Number of computers in Prius

Someone will post the complete list again, but I believe it's 13 (14 if you have Navigation).

 

I tell people about the 12-14 computers all the time, but feel uncomfortable doing so. In reality most of them are "microcontrollers". Yes they have microprocessors inside, but no, they don't run an operating system, don't boot up, don't have external memory or external storage, etc. Only one or two do so.
Which is good. You never hear of a "Computer crash" in a Prius.

 

Wow, only 14! I would have guessed many times more than that.

For comparision, a 1999 BMW 7-series can have 65 microprocessors.

 

I believe my Auto Enginuity scanner recognizes 16 or 17 seperate "systems". A few controllers have more than one system in a chassis.

 

When I went to the new-owner reception last summer, they told us the reason the battery could die after several weeks of not starting the car was that it was maintaining 16 different computers while the car was turned off.

 

Oh yeah, 11 milliamps for the whole shootin' match. To me, that's
pretty dern good standby state on the part of all the ECUs...
.
_H*

 

Absolutely, considering an average domestic vehicle hovers around 30mA after the anti-theft and body controller go to sleep.

 

I'm not sure how long a Prius can stand idle without being started before the battery dies. Last summer my wife and I went to Eastern Europe and our Prius sat in our garage for a month with no problems. Next week it'll be sitting in the garage for another month while we venture off to Italy. We never really thought of having any problems with the batteries after all everything is just sitting there in standby waiting for the power up.

 

Buy an automatic trickle charger with a "battery maintenance" mode. This one is correct for AGM batteries. Their voltage is a little higher. http://www.vdcelectronics.com/optima/Optima-type_NL.pdf
Optima Battery Charger and Maintainer
This charger is set up to desulfate the battery. It will improve the ability of the battery to store a charge.

 

Hobbit has a base model Prius. Using his figure of 0.011A parasitic current draw: 24 hours/day x 30 days/month x 0.011A = 7.9 AH

Since the base model Prius battery has a 28 AH capacity, it should be fine when parked for a month. However, a Smart Entry/Smart Start-equipped Prius will have a higher parasitic current drain if that feature is not turned off. I haven't gone to the trouble to measure that yet.

Toyota's advice is to disconnect the 12V battery if the car is left stored for 10 days or more.