Hybrid Battery Not 100% Full

[ilovelexus2007]

Is it normal for my battery to ALWAYS stay at 3/4 charged? I've been driving freeway a lot lately using mostly the gas engine, so I guess it should give enough time for my battery to fully charged.

Please share your experience. If it's not normal, what should I do?

[katzjamr]

it is rare to see the battery charged fully all bars to the top. i have only seen this once in 34,000 miles going down a long mountain pass. it is more normal to see a range of two bars to one bar from the top in everyday driving. in my experience 3/4 charged is normal, however mine doesnt stay there it goes up and down in the range i have described. Usually if i am able to drive at 30 to 40 mph on electric only, on flat stretches of hiway it will go down to the two bars and start charging.

[RX400h]

This what I've seen, as well.

[450H_Calgary]

My battery also only charges to short of 2 bars from the top - I have driven for long stretched down mountain roads where it charged for miles and never "tops up".

Also, I regularly deplete the battery to the last 2 bars (it turns purple) and the engine kicks in to re-charge. Anyone else comment on the capacity and charging issue?

My dealer said, no surprise, that the diagnostics indicated all was normal.

[LexRexBlue]

Mine usually charges all but one bar and is green. (I coast down a hill daily to get out of my street) However, when the air conditioner is on it quickly gets depleted.

[SOMEONE ELSE'S GOT MY NAME]

hi iloveprius,

Even if your battery meter is all the way 'full' ... the traction battery is STILL not full. It never is. It's not designed to be. If your meter ever shows full, that actually means it's appx. 80% full. This feature actually is the most efficient way to make the battery last for over 100,000 miles. In fact, there are some Prius' battery packs (canadian taxi companies) that have over 300,000 miles.

Same battery scenerio is true, when your meter 'looks' empty. Again, it's not. The ECU's prevent the traction pack from dipping below 20% ... so if you get to what looks like 'empty' ... don't worry, they're not. The engineers decided that to let the batterys completly depleat, would shorten their lives. Toyota tries to make the system idiot proof. But there IS a way you can defeat the 'idiot-proof' system. Turn on your AC when in stealth mode, and shift to neutral. The ICE won't come on to recharge the pack, unless the hybrid is either in 'park' or in 'drive'. In other words, "DON'T ever do that". :P

[wwest]

Is it normal for my battery to ALWAYS stay at 3/4 charged? I've been driving freeway a lot lately using mostly the gas engine, so I guess it should give enough time for my battery to fully charged.

Please share your experience. If it's not normal, what should I do?

While the Toyota HSD system is fully optimized, FULLY optimized, for use/driving in city stop and go traffic, that is often not the case for freeway use/driving.

Absent the ability for the use of regen capability to recover energy otherwise lost to heat there is little reason to optimize the HSD system for freeway use, it will always come out slightly on the negative side when compared to non-hybrid vehicles of roughly overall equivalence.

Even simply cruisng along on a level roadbed at a relatively constant speed the CVT's electric motor(s) must remain powered, consuming power, althought the ICE is running continuously and IS the main driving force. Absent this uniqueness of the CVT the ICE could be the ONLY driving force for freeway use and therefore the hybrid battery would not have need to be recharged at all.

It appears that our prius "waits", intentionally waits (in hopes a regen capability/opportunity arises..??), to begin using the ICE to recharge the hybrid battery until the charge level gets fairly low. About 5 charge cycles between Seattle and Portland, 175 miles or so, seems to be the norm.

IMMHO the HSD system should have a mode switch so I can "tell" it that for the next "n" miles there will be no likelihood of/for regen opportunity.

Only then could the system be more fully optimized for freeway use.

[SOMEONE ELSE'S GOT MY NAME]

While the Toyota HSD system is fully optimized, FULLY optimized, for use/driving in city stop and go traffic, that is often not the case for freeway use/driving.

Absent the ability for the use of regen capability to recover energy otherwise lost to heat there is little reason to optimize the HSD system for freeway use, it will always come out slightly on the negative side when compared to non-hybrid vehicles of roughly overall equivalence.

. . . snip

hmm, looking at the numbers below:

EPA gas mileage (city/highway, mpg) For RX350 19/24

EPA gas mileage (city/highway, mpg) For RX400h 31/27

Not sure what you mean by "... little reason to optimize HSD ... for freeway use"

It seems the highway numbers for the 400h ARE better than the 350's straight ICE. So are you saying that if the 400h's ECU's controlled battery function differently, that the highways numbers would be / could be even higher?