SL/R230: Consumer battery to Lithium
Get over the cost - this is an R230 and batteries are wear items.
Get over the cost - this is an R230 and batteries are wear items.
While the batteries might be a wear item, they don't need to be a cost item. I bought a new rear (consumer) AGM battery from AutoZone in likely 2022. Due to letting it often drain, it was in bad shape by late 2024. I removed it and took it back to AutoZone hoping for some warranty. They looked up my phone number and name, said it was a full warranty and brought me a brand new one. No testing needed, No receipt needed. No cost.
When the original marine batteries drained, the boat would simply go slower and slower, but would move even if the batteries were down to 10V or so.
However, when the Lithium batteries drain to a certain point (around 12V) the battery just shuts off to protect itself.
Considering how these cars always drain the consumer battery, with a Lithium battery I think we would often find it "dead" instead of just weak.
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Some are imported Varta-made batteries, while others are relabeled Interstate batteries.
(Nothing wrong with the latter in terms of battery quality...just not worth the price premium for a MB sticker.)
If I knew for certain that I was buying an imported Varta battery, I'd go OE Genuine MB, so something to consider for the future.
In the meantime, I've been running Duralast AGM batteries in most of my vehicles for years now without issue.
These cars need at least a trickle charger on the consumer battery when sitting for even a few weeks. When I bought my SL600 from the MB dealer a few years ago with brand new MB batteries, the batteries did not last even a year because I often forgot to plug in a charger when the car sat for more than a few weeks. Maybe my BCM is defective, but after the consumer battery drains, the starter battery connects and also drains. I replaced my consumer battery with a Duralast, accidentally drained it again one winter and got a free no hassle replacement from AutoZone.



Last edited by smiles201; Nov 18, 2025 at 08:17 PM.




Last edited by tonylinc; Nov 18, 2025 at 08:35 PM.







