12 v prime battery

A good question. I still have my original 12V in my 2020 Prime that I got in July 2019.

If it is anything like my previous Prius, Toyota had a monopoly on the replacement starter batteries. Probably dealer for me.

 

The 12V batteries on my 2018 and 2020 appear to be operating nominally... and from the looks of it, they'll hold in this state until I replace these cars with the upcoming generation.

NOTE: Both cars are equipped with a 12V battery maintainer.

 

It uses the same 12v as the 4th gen (2016-2022) hybrid prius. The one in my 2016 Prius made it about 5 years before needing to be replaced.

 

On-board chargers IIRC? NOCO Genius? Any current favourite?

I have a wall-mount charger, but keep thinking about onboard style, maybe in future. Two stumbling blocks:

1. limited room in engine bay
2. Short cable lengths on available chargers (can be remedied)

 

Hi Mendel

I just settled on the "Noco/Genious" brand purchased at Canadian Tire many years ago. At the time, I bought 2 of these since they fully supported a good number of different battery types & chemistries.

So far, these have served me very well without needing to replace a single 12V battery on any of my cars since then. I simply attach the unit to to lid of the fuse box with 4 nylon bolts, washers and nuts while making sure its water tight and vibration proof. Then I have the block heater cord share an extension with it that just sits capped in between the upper grill fins.

Once in a while, remember to plug it in overnight and see the mA go from 700+ to just 20. That'it.

 

Battery Tender Jr.

"The lightweight charger comes with a 12-foot output cord, fused alligator clips, and a fused ring terminal harness for hard-to-reach spaces. With the included Quick Disconnect Cables, you can connect and disconnect the charger in seconds."

 

You're right, life of OEM 12v battery depends. As far as replacement, Toyota's OEM replacement is competively priced with others in the market. Further, Toyota has an 84-month warranty, 24-month free replacement and 60-month proration in a simple two-tier priced plan.


Toyota Prius Prime Vehicle Battery - 00544H4052470 - Genuine Toyota Part

 

Our Prime still has the original battery from late 2016. It's doing fine. Every few months I connect the battery to a top quality 10 amp charger and give it a full charge which seems to lengthen the life. A check with a battery tester indicates that this battery remains good. The Toyota replacement battery costs less than a battery from NAPA and more than one from O'Reilly, and Toyota offers a better warranty. Summit offers an ACDelco AGM battery for $167 w/free shipping (this would be my choice.) Both the NAPA and O'Reilly batteries appear to be made by East Penn/DEKA.

 

Yeah that seems THE way to go, very crowded in there. If you sell the vehicle and have removed that charger, you could likely seal the holes with automotive hole plugs that look near-stock, avoid shelling out for a replacement cover.

 

I agree. I actually did the very same in my previous cars (Gen 2 & 3 lift-backs). This particular unit fits quite well on top of the fuse box with plenty of hood clearance left. When selling the cars, I just unlock & lift the fuse cover, remove the bolts and cover the bolt holes with automotive grade tape. Barely noticeable afterwards and then just move all the hardware to the new car.

Below is an older image of the very same unit on one of the Gen 3's. In this case, I simply connected the units's fused red wire to the usual booster contact inside the fuse box. Simple and "secure".

 

Unless the battery is abused (vehicle not seeing long trips regularly, sitting in the accessory or off mode with lights on etc.), it will last for a long time. I believe there are caps to add distilled water as well.

Any battery with the correct size (LN1/H4/140R) will be fine, as long as it has the 76-minute reserve capacity of the OEM battery or longer. Toyota TrueStart H4 sold at the dealer is of high quality. Either flooded cell or AGM is fine, neither necessarily being better, quality of either varying with the manufacturer or model.

 

Yes, the Yuasa OEM battery has caps to top up the electrolyte with distilled water. The caps have slots just the right size to fit a 100 yen coin; I use a quarter held in Vise-Grips to unscrew the caps. Once a year seems to be a good interval to check the level.

 

Charge before topping off the fluid level.

 

It is 65% charged.

Curious case of a 50% depth of discharge for a lead–acid battery | EcoSoch

 

Funny you should ask! Went to start my 2017 Prius Prime Plus yesterday morning (which up til now had never had a problem) and it wouldn't start, even though the traction battery was full, because the 12V battery was low(!) A voltmeter indicated 9.5 V which looks pretty bad for a 12V lead-acid. Well it has been six years, so I replaced it with "DieHard Gold Battery: H4 Group Size, 480 CCA, 600 CA, 96 Minute Reserve" from an auto parts store. I'm not sure if there's any more specific part number than that, at least it fit mechanically and the car ran OK, including starting the gas engine immediately when I turned on the front defrost. Had to reset the clock in the car (you'd think it could work off of GPS time, but no).
I noticed the battery was originally at 12.8V when I turned off the car yesterday, but this afternoon after just sitting in the garage maybe 15 hours, it's down to 12.4 V which is not a full resting voltage. Maybe the store didn't sell it fully charged, and the short drive home wasn't enough to charge it?
I disconnected the battery ground terminal and used a DMM meter to measure the DC draw from the car on the 12V battery, and (after a brief period of about 0.5 A) it flickers between 15 to 20 mA which is not that much, but that's way more than needed to just keep a clock running. Anyone know what's the 12V current draw in a Prius Prime Plus when parked and cold is supposed to be?

Note: I see the 12V battery does get charged from the traction battery while the car is parked with ignition on in EV mode in the "READY" state, as the battery went from +12.8V to +14.4 V when I did that.

 

The original 12v battery in our 2016 always rests at a voltage in the low 12's, and it continues to work fine. It does get driven just about every day.

 

Several modules continue to run. 20ma is fine. If the 12v battery discharges quickly at 20ma it has lost most of its capacity, which is different than the current state of charge. A good battery should hold up three weeks or longer and still function.