Third day with new car, dead 12V battery, second day in a row :(

Now, that is a lot better.

I went through the checkout to see the shipping charges, and they said that this item was not shippable, probably because it is hazardous material. So, you can't get it online at a discounted price.

Moreover, it is a standard battery. It is not an enhanced flooded-cell battery (EFB). Therefore, it is no different than any DIN H4 battery you could buy at an auto store. It is made by Varta as well as Exide if not more OEM manufacturers.

Car Battery 12V 51Ah/52Ah Škoda 000915089C

Batería Economy ‘51Ah-12V’ ORIGINAL VW SEAT SKODA AUDI, 000915105DC 000915089C | Tienda de recambios wagenparts.com

Given that it is neither EFB nor AGM and I can't get a discount on it because it is not shippable, I will pass. Why deal with a Volkswagen dealer to get a standard DIN H4 battery you can get at every store? Besides, you won't see what you will be getting when you place the special, unreturnable order at the Volkswagen dealer. It is not to mention that it would look odd to have a Volkswagen-labeled OEM battery in a Toyota. People might think that you got it at a junkyard when you sell your car.

As I said, I am planning to get an ACDelco LN1 AGM from RockAuto.

 

Ok, you’re not arguing? I put the part number on the post. I still don’t know what all this outrage is about. I didn’t make anything up. Do whatever you want. I will probably call an Audi or VW local dealer if I need a battery just to see, but it will be at list price or more the way these guys are here. Also a Chevy dealer to see about a Delco. Maybe some other makes. Since I have a battery monitor, my battery isn’t going to be going low if I have any say about it.

 

I don't know what outrage you are talking about. You made incomplete/inaccurate claims, and I asked for more information. The price ($72) you posted didn't exist, and they are not available to ship even at higher discounted prices @Trollbait kindly quoted because it is hazardous material. We have been talking about batteries, but you seem to easily get offended and lash about instead of exchanging information.

 

Good choice on the Delco in my opinion. Seems like an upgrade from the Walmart. No love for the True Start I guess?

 

Toyota TrueStart is also a standard flooded battery, not an enhanced flooded-cell battery (EFB). It is not to mention that it is probably expensive. So, I want to upgrade to an AGM battery. An EFB doesn't seem to exist in the EN LN1 size in the US aftermarket. However, the newer Volkswagen OEM EN LN1 batteries could be EFBs, but you would have to take a chance on whether they are and deal with the Volkswagen dealers. Nevertheless, an AGM battery is probably a better choice for a Prius than an EFB anyway.

 

The Turquoise Jewel's battery seems to be running at about 53% capacity (12.10 V open circuit) since the full drain in August. I don't know whether the full drain caused the capacity degradation or the capacity degradation caused the full drain in a month or less of idling. The car is a month short of four years since the manufacture now.

I reduced the contestants to three:

EverStart Maxx 140R standard flooded-cell (Walmart): $159.84 + $14.00 core − $14.00 core return
ACDelco LN1 AGM (RockAuto): $135.79 + $12.00 core + $11.99 shipping − $6.79 coupon − $10 AutoZone gift card for core return
Uplus LN1 AGM (Amazon): $132.99 + $0 core + $0 shipping − $10 AutoZone gift card for core return

Uplus seems to be a really good company using the latest technology; so, I decided to go with Uplus. It was also by far the cheapest.

I will update on how the Uplus LN1 AGM works on a Prius.

Final thoughts: Flooded-cell batteries don't seem to work well on Priuses, and they seem to require AGM batteries. However, Toyota has downgraded to flooded-cell batteries in Gen 4/Gen 5 because they wanted to reduce the weight of the car by about 5 lb (AGM batteries are heavier) and reduce the cost of the car (by about $100?) Perhaps they will skip the AGM technology in Gen 6 and go with an LFP 12-V battery.

Uplus LN1 AGM battery on Amazon

 

AGM battery on your Turquoize Jewel ......very interested to know how this works out .

 

Too bad you don’t get a battery monitor thing to check things out before and after. I would be interested to see how the agm operates compared to flooded cell. If any difference. I replaced a 2009 Camry hybrid 12 volt agm last year, and it had a date code from 2008, original Panasonic.
Mentioned before, but the battery lawn mower in family I bought new in 2009 uses three 12 volt agm’s. They are still doing fine. I can’t even believe it, and they are made in China.

 

Yes, and I looked at the plot you posted. It seems to charge at 13.4 V; so, it should be good to charge an AGM battery. So, the charging system and battery sensor do not seem to care whether is flooded-cell or AGM. In fact, AGM would probably work better than flooded-cell, as the internal resistance is lower, it charges faster with less energy loss, etc. I won't bother with a battery monitor, but I will measure the battery voltage to see if it stays charged at about 12.89 V open circuit, which is about 100% SOC for an AGM battery.

I am guessing the only downside of an AGM battery will be that it is heavier by about 5 lb in this case.

Incidentally, the battery measured 12.30 V open circuit today, which is 71% SOC. So, perhaps replacement is not needed much, but oh, well.

Okay. Who HASN’T had a 12-V-battery issue with their 2023–24 Prime? | Page 6 | PriusChat

 

@Mr.Vanvandenburg, from your experience with the battery monitor, has your Gen 4 Prius Prime regularly charged the flooded-cell battery to about 12.64 V open circuit, rested, which is 100% SOC, or has it often charged it to a lower SOC and left it a lower SOC?

