My battery gauge no longer fills up!

I think what you are seeing is normal. I never saw a "full" battery on my 04 and have not seen it on my 09. I do have to admit that I usually have the Consumption screen showing as the Energy screen is just eye candy and provides no real useful info.

The ICE will spin up to bleed off excessive charge on the traction battery. Possibly you viewed the screen just after a bleed-off.

 

I understand your worry, even with our "hills" my Prius reguarly fills up the screen with all green bars. I would inquire further at the dealer as how they tested the battery and make them give you a print out.

 

It could also be weather related. The cold weather could be effecting the charge rate. I know for me the only time I see full green bars is when I'm heading down MAJOR hills, like the Eisenhower tunnel westbound downhill.

 

I live in colorado too, on our trip to steamboat the hybrid batteries were drained the whole way up and then on the way back down from steamboat we didnt get the green FULL battery but did get this:




Then when driving back to Minnesota for my Grandfathers funeral I got a green battery around town multiple time, but never in Colorado.



Its a fun game to play but I think the Prius does whatever it wants.

 

Lower temperatures bring on the green (7 or 8) bars more often.

And as I've observed, vehicle aging does too.

Now at 107,000 miles with the morning temp in the 40's, seeing more green is pretty obvious. The final 5 miles of my commute is a modest decent at 55 MPH to the river then a shallow hilly stretch of 50 MPH followed by 45 MPH. That seems to be the perfect formula for green appearing at mile 2 then retaining it all the way to my parking spot 3 miles later, now. It didn't use to be that way though. In fact, I didn't see the green last year until the final mile. Before then, almost never.
So, I'm curious to hear reports from others... especially when the reverse happens with owners that routine drive over mountains. It's basically flat here in Minnesota by comparison.

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I don't live in Colorado but I've driven there a number of times. I noticed that in long downgrades if you put it in B mode before the battery fills it will really rev the engine and try to leave that top bar as buffer for when you need to use the brakes. If you listen carefully to the inverter whine you'll hear the pitch shift when you use the brakes going down a hill in B mode if there is battery capacity. If there isn't you don't hear the pitch shift. My assumption is that there is still a little bit of regen capacity left while it is spinning the engine full-out in B mode that it'll take advantage of until the battery is full.

Try one of those long hills without using B mode and the battery indicator should fill all of the way. Just be sure to shift it to B once it does so you don't overheat your brakes!

 

FWIW, i've been driving my '09 for about a week now, and 1500miles, and i have yet to see the top bar light up...

 

On downhills, speed is a big factor in relation to battery charge. When you descend a big hill at low speed (but still high enough for regenerative braking), it's easy to charge to full green. On a high speed descent, it's not so likely.

This is because of aerodynamic losses. At high speed, much of the recovered energy is used to push the car through the air. Looking at it another way, if you weren't descending a hill, you would be using a lot of gas just to move at that speed. The energy is used to push air, not charge the battery.

I saw this a lot on our recent trip out west. In Maple Canyon, it was a 2,000 foot descent to the basin floor, most of which was on a narrow gravel road. I would do the descent at 15 mph, and easily got full green bars every time, finishing the route with heavy engine braking.

On many of the mountain highway passes I could descend indefinitely without charging to full green, or would hit full green but need only light engine braking. In these cases we were doing 65 or 70 mph.

Tom

 

Hi Dagnarus,

On a downhill run, foot off the throttle, there is a fraction of regen braking applied to simulate "lower gear" engine braking in a non-Prius. If you touch the brake pedal, but don't press it to the point of actually applying the binders, then regen braking is maximized and remains so until speed is reduced to the point that adequate voltage is no longer being achieved by the motor-generator to provide recharge current. Under maximum regen braking, the recharge rate is maximized because the highest possible current can be directed to the battery pack. So, in addition to all the other details, keep note of whether you touch the brake pedal during descent or not. If you are on an incline steep enough to use "B", then the recharging rate will be very different than if you are in "D" and touching the brake pedal lightly (just enough to activate maximum regen braking).

Just an FYI: there are two situations to avoid in order to maximize the lifetime of any rechargeable battery: one is full discharge of the battery, and the other - which is somewhat counter-intuitive - is fully charging the battery. The Prius charging algorithm appears to be designed to avoid either of those conditions in order to provide assurance that the battery pack will last the "lifetime" of the vehicle. I also own a 2000 Insight, and the electronics module on that original U.S. model actually incorporated a design flaw that allowed the battery pack to be routinely fully charged under very conservative driving conditions. Honda identified the flaw and, after more than six years they replaced both the appropriate electronics and the battery pack in my Insight due to early signs of failure of the battery pack. My point is to avoid the pessimism of some folks on this subject. The Japanese aren't ruled by bean counters like American auto manufacturers. You may have to get past that garbage attitude with some dealership employees, but you won't find it when you get high enough to speak with a person who cares about the company reputation.

 

My experience is that I almost never get a full (8 bars) battery in warmer weather, but get one fairly often in winter.

My commute to work is 3 miles of suburban driving (about 10 traffic lights, usually get stopped by about 4), then 12 miles of expressway (57 to 62 MPH), then 0.6 miles of suburban streets with one light.

During the summer, the ICE warms up within a mile or so, so it will shut off at a stop light. The battery usually stays at 4 to 6 bars, and very occasionally goes to 7 bars.

In cold weather the engine will keep running to warm itself up. I frequently have 7 (green) bars several times during my first 3 miles, with 8 bars appearing once or twice a week. My guess is that MG1 may be used to load the engine (to warm it up faster) with the power going to the battery.

I first noticed this with my 2005 Pri with the first cold weather Fall 2005 (I picked up the car in May). The pattern of no green in warm weather and frequent green in cold weather continued until I traded the car this August.

On my new 2008 Prius, I never saw a green battery until we got our first cold weather this fall.

Norm

 

I think the first sentence says it all. In cooler weather the engine continues running when you are stopped. MG1 is not used to load the engine per se, but is forced to spin (backwards) so that the car can remain still and will generate some power which has to go somewhere. If this explanation is incorrect I'm sure someone else will chime in.