12V Battery vent on Prius 2006

[phjohan]

Greetings,

I could not start the Prius nor open the rear hatch door. This is a Prius 2006 2nd generation. I measured the Battery voltage and noticed 5VDC. This is quite abnormal. Of course, the Battery is almost 5 years old. What I also might deduce, the virus has caused little driving activity and more stay at home so that maybe the reduced voltage. I recharged the Battery and after some time all was fine and the recharged voltage was 13.5 VDC. Anyway, I decided to look for a replacement battery at Daparto and found a Bosch battery; Bosch battery, starter battery, accumulator S4. Upon installed, I noticed that the vent line did not fit into the battery vent. This made me confused because of the claimed replacement battery. I sealed both vents, recharged the new battery, installed the battery without the vent line, and did some research. Discovered that the S4 battery is maintenance free and does not require a vent line. Also, non-hybrid cars did not require the vent line but this battery is installed in the trunk. Has anyone had any similar experiences or does something else need to be done?

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[QuantumFireball]

The 2nd/3rd generation Prius should be used with an AGM Battery as the Battery is located within the cabin and AGM is safer. But the charging system is also designed with AGM batteries in mind, which have slightly different charging characteristics to traditional flooded cell batteries.

It appears Bosch S4 is a normal flooded cell Battery so it appears to be the incorrect type for this car.

The vent is not about maintenance - lead acid batteries emit hydrogen gas (AGM batteries produce less gas), and your battery is not designed to be used in an enclosed space (e.g. inside the cabin of the car) and therefore does not have provisions to connect to a vent line, so it could potentially just emit hydrogen gas in an uncontrolled manner into the cabin.