12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007, 2008 and 2009 with installation kit and free shipping

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12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007, 2008 and 2009 with installation kit and free shipping

Price is now $138.00 with $25.00 mail in rebate! (We will send a rebate coupon with your battery.)This rebate is valid on batteries purchased made from 1 July 2009 to 31 August 2009. One rebate per battery and two rebates per household!

If you need a battery for a 2000, 2001, 2002 or 2003 Prius click here.

Price includes our installation kit.

You can pay about the same amount for a flat plate Toyota battery or buy the Optima and get a better battery! (see chart below)

What makes this a better battery?

Because of the spiral design the lead plates do not have to be strengthened with an alloy and are 99.99% pure. This results in lower voltage drop as the battery discharges and contributes to the longer life of this battery!

This is the ideal battery for the Prius. We have sold them for over a year now and the battery has a very low failure rate! On a Prius the 12 volt battery does not start the engine the high voltage battery does. You do not need the RED TOP battery which is chemically configured to provide a lot of starting power. Instead you need a battery that can handle the slow stead drain than occurs when the car is parked from: the clocks, the memory chips, the security system and the remote entry and key less starting system. THIS YELLOW TOP BATTERY IS DESIGNED FOR THE DEEP DISCHARGES THAT THESE SYSTEMS CAUSE WHEN THE CAR HAS BEEN PARKED FOR A WHILE.

How much work is this to install?

You pop hood, disconnect battery terminals, unscrew hold down bracket replace battery and then attach above and close hood.

So it is more work than a traditional car but very doable if you have the tools!

Minimum tools needed:

Flat screw driver
10 mm wrench or 10mm deep socket
10mm socket
socket extender
12mm wrench or socket
1/2 inch wrench or 1/2 deep socket (13mm will do)
vise, large adjustable wrench or vice grips
tape

Our free shipping is UPS ground or Priority Mail (2 to 4 days) whichever will be faster! Toward the end of the week most of the orders go via Priority Mail because UPS does not move packages on weekends.

The three main contributors of premature battery failure are:

Heat! Yes batteries have less output when cold but they also last longer.

Vibration which causes distortions in the plates and eventually shorts.

Repeated deep Discharges

This battery is made by sandwiching the acid filled mat and the lead together and then tightly wrapping them in a spiral. The eliminates the vibration as a cause of battery failure.

This Yellow Top battery is also chemically configured to handle repeated deep discharges not huge starting currents.

If you want a battery that lasts longer. This is it! You will pay about the same at a Toyota Dealer but this is a better battery! We offer free shipping on this battery via UPS or Priority Mail whichever is faster to the 48 contiguous states! You should have your battery in 1 to 4 days!"

_____ is Optima red top battery _____ is Optima yellow top battery

soc-% state of charge ocv - open circuit voltage for deep cycle

soc ocv
100 13.18
90 13.01 The 2004-2009 Prius has a drain of approximately 12 milliamps with smart key turned off (Thanks hobbit). After two weeks the battery would still be at 95% soc and the battery good for 10,000 cycles. However, age and heat also effects batteries.
80 12.83
70 12.65
60 12.46
50 12.28
40 12.08
30 11.89
20 11.68
10 11.48
0 11.27 Look at the graph! A battery chemically configured to take deep discharges (yellow top) has 7.5x(300/40) the life compared to the red top!

The US Prius models come with batteries with Japanese size electrical posts. We provide an installation kit with new electrical connectors and a connector and plug to allow you to connect the vent holes in this battery to the vent tube in the Prius. This Optima battery can replace the Toyota 12 volt battery for the Prius with Smartkey or navigation system Part number 2880021170 or for a Prius without the Smartkey or navigation system Part number 280021050.

Comments from customers who have used this battery in the Prius for over a year!

"The battery has performed absolutely flawlessly and is one of the best improvements you can make to a Prius . Easy to install, everything is included.

In general, I am totally sold on Optima batteries; I use them for my cars and boat, my oldest one is about 10 years old and still works.

Toyota puts so much emphasis on how the Pruis main battery lasts the life of the car; but what they don't tell you is that the accessory battery is a cheap ass lead acid that, even in a best case scenario, will be dead after 5 years. The Optima should correct this issue and bring the accessory electrical system to the level of the rest of the car.

