Timely thread for my E39. I first replaced the BMW branded battery with a lead acid H7 from WalMart for $149 +$12 core. They were close by and I was in a pinch.

But the positive experience there had me looking online for an H8 AGM.

• I searched at Costco to find them ~$179. The local store said that the H8 wouldn't fit. (It does)
• AutoZone and Advance was near $200 for the house brand.
• A WalMart in a neighboring state had the AGM H8 for the same price as the lead H7. Winner Winner, chicken dinner

I purchased and installed the H8 AGM in the E39 and returned the H7 to WalMart the day after I bought it. After core and local taxes, the H8 at Walmart was $160. The battery has a 5 year pro rated warranty. I would install one in the X5 if needed. I purchased an expensive XS brand AGM almost 2 years ago. It came with screw down stand offs that were too tall for the E53 battery block. I found shorter ones at a Batteries Plus and all has been well. This battery has been working well since then.

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