Replacing the battery - larger size possible?

Hello everyone,
"In my TDI, there's a 64 Ah battery installed, which I now need to replace. Can I theoretically replace it with an 80 Ah battery? What does the alternator say about this? Will it just take longer to charge, or will it never be able to fully charge the battery? Will the 64 Ah still be available within the same charging time, and the remaining 16 Ah would just be a 'bonus'?"

Tino Kossmann wrote:

uses a 64 Ah battery. . . Can I theoretically replace it with an 80 Ah battery? What does the alternator say about this - will it just take longer to charge, or will it never be able to fully charge the battery? "

The 80s battery will also be fully charged. In practice, you won't notice any difference in terms of charging time.
However, if the cold-cranking current of the 80-amp system is lower than that of the 64-amp system, you might experience (cold) starting problems...

Quote:

Stehen die 64 Ah dann in der selben Ladezeit zur verfügung und die restlichen 16 Ah wären nur "Bonus"?

Define "bonus"...

Here's a text from Audiotechnik-Dietz that should also answer some other questions:

Second battery
Eine Frage die in diesem Zusammenhang immer wieder auftacht: Kann meine Lichtmaschine überhaupt zwei Batterien oder meine Hochstrombatterie laden? Die Antwort lautet ganz eindeutig: Ja, es dauert nur länger bis sie voll ist. Kurzstreckenfahrer sollten sich aber ernsthaft Gedanken machen, über eine Nachrüstung einer Lichtmaschine die einen höheren Ladestrom liefert. Werden jedoch zwei oder mehr Hochstrombatterien verwendet ist der Kauf einer größeren Lichtmaschine eigentlich Pflicht. Durch einen ordnungsgemäßen Umgang und gelegentliches Aufladen der Batterie kann die Lebenserwartung deutlich gesteigert werden. BWhen charging a high-current battery, it is absolutely essential to ensure that the voltage at the terminals never exceeds 15 volts at any point during the charging process.n. Ab welcher Leistung ist der Kauf einer Hochstrombatterie eigentlich sinnvoll? Als Faustformel kann folgendes gelten: Ab 500 Watt Sinus kann der Einsatz einer Hochstrombatterie als sinnvoll betrachtet werden. Ab 1000 Watt Sinus wird i.d.R die vorhandene Batterie rein als Starterbatterie, und zur Versorgung der kfz-Elektrik eingesetzt. Die nachträglich erworbene Hochstrombatterie hat ausschließlich die Aufgabe die Car-HiFi-Komponenten zu versorgen. Diese Formel kann nach oben hin beliebig erweitert werden. Voraussetzung ist auch hier wieder ein ausreichender Ladestrom. 'In vehicles that include a multitude of electronic components, such as onboard computers, climate control, various window heaters, auxiliary heaters, seat heaters, etc., it is generally advisable to use high-quality car audio systems...'Fi-Anlagen eine zweite, möglichst eine Hochstrombatterie installiert werden. Eine Hochstrombatterie hat zwei entscheidende Vorteile gegenüber einer werksseitig eingesetzten Batterie. Erstens der geringere Innenwiderstand, zweitens der höherer Kälteprüfstrom. Diese zwei Faktoren haben einen entscheidenden Einfluß auf die Qualität des Musikgenußes. Eine souveräne Klangvorstellung und idealle Impulstreue ist nur gewährleistet wenn der Innenwiderstand so klein wie möglich ist ( weniger als 3,0mOhm), und der Kälteprüfstrom einen deutlich höheren Wert aufweist ( mindestens 700 Ampere ) als eine herkömmliche Batterie. Die Angabe Stundenampere (Ah) spielt im wesentlichen mehr eine Rolle für den Dauerbetrieb einer Heizung. Es gbut is definitely not considered harmful if. hier ein Wert von 50 Ah oder mehr vorliegt. Ein oftmals größeres Problem ist es einen geeigneten Installationsplatz für die zweite Batterie zu finden. Da bei den meisten Fahrzeugen der Motorraum relativ dicht besiedelt ist, bleibt als Lösung oftmals nur der Kofferraum. Dieser Montageort hat aber im Bezug auf die Kabellänge, einen entscheidenden Vorteil. Der Spannungsverlust zur Endstufe ist um Einiges geringer. Bei der Installation sollte auf eine feste und sichere Montage geachtet werden. Für eventuell abweichende Gase muß auf eine ausreichende Luftzirkulation geachtet werden. Für die Installation der Zweitbatterie muß nun noch ein Hochstromrelais verwendet werden. ( HCR 180 ) Dieses wird in die Ladeleitung zwischen erster und zweiter Batterie montiert. Der The cable leading to the relay must be equipped with an appropriate fuse. This relay is opened and closed by the ignition. In practice, this means that even if a secondary battery is deeply discharged, starting the vehicle is still possible. The prerequisite for this is that the radio is powered exclusively by the constant positive terminal. Compared to isolation blocks that use diodes, a relay does not cause any voltage drop due to its design. Despite this advantage, which allows the vehicle to be started, harmful deep discharges should be avoided. The negative consequence would be a significant reduction in power or even damage to the battery. For this reason, Audiotechnik Dietz has developed a special protection relay (BPC 180). The function of this relay is relatively simple and yet very effective. If the voltage drops below 10.5 volts, which would indicate the beginning of a deep discharge, it interrupts the remote or power supply to the car audio system. The circuit is only closed again when the voltage is above 10.5 volts; it is recommended to start the vehicle to provide the depleted battery with sufficient power..'For this reason, Audiotechnik Dietz...'A special protection relay (BPC 180) has been developed. The function of this relay is relatively simple and yet very effective. If the voltage drops below 10.5 volts, which would indicate the beginning of a deep discharge, this relay interrupts the power supply to the car audio system. The circuit is only closed again when the voltage is above 10.5 volts; it is recommended to start the vehicle to provide the depleted battery with sufficient power.

