Originally Posted by Captain Jim

12 Volt Battery Replacement / Upgrade on a 2007 Toyota Camry Hybrid with photos

Three years old and 30,000 miles, is a reasonable time to replace a 12 volt battery.
Mine died in my driveway, thus giving me more options than 100 miles away from home.
In the end the battery measured 1.7 volts, not the typical 12 volts, the battery gave me signs that it was dying, the key would not start the car twice about 10 days before the battery quit. It was a omen of bills to come, I just didn't know it.
Having the time to research the OEM Panasonic S65D26R battery, I found that the S65D26R is an AGM type battey, and costs $320.00 from Toyota. Paying Toyota this amount of money would NOT be my first choice. The battery warranty is somewhat like the tire warranty, independant of, and outside of, the overall Toyota warranty. What so much? Well the OEM Toyota battery is an AGM, Absorbed Glass Mat battery. An AGM differs from the typical lead acid battery as it has an absorptive material between the positive and negative plate of each cell separating it and allowing the liquid electrolyte to contact both material, you may think of it a providing a 99 to 100% humidity inside of each the six, 2.1 volt cells that make up the 12.6 volt battery. Since they are sealed, they will not vent to the atmosphere and loose their moisture, unless there is a dramatic pressure differential (this happens very rarely) , and then a small pressure relief valve will monetarily open. Since this is in your trunk space, an AGM is the best overall choice.
Battery websites, like Interstate battery say that I could replace my battery with a typical lead acid battery for about $75 bucks. This is a real option, you just need to know that you may have battery fumes in your trunk from it.
But there is a two wire connector that also comes out of the OEM Toyota battery. This is a temperature sensor, it measures 2.27 kilo ohms FYI. It is meant to monitor the temperature at the battery to prevent over charging. You remove it from the OEM battery by pealing back the top sticker, and by using a small screwdriver on the hot glue, pry and pop the sensor free.

I chose to put in an Optima yellow top Starting Deep Cycle, size D35 with bottom spacer battery, it cost $225.00
these are the batteries that are used in Alaska, and they last 7+ years.

You will need a 10 mm 1/4" drive socket and extension.

There is enough space and wire to have the positive and negative terminals in front, or in the rear, as you mount the battery.

I attached the sensor to the battery with a tie wrap to the hold down bar, and mounted the connector with double sided tape.

There will be a spark as you make the final connection, this is normal.

Since you removed the 12 volt battery, the "Check Hybrid system" message will appear on the console. I just power cycle the car three times and it will reset the computer and remove the message.


It is Ok to send a message to me via email. Jc

Originally Posted by brianrounds

How do you power cycle your car?

Originally Posted by GeorgiaHybrid

This is from the Toyota Camry service manual:


HINT:After replacing the auxiliary battery, the hybrid system may NOT start. Follow the procedure below to initialize the system.
1)Put the shift lever in the "P" position.
2)Open and close any of the doors.
3)Restart the hybrid system