After battery replacement

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New member
Feb 20, 2024
My 27 kwh battery has been replaced with a 40 kwh aftermarket pack. Since the replacement my consumption is consistently 30% higher than before. Moreover, my granny charger charges the new battery too quicky - just as if it was still the original small battery. I wonder if it is a software problem, maybe the necessary calibration hasn't been done properly.

Has anyone here ever experienced the same problem? Is it possible that the BMS still "thinks" it is dealing with the old battery? Anyway, how to do a proper battery pack calibration? Do I need a software update?

Who replaced it? I'd start there as they should have the most knowledge when it comes to the work done on your vehicle.

That said: I do recall the Nissan LEAF needing some cleaver solutions due to software issues with the replacement batteries but can't recall the exact details since I've lost interest in that car.

Back to our car, if you want to recalibrate the battery yourself the following has to happen:
(The battery needs to be 15C the entire time - so forget about doing this in the winter)
1. Charge it to 100%
2. Discharge it to below 18% (Closer to 0% is better) without plugging in-between.
3. Recharge it to 100% without interruption

Given that your battery has had a massive increase in capacity, you might need to run your car down until it literally won't drive anymore just because it actually has no idea where the bottom end of your battery is. That said, the computer still might be the limited factor depending on how it was set to operate. It might only care about voltage which is fine because your battery just magically decreases voltage slower than expected, but it might also have a parameter that says 27kWh only.

All in all - good luck!