Energy Monitor - Prius C 2012

Reading paper manuals is probably getting to be a lost art. I think we are all so used to opening up a .pdf file and searching. I actually looked but could not see an explanation for the green - blue color change. I will look again. I saw something on an archived message that suggested the green somehow relates to higher current flow or more than the battery really can make use of. Noting there's no big bank of resistors on top of the car I suspect we have to use our brakes if there's more power being generated than the battery / engine can take.

Danielle

Read the manual on how braking works.

Short answer: not at all. Under normal braking, regen happens regardless of the battery's ability to store it. If the battery is full, the regen system will dump it as waste heat.

Friction braking also dumps it as waste heat--let's face it, all energy will be dissipated as heat--but at least with the Prius you're using the wiring to dissipate the heat instead of using up brake pads that have to be replaced.

The traction battery in our Prius is normally kept at ~60% charge between a low of 40% and high of 80%. My testing with descending a 500 ft hill at 60+ mph has shown regenerative braking from the hill descent barely peaks out the traction battery charge. It is unlikely, unless you live in mountainous areas, that you'll fill the battery. As you've guessed, the hydraulic brakes are fully capable of handling anything the battery can handle.

Actually, the Prius acts as if braking is 'off loaded' by the regeneration. At modest braking level, it doesn't seem to engage the brake pads except to rub off the rust.

Bob Wilson