Back on topic I just installed an Everstart 121r from Walmart and it fit very well. I think it is .1 mm wider so was snug but okay. 600 cranking amps. My battery size guide said it is 1 inch taller then 140r but when I put Orem battery and 121r side by side height was identical.
I can assuredly tell you that the 12 volt in MY 2016 Two is not a conventional LA unit. It is specialized gel cell, and quite hard to get. I had to wait for a month for my second battery to be replaced under warranty. The battery is manufactured by Interstate for Toyota and is branded as a Toyota battery with an 84-month warranty (24-month replacement at no charge, thereafter prorated).
This? EverStart Maxx Lead Acid Automotive Battery, Group 121R - Walmart.com $120 for a 12V battery. That's more like it. I have to remember this info. Thanks.
Thanks for the reply. Dealers may be a reliable source of information about the availability (or lack of it) of the battery they have for sale as a Toyota service part (00544-H4052-470), but I’m afraid yours has misinformed you about its characteristics. The auxiliary (12 volt) battery in fourth-generation Prius and Prius Prime (Prius PHV) cars is a wet cell (“maintenance free”) lead-acid battery, not a gel cell or AGM, as used on older Prius models. It’s a standard, if not especially popular, size, but there are now readily available aftermarket equivalents. See my previous postings: 12V battery group size | Page 5 | PriusChat 12V battery group size | Page 9 | PriusChat Gen 4 12 Volt battery. | Page 4 | PriusChat Gen 4 12 Volt battery. | Page 5 | PriusChat
i wouldn't even trust them regarding availability. ask if you can go in the back room and browse around.
Warranty replacement. Toyota paid loaner until battery available. Not a high level of distrust on my part.
I've been monitoring my 12v aux battery since my 2016 was new, purchased on 5/31/16. I've noticed that unlike cars with conventional alternator charging, my 12v battery only reads in the range of 12.4 vdc—12.8 vdc when checked immediately after driving. I understand that the 12v battery is charged/maintained via a converter, which I assume is a step-down transformer supplied by the drive battery. My Prius has less than 7000 miles since new, the car is always garaged in southern CA with very moderate weather extremes and since the car is not driven regularly I've had a battery maintainer on it since new. It appears that the specific gravity of the electrolyte is a mite low under the circumstances. Also, my maintainer keeps the battery float voltage at 13.2 vdc and when I put a conventional ferroresonant automotive battery charger on it the voltage almost immediately goes to over 15 vdc with less than 1 amp of output current. I've had a wide range of experience with battery systems of all manner, both personally and professionally and this behavior is something that I've rarely ran into. With the Prius I can't tell how fast the battery is spinning the starter like I could on a conventional vehicle and I don't currently have a load tester. I want to have this system checked for any problems before the car goes off warranty next month. Does anyone have any specific information or suggestions in this regard that might be of help to me. Thanks in advance for any help.
Re "... I can't tell how fast the battery is spinning the starter ..." - that's because it doesn't spin the starter ever. No, it runs the various components like lights, door-locks, then when you press the POWER button, it fires the computers - which get the system going. When you press the accelerator, the car always starts using the Hybrid battery (EV Mode) - even if just for a fraction of a second (and in reverse only ever runs in EV Mode. If the Internal Combustion Engine (ICE) is needed, it's the Motor/Generator powered by the Hybrid system which starts the ICE. Meanwhile, the 12volt battery runs the engine ignition, water pump, wipers, lights, gauges, computers, window winders, power steering etc. This video might give you some idea of what's going on:
Solar BA5 is one electronic load tester on the market, relatively low priced, for DIY use. They have a new model, and there's several other brands.