Okay. Who HASN'T had a 12V battery issue with their 2023-24 Prime?

What do you use for a battery maintainer/charger?

 

$30. Noco

 

Okay… I have been looking at NOCO but they have the NOCO Genius Products that plug into an outlet and slowly charge and condition your battery and then they have the NOCO Boost Products that allow you to jump start an already dead battery while out on the road. I’m thinking I need a Boost to charge when away from a plugin source and I also need a small NOCO Genius device to maintain my battery while at home or near a commercial power source. Showing my lack of confidence here in Toyota and their 12 volt battery. So which one do you have? Boost or Genius?

 

i have this maintainer for when i'm away for awhile.

ref=asc_df_B07W46BX31

i should get a booster for emergencies, but i've been lazy

if i do get one, it will be cheap, because it doesn't need to spin the engine on a prius:

ref=asc_df_B08Z3B5VXR

 

I have the NOCO Genius 10 for keeping the 12v battery maintained and a motomaster booster pack (about the equivalent of the GB40).
I have the NOCO Genius 2 for my Bike but it's really not big enough to handle the car and I have a small solar panel for my lawn tractor.

 

I got my Prime XSE back in early January this year, and I can't recall any abnormal battery problems for about the first 2 months. When my battery began to go dead in less than 3 days, I had the dealer check it out. They said the battery was still within spec, so it won't be replaced under warranty. I asked what may be drawing it down, but they were vague and evasive about it. They told me that leaving the headlights in "auto" mode was probably draining power. A bit silly, as there is no "off" position on the light switch. They also unplugged all my 12V accessories, (dash cam, cell phone charger and mobile booster) and left it all on the floor. Not one of those things draw a single milliamp of power when the car is off.

Less than impressed with my local dealer, I sought a second opinion from another dealer. The also told me that the battery tested OK, and had no answers about the parasitic drain. but at least they didn't give me any stupid excuses like the first one had. They did suggest installing a battery maintainer, which I did, which was a bandaid solution until I could get it resolved. The NOCO battery maintainer had 3 settings; "lead-acid flooded, AGM and Lithium." I phoned two dealers and they both said, "AGM" I tried to it verify online, and most of what I found also said, "AGM," but I later found this to be wrong; it's a flooded lead-acid cell.
I considered installing another battery, which on second thought, made no sense. The problem was obviously excessive current draw. Since I was incapable of finding the source of the drain, and two dealers also failed, I consulted this forum and other sources for possible answers.

Then, yesterday, my phone app wasn't connecting properly to my car. I called Toyota Support, and they reported that my wireless network module was offline, and I should make an appointment with a dealer. I am off to a third dealer today, and they assure me that they know how to troubleshoot the problem. Hopefully, I'll have an answer later today.

 

Anything like that should work. I find it doesn't take much power to start up the system. Once that happens, the DC converter kicks in and starts charging the battery from the hybrid system.

Still, I wonder why there couldn't be some sort of interconnect, so that the system could be started from a tiny portion of the power stored in the hybrid battery. Has anyone done a mod where you could activate the DC-DC converter to activate the system when the 12V battery is dead?

 

NOCO is a good choice. I use a NOCO 2. It doesn't give you any surprises like other maintainers which can turn themselves off for no apparent reason. It's a nasty surprise when you go to start your car and the battery is dead, even though the maintainer was plugged in.

 

I think it could be done, but they probably don’t want to spend the money

 

They would definitely sell fewer replacement batteries.

I've always admired Toyota's commitment to quality. Toyotas are known to have the best vehicle longevity for many years running.
However, when it comes to dealer shenanigans, they seem to have a very hands-off attitude. I think this hurts their brand as much as would shortened vehicle longevity.

 

I'm currently waiting at the 3rd dealership, and the service manager just talked to me. He said the battery was out of spec, and they will be replacing it under warranty. Interesting how the first two dealers tested the same battery and declared it in-spec.

At any rate, I'm keen to find out how they made out testing the wireless networking module. He did say that they usually work fine once they are reset. At any rate, I'll know more when they finish working on it.

