12V battery: convert to a cheap alternative?

[Taycanistra]

Thanks, is there a reliable H3/LN0 form factor 12v LiFePO4 battery available from another manufacturer?

Like I know-not.But maybe someone else knows better.

Sponsored

 

[Gino]

I've used a $650 EXT1200 LiFePO4 in my GT4 since 2017, it's 600 CCA instead of 660, but should be close enough.
They also have $900 ETX1600 with 760 CCA.
Either one would need a battery mount kit and something custom to connect electrically to that OEM cover.

https://earthxbatteries.com/product/etx1200/
https://earthxbatteries.com/product/etx1600/
https://www.rennline.com/search.php?search_query=battery mount kits
https://rennlist.com/forums/gt4-spyder/932192-0q-pure-white-journal.html#post14689773

Otherwise, looks like a replacement is $1,400;
https://porsche.oempartsonline.com/oem-parts/porsche-battery-pad915105

IMO I won’t consider an alternative AGM battery which will last at least 50% less than the stock Li-Ion. Unless Porsche begins offering an AGM alternative then I won’t take the chance. I’ve had zero issues with my 4 year old Taycan regarding the 12V battery and expect it to last the 10 years they suggest. If it does then I’m happy to pay $1200 to $1500 every 10 years. I’ll likely replace it at 10 years even if it still works because I am of the philosophy that you replace parts when they have reached their useful lifetime rather than wait for them to fail. When it comes to batteries they don’t give you any warning sometimes so if I am fortunate to have my 12V battery last 10 years then I will just replace it to get another 10 years. If at some point in the future Porsche upgrades to a solid state battery which will last the life of the vehicle then I’ll buy that to take one potential failure off the table indefinitely.

 

[Gino]

There is nothing wrong with it. Taycan GATEWAY supports AGM batteries, merely coding the Gateway and changing the type from LiFepo$ to AGM is enough to ensure it's always correctly charged.

Porsche just chose the Lithium for the sake of it. They did the same in tje Cayenne and switched back to AGM in 2025 models onwards.

Changing to AGM is perfectly fine, we've done hundreds of cars literally

AGM batteries last 5-7 years max on average so if the AGM is 50% cheaper but lasts half as long then the Lithium Ion is the better choice IMO.
Porsche could care less if you buy an AGM battery from them every 5 or 6 years at $500 to $600 or a Li-ion battery every 10-12 years for $1200-$1500. The longer lasting Li-ion is the more reliable, long term choice than an AGM which is one more thing to go wrong sooner than later. The cost per year for both batteries over time is roughly the same.

 

[abatis]

This may not be an issue, but attempting to install one of the OTA Taycan updates when my 12V battery was below ~13.5 V failed. I hooked up a Noco lithium charger that was charging above 14V, the update ran. Hopefully, a regular 12V AGM will support all OTA updates.

 

[ecko04]

If someone is buying an H3/LN0 group size AGM battery at $500-600 USD, I have a bridge over the Atlantic that I’d like to sell you.

Someone could buy 4 to 6 of them for the cost of 1 lithium.

 

[Vercingetorix]

All I have to say is anybody contemplating an AGM should do some serious research. Diysolarfurm is a good place to start.

 

[ecko04]

OP started the thread inquiring whether or not there were cheaper alternatives to the lithium battery, the answer is yes.

Whether you are team lithium or team AGM is a preference.

I live over an hour away from the nearest Porsche dealer. If the lithium goes out on mine I’ll likely switch to AGM just for the convenience factor but I’m not going to proactively swap.

Having another option is appreciated. All this talk of which is better and all that is dumb — it’s. 12v battery.

 

[69Mach390]

If someone is buying an H3/LN0 group size AGM battery at $500-600 USD, I have a bridge over the Atlantic that I’d like to sell you.

Someone could buy 4 to 6 of them for the cost of 1 lithium.

Yeah seriously. While the lithium battery is clearly “Porsche prices,” the AGM should not be that expensive.

And while the lithium battery part is $1200+, some have quoted $3k from the dealership to swap it out (also Porsche prices).

 

[ct14garage]

AGM Conversion for Dummies

Panamera / Cayenne: There's more than enough space to fit a considerably larger AGM battery than the lithium it replaces, so you can fit one of the same CCAs which are necessary for cranking the ICE.

Taycan: LN0 AGM obviously has less capacity than the Lithium of roughly the same size it replaces. But it DOES NOT matter. Taycan Gateway is prepared to work with an AGM battery and it lets you code the specific capacity of the battery you are installing. In the case of Taycan LN0 AGM is 40Ah. Just code into the gateway using PIWIS or a dongle that you've installed an AGM of 40Ah and it will work exactly exactly the same.

Taycan does not require much from the 12V battery. The moment you turn on ignition the HV battery takes over the 12V system via the the 12V output of the DCDC inverter.


LN0 AGM we buy them here for $50 a piece. Even if it only lasted 1 year.... over a period of 10 years that's $500 vs $3500 that 123Systems LiFePo4 costs.


Hope it's clear

 

[gamueller]

AGM Conversion for Dummies

You would clean up with a shop in the Bay Area!

 

[Dee]

LN0 AGM we buy them here for $50 a piece. Even if it only lasted 1 year

I don't think customers like it when they get locked out of their Taycans once a year although they save a lot of money....

 

[gamueller]

I don't think customers like it when they get locked out of their Taycans once a year although they save a lot of money....

(Shhhhh... There's a mechanical key in your keyfob)

 

[ct14garage]

I don't think customers like it when they get locked out of their Taycans once a year although they save a lot of money....

I said even if.....

Taycan AGM conversion til date we still haven't had a single customer complain or come back.... and the earliest ones we did are well over 2 years old now....

Cayenne AGM conversion just today I had a customer whose Cayenne we converted to AGM in December 2024 just failed today.... Battery is dead and won't pick up a charge. BOSCH brand. Probably a defective battery. Luckily it's still within warranty from my supplier

 

[Dee]

(Shhhhh... There's a mechanical key in your keyfob)

I know buddy, I've been around for a while.
You still can't open the bonnet to charge the 12V battery.
You still need to connect a foreign 12V power supply to the terminal in the footwell.
No one wants to be in that situation.

 

[Scandinavian]

I said even if.....

Taycan AGM conversion til date we still haven't had a single customer complain or come back.... and the earliest ones we did are well over 2 years old now....

Cayenne AGM conversion just today I had a customer whose Cayenne we converted to AGM in December 2024 just failed today.... Battery is dead and won't pick up a charge. BOSCH brand. Probably a defective battery. Luckily it's still within warranty from my supplier

I have for some time been thinking of installing one of these CTEK cables on the 12 volt battery. And then hide the plug somewhere accessible without requiring to open the bonnet. However I have earlier not done so, since Porsche could void the warranty due non approved accessories ??

After the latest episode I will however ask Porsche to install this cable. Lets see what the response will be. It is far to complicated to open the bonnet otherwise.

What do you think?

edited to include photo. It was late after a long day.

Sponsored