the 12v & the av non mechanical driver

12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007 and 2008

Upgrade!

I did and feel it was a pretty good $150 investment.

I had two optimas in my Jeep (dual-battery system for winch)...they lasted 8 years! and I was not kind to them...heck it was a Jeep.

I had one other optima that was transferred from one vehicle to the next for 4 cars and 10 years.

 

Just be thankful you don't have an '04 like mine with the hyper sensitive Traction control that will leave you helpless on a bit of snow and ice. Thus I run very aggressive studded snow tires in winter, which kills the fuel economy but I'm not going to dink around with second guessing the Trac system

As far as cold climates, I'm going to guess there are more Prius cars sold in California than all of Canada and Montana, combined. I do admit, the A/C is ice cold. But if you don't block the grille - we used to call them a "winter front" - then you will freeze at -40

I still believe a lot of the 12 vdc battery issues are from improper dealer PDI. If your Prius was already 3-4 years old, I guess I would say "time for a new battery."

At 3 months old and battery trouble? No way. As I have stated in other posts, the constant voltage source simply cannot charge the Prius 12 vdc battery in cold temps. Once the battery becomes discharged, you enter into a spiral where it gets weaker and weaker until the Prius refuses to boot one morning.

 

I think if the Toyota engineers had just put a temperature sensing voltage control circuit in the charger the extreme temp issues would have been solved. It just needs to increase the voltage a bit when the temp gets below 0C - from 13.8 to 14.3 or so. Then the existing battery would fully charge and there would be no issue. Many alternators do this now.

They were probably trying to minimize the gas produced by the 12 V battery, but in cold climates that isn't an issue when it's cold. Getting full charge in the battery -IS- an issue.

 

Finman... what do you make of all the bad press that particular (51R) battery has gotten - especially in the Honda Community?

 

Agreed! Just an ambient temp sensor would be enough. Some fancy hobbyist or specialized battery chargers actually have a thermister you stick on the battery, so the charge is precisely controlled

This is one such charger

12 Volt 2-4 or 8 Amp BatteryMINDer Charger and Maintainer

Kussmaul has a lot of experience with standby charging and air supply for fire trucks and other emergency equipment

Kussmaul Electronics Co., Inc. Auto Charge 75 Data Sheet

 

I would like to do more testing on my Prius, but from the simple measurements I have taken with a handheld Fluke, there appear to be two steps to the constant voltage source.

I've been trying to borrow a very expensive AEMC power quality analyser from work. I could leave it hooked up to the 12 vdc battery - it can record both voltage and current - and have it record for 24-48 hours. I'm now very curious to get the results from such a test

It looks like the last thing we have to fear is a Prius overcharging the 12 vdc battery. Just the opposite.

 

So I'm now wondering if that particular dealer even bothers to do the proper PDI? I recently emailed you the pdf of the procedure, it is a bit picky but if that is what the car requires, so be it

What started to kill my battery was city driving of 12-30 mins at -40, headlights on, Max Heat (Didn't have the winter front made yet), and constant electric defrost.

It took almost 2 weeks but I started to notice changes in how the car booted up. At the time I had a condo with heated underground parking, so once I poked the power button, the Auto headlights came on. In Canada the Prius has auto headlights

The headlights started to really dim as the brake boost and coolant transfer pump ran, then would suddenly brighten as the inverter kicked in. Another week went by as the problem got worse, once the boot process sort of "hung" and the headlights went out, then the dash went black

I knew I would be overseas 5-6 weeks on business, so I decided to remove the 12 vdc battery and lug it up to my suite. I left it hooked up to a VDC Electronics Batter Minder, and left the next morning on my flight

I had to return after 3 weeks as my Mom passed away suddenly. When I returned, the VDC had a blinking green LED, which indicates the battery has a full float charge and is desulfating the battery. I hooked it up and when I booted the car, the headlights barely flickered

So I hooked up the permanent VDC harness and got into the habit of just plugging in the unit whenever the car sits overnight or longer. For example, I've been at my hobby farm almost a week now, and left the Prius back at the house. Have had it hooked up to the VDC the entire time

If your Prius has the same ride quality as mine, I'm not too optimistic. I have to drive down almost 4 miles of gravel sideroad to get to my hobby farm, and it used to be very washboardy. The Prius does *not* like washboardy roads!

This fall, they started a small logging operation on Crown land about 10 km from my place. The logging trucks are making pretty deep ruts in the road. The one time I took the Prius out, I did a lot of scraping underneath

With the FJ, especially on the Toyo Open Country 16 inch winter tires, it simply soaks up the bumps. Since I'll only put 4,000-6,000 miles a year on my FJ, I don't mind driving out and using it for the purpose it was built for. Even at -30 F, I'm averaging 20 MPG so that isn't too horrible for a vehicle that size

 

Why not just move to a part of the world habitable by humans?
Other manufacturers have inbuilt battery tenders and block heaters for cold climates I assume?

