asrose

Has anyone noticed that the ES-300h battery indicator never reads "full" no matter how much highway charging and braking?

Also, as it comes to a stop, it seems that the brakes have a "skip" feel - kind of like after you spray tire block and some gets on the rotating disk?

Thanks for your observation input.

RXSF

the battery does not like to be fully charged; it prefers to be two bars from full. I am sure Toyota and other manufacturers have done a lot of research on this, and they have concluded that in order to prolong the life of the battery, it is best to not keep it empty or keep it full. Notice when you are driving on the highway, arrows are pointing to the battery one second, and then points away from the battery the next, all to keep it at the same level. If you are ever on a long stretch of downhill road and the battery does become fully charged from all the regen braking, notice that it will do as much as it can to get rid of that extra juice. In fact, I have been on the freeway at 60+ mph and I can see the just the battery giving me power to get rid of it.

On the other end, if you are near empty and go onto the freeway, notice that the flow of energy is always going to be towards the battery (instead of the earlier scenario where they point to the battery for 1 sec and then away the other second) to charge it up to the optimal position.

As for the brakes, there is a different brake feel when the car is using regenerative brakes and when it is using normal brake pads. On Lexus hybrids, the regenerative brakes stop when braking over bumps in the road (like a pot hole) and switch back to normal brake pads. This transitions makes it seem like you have lost brakes for a split second and causes what some may describe as a "surge." There are a lot of threads about hybrids surging and this is what they are referring to.

Whenever I am braking and hit a bump in the road and notice that the brake pads have taken over, I usually release the brake pedal for a split second and then re-engage it to reactivate the regenerative brakes.

asrose

Thanks for the advice,

I agree with your battery observations. The brakes seem to slip or grab when approaching a full stop (not going over bumps or rough pavement) - is that normal?

RXSF

only at the last moment before you get to a complete stop should the brakes switch over to the pads, but it shouldnt be totally obvious

Rockville

You are feeling the normal switchover point from generator braking to conventional friction braking. If you have a sudden stop friction brakes are used also. The motor/generator state is determined by acceleration or demand such as climbing up a hill which will use stored energy in the hybrid battery. When decelerating or coasting downhill the forward momentum spins the motor generator and electricity is produced to recharge the hybrid battery. The more electricity that is produced the harder it is to turn the motor generator. This fact is the means of regenerative braking. Normally the energy used to brake by friction is given off as heat and lost....

Your hybrid battery charge meter only shows the top ten percent of capacity. The use of EV mode requires that the charge is high and the coolant and catalytic converter is at running temperature. Once you have driven enough to satisfy these conditions you will be able to drive for short distances at low speeds on battery power alone. Since this discharges the hybrid battery it may take more gas or downhilling to regain charge.

Rock