2018 Prius, it still starts but the battery test which I did myself shows 134CCA. It also reads around 12.2 volts. My local dealer is charging $181 for a True Start 84 month battery, 2 years, free replacement. So I am leaning towards that.
12.2 volts on a 4 year old battery, what seems to be the problem? It shouldn't need a replacement. At most, you might want to just charge it up, but it's not even that low.
Which battery tester did you use and what settings did you use? Also, what numbers are on your battery. 12.2 volts is actually not that low for a Prius. I would put a charge on it (stay 5 amps or less) and test it again before I’d buy a new one.
I used a Konnwei Battery tester set for 295CCA. The 134CCA is not good. It would never get above 12.2 and it should be at least 12.5. It was on it's way out. It failed on their battery tester. So I went to the dealer in Fort Worth and with a coupon, I bought a 84 month True Start, with 470CCA for only $162 out the door installed. Cheaper than my local Auto Supply stores. I tested it when I got home and it was 471 CCA. They even greased up the terminals to curb corrosion.
I think you made a wise choice (FWTW). And that price and service are great. You seem to have a good dealership to work with.
CCA is irrelevant in a PRIUS. Was it showing signs of failing? Mine is almost 6½ yrs old and going fine.
CCA IS relevant to battery health, though. Couple that with high internal resistance and what energy is left in the battery drops quickly when any load is put on it.
Yes, the battery wasn't in peak condition - but it's only used to close relays and power accessories. The starting motor, in the transmission, is powered by the traction battery. IMHO: If the battery started getting below 12VDC and/or there was weird sensor errors - then I would've replaced it. The battery on my dirt/camping truck is more than 7 years old and always around 11.75VDC when I put the charger on it. I don't drive it much, because of gas prices, but I have started it at that voltage and throw a jump pack into it, when I'm in a hurry. I do take care of my batteries and check electrolyte levels annually. Just my 2 cents......
But you would think the dealer had a battery saver to keep my settings. I had to set the clock and calendar plus a few other settings. Not a big deal but they should of done it.
Because the car would be trying to charge it constantly which uses more electricity. If fact, our last trip we got over 70 mpg, before it was less.
I suspect that would be negligible - but you've got a new battery - so should be right for 6 or so years now.
You would think but the Prius is so optimized and sensitive that wind, rain and cold effects the mileage. Back when I had a 2010 Prius and the battery failed, after replacement, the mileage increased. A bad battery is a constant drain as the computer thinks it needs charging but never tops off.
The system is designed to maintain a full charge status of ~12.5 volts, charging at a maximum ~14.1 volts. If the 12 volt battery cannot hold that charge, then the system continually tries to get it there via the hybrid battery, thus requiring the ice to run more frequently to charge the hybrid battery. The more frequent draw and charging of the hybrid battery increases the temperature of the hybrid battery, resulting in the system limiting the use of the EV mode to reduce the load on the hybrid battery to minimize its temperature, resulting in the ice running more frequently to move the vehicle, resulting in an increase in gasoline use. The health of that little 12 volt box is more critical than most of us realize.