My factory battery died when one cell failed; the car was 1 year old at the time. As you know, Prius, with all its electronics does NOT have a simple circuit to shut down the interior light! It is therefore only a matter of time until one does not shut the door all the way and the next morning the battery is completely dead. This is what happened to me twice. When I charged the factory battery for the second time it failed. The symptoms were somewhat strange as it would still run but after sitting a few days it would not.

It is good to know that with the Optima kit the chances of recovery are much better . And I don't think I'll ever have to worry about having to replace it due to age.

Regards,"

P. G., Cherry Valley, California

"I just wanted to let you know that the Optima battery in my '04 Prius has been great. We had a few sub-zero mornings last week -- the kind that in the past, with the OEM battery, had me running a long extension cord and portable charger out to where my car is parked overnight to get it started. I had been taking to turning off the keyless entry system to try and avoid a cold-morning dead battery. I found the OEM battery to be the car's achilles heel, because when it is weak, you have to resort to the physical key to get in the car, and even then you can't get the back hatch open to access the battery.

But this winter with the Optima battery in place, not an issue. No matter the temperature, the car 'boots' properly, so all other systems, including the gas engine, start up without problem. I've always been a fan of Optima batteries, and adding one to my Prius brings up the 12V traditional electrics up to a quality level commensurate with the rest of the car.

Thanks for a great kit to install the battery."

M. A., Fort Collins, Colorado

"I've had no problems since I replaced the battery. The sound system sounds great. I haven't let the battery discharge deeply (I've learned to turn off the wireless key when I'm on vacation), but I trust the yellow optima is the right battery for a deeper discharge and a good choice for this application."

J. G., Monte Sereno, California

optima spiral technology

The unique design of the SPIRALCELL TECHNOLOGY. provides many features not available in ordinary batteries. The following is a summary

SPIRALCELL TECHNOLOGY PROVIDES: More plate surface, closer plate spacing, ability to use high purity lead. RESULTING IN: Low internal resistance. This low internal resistance gives you more power in a smaller box, ability to recharge much faster and higher cleaner voltage characteristics during discharge

Immobilised plates (locked in place). RESULTING IN: Improved vibration resistance, no shedding of active paste material, lower gradual loss of power and capacity as the battery ages. This gives you a battery that lasts longer and performs better throughout its life.

Voltage 12 (12v or 12 volts)
Amp Hour 38
CCA* 450 (Cold Cranking Amps)
Shipped fully charged ready to install
Maintenance-Free
Valve-regulated absorbed glass mat (AGM) eliminates acid spills and terminal corrosion.
Vent hose holes for emergencies in case the battery is heavily overcharged. (You need a connector and plug that we provide with our installation kit)
More than 15 times the vibration resistance of an ordinary battery.
Last up to twice as long
Length 8.9" and 9.15" at top cover
Width 4.5" and 4.9" at top cover
Height 9" including posts
Weight 28lbs
Warranty: 3 year exchange, excludes damage due to misuse or neglect, improper charging or improper application of battery
Free shipping to 48 contiguous states: Ships the same business day you order via UPS ground or Priority Mail whichever will be faster! Just select the shipping method "Free to 48 states for $50 order"

The Federal Magnuson-Moss Warranty Act of 1975 prohibits a manufacture from curtailing warranty coverage due to after market parts unless it can be demonstrated that they caused the problem. (For more information click here and scroll down go to paragraphs under "Tie-In Sales" Provisions.)

This sealed battery has no free liquid electrolyte because it is absorbed into the glass mat. Consequently, there is no acid that can spill into the trunk. It also has attachments for a vent hose so any gases are vented outside of the car. The battery does not normally emit gases but can do so with heavy over charging with pressure building up and the valves in the batteries releasing. This should not normally never occur because the Prius high voltage to low voltage converter puts out around 13.8 volts. 13.8 volts is the voltage the battery puts out at no load and at that voltage the battery can not be overcharged and it is the maintenance voltage for the battery. However if one cell shorts out or the voltage unexpected goes high gassing can occur.

The 12 volt battery is not used to crank the gasoline engine in the Prius but it does supply all the 12 volts circuitry which includes all of the computers in your car. If this battery fails, the computers will not start and the Prius will not start. A weak battery can also pull the 12 volts power down to a lower voltage. This can cause problems with all of the computers that control your car. (When I had a problem with my car the first thing the dealer insisted I do was replace the battery. The problem was caused by something else but the battery was weak.)

