Replacing the Prius Auxiliary Battery with a Mazda Miata Battery .?

I have a 2002 Prius. The 12 volt Battery is dead. The dealer indicated that a replacement battery is $135.00 plus a $50.00 for a bracket kit. The parts person indicate that Toyota has a bulletin about the original OEM battery discharging on owners with short trip driving habits. The new battery is bigger and offer more storage capacity. As expected, non of the auto parts stores offer a replacement battery. I looked up replacements on the web and came across this site: http://www.elearnaid.com/12vobaforpr2.ht... which claims 200 successful replacements with a Mazda Miata Battery and home made upgrade kit.

Can anyone shed some light on this claim? Have you used such substitute? Are there any concerns or negative impacts on the vehicle electrical system? Are there any other feasible alternative?

Thanks,

KM

Replacing the Prius Auxiliary Battery with a Mazda Miata Battery .?

The Prius' 12v accessory battery is located in the trunk, and therefore special consideration should be given for outgassing/ventilation. Physical sizing is also an issue (hence why you need the new fitting kit), as is the oddly shaped/positioned Japanese battery posts. (OE battery is an AGM type and about the size of a motorcycle battery.)

The bulletin you mention is US TSB EL014-03. If you are a member of the toyota-prius-sat1 yahoogroup (free membership), you can view it at:

Toyota Technical Service Bulletin EL014-03, dated Oct. 2, 2003, titled "Battery Capacity Improvement" for 2001-2003 Prius. Lists part numbers and installation instructions for a newer, larger capacity 12v accessory battery.

http://autos.groups.yahoo.com/group/toyo...

More info on the Classic NHW11 Prius' battery (US model years 2001-2003), as well as alternative replacement information, is at:

http://autos.groups.yahoo.com/group/toyo...

(Personally, I've already done the Toyota upgrade route last year, after I let my 2001 Prius sit undriven for 2 months which killed the then 6 year old 12v accessory battery... (Your dealer's pricing is cheaper than mine was!) Unfortunately for me, having someone starting the car for 30min every 1-2 weeks wasn't enough to keep the new battery happy, and I'm again looking for a replacement 12v already a year later, as I'm back to the portable jumpstart to get it going again... %26lt;sigh%26gt; the price I pay for moving somewhere where I don't need a car... I may go the elearnaid route, and get a smart battery minder and plug into the garage outlet, but haven't decided yet.)

Good luck!

Replacing the Prius Auxiliary Battery with a Mazda Miata Battery .?

A 12 v. battery is a 12 v. battery. You cannot damage the electrical system by putting one in that has more CCA's. I have always put bigger batteries in every car I have owned. The more you have to work with the better off you are. The only obstacle is the dimensions of the battery compartment.

Replacing the Prius Auxiliary Battery with a Mazda Miata Battery .?

"This sealed battery is designed to go in a trunk and utilizes absorbed glass mat technology. This advanced battery has no free liquid 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." Normally a battery doesn't go in the trunk and I wouldn't recommend it. Putting one in the trunk usually means putting it near the gas tank and even though it sounds like a good idea to say freshen the air in the trunk it isn't because the battery might explode. It also makes the battery no-good before it explodes.