I got my oil changed yesterday and the tech informed me my battery should be replaced. I thought 12.4V was okay? Maybe the other values are the reason?
It's good; this car will start all the way down to 11VDC. Check the electrolyte levels and recharge if needed. If it's going to fail, it'll probably do it on a cold winter morning. You can use a cheap jump pack to get it started. If your nervous about it, replace it. I routinely had batteries last me at least 10 years, sealed batteries - not so much. I believe your 2016 has a lead acid battery under the hood, drivers side. Electrolyte access ports using a nickle or quarter to unscrew.
Dealer battery tests measure the "starting amps" which is the maximum current that the battery can deliver. It is an indication of battery health, but has little relevance for a Prius. We do not use the 12v battery to spin start the engine. Our 12v battery just needs to run a couple of pumps and initialize the Prius electronics which is a much lower current than starting a non-hybrid car. My 2020 Prius battery is 5 years old and the dealer has flagged it for replacement for 2 years. It still reliably starts my Prius and I will replace it when the resting voltage falls below 12v and /ordrops more than a volt under load (headlights on). JeffD
According to his picture, it's still outputting >375CCA - more than enough to do it's job. The highest draw on that battery is the ABS and Evap test routines; everything else runs with the DC-DC converter turned ON - unless you kill it by leaving it in ACC mode.
Thank you so much, guys. The battery was installed on 12/2021 and I've never had it draw all the way down, so I figured it was still relatively healthy. My plan is to replace it regardless on 12/2026 -- all I ask is that the battery stays alive for five years!
The battery should last longer than that; if properly maintained. I've had to put mine on a charger about once a year. I check my battery monthly and found it down to 11.75VDC. Whenever I find it below 12VDC, I check electrolytes and put it on a charger. It's never failed to start when I wanted it to.
I took my Gen 3 home from the showroom with a bad battery. I found out when I used ACC for testing, and it only lasted about 10 minutes before going dead. I called the dealer, they tested it, and told me that I was getting a new battery. What I think caused it to fail was that it had been sitting in their showroom for several months. The hybrid charger was plugged in, but on the gen 3, it does not maintain the 12V battery. Customers and salespeople turning on the system, and likely forgetting to shut it off, required it to be boosted many times. This eventually degraded the battery.
can you post a picture of the top of this battery. The 378 CCA value would be good, for a 3rd gen, stock AGM. Stock 4th gen battery is conventional, flooded-acid battery, perhaps with similar CCA spec. Your replacement is possibly the same, or compatible aftermarket option. With similar CCA spec, or perhaps higher. the criteria for replacement is typically CCA dropping lower than spec. While the battery is not called upon to “crank”, measured CCA spec is still a good indicator of the battery’s viability. say for example the replacement battery has a CCA spec of 450, then measured 378 would indicate a deteriorating battery.
Looks like this is a 480 CCA battery. I also ran the quick diagnostic check and the battery is at 11.8V, though I must admit it took me about five minutes to figure out how to get into the diag mode! So is a loss of 100 CCA troubling enough for me to replace this? I feel bad that I cheaped out and didn't get the AGM Platinum.
Yeah the battery you've got in there is rated 480 CCA, and getting a measurement of 378 doesn't bode good. The best way to measure voltage is with the car OFF, with a digital multimeter, or a battery assesment tool like your first pic. The car's displays require the car to be on, which will likely drop the voltage. Too: voltage is sketchy indicator, measured CCA is more significant. At-rest voltage can bounce around a lot, depending on previous driving, recent charging session, etcetera. AGM is not that relevant, Toyota used it primarily due to previous gen batteries being inside the cabin, instead of under the hood. I'd research what the stock battery was, get that or similar spec aftermarket.
Now that you can check the battery with the diagnosic, Turn on the head lights and see how far the voltage drops. If it drops more than about 0.5 volts, you need to fix the situation. Your battery may just need to be charged. Our Prii have a very slow charging mechanism so if you normally drive short trips, the battery never gets fully charged. This is bad for lead acid batteries as the battery plates develop a layer of lead sulfate crystals (lowering the CCA). A desulfating battery Minder (AKA Battery Maintainer) can fix this problem as long as the battery is not too far gone as well as top off the charge level. JeffD
Thank you guys -- OK, ran the second test. When I went back out to the car, the voltage was down to 11.6. I turned the headlights on. It went down to 11.5. Waited a minute, and ran the test again, and the results were the same -- 11.6 to 11.5. What does it mean if it only drops 0.1V? Through Advanced Auto Parts/Autozone, a new AGM 570CCA battery will run me about $300. However, I see on Amazon two batteries that'll fit: 1) UPLUS BCI Group 140R Car Battery, AGM-L50-UP Maintenance Free 12V 50Ah Premium AGM Batteries H4 LN1 Automotive Battery, 570CCA, 80RC 2) Marxon Group 140R Car Battery 12v 50AH 570CCA H4 AGM Batteries Maintenance Free Automotive Start Stop Replacement LN1 Battery for Audi BMW Volkswagen Toyota Chevrolet They're half price -- why are they so much cheaper? Even I, a non-gearhead, can replace a 12v-- I did so a few times for my Gen2 Prius, which was less convenient since the battery was in the back. Are these Amazon batteries worth their salt? Searching for these on the site seems like they work OK: Third day with new car, dead 12V battery, second day in a row | Page 12 | PriusChat But that post mentions vent holes and needing to charge the battery with a specialize charger...? I remember there being a vent tube out for the Gen2...
Exhorbitantly high CCA is not needed, and typically comes at the expense of amp hours. Are you looking at this AutoZone page: Car Battery - The Best Car Batteries at the Right Price Something's haywire with the cheapest ones description though: title says 470 CCA, while "Notes:" says signif less. BTW: Gen 4 battery's in the engine bay, so no need for AGM or vent tube.
A maintenance charger is inexpensive insurance for your battery. There are many models. One that does desulfation for about $70 is: Amazon.com: NOCO GENIUS5: 5A 6V/12V Smart Battery Charger – Automatic Maintainer, Trickle Charger & Desulfator with Overcharge Protection & Temperature Compensation – For Lead-Acid & Lithium Batteries : Automotive JeffD
That's a sealed unit battery, so they're going to 'burn-out' in and around the end of the warranty period. That's why I prefer the accessible flood lead acid ones. Have you tired putting it on a battery charger for a bit? May be able to get a few more years out of it. I believe your only going to pull around 50A to engage relays and while the car is running it's self diagnostics - so you still got plenty of 'head-space' to work with. Once those relays are engaged, your traction battery becomes the primary source of the cars power. If you are going to replace it; I'd check your local warehouse stores - Sam's Club, Costco, BJ's. They usually have better prices and warranties. If it was me; I look for another accessible flooded lead acid battery - I'm still on my original OEM.
Another good investment is an automotive battery tester, sim in function to one you show in the initial post. You enter your battery type, the CCA spec, run the test and it'll give results and usually a verdict as well. If I was shopping I'd probably get Solar BA9. I'm used to that brand, currently have the BA5
Get a battery monitor like Ancel B200, about $24 on Amazon. Keeps track in real time, and stores the data for up to 5 days on a graph. You will know when to charge manually and what your car is doing with charging the battery. Both voltage and state of charge. For charger I recommend Walmart Everstart waterproof, about $40. I left mine attached, ran over it on pavement then backed up and ran over it again. No damage. Simple to use just plug in, no buttons to go bad.
