Battery Degradation

[The Critic]

Old:

New:

Replaced with the same - NAPA/Deka AGM for a Prius application.

The old battery was in-service for 40 months. Both batteries were fully charged before testing.The old battery had also been drained to <3V on two separate occasions. With the upcoming cold weather and the need for this vehicle to be reliable, NAPA’s 20% off sale was enough motivation to replace it.

 

[hemitom]

With those results i would have no issue's running the old battery.

 

[ripcord]

With those results i would have no issue's running the old battery.

Me, too. In a Prius, the CCA's for the battery under the back seat are irrelevant. That battery merely supplies a low amperage current for running the computer, interior lights, etc while the engine is off. It is not used for starting the engine. The traction battery is what is used to start the engine.

 

[brianl703]

Does that battery actually crank the engine or just power up the computers so the high voltage battery can crank the engine?

I replaced the 10-year-old H5 AGM battery in my Volt a couple months ago. Nothing wrong with it per the tester, but I figured 10 years was enough. The high voltage battery is what cranks the engine in the Volt.

 

[The Critic]

With those results i would have no issue's running the old battery.

Normally I would agree, but I have had bad experiences with batteries that have been fully drained and recharged multiple times.

Does that battery actually crank the engine or just power up the computers so the high voltage battery can crank the engine?

@ripcord was correct.

 

[ripcord]

A popular battery mod for Prius owners is to replace the automotive 12v battery with a 12v deep cycle mobility scooter battery. They are A LOT more tolerant of being run way down and recharged than a automotive starter battery and have charge/discharge characteristics that match well with a Prius.