[migrant]

2018 530I, looking to change the auxiliary battery in the engine compartment. Label on the battery (original Varta) reads 50AH 570CCA.
Online matches (Autozone, Amazon) are rated at 14AH 200CCA

Can someone please advise what non-BMW battery to buy?
I used AC Delco Gold for the main battery, would prefer the same for aux.

https://www.amazon.com/ACDelco-Profe...=2018+BMW+530i

[flipicaneze]

https://www.interstatebatteries.com/...i-xdrive-l420l


If I am not mistaken, I think the battery under the hood is the H6 from Interstate.

For the actual BMW part number look up 61-21-6-805-461 for the 70AH. Unfortunately my local dealer (bmwpartsnow.com) doesn't sell the batteries, must be they want to charge for the install themselves.

[Mosaud1998]

There's an auxiliary battery? I thought there was only one and that's under the trunk.

[430Scud]

Originally Posted by Mosaud1998

There's an auxiliary battery? I thought there was only one and that's under the trunk.

Generally there are two. The trunk battery is the main or starting battery. The aux battery is in the engine compartment, and (I believe) is used whenever the engine is off, when using the "start stop" function. The aux battery keeps all the accessories, headlights and HVAC running. This way it does not run down the main battery and the car will start easily when you step on the gas pedal.

[maDjzo]

ACDelco 88866037

I believe that’s a direct replacement.

RealOEM shows OEM part: 61219364597

https://www.summitracing.com/parts/ado-ln1agm