 

I really don’t know, but it varies. I still charge manually often. Since putting car in park at long stops it has kept the battery up a little better. I wonder if agm “ accepts charge” better will have any effects. The uplus battery site says made to accept charge well.
The car doesn’t charge below 13 volts. As graphs show very little charging is going on. Whether this is normal or not almost requires another person using a battery monitor. Right side of graph battery was manually charged with a cheap little .8 amp charger.
In any case I am a candidate for the tv commercial poking fun at seniors occupied with the mundane.

 

I got my 2024 Prius Prime a week ago and had my first dead battery. I went out last night to a dead battery. I had left the charge cable plugged in. IMHO, this is a recall issue. Having been a programmer for over 50 years I can say that the software that runs the car leaves a lot to be desired. Why, when plugged in and you have ‘unlimited’ power, does the system not trickle charge the 12v battery? To have the battery die because the car was plugged in for 24 hours is a safety issue.
I called Toyota Roadside assistance, which contract out to AAA in Southern California, and there were no trucks available to provide a jump. I Southern California! Not only that but Toyota marked the issue as closed even though no service was provided. When I called back they said that they can’t leave issues open.
My window was down when the battery died and now it doesn’t know it’s state and keeps warning me the window is down when it’s not.

 

You put your car in park at red lights??

You don't seem to drive your car. How old is your battery?

 

Move to LA from OC. AAA arrived in half an hour when I called.

Curiously, could you look at the production date of your Prius Prime? It can be found on the label on the inside of the driver's door frame. That way we can know how long it has been since the production.

There is no trickle-charge from the AC charger in Gen 4/Gen 5 Prius Prime. In fact, it drains the 12-V battery when plugged in and not charging.

Yes, the 12-V charging system has issues, as well as the OEM battery. When the three-year warranty is over and you need a replacement, get an AGM battery. I don't think a flooded-cell battery is able to withstand the demands of the 12-V system in Gen 4/Gen 5. Gen 2 and Gen 3 used to have AGM batteries.

The Uplus EN LN1/DIN H4/BCI 140R AGM battery I ordered from Amazon just shipped via FedEx from Azusa, LA County; so, I should receive it tomorrow. My OEM battery still has at least 70% capacity; so, hopefully I am not wasting my money.

 

Yes I drive my car, and do shift to park if the light is long, because that starts 12 volt charging. Since I have a battery monitor I can see when charging starts and stops. During most of my driving the 12 volt is not being charged. I made a usual 140 mile trip again, and the 12 v wasn’t charging most of the way. Too bad no one else has examples to compare with. Especially these Gen 5 people that are having 12 v problems. Maybe the issues could be resolved by the collective instead of just talking about them.

When I shift to park I put my foot on the brake and have hand near or on the shift knob. It engages quickly and I have no lag with traffic.

My battery is about 18 months old.

 

But how can you tell by looking at your battery monitor, which only measures the voltage, whether the battery is charging or not? Besides, you can't overcharge a battery, which could otherwise ruin it, especially if it is AGM.

As far as I can tell, your battery seems to be charging OK because you are seeing 12.64 V between drives.

 

It says battery ok or charging. The graph isn’t the main screen. Battery ok setting can be adjusted in settings. Battery ok means not charging, like I took this picture inside the house sitting in a chair and the phone picked up the battery, which is outside.
The graph is real time and moves along like a reading every second.

 

I wouldn't read too much into this. The monitor only measures the voltage and temperature, right? That means, it is making a lot of assumptions. 12.63 V should be 99%, not 88%, SOC for a flooded-cell battery; so, that is incorrect as well.

Moreover, what you are seeing when you put the car in park at a red light is likely a small change in the DC–DC-converter voltage arising from shifting gears making the battery monitor think that the battery started to charge, while nothing is really happening. So, if I were you, I wouldn't bother doing shifting to park at a red light, which could cause wear and tear to the transmission parts.

 

It's not a recall, but there is a related service bulletin. Copy of it here:

Parasitic battery drain? | Page 4 | PriusChat

It's a reflash of the charge control ECU, not a replacement part.

 

I had the dead aux battery issue on 14 August. Before that, no issues with my 2024 Prius Prime. I use a level 2 charger so the car typically fully charged 3-4 hours. That charge event I left the charge cable installed overnight. Day later car would not start and flashing lights on dash etc. used my jump starter per the owners manual and charged battery and it tested ok. No issues since but I remove the cable as soon as notification charging complete.

I had my 6 month service due so I advised the dealer service advisor of my issue. I provided a copy of the TSB along with details of what occurred and why I felt it was related to the charge cable being left installed. First I had to authorize a diag charge in case it was something I did. Wth…..

The diag summary :

car did not need to be jump started when tech got car. DUH….car started up just fine. Performed service and test and still started up just fine. Battery tested good. See print out stapled to RO.

From what I could determine, the tech was not made aware of the TSB or if he was, did not follow the work instructions.

In fact, Toyota has a troubleshooting procedure for aux battery is discharged. I paid $25 for 2 day access to the TIS. I do not believe that procedure was used on my car to investigate why my battery went flat that day. The service advisors give no credence to forum reports of other owners having dead aux battery reports.