charging to 90%

[JoulesThief]

Charging the car to the needle full is the only proper way to get a full equalization charge among all the cells in the battery. Equalize balance recharging is important.

 

[kirby]

Charging the car to the needle full is the only proper way to get a full equalization charge among all the cells in the battery. Equalize balance recharging is important.

Does the VW on-board charger only balance cells near 4.2V?

This doesn't have to be true with Lithium batteries. A charger (not the EVSE, the actual on-board charger) can balance the cells any time it wants. I've seen chargers that can be setup to keep cells balanced thru the entire CC and CV phases. Others start balancing at a fixed voltage (3.9, 4.1, etc), while others start at a percentage below the termination voltage, so if the user chooses to charge only to 4.0V (I think that's 83% of full on a new LiPO?) the balancing will start at 3.9.

I don't know what the VW charger does, however.

 

[mpulsiv]

Charging the car to the needle full is the only proper way to get a full equalization charge among all the cells in the battery. Equalize balance recharging is important.

Does the VW on-board charger only balance cells near 4.2V?

This doesn't have to be true with Lithium batteries. A charger (not the EVSE, the actual on-board charger) can balance the cells any time it wants. I've seen chargers that can be setup to keep cells balanced thru the entire CC and CV phases. Others start balancing at a fixed voltage (3.9, 4.1, etc), while others start at a percentage below the termination voltage, so if the user chooses to charge only to 4.0V (I think that's 83% of full on a new LiPO?) the balancing will start at 3.9.

I don't know what the VW charger does, however.

If cell balancing kicks in at 3.9 Volts, then there's no point to charge 100% SoC.
100% SoC = 4.07 Volts (with ~12% buffer, thanks to German engineering)
80% SoC = 3.94 Volts
70% SoC = 3.87 Volts