But I ignored the warning signs and left the headlights on auto.

And you know you wouldn't believe it but ...

my 4x4 performs better on corregated and badly rutted dirt roads even though I have fitted winter tyres to it!

My god, what do you know??

 

Like it here better

Block heater, yes. Battery tender, no. The exception is HD equipment and fire trucks, they have to be ready to go at a moments notice. Kussmaul makes a tender and air brake pump just for them

Kussmaul Electronics Co., Inc. Fire Products Home Page

Tee hee, you're funny!

I used to have a 2000 GMC Sierra pickup with auto headlights that could *not* be disabled. Had a lot of issues with that truck, but never with the battery

I suppose at -40 I could have switched off the headlights and illegally drove in the dark with just the daytime running lights. I could have also turned off the heat and rear defrost, and simply poked my head out the open window

It's clear that some folks have had battery issues in temps of -30 C and colder. Especially if a dealer tells the Prius driver that a lot of their Prius cars suffer the same problem.

In temps of -30 C and colder, I've had battery troubles with every piece of equipment I have owned. Using a Battery Minder, and for the equipment outside a battery warmer, made all the difference

I imagine in temps of +40 C, a different set of rules also apply to car maintenance and operating. Eg, AC must be properly serviced and radiator must be reguarly flushed

The poster did ask about bumpy gravel roads and I gave an honest assessment of how my Prius performs on washboardy gravel roads. Winter tires typically have soft squishy treads and softer sidewalls for enhanced snow/ice traction in temps of -30 C and colder

That same tire design results in a much softer ride, which I prefer anyway. My FJ was designed for offroad conditions, so naturally it has much greater suspension travel and softer spring/shock rates compared to my Prius

There is a difference in ride quality comparing either the FJ or the Prius running the "all season" tires (Goodyear Fortera TripleTred on the FJ, Michelin Harmony on the Prius) vs the winter tires/wheels (Toyo Open Country G-02 Plus on the FJ, Goodyear Nordic studded on the Prius). The winter tires hands down provide a softer ride quality

There is a badly frost heaved section of highway here in Winnipeg that I'm sure any Winnipeg resident is familiar with: Dugald between Plessis and Lagimodiere, especially the west bound lanes

About every car length is a 1-3 inch sharply uplifted chunk of pavement. Most likely, improper road construction, poor soil conditions (Lots of clay in the soil causing poor drainage), and temp cycles (+35 C in summer, -40 C in winter) all caused the frost heaving

My Prius jumps in terror at every sharp bump, especially near Olympic Building Supply. The FJ soaks up the bumps with mild motions at worst. But again, the FJ is designed for such driving

I purchased my FJ strictly as a weekend toy (Get it? Toyota - toy?) for zipping out to the hobby farm. The Prius is and remains my daily city commuter. Now with the deteriated road conditions to my hobby farm, I'm very glad I go out in the FJ and not the Prius

It's not just the Prius that I feel rides too stiffly. A lot of new cars now have a "sporty" ride that really doesn't help you over poor road conditions. The old land yachts I remember as a child would float over such roads at 10 mpg, but I'm not wishing for their return

 

I drove my early 2004 Prius in North Dakota for about two years before moving to Spokane. I never had any trouble with either the battery or the traction control. The TC seemed to get me going at icy intersections faster than any other cars except 4WD and AWD. And a little over 4 years after buying it, the battery still has not given me any trouble. I am always careful to shut all the doors, though, and I've never left my lights on when the car is parked.

If you mean Alice Springs, no thank you.

 

Well, I got the battery, then found the Honda forums and a few having issues. some having no issues, and still others wanting blood from Optima.

Time will tell, now that I've got it installed.

I will see what happens. I really don't know what to think. Basing my Optima experiences on my past three red-tops...I'll be talking about replacement in 8 years!

Nothing's perfect. YMMV, and all that. Maybe my plug-in Prius will be ready by the time the 12 volt comes into play again. No one knows.

All the same, lots of people swear the Prius sucks with it's "stalling", traction control too aggressive, and any other of a myriad of ailments.

Kinda a crap shoot anyway, since it's all human-made machinery. I'll deal with stuff that stops working when the time comes.

 

I'm convinced only a relative handful of 2004 Prius have the hyper sensitive Trac issue. If I recall, Tideland Prius had issues until the dealer fried the computer during a reflash. With a new computer, the Trac issue went away

I also recall Dave in Olympia comparing his first Prius to his current one, and noticing a difference in Trac behavior.

Clearly, if only a relative handful of Prius cars experience an issue, then the average Prius owner will wonder what all the fuss is about. As an example, my Prius also had the Stall happen, which was an issue that was easy to ignore unless it happened to you during rush hour on Kenaston here in Winnipeg

 

I suspect most of the people who think the Prius sucks have never driven one. Only a few Prius drivers are dissatisfied.

I've wondered myself if this was the case. Though I have no slippery hills, the slippage/stalling reports seem so unlike my experience.