Since the 12 volt battery does not start the gasoline engine you can still use the car with a very weak battery. So much so that at least three Classic Prius users have told me that their Prius now gets better mileage with the new battery. One told me that getting a new battery restored his mileage back to the original mileage he was getting when the car was brand new and another told me that he is now getting better mileage then he did originally. Here is the third owner's comments: "All installed and working GREAT! My mileage has jumped amazingly (>10 mpg). Would have saved considerable amount of money by replacing earlier. Thanks again for being there." (for another similar story go to the bottom of this page.)

So if your 12 volt battery is weak it could also be affecting your gas mileage because your Prius is wasting energy trying to recharge a battery that will not take a charge.

Another classic user had let the 12 volt battery degrade to a point that he had to turn the ignition on and off four or more times to start the car. He told me his gas engine would never shut down when he was driving.

In short, if your 12 volt battery is four or five years old we recommend you replace the battery. The normal battery life is four to five years.

Prius battery test procedure for 2004 to 2009 Prius Cars

Here is a battery test you can perform on a Prius battery that is easy to do. It will not always detect a weak battery that does not allow you to park you car for long before it is drained down by the security system.

However, this test requires no tools, is easy to do and will give you some idea of the state of your battery. You can also perform this test after the car has been parked for a while to see how well the battery holds up under the drain from the security system.

Do this test after you have driven the car for at least 30 minutes. This will give the battery a chance to be fully charged.

Put the transmission in Park.

Engage the parking brake

Push in the power button. (if not already on)

Push Display button. top button to left of screen - "DISPLAY" will now appear in the upper left corner of your screen.)

Push on the upper left(1) on the display just inside the box, withdraw, then push on the lower left display(2).(see picture) Do this three times. Keep trying till the screen changes. If the word "Display" in the upper left hand corner of the screen goes away hit the display switch again.

Push on Menu in upper right of display screen.

Push on Display Check

Push on Vehicle Signal Check

You will see the 12 volt voltage displayed. In accessory mode the voltage should be 12.6

With no electrical accessories on including lights the voltage should be fluctuate between 12.6 and 11.9. The lower the voltage, the less of a charge your battery currently has. If the voltage is low do not proceed as the load test might totally discharge your battery. (If you see a voltage around 13.8 you are seeing voltage from the high voltage battery being converted to around 13.8 in an attempt to recharge your battery. This normally does not occur till after you start the engine but might occur earlier if the battery is very drained.)

You can also test the battery by turning on the headlights, rear window heater and the heater fan. For a new battery the voltage would be around 11.3. If the voltage drops below 10.2 it should definitely be replaced. For voltages in between the lower the voltage, the lower current charge of your battery.

Note: If in doubt disconnect the 12 volt battery completely (start with the negative post to avoid shorting the battery) and hook it up to a battery tester.

Included is our installation kit which includes all the parts you need and detailed installation instructions.

You will need a vise large crescent wrench or a vise grip, a 10MM wrench, a 10mm socket, 12mm wrench or socket, a socket extender, some tape, and a 1/2 inch wrench or 1/2 inch deep socket. You have to follow the normal precautions of disconnecting the negative battery connector first and connecting it last or your can short the positive connector to any exposed metal in the car. If you follow the detailed instructions, that come with the installation kit, you will not short out the battery but you may want to buy the kit and have your battery professionally installed.

2004 to 2009 Prius Customer comments:

"I installed your Optima battery kit tonight in my '04 Prius. Shame on Toyota for making battery replacement so hard, and Kudos to you for making a nice replacement kit and good instructions!

J. H., Minneapolis, MN

Classic Prius Customer comments:

"I had been seeing a slow, consistent drop in my mileage (mid 30s during cold weather) over the past few months. I was suspect that the 12v battery was going bad (I have a 2002 Prius) and found your site on the net. I ordered one of your replacement batteries and install kit, which arrived in just a few days. Installation was straight forward, except getting the nut loose from the positive side terminal, that thing is on there! I saw an immediate jump in my mileage, back to the low 40s. It amazes me that the 12v battery was taking so much energy from the system. Anyway, I just wanted to thank you for the great service and a great product." J. B., Eugene, OR

Please Note: California Proposition 65 Warning Battery posts, terminal, and related accessories contain lead and lead compounds, chemicals known to the State of California to cause cancer and reproductive harm. Wash hands after handling.