Originally Posted By: The Critic
I understand your position. However, the issue with BMW is that the newer models use a "smart" charging system that relies on the aH rating of the battery in order to deliver a proper battery charge. Installing a battery with a different aH rating (or a different type) will often require the car to be re-coded.
Any idea how advanced? Lithium-ion batteries have gone to complex systems with all sorts of onboard diagnostics and status. They'll keep a more or less accurate battery capacity estimate, number of "full" charge cycles (relative to capacity). That's pretty much needed to keep batteries from overcharging and to prevent devices from drawing down power until the battery is damaged from deep discharge. It also gives a far more accurate percentage indicator of capacity.
I get a percentage readout with one of my car battery chargers, but I can tell that it can be way off and is just basing everything on sampling the voltage.
I understand your position. However, the issue with BMW is that the newer models use a "smart" charging system that relies on the aH rating of the battery in order to deliver a proper battery charge. Installing a battery with a different aH rating (or a different type) will often require the car to be re-coded.
Any idea how advanced? Lithium-ion batteries have gone to complex systems with all sorts of onboard diagnostics and status. They'll keep a more or less accurate battery capacity estimate, number of "full" charge cycles (relative to capacity). That's pretty much needed to keep batteries from overcharging and to prevent devices from drawing down power until the battery is damaged from deep discharge. It also gives a far more accurate percentage indicator of capacity.
I get a percentage readout with one of my car battery chargers, but I can tell that it can be way off and is just basing everything on sampling the voltage.