Dan.jel wrote:

Kann meine Lichtmaschine überhaupt zwei Batterien oder meine Hochstrombatterie laden? Die Antwort lautet ganz eindeutig: Ja, es dauert nur länger bis sie voll ist.

. . . but only if the combined heat and power (CHP) system is running at full load, which is rarely the case in practice.

Most often, the battery management system (BMS) at the factory battery still has 10 amps or more in reserve, which can be used to charge a larger battery – without the charging process taking any longer than it would with the factory battery.

All of this, of course, only applies if the chemistry of the larger battery allows for the same charging speed at the same charging voltage (~14.4V) as the original battery from the factory.

Hi,

as practical experience:

Mein Vater hatte im 1.8T Passat serienmaessig eine mickrige 44 Ah Batterie drin, die nach knapp drei Jahren tot war. Mit nahezu Vollausstattung hat das Auto einen nicht gerade kleinen Ruhestrombedarf, dazu kam noch einiges an Kurzstreckenbetrieb. Angesprungen ist er bis zuletzt (es sei denn, er stand laenger als zwei Wochen), weil der Motor gut in Form ist und als Benziner ja auch nicht so arg viel Strom zum Starten braucht. He didn't survive, though. He only ran for 10 minutes while connected to a VAGCOM device, and after that, the voltage dropped to 8 volts.

After that, we installed a 72 Ah battery, which is a significantly larger upgrade than you're planning. So far, it's working perfectly, and the car still starts without any problems even after being parked for more than two weeks.

Best regards,

Jan.

Hello,
Install the largest battery that physically fits, but make sure the cold cranking current (starting current) is not smaller than the original specification.
The larger battery provides greater reserves for auxiliary heating, parking lights, etc.!
It will likely be charged by the LM (likely referring to a battery management system), and the increase in amp-hours (Ah) probably won't be significant due to its dimensions!
Best regards,
Günther.

Thank you!

Is there a list somewhere that specifies the cold cranking current (CCA) my engine needs or that my battery is supposed to have as standard equipment? I've already installed a second battery, and I'm not sure if it has the original specification.

Audi 80 1.9 TDI, 90 hp, B4 model, 1Z engine, manufactured in March 1994 (later 1994 model).

I can also only confirm Jan's experience. Back then, I installed the largest battery available at Globus in my Passat (something around 98 Ah). I never had any problems with it. It just has to fit mechanically...

Tino Kossmann wrote:

Is there a list somewhere that specifies the cold cranking current my engine needs / that my battery comes with as standard? Audi 80 1.9 TDI, 90 HP, B4, 1Z, manufactured in 03/94 (newer 1994 model)

According to the 1997 catalog, the Golf 3 TDIs came with batteries that had a capacity of 61 Ah and a starting current of 330 A.
I wouldn't recommend anything smaller than that.

The battery in the Audi 80 B4 is located in the front of the engine compartment, behind the splash guard, under a cover. However, the standard battery almost completely fills the space under the cover. How do you manage to fit a larger battery in there?
Or are there manufacturers that produce batteries with greater capacity while requiring less space?

I've now installed a "Moll M3 plus K2" battery with 71 Ah - it fits inside, although I no longer remember the exact dimensions.

Tino Kossmann wrote:

"Moll M3 plus K2" with 71 Ah

That sounds great, where can I get something like that, and at what price?

What is the specified cold test current?

on eBay, or from a seller based in Cologne - try searching for "Moll K2".

Costs 82.75 Euros, dimensions are 278x175x175 mm, and the cold test current is specified as 590 A - which should be sufficient .

Since not all batteries are the same, I recommend checking out the ADAC test report. They tested several batteries. This might be another helpful factor when choosing a manufacturer. The list certainly doesn't include all available batteries, but it's informative.

...and what I can confirm from this test list is:

VW batteries are very good.

I still have the original part in my tractor (it's dated older than the vehicle itself).

Despite features like seat heaters and coolant glow plugs, it (the car) is still working perfectly after more than 9 years!

It's the 61Ah battery that Ulf mentioned (compatible with the standard 120A alternator).

m;

I have a 70Ah VW battery here in Soltau that's currently connected to a trickle charger.
Kann für 30 Euro mitgenommen werden.

I had installed an Optima Yellow battery with a capacity of approximately 75Ah and over 1000 amps of cold cranking current right from the start, because of my very power-hungry amplifiers.