Battery Charge

<div class='quotetop'>QUOTE(horpelkrufkin @ Feb 18 2007, 12:17 PM) [snapback]392384[/snapback]</div>

Welcome to site. Forget about the idiot salesman. The car will take care if itself. The traction battery's state of charge (SOC) stays in a relatively narrow band. It is never fully charged nor fully discharged. This increases the life of the battery. Relax and enjoy the car.

 

Another thing to concider is that if the battery were fully charged, you wouldn't have any room to put any energy from regenerative braking. The car tries to store excess energy, but at the same time use that energy when needed and make room for more excess energy.

If you really want to see all the bars lit, you can drive down a nice long hill. Also, with cold weather, the ICE will probably be running more often than normal, and the excess energy will be sent to the battery. Cars driven in really cold weather will typically stay in the 7 or 8 bar range.

Some people on here have speculated that "B" will charge the battery faster, and some salesmen have been reported as saying that "B" stands for battery. The "B" mode is just for steep hills where you find that you're riding the brakes to the point of using the friction brakes. Instead of wearing those out, the ICE can be used for compression braking (engine braking). However, like the friction brakes, the energy from compression braking will be dissapated, and will not be recovered.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Feb 18 2007, 11:14 AM) [snapback]392414[/snapback]</div>

Here's a little more technical information and some graphical representations of the battery SOC from various people on this and other Prius forums: Toyota_Prius_Battery_Specs.
http://www.eaa-phev.org/wiki/Toyota_Prius_Battery_Specs

Just in case you ever see that sales guy again, you've already discovered the "B" mode is for "Compression Braking", and you can force charge the battery pack at will by placing the car in gear, keeping your foot on the brake peddle and giving it various levels of accelerator. You won't be able to tell, but the more gas you give it the faster the engine runs and the higher the rate of charge, from about 5 to 50 Amps. The battery is full once you can no longer get the engine to "load up" under the load of the generator that produces the charge. Of course this isn't a particularly helpful, perhaps you might want to do so if you intend to leave the car unused for more than a year, I believe you are supposed to start it up every 3 to 6 months... Anyway...

 

<div class='quotetop'>QUOTE(horpelkrufkin @ Feb 18 2007, 01:17 PM) [snapback]392384[/snapback]</div>

In my personal opinion, your sales "expert" is either a crack addict or so inbred he cannot tie his own shoelaces.

Once you power down the car, the HV relay is open. The NiMH battery is electrically isolated from the rest of the car, and should be fine for 6 months. Maybe a year.

The little 12 vdc auxilary battery is crucial, if it goes dead you cannot boot the computer to command the HV relay to close. The 12 vdc battery is about the size of a lawn tractor or motorcycle battery, so it doesn't take much to run it down. However there is an emergency jump point under the hood, which is well documented in your owner manual.

One of the best ways to reduce electrical drain on your 12 vdc battery is to poke the SKS disable button under the steering column. I've checked my car a few times and the standby draw is around 28 mA. If the brake boost pump should happen to run that takes a few amps, not sure how many as I haven't had the meter hooked up when it was running.

I'm frequently away on business and have a VDC Battery Minder hooked up to my 12 vdc battery. It keeps a float charge on the battery, and will also desulfate the battery too. Have been using it for a year now, works fine.

 

<div class='quotetop'>QUOTE(horpelkrufkin @ Feb 18 2007, 08:15 PM) [snapback]392636[/snapback]</div>

Yes. I really only use 'B' when I'm coming out of the mountains, the battery is 'fully' charged, and I need to limit my speed. 'B' works really well for this. For regular in town driving it's not useful unless you want poor gas mileage. You probably won't use it too much in OK but you may find it useful from time to time.

Oh, and welcome to PC! Glad to hear that you're enjoying the car.

 

<div class='quotetop'>QUOTE(horpelkrufkin @ Feb 18 2007, 10:15 PM) [snapback]392636[/snapback]</div>

Welcome to Priuschat! I'm sure that this site will let you enjoy your car more via a more thorough understanding of its inner workings.

If you hold the brakes with the car in D and press the accelerator pedal, the engine will spin the 2 Motor-Generators and charge the traction battery. However, as efusco indicated, doing so is not necessary in the normal course of driving the vehicle. It will largely take care of itself. The onboard computers strive to keep the traction battery in a narrow window of charge. Doing so allows the battery to last longer.

minor side note:

Breakv) to smash, split, or divide into parts violently

Braken) a device for slowing or stopping a vehicle or other moving mechanism by the absorption or transfer of the energy of momentum, usually by means of friction

 

Sheesh. Have that *salesdroid* read this. Getting him to
*care* about getting his fact straight may be another matter, though.
.
There is actually rationale for why force-charging works. A common
testing scenario that auto techs do is called "transmission loading"
in which an automatic transmission is put in gear, brake held, and
given gas for the sole purpose of putting a load on the engine. The
energy produced goes up as heat in the fluid torque converter in the
tranny. Well, the Prius doesn't have that so the most logical place
to put the energy is ... guess where. But you can only do that up
to a point; once the battery is at 80% [showing "full" on the MFD],
the "loading" scenario gradually stops and you can't do it anymore.
No place to dissipate the energy any more.
.
So Toyota appears to have made a nod toward this common testing
trick, but with certain limitations.
.
_H*