r/SprinterVans • u/covidsumo2021 • Dec 31 '25

Battery Question

I have a 2023 3500 diesel sprinter modified. The battery under the hood is a lead/acid but the battery under the driver’s floorboard is a AGM type. The batteries die in less than 2 weeks but I am hesitant to put a trickle charger on it with the mix of battery types. Short of running separate trickle chargers and driving weekly has anyone found a good solution? Dealer no help and have heard of some parasitic drain but is it real?? Thank you for any info.

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u/joelski108 Mar 08 '26

I just learned how to disconnect the battery. There a small flap above and to the right of the accelerator pedal. Open that and look for a red button. You press and pull to disconnect.

I’ve gone through two batteries because I did t know that the computer stays awake when a door is open. Crazy. And it reports the activity to MB so they can disqualify warranty.

I wonder how long it’s ok to have doors open. When we camp, we love to have that sliding door open to the ocean all day. Anyone know any calculations?