Resistance is futile

Glad to meet you! I'm new here, too. The Prius certainly is a technophile's dream. It sounds like this forum might be a hazardous place for someone with your tendencies though. Kind of like an alcoholics support group that meets at the pub!

I'm currently shopping for a Prius to replace our old '94 Chrysler. She's got about 200,000 miles on her and the electrical is failing. Hubby drives that one now; because I've got the longer commute I drive the more efficient RAV4.

I've noticed that in recent weeks I've starting playing a game while I'm driving to see how how I can get the average MPG on the RAV4's HDD to go. I'm just waiting for a cop to pull me over and demand to know why I'm driving so pokey. I don't do it when there's a car behind me though--only when I have the road to myself.

So now this geek wants to shift up to something REALLY nerdy like all the status displays on the Prius. I tested out a Prius V and a C today and all the output on those warmed the cockles of my geeky heart.

I am certain that you can empathize.

P.S. There's no way that I'm going to lose the Prius to my husband. He's been dishing out so much abuse over the years to a Prius-driving co-worker that he'd never live it down if he drove the car. He'll get the RAV4.

 

I had a a 2003 Baja that gave me 20mpg in my daily commute. I am now double that!+

Nerdy will count as gas gets higher I guess.... $4+ is not getting most to slow down....

All I can say that since the Prius, I have been more relaxed in my drive....

 

Welcome to the Prius family with the Gen3. Since you like modding, I am sure you'll soon be contributing.

 

Welcome aboard and thanks for the writeup. Always fun to see what drives a person to a Prius.

 

@ Root and Ralleia – You have learned that resistance is futile, as you are now assimilated into the “Prius Collective.†Welcome to the Prius Hybrid Hive, and The Fight In The War On Petrol Terrori$m, One Gallon Of Gasoline Not Used At A Time. lane:

 

:welcome: to PRIUSchat. :cheer2:

As you've said, the situation you've described is going to produce low
MPGs, probably ~35 MPG. A block heater will help a little. The problem
is that for the first 10 minutes or so, 3-5 miles, the Prius is going
through some operating algorithms meant to minimize pollution, not
maximize MPGs. First, the ICE runs rich to pass some fuel on to warm
up the Catalytic Converter (CC)...

At the same time, the HSD is drawing on the HV battery to take up a
good portion of the torque you ask for by pressing on the go-pedal.
This in turn leads to the ICE running to spin the Motor/Generator (MG)
to "refill" the HV Battery when the car is stopped or gliding.
No way around it, the HSD prefers the SOC to be just below 60% in the
summer, and 60-65% in the winter, and it will get its way.

There's another more insidious issue. The 12V battery is quick to
discharge and slow to charge. 1-2 miles of low speed weekday use
probably won't be enough to keep the 12V battery charged to the
preferred high-12Vs. Over time, this can lead to having to replace the
12V battery -- ~$260 dealer installed -- very early, rather than the
typical 4 year service life.

This issue can be side-stepped by putting the 12V battery on a battery
minder or battery keeper overnight.

Just thought you'd want to know...

 

But wouldn't that be true of any car that you drive for only a few miles a day, gasoline OR hybrid?

 

Congrats--enjoy.

 

Well, yes in a small way, NO in a big way.

Yes, regular ICE powered cars draw on the 12V battery to start
the ICE. After that, electrical power is provided by the
alternator. An ICE powered car's battery is much larger than the
Prius' battery because it has to spin up the ICE. But, the alternator
is typically spinning merrily away under the hood all the while the
ICE is running recharging the 12V battery.

And NO, in the Prius, the 12V battery is needed at start up only
to boot up the various computers and ICUs. Once some initial checks
are make successfully, the HV battery comes on line and is used
to power one of the two Motor/Generators to start the ICE.

Once the HV battery is on line it powers the 12V buss via the
DC-to-DC converter. The 12V battery is also recharged, but very,
very slowly.

The 12V battery is far more abused by the owner and environmental
conditions than by the car's operating algorithms. These abuses include
heavily discharging the battery by leaving light on/doors ajar, and
service in extremely cold, but more so extremely hot locales.

Those in the know have said that just to keep the 12V battery
topped off in a car that is sitting unused, the car needs to be run at
least 30 minutes a week to keep the 12V battery well charged.
And that's with very little power being used for minimal background
housekeeping purposes.

I think few owners will disagree when I say that the 12V battery and
its need to be treated very, very knowledgeably from the very get-go
is the weakest link in the Prius Hybrid Synergy Drive system and even
in the Prius owning/driving experience.

 

Ah, thank you for sharing the pearls of your wisdom and battery knowledge with this fledgling. I must admit that I have been very guilty of 12V battery abuses in the past, resulting in inadvertent deep-cycling (and permanent damage) of the battery, shortening the battery life. It wasn't until I got into photovoltaic design that I even got familiar with concepts like allowable depth of discharge. But car batteries are still pretty much a mystery to me!

Regarding the high-voltage nickel metal hydride battery in the regular Prius (I don't want to touch the LiOn in the plug-in), I read somewhere that the Prius has a whole little computer just devoted to making sure that this battery is at the appropriate temperatures and everything is good for this very important battery to be charged and maintained. So I guess the care and feeding of the "main" battery is already managed?

So it is up to the owner to manage the care and feeding of the low-voltage battery. I suppose there is no automatic monitoring nor built-in tools to help monitor of the state of this battery?

 

The dealer installed an "smart" charger (works with AGM chemistry) before we picked up the car as part of the winterization. They suggested that we use it if the car was going to be left for over a week but nothing beyond that...

 

Oh, goodness. GEEK ALERT!

But seriously--there's actually something useful that could be done with that optional roof PV?

When I first started looking into the Prius last year and when one of the salespeople told me what all that panel did I was extremely under-impressed.

It can actually perform an useful function???

 

It's pretty darn hard to mess up the HV battery.
That said, you want to keep the air vent on the passenger side
of the back seat clear. The HV battery is cooled with air from the
cabin. If the battery is too hot, it is not used and the car is very
sluggish. This isn't immediately terminal, once it cools off, things
go back to normal. The battery can also get in this state by parking
the car in an uncovered spot, in the mid-summer, 100+ degF mid-day
sun for 3 or 4 hours.

There is an on-board 12V battery monitoring function. See the first
post in this thread. You might want to read the whole thing as an
intro to the vagaries of a 12V battery going/gone south:

http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html
[Edit] I know this to be true for the Gen II, I don't know for sure
that it is also true for the GEN III. :mmph:

One last thing: should you ever be caught with a low/discharged
12V battery, be very, very careful. If jump you must,

DO NOT ALLOW THE JUMPER CABLES TO BE REVERSED. Also,
DO NOT "SPARK" THE JUMPER CABLES.
(Sorry for screaming, but this is important. )

In either case there is the possibility of irreparable damage to
one or more of the computers with repairs possibly running as
high as $4K.

 

Yes resistance is futile. Welcome aboard. I like the solar roof idea, but not sure it works for me.

 

Is that 100+ ambient, or internal cabin temperature?

Nebraska rarely gets over 100 ambient, but inside the cabin the heat builds to way over that in the sun.

Goody! Thank you--I'll check out that thread.

Holy moley--I had not even considered the potential differences of jump-starting a hybrid versus a straight gasoline-engine car. The latter scares me enough of at it is (yes, I'm a total wimp where electricity is concerned! )

It's a good thing to be aware of to plan in advance in any case. AND a good motivation to pay particular attention to the low-voltage battery to prevent such a need in the first place!

 

LLAP

Love the title of this thread