Battery Indicator never full

I see my battery indicator showing full from time to time but as Paradox says it doesn't really matter one way or the other as the car manages that side of things

 

I drive small mountain roads, so I get the opportunity to see the battery fully charged. When I'm going down the hills and curves of the Ozarks, especially when using the jake brake (B), it'll get full. Even those two little notches at the top get filled in.

 

When the battery gets 'full' you can't do any more regenerative braking. There would be no place to put it.

Since this is a bad result, the computers try for about 75% full. You will really fill it up going down long hills, (more than 600' or 200 meter drop) or gentle braking from top speed.

When I lived in Toronto in 1987 I did not notice any big hills so it is likely you have not had occasion to fill the battery.

 

This is a bit like setting off to walk across a desert but choosing not to fill your water bottle beyond half full on the grounds that if you find a water hole you won't have any room to take advantage of it.

If the battery were to be fully charged then simply dissipate the energy via the friction brakes and use the energy you previously stored when it's required.

 

I take it you are a flatlander?

 

I take it you have not noticed the Plug-in owners angry that the engine rotates to burn off energy they got by charging to full.
Full charge, coast downhill -> engine runs? | PriusChat

As one who has walked the PCT from Campo, CA to Mt Adams, WA, we never carried water to more water. The stuff is a pint per pound. My youngest brother had as much as 22 pounds of it in his pack, across the Colorado and Mohave deserts, but only because we would not see water on that couple of days. (I carried the tent and gear, my older brother the cook gear, we balanced weight with food)

 

I assumed the engine would only run to prevent overspeed of MG1 but not owning a pip I can't really comment.

I suppose I should have said lets assume water has no significant mass in my analogy

 

Doesn't really make any difference to the argument me thinks. Not collecting energy right now on the grounds that we might like to collect energy later still makes no sense eh lol

 

Thats because you are thinking of it as a last possible energy source, not the first line of braking.

 

Well it depends if you main concern is brake lining life or fuel I guess

 

That isn't how my Prius works.

Whenever there is free energy (regenerative braking) available for collection, and unfilled capacity available in the battery, that energy is collected. Then the car tries to use it relatively soon.

But energy from the gasoline engine is not free, it has a cost. The Prius generally pays this cost to charge up to 6 bars, but then stops. (Cold weather engine warmup sometimes pushes to 7 bars.) That always leaves more than enough room to collect whatever 'free' regen energy becomes available in my normal flatland driving style, so none of that 'free' energy is ever left on the table for lack of storage capacity.

Hilly situations are different. The descending departure route from my house often tops the battery with regenerated energy and discards a small amount of free energy. With the available components, no charge plan can accommodate all driving situations, but this scheme seems to strike a good balance overall.

Many folks don't seem to realize that recharge energy from the ICE is not free. Burning fuel to fill the battery, then throwing away 'free' regen energy for lack of storage capacity, costs fuel / MPG / $$$.
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There is another reason to not habitually fill the battery to the top -- this condition reduces battery life. Maximum battery life expectancy occurs at a lower average charge level.

 

You have a good point re using the ICE to charge the battery and one I hadn't considered.
As far as battery life is concerned, I think it's been mentioned before but I believe the battery has more capacity then the indicator suggests so we most likely never see full charge as it were

 

As the first line of braking, it gathers all the 'free' energy a Prius (non PIP) will ever see, if you had already used gasoline to fill the battery, you would never get any 'free' energy in.

If there was not regen, most of the point to having a battery at all is lost in my opinion.

 

I have to say I hadn't really looked at it from that stand point and what you say does make sense.
Fuzzy1 suggests however that the ICE only charges up as far as 6 bars

 

I believe that even 'full' on the SOC indicator, while not truly full, is still well above the optimum for life expectancy. Even 6 bars may be above the optimum, but is a better combined balance for this and other product considerations.

 

I have never gotten mine all the way "full" either. Sounds like it is no big deal-but I was curious. Thanks!

 

I believe the reason is for longevity of the battery. Maintaining it between 40 and 90 percent maximizes battery life. As long as the MPG was calculated using the same firmware it seems fair.

I had one of the 2009 Honda Civic hybrids that Honda chose to reprogram because battery packs were failing too frequently well before the warranty expired. I recall after the update the battery never fully charged. Unfortunately in the case of the HCH it was never designed to only use part battery capacity and became a nightmare to drive.

Galaxy Nexus ? 2

 

I recently moved to Vancouver from the prairies. Learning to climb and descend hills efficiently is an ongoing challenge, especially with the crazy leadfoot drivers around here.
I've estimated the descent from my residence with is at 280 meters above sea level down to the main highway is around 220 meter descent in 2 km with 2 stop signs, one halfway down the hill and another at the bottom. This descent 90% of the time results in a full indicated battery, which would be 80% actual SOC from what i've read.

One thing i've wondered when descending a long steep grade, is it better to ride the brake pedal and send a steady small charge to the battery or pulse the brakes? I remember learning how to drive in the mountains with a conventional car its best not to ride the brakes to avoid overheating and warping the rotors/brake fade, etc.
My practice with the prius has been to ride the brakes until the battery indicator shows full, then pulse the brakes or engage the B mode to avoid overheating the brake pads.