Battery on display

[Cbatoday]

Why does the Battery on the display never show all the Battery at full percentage 

 

[Mike169]

Hi, have you tried putting a voltmeter/multimeter on the Battery to see what the voltage is and does it increase when the engine is running?

Regards, Mike.

[ian rooke]

HI is your car a hybrid if it is then the traction Battery only charges to 80%to lengthen the life of the Battery I would not try to take the voltage of the traction Battery (200 volts) with a voltmeter set to 20 volts or less 

[PeteB]

The Hybrid Battery gauge only shows a 'window' of the true State of Charge that the software allows for Hybrid running.  If the gauge ever showed empty, SoC is really about 40%, and if it reached a true full (some time after the 8th bar lights up) it would really be about 80%.  As Ian says, this is part of the secret of the long life of the Hybrid batteries (along with careful charge/discharge rate management and temperature control).

You will rarely, if ever, experience a truly full Battery (unless you live somewhere extremely hilly, like parts of Scotland) and never see zero bars lit.  The behaviour of the Hybrid system changes subtly as the SoC reaches high or low values, as it likes to keep some room to receive 'free' energy when slowing or braking (especially downhill) and have enough in reserve to give a boost when you need max acceleration or to ascend a very steep hill.

I'd covered over 70,000 miles in 4 years in my first Prius Gen 1s before I experienced my first HV Battery "max out", but a holiday in Scotland made it a daily occurrence.  When reaching the bottom of a 5-6 mile 20% (1 in 5) hill, you got a good idea what an EV would feel like as the Hybrid System tried like mad to use up some of the excess electricity so there'd be room for more free energy when braking or going down the next hill.  The Gen 1 had no EV button, but while maxed out modest pressure on the accelerator would see electric only driving up to at least 60 mph!

"Maxed out" doesn't just mean all the bars are lit - it takes quite a lot of extra regeneration after the eighth bar lights up before the system truly maxes out (like the fuel gauge, each bar covered a range of quantities).  The car's behaviour changes when this happens, and you're likely to be very aware of it because the sound changes, but mostly the braking changes.  It's still well power assisted, so won't be onerous, but B mode (S mode in some models like the RAV4 Hybrid) certainly seems to make it a bit less of a chore.

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