I cannot speak for AGM batteries, but in my 40+ years of driving, there has been a fairly strong correlation between the times when I've left a light on (had an alternator/regulator failure, etc.) that caused my battery to go dead, and my needing to replace that battery a short time later. And, the correlation is even stronger in a battery that has seen significant service. Yes, they can be recharged, and will work for awhile, but they often fail again of their own accord not too long thereafter.

 

The Optima AGM batteries list 300+ cycles in the specs; which should mean they can be totally discharged and charged back up 300+ times correct?

 

Ron,

Can you confirm that there's no temperature sensor in the 2012 model?

Thanks.

 

Jim,

On a side note, I checked just now, the "OPTIMA Battery Search:" feature on your web-site doesn't list the Prius when I choose 2010 for the year and Toyota for the manufacturer.

FYI.

 

I'm not Ron, but I could find no temperature sensor connected to the 12V battery in my 2012 TCH. If there is one, I'd also like to know where it is.

 

It depends on whether or not you want to connect the vent. The D35 has a vent connection, and the D34 (or 34M) does not. The D34 is a similar size and capacity to the OEM. The D35 is smaller and comparable to the OEM on the Prius I presume.

 

No, it wouldn't unless there is some kind of current limiter in the circuit. Not likely. Your best way to limit current is with the charger. Either use a small 2 amp charger, or a larger charger set to 2 amps.

 

Not that I can recall. Car is out now or I would check again for you. I really don't think so, but I did miss the vent, so anything is possible...

 

Should one disconnect the 12V battery, if one is away from home and need to jump the car? I ask since I remember reading earlier in the thread that it was likely the jumping that was destroying the deep cycle battery that otherwise would have been good for a number of deep discharge/charge cycles. Otherwise how can we explain the OEM battery deaths so soon?

 

I have looked at the manual for the recommended jump starting procedure and it says:

Make the cable connections in the order a,b,c,d.
a. Connect the clamp of the positive (red) jumper cable to the positive (+) terminal of the discharged 12 volt battery.
b. Connect the clamp at the other end of the positive (red) jumper cable to the positive (+) terminal of the booster battery.
c. Connect the clamp of the negative (black) jumper cable to the negative (−) terminal on the booster battery.
d. Connect the clamp at the other end of the negative (black) jumper cable to a solid, stationary, unpainted, metallic point of the vehicle with the discharged battery.

The recommended connecting point is  in the above illustration.

The illustration points to the metal inverted U shaped object that normally holds the trunk lid closed. Could it be that if someone connects the negative from the jumping battery to the negative on the dead battery that the risk exists for damage to the dead battery (and not otherwise if one strictly follows the instruction in step d above)? Just wondering ...