ono, you are most welcome.

if i understood you correct, all you did was to replace oil and tires, and 12V battery is still the same you bought the car with?

well, though mu diagnostic menu shows battery voltage at 11.9 - 11.7, when measured with voltmeter on the terminals, battery shows cool 12.55V. i'll just let it be and will simply be monitoring it.

 

Yes. At some point, the 12V battery charge level was some 6.8V. So, I had it charged to the full. And it has remained so for the past 4 weeks.

At 11.7 - 11.9, the owner's manual states you should have the battery charged. That voltage is low and could affect the car's performance. I suggest you keep monitoring it or have it charged later.

Maybe your car used up a portion of the 12.55V to give you the ''diagnostic results displayed on the NAV'' and the net voltage is what you have displayed on the NAV. Remember the 12V battery powers all other auxilliary equipment in the vehicle including the NAV system.

 

well, i do not mind charging it, question is - what do i charge it with? i have 2 stage regular automatic charger, 2 and 6 amp, and i had it on battery for about 10 hrs at 2 amp. light on charger never turned green.
i think, there are special chargers for deep cycle batteries, aren't there?

 

It seems to me that Toyota could resolve this issue without much difficulty. The car is designed to draw from the 12V battery while the car is parked -- at least to run the smart-key system and the alarm system. The 12V battery is small, so it can only run those systems for week or so. The car has plenty of computers, some of those computers are running the entire time, and it has the means of recharging that little battery.

The car _could_ monitor the level of the 12V battery, and it _could_ recharge the little battery before it gets too low, and it _could_ alert the driver when the little battery gets to the point of needing to be replaced. Basically, when the little 12V battery gets low, the car _could_ turn itself on for a few minutes to recharge it. It could even turn on the generator (a.k.a., engine) if needed. The same software _could_ turn on the generator if/when the BIG battery needs to be recharged, during periods of extended storage.

In future electric-only models, the car could send an email or text message to the owner, to say that the battery is getting low and that the car wants to be plugged in for a recharge... same concept.

Basically -- the thing has more computers than the space shuttle. It _could_ actually use them.

 

Owners manual states you should charge at 5A steady. I suggest you read the Owner's manual if you have it. Will be quite helpful.

 

well, i do have manual, but i did not see where it says so. i'll look at it again though. that manual is written in almost caballistic way...

just in case, here's a well of wisdom on deep cycle batteries:

http://www.marine-electronics.net/te..._faq/b_faq.htm

 

found it in manual. it's in a yellow box, i never really read those.... charging as i type. 6amp. where's 5, there's 6, nothing's gonna happen. they say those can take a lot of time to get to full charge...

 

Steve, i have a solution for you. Buy a Bentley. It'll do all this and then some. That comes with a car that "is designed and made to last over a hundred years".

 

On a similar note. I also have a 2007 and can get 35mpg at best. How can I check to see how "strong" my battery is? I feel I should be getting better mileage. Follow all the standard ways to extend MPG. Thanks

 

more knowledgeable than i will be of help, but i do not think 12V battery has much to do with mpg, as it is not in any manner involved with driving.
anything from tire pressure through geographic location can influence your mpg. but that might be a story for a separate post, don't you think? will easily turn into volumes of advice.
any parts store will check your battery, but you need to pull it out. also, be prepared to sales pitch.