importance on having reserves.
In my opinion, even in extremely cold weather, my car should be able to handle a few days of short trips. This includes using features like pre-heating and afterglow, auxiliary heating, windshield heater, seat heaters, lights, rear window defroster, radio, etc.

Regards,
t.klebi

Hi,

Quote:

My main goal is to achieve the lowest possible wagon weight, and a difference of 6 kg is already quite significant in that regard.

I understand that already... but wasn't fuel efficiency ultimately also a goal? That was the aim.

Quote:

I personally once completely drained my car battery just by leaving the interior lights on.

"...I almost did it last year... The interior light (10W?) ran for about 40 hours while I was on a business trip and the car was parked at the train station. In that situation, the large battery proved to be a lifesaver."

Best regards,

January.

...I almost did it last year... The interior light (10W?) ran for about 40 hours,
Here's how different interior lighting can be.
In my case (a Seat Alhambra), the power consumption was as high as 85 watts (> 7 amps). That was enough to drain the battery during a prolonged cleaning session.
Regards,
t.klebi

t.klebi wrote:

Isn't it perfectly normal for the charging process to reach the clamping voltage of almost 14 volts frequently? The smaller battery isn't being charged more often than the larger one, is it? If Ulf only drives long distances and the small battery provides a high cold-cranking current despite its small capacity, I wouldn't be worried about any problems. It only becomes problematic when the charging time (driving time) is insufficient. The reduced state of charge of the battery leads to increasing sulfation, which ultimately results in premature failure. Regards, t.klebi

Okay, the voltage-limited charger makes the problem seem less severe, although gassing doesn't start abruptly at 14.4V, but may begin earlier with a fully charged battery. With my voltage-limited charger, at least one battery cell will definitely show signs of overcharging by the next morning. In reality, you would have to constantly monitor it to avoid this.

The smaller battery will be discharged and charged more deeply solely due to its lower capacity. This results in deeper partial cycles. 45Ah is not the same as 70Ah, and if VAG (Volkswagen Group) installs a 70Ah battery from the factory, there's likely a reason for it, especially when they calculate costs down to every tenth of a cent in other areas.

Jan6k wrote:

...I almost did it last year... The interior light (10W?) ran for about 40 hours while I was on a business trip and the car was parked at the train station. In that case, the massive battery proved to be a lifesaver.

Fortunately, the onboard control units are working correctly today; at the latest after 1 hour, everything will be off, including the 12V socket in the trunk .

Fortunately, the onboard control units are working correctly today; at the latest after 1 hour, everything will be off, including the 12V socket in the trunk .
Unless you open and close the doors every few minutes to make sure everything is nice and clean.

Regards,
t.klebi

Well, Ulf's question was simply about whether it was possible or not. He also asked why it wasn't working, and those concerns are valid. However, Ulf's car is still running. Even though his reasons might not be understandable to everyone, he will now take over the research work for us and let us know when he needs to switch. We can wait until then.

Furthermore, with a 6 kg weight reduction, concerns no longer apply, because pure logic should never prevail in this situation.

My factory battery is still in the car as of 07/02, because it has been working fine so far (last winter I thought it was about to die, but it recovered), so I don't even know what kind of battery it is; I've never checked. I even still have that heavy plastic cover around it.

45 Ah is not the same as 70 Ah, and if VAG installs a 70 Ah battery from the factory, there's probably a reason for it, especially when they calculate down to every 1/10 of a cent in other areas.
That's because a car shouldn't break down, even when used for short trips.
It would be quite difficult to advise the buyer to always drive at least 20 kilometers after every engine start.


Regards,
t.klebi

Hi,

Quote:

In my case (a Seat Alhambra), the power consumption was as high as 85 watts.

What a mobile palace with appropriate interior lighting!

Quote:

That's because a car shouldn't break down, even when used for short trips.

And that's working great... my battery mostly sees short-distance driving – especially and particularly in the winter.

Reasons for that... I understand... but I'm waiting for the day when Ulf puts his TDI engine into an Elise or a similar chassis. That would solve all the weight problems.

Best regards,

January.

Jan6K wrote:

... but I'm waiting for the day when Ulf puts his TDI engine into an Elise or a similar chassis. That would solve all the weight problems.

Offering a Jetta 1 GLI without an engine, for transplanting the gearbox. Say goodbye to weight problems!

goettmann wrote:

56€ for a 45... Sure, I'll try. You know the dangers and can take corrective action in time...

Bertil wrote:

Hello Ulf, Your plan is borderline. More details via private message.

Okay, here's a brief summary at the end of the first winter of the mini-battery system.

I didn't make it easy for her because I turn off the engine during longer red lights or when going downhill. In winter, the headlights and electric power steering draw significant amounts of current from the battery for several minutes, plus potentially the windshield wipers and the small amount of power needed for the ignition, ESP, and other systems.

As a counterbalance, I would connect the Ibiza to my small battery charger, which is now voltage-regulated and temperature-compensated, every few days, and fully recharge the battery over several hours each time.

"Occasionally, the ABS warning light illuminates for about a minute after I restart the engine while driving. However, I use the start-stop button because turning the ignition key is too cumbersome, and also because the power steering only starts working after the engine has started. Rapidly descending hills through tight curves with passive power steering feels like intense strength training due to the extremely heavy steering, and it reduces reaction time in sudden danger to almost zero."
Therefore, my stop button only interrupts the signal to control unit (CU) via terminal 15. This means that all other functions remain active and register the voltage drop during startup without a previous boot cycle; or, in other words, the power steering continues to operate even with the engine off.


Under the most extreme cold start conditions, the engine block likely cooled down to approximately -3°C (although, thanks to the garage attached to the house, which is slightly heated due to heat loss from the walls). Based on the starter motor speed, I never noticed any signs of a battery being overloaded.


Preliminary conclusion: For a weight reduction of approximately 6-7 kilograms, I would do it again.

It's not a diesel... My fun car (Citroen Saxo 1.6 VTS) has had an 18 Ah motorcycle battery since autumn. I needed the original 66 Ah car battery for other purposes , so the Saxo ended up with a custom-made bracket and the motorcycle battery.

The €26 item, a lead-acid battery, was being sold at a clearance price at the nearby Unger store. It was "dry" (meaning without any initial charge), manufactured in week 50 of 2009. The normal price is €44, but these had been filled and put on the shelf at an unknown time previously. If you know how to properly activate a dry lead-acid battery and have the necessary patience, you can get a practically brand new battery that you can either build up well or quickly ruin through improper handling.

Of course, the Saxo started without any problems in the autumn and was driven several times. It was never used for short trips, but also rarely driven in the dark or cold weather with high energy demands. During the winter, the battery was placed in a cool but frost-free basement and allowed to "warm up" about once a month using a small CTEK charger. Weight advantage: 6.7 kg versus 20.4 kg.

Hutfahrer wrote:

Not a diesel engine... My fun car (Citroen Saxo 1.6 VTS) has had a motorcycle battery, an 18Ah one, since autumn. . .

The logical continuation of my experiment:

Gasoline battery for a diesel engine.
Moped battery for a gasoline-powered engine...

And what happens next? Button cell battery for the scooter?

ulf wrote:

And what happens next? A button cell battery for the scooter?

Kickstarter?

Roger wrote:

ulf wrote: And what happens next? A button cell battery for the motorcycle? Kickstarter?

The use of physical strength is not allowed here.

ulf wrote:

.... Intermediate conclusion: For approximately 6-7 kilograms of weight loss, I would do it again.

Okay, let's get down to business.

Do you think this procedure is feasible for everyone and everywhere (i.e., even when parking under a streetlight at -25°C)?