[smreighard]

I see a lot of people mention that their battery will get full from going down hills or things but I just completed a 80 mile trip with a fair amount of downhills and never saw it get above 4 bars. No heat or extra loads (not even radio) were on and while I still averaged 52.6 mpg according to the screen, would I get even better mileage if the battery would get to full charge and why wouldn't it get above 4 bars on a several mile long downhill where I never touch the go pedal?

 

[jareza]

How long have you had your sienna and whats your mileage?
This has happened with my prius, corolla, and now sienna have all had the same issue and the more I drive them (1000+ miles) the more I see the battery get all over the indicators
My advice? give it time

 

[ROJA]

I believe the best way to recharge is to lightly apply the brakes on a downhill or as you approach a stop or light (but obviously look to your surroundings and only do this where safe). You can see in the eco gauge in the MID that you are charging the battery. On a longer downhill you should see your battery go up to 7 bars (or sometimes even all 8).

 

[pamhar]

Depends on the route and how hilly it is.

There is semi regular trip we take in Canada, about 400 miles long, that the battery indicator stays same.

First time it happened I even posted here about it.

 

[jareza]

yes, as others have mentioned if you tend to push hard on the brakes, then you will not regen from braking since the actual pads are doing the work for you.
midly braking is done by the regen motor and thats when the battery charges

 

[fotomoto]

Not to scare you but a full battery is not necessarily a good thing and Toyota's control logic tries to keep that from happening. Once it's full, the car will try to use as much EV as possible to reduce the SOC (state of charge) back to a few bars. Rolling hills won't typically do it because there's uphills in between and the excess charge is spent climbing those.

 

[JohnHartshorn]

Go to the mountains. Drive up to the top. At this point, your battery indicator will be one or two bars. Now drive down the mountain. When you get near the bottom, your battery indicator will be full. You will also have noticed a rather annoying whine coming from your engine. Since the battery can no longer be charged, what you are hearing is engine braking.

For Fotomoto, in Toyota speak, a fully charged HVB is really only ~85% of capacity. The computer keeps it from overcharging. At the other end of the scale, the computer will keep it from going below ~15%, and will start the engine to charge it.

 

[20swrt]

I see a lot of people mention that their battery will get full from going down hills or things but I just completed a 80 mile trip with a fair amount of downhills and never saw it get above 4 bars. No heat or extra loads (not even radio) were on and while I still averaged 52.6 mpg according to the screen, would I get even better mileage if the battery would get to full charge and why wouldn't it get above 4 bars on a several mile long downhill where I never touch the go pedal?

Not even during start-up in the morning ? Usually when the engine is warming up it goes up to 7-8 bars.

 

[smreighard]

Thanks everyone for the replies. I drove it again yesterday on some hills and no matter how much I brake, it wont go above 4 bars in the display. It also never went below 3 either so....

Not even during start-up in the morning ? Usually when the engine is warming up it goes up to 7-8 bars.

Nope. I live at the bottom of a small hill and the engine comes on going up the hill but then goes in EV until I get out of my neighborhood and need to go over 25 mph. Was even kinda chilly yesterday with temps in the 50s. (dont make fun. I used to be a northerner but my blood has acclimated to the South. haha!)

 

[JohnHartshorn]

Thanks everyone for the replies. I drove it again yesterday on some hills and no matter how much I brake, it wont go above 4 bars in the display. It also never went below 3 either so....

I would say it's working exactly as designed.

 

[20swrt]

Just to clarify O/P. It is not normal if you never saw it go above 4 bars. The very first 2 minutes after the ICE runs - try to just stay in place (stationary). Battery level should rise up above 4 bars. If the engine does not run - turn on your AC (Just for testing purposes).

 

[Solar2go]

I've seen documentation from Toyota that charging of the battery is limited by the software to protect the battery. That's why you never see 5 bars. Fully charged or discharged Lithium Ion batteries are unstable and can suffer a thermal runaway, battery fire 🔥.

 

[20swrt]

I've seen documentation from Toyota that charging of the battery is limited by the software to protect the battery. That's why you never see 5 bars. Fully charged or discharged Lithium Ion batteries are unstable and can suffer a thermal runaway, battery fire 🔥.

This is simply not true. On the 4th gen Sienna - getting 5 bars or more is very normal. Please note - when the indicator shows full bars - it only means 80% of the full capacity of the HV battery. The 4th Gen Sienna does not have Lithium-Ion (yet). As of this writing - we only get Ni-MH batteries.

 

[pamhar]

I've seen documentation from Toyota that charging of the battery is limited by the software to protect the battery. That's why you never see 5 bars. Fully charged or discharged Lithium Ion batteries are unstable and can suffer a thermal runaway, battery fire 🔥.

I've seen full bars on our Sienna.

Lowest is 2 or 3 bars.

 

[ROJA]

@smreighard That isn't normal. Can you go to the top of a long hill and then have a kid or passenger safely record a video of the MID as you come down the hill gently braking. Put the display in front of you (MID) to the vehicle page and scroll up/down to the screen where it is showing the number of battery bars as you descend. I just tested and I will go from 3 bars to 5 bars in about 6 blocks if I'm gently braking (and on a longer hill I'll easily get to 7 bars and sometimes all 8).

Try keeping it in the middle of CHG (see the red circle below) by modulating your braking.

(please follow all traffic laws and only do this where safe and legal)

 

[JohnHartshorn]

I've seen full on our Sienna.

Lowest is 2 or 3 bars.

"full" is ~85%.