High voltage battery always in high charge state

[kkayser]

When the outdoor temp is under 30 F or so, my high voltage battery charge indicator is always at seven bars (light green) after I have driven a short distance on the freeway or highway. As long as I drive on the freeway, the indicator stays at seven bars. When I exit the freeway, it takes real effort to get it down to four bars and will not go lower than four bars. When the weather is warm, the charge indicator will sometimes go down to two bars and will never go above six bars.

I would appreciate hearing from anyone with a 2004, who drives in cold weather. Does your car do this or does it NOT do this.

[efusco]

Most of the time you will see a higher than normal SOC in cold weather....what you're observing is totally normal.

I've learned to drive a bit differently in cold weather, I use an engine block heater and grill blockers to reduce the need for the ICE to run so much just to get and keep itself warm. It is the excess running and need to spill the energy produced from that excess running that tops off the battery in cold weather.

[SomervillePrius]

I had similar experience here in Boston where it finally got gold (low teens). The solution was to buy $4 of pipe insulation and cut into pieces and block the front grill of with (So please follow this link) . Before I installed the pipe insulation the engine would run almost constantly even when we where around 20F and the battery was almost always green. With the pipe insulation the engine shuts off much more frequently, the battery stays in blue, and the cabin heats up quicker. It's like gaining 20F or something :-) Best $5 I've spent in a long time, even with 4F today the engine shut down at a read light (after 15 minutes) and my gas milage while bad wasn't as bad as without the insulation at 30F! I love it. YMMV

[buzzard bill]

<div class='quotetop'>QUOTE(SomervillePrius @ Jan 26 2007, 10:56 AM) [snapback]381099[/snapback]</div>

I had similar experience here in Boston where it finally got gold (low teens). The solution was to buy $4 of pipe insulation and cut into pieces and block the front grill of with (So please follow this link) . Before I installed the pipe insulation the engine would run almost constantly even when we where around 20F and the battery was almost always green. With the pipe insulation the engine shuts off much more frequently, the battery stays in blue, and the cabin heats up quicker. It's like gaining 20F or something :-) Best $5 I've spent in a long time, even with 4F today the engine shut down at a read light (after 15 minutes) and my gas milage while bad wasn't as bad as without the insulation at 30F! I love it. YMMV
[/b]

I live in the upper peninsula of Michigan. I installed the grill blocker and found the same result. The 1" X 60" pipe insulation cost $1.76 including tax. yesterday the temp was -3.

[jayman]

My first winter in Winnipeg with the car, the SOC was ALWAYS green at -40. It's normal.

[molgrips]

When I was a kid (early 80s) people used to put aluminium foil in the radiator grille, possibly to achieve the same effect in cold weather. Might help the Prius? I don't fancy having pipe insulation on the front of the car...

[jjs357]

<div class='quotetop'>QUOTE(wauwis @ Jan 26 2007, 12:35 AM) [snapback]380963[/snapback]</div>

When the outdoor temp is under 30 F or so, my high voltage battery charge indicator is always at seven bars (light green) after I have driven a short distance on the freeway or highway. As long as I drive on the freeway, the indicator stays at seven bars. When I exit the freeway, it takes real effort to get it down to four bars and will not go lower than four bars. When the weather is warm, the charge indicator will sometimes go down to two bars and will never go above six bars.

I would appreciate hearing from anyone with a 2004, who drives in cold weather. Does your car do this or does it NOT do this.
[/b]

I drive in the Philly suburbs in a 2004 (option package 9). I also experience the almost constant green battery.

It seems worse this winter than the previous 2 and my mileage is now routinely in the mid to upper 30's where it was in the low to mid 40's during previous winters. The outdoor temperatures have been above average until about 3 weeks ago -- we have been below average almost constantly since then.

I am driving the same commute I have previously -- about 10 miles one-way over moderately hilly suburban roads.

Something seems different. I did do a tire upgrade -- Goodyear comfortreds -- so that may be the culprit for the lower mileage. But the parking brake seems to not release fully (although the brake warning light does go off) and so I have taken to not engaging the parking brake. Seems like maybe my mileage is up a bit since I started this.

I think I will try the pipe insulation "mod" and see how that goes.

In any case, you are not alone in your experiences.

Jim

[john1701a]

<div class='quotetop'>QUOTE(SomervillePrius @ Jan 26 2007, 09:56 AM) [snapback]381099[/snapback]</div>

Before I installed the pipe insulation the engine would run almost constantly even when we where around 20F and the battery was almost always green.[/b]

I've heard others claim the same thing. But when stealthing at -2F this morning, I wondered why the heck is different in my situation. My engine shuts off routinely at stoplights, and about half the time remains that way until the light turns green. So I have yet to add insulation.

Perhaps it is just a matter of heater setting. My is on Manual at "MAX HEAT" with the blower on medium aimed at the feet & windows.

Whatever the case, I'm still surprised efficiency doesn't vary that much between 0F and 20F for me. But I suppose it is just like having the kayaks on top. Once you exceed 60 MPH, the efficiency almost plateaus from there to 70 MPH... just a very small difference. My guess is the thermostat is shut a majority of the time anyway.

In short, I see green (7 bars) routinely.

MPG is low 40's, despite seeing -9F late last night.

[jayman]

<div class='quotetop'>QUOTE(john1701a @ Feb 3 2007, 07:42 PM) [snapback]384960[/snapback]</div>

I've heard others claim the same thing. But when stealthing at -2F this morning, I wondered why the heck is different in my situation. My engine shuts off routinely at stoplights, and about half the time remains that way until the light turns green. So I have yet to add insulation.[/b]

I've often wondered that myself.

For example, my Prius is completely helpless on snow/ice with the "all season" tires, yet others claim no problems in a blizzard with their “all season” tires. And in city driving without a winter front, even in temps of -12 C it would never stealth. Some folks claim their Prius will track straight with one finger on the wheel at 75 MPH and others have had issues at 65 MPH.

I guess normal manufacturing variance comes into play here.

<div class='quotetop'>QUOTE(molgrips @ Feb 3 2007, 06:00 PM) [snapback]384942[/snapback]</div>

When I was a kid (early 80s) people used to put aluminium foil in the radiator grille, possibly to achieve the same effect in cold weather. Might help the Prius? I don't fancy having pipe insulation on the front of the car...
[/b]

Oh no, you can't even notice it unless you walk right up to the car. The closed cell foam pipe insulation is black, so it blends right in. To cover the lower grille, I use a piece of rubberized felt that is commonly used in paper machines to pick up the wet fiber. It's also black and blends right in.