I have a 2009 toyota camry hybrid. I am under the impression that changing the 12 volt battery can mess up the computer in the car. My hybrid is now 3 years old, and i am wondering how to know the battery is fading. My experience with oem batteries is that they last about three years and not much more. is the 12v battery in that car specific to hybrids? the expected workload is quite different for the hybrid. Can i change it myself as i have been doing it for my own cars for about 40 years?
Thanks,Lee in PA
You’re correct about disconnecting the 12 volt battery on some vehicles where it can cause problems with computers/modules. Here’s a link that describes this problem. http://www.aa1car.com/library/battery_disconnect_problems.htm
I suggest that you contact the dealer’s service department and ask them if any problems will arise from disconnecting the 12 volt battery in your vehicle.
Tester
There’s this adapter for a 9 volt battery to plug in your WORKING 12 volt outlet or cigarette lighter outlet which will maintain computer settings while the car battery is disconnected. Most places that replace batteries will use it.
I am a few years late to this discussion but I will try and add some good advice.
The OP (Original Post) asks five questions:
1. I am under the impression that changing the 12V battery can mess up the computer in the car.
The answers by #Tester and #pleasedodgevan2 are good. The best way of changing any modern car battery is to do like pleasedodgevan2 suggests. That is how I did it. Yes, you can simply pull out the old battery and put in a replacement but you will have some resetting to do afterwards (eg clock and possibly some other configuration settings on the dash). There are many more than just one “computer” in modern cars.
2. My hybrid is now 3 years old, and i am wondering how to know if the battery is fading.
The Toyota manual suggests checking the battery voltage 20 minutes after the hybrid system is turned off.
Guideline open voltage at 68°F (20°C) is:
12.6V - 12.8V Fully charged
12.2V - 12.4V Half charged
11.8V - 12.0V Discharged
If your battery reads less than 12.6V you should fully recharge it using a good quality external charger. The voltage should then be rechecked after say 12 hours of rest and it should still read > 12.6V. Alternatively, if you need to run the car, you can use the guideline above. If the battery doesn’t hold its voltage , it should be replaced.
3. A. My experience with oem batteries is that they last about three years and not much more. B. is the 12v battery in that car specific to hybrids?
C. the expected battery workload is different for the hybrid?
A. In my opinion a good quality battery, well-specced and not abused, should last at least 5 years. I was surprised to see the OEM battery in the TCH needing replacement after just 3 years (so, in this, your experience is more reliable than mine).
B. The battery is not specific to hybrids other than Toyota recommending it should be AGM (Absorbent Glass Matrix) technology and at least 50Ah. AGM is better suited to constant cycling than cheaper batteries (standard and EFB, see https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm)
C. Yes. The workload profile for a Hybrid 12v battery is quite different than conventional.
4. Can i change it myself as i have been doing it for my own cars for about 40 years?
Yes you absolutely can. However if you can find a good supplier, they will also do the installation for free or minimum cost. In my case the supplier included the installation so I was more than happy to have him do it while I waited.
Summary:
My TCH came with an OEM Panasonic AGM (355 CCA, 51Ah. In Australia, Toyota’s replacement price was around $AUD500 plus installation. One Toyota dealer quoted me $AUD600 all up. Because of these prices, many owners have replaced the OEM battery with other brands, eg Optima in USA. The best replacement I found was a Century S55D23R (550CCA 50Ah). The CCA rating is largely irrelevant but the capacity rating shouldn’t be less than 50Ah for a TCH. I would have liked more Ah but couldn’t find a bigger AGM battery that would fit. The Century battery, fitting included, was $230.
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