 

All done at the dealer. They installed a new battery under warranty, and I will test for draw when I get home. I'm hoping the reset of everything solves my problems.

 

dealers have a large lobby, manufacturers hands are tied. additionally, they rate dealers by car sales, not customer satisfaction

 

Going out of town for a couple weeks, what's my best bet? Just disconnect the negative battery terminal or buy a trickle charger and hook it up? I'm assuming the trickle charger needs to be hooked up directly to the battery and not the remote jump points under the hood.

 

Sadly, I think that's true. I just wish that they would crack down on the dishonest dealers more.

I'd get a battery maintainer instead of a trickle charger. I destroyed a battery with a trickle charger.
Unhooking the battery can result in a real pain in setting up your profile again.
Today, I spent 45 minutes with dealer getting set up after they reset everything.

 

When you say trickle charger, I think what you actually mean is a battery maintainer. There's an important difference between the two. A battery maintainer is "smart" where a trickle charger is "dumb". A maintainer can sense the state of the battery and stop charging when it's full. A trickle charger will just keep charging forever, eventually killing the battery. More than likely, anything you buy nowadays will be a maintainer, but it's still good to know the difference between the terms in case you go to an autoparts store and ask for the wrong thing and the (lazy or unknowledgeable) clerk gives you exactly what you ask for instead of what you really need.

As for your situation, you've got four choices; all come with pros and cons.

1a. Don't do anything. Use this as a test case and see what happens. Will your particular car hold a charge over a couple weeks? At least this way you'll have an answer. And it doesn't cost you any money. If you come home and the battery is dead, call Toyota Assistance for a jump. Might be an inconvenience, but you'll gain knowledge and not be out any money.

1b. Don't do anything to the battery, but have a jump pack waiting in the car. You gain the same knowledge as above, but you don't have to wait for a jump if the battery does end up dead. You do have to spend money on the jump pack, but many(including myself) consider that a piece of essential emergency equipment anyway.

2. Disconnect the battery. It's free and you're sure to have a functional car when you return. Flip side is that you'll probably lose a ton of settings and it's a PITA to reconnect the battery if you have to close and latch the rear hatch while you're gone(you'll have to crawl over the folded rear seats to get back to the battery or to reach the emergency hatch release).

3. Get a battery maintainer. You'll have to spend money, but you'll have maximum peace of mind. Beyond the expense, the other downside is that you'll never know if the battery really can go a couple weeks without draining. If you go this route, hook it up directly to the battery and just have the cord come out the hatch. If you're careful, I think you'll still be able to close and latch the hatch as long as the power cord is thin enough.


There's no right or wrong answer. Pick whichever best fits your wants and needs.

 

Unfortunately, not before you tormented everyone in the other two threads on the four obvious points we made and got one of the threads locked by the administrator. These were those four points you disputed:

• You should have the Toyota dealer resolve the battery problem because it is still under warranty.
• Gen 4 and Gen 5 Prius and Prius Prime don't have an AGM battery. It explicitly says "Add distilled water" on the label. The OEM also says it is flooded-cell.
• You obviously had a bad battery because no parasitic drain can drain a charged battery in two hours. Your battery was simply not holding charge.
• The battery sensor is obviously a separate component. The battery itself is a generic EN LN1/BCI 140R/DIN H4 battery (required to be centrally vented in Gen 5).

I am guessing that the Toyota dealer did not have the OEM GS Yuasa EN LN1 in stock but installed a Toyota TrueStart DIN H4 instead. Was that the case?

As for the reason why your battery bit the dust, we may never know. As I've been telling others, it is important to keep these Gen 4 and Gen 5 batteries fully charged by frequent long trips, avoid keeping the car plugged in, and avoid sitting in the car with the car not in the READY mode. If your battery sees prolonged periods of a low charge, it could die quickly. Especially if the battery already comes with a low charge when you purchase the car and you never manage to fully charge it, it could permanently fail in no time.

 

I see you're cruising to get this thread locked also. I wanted to share my experiences in order to help others who may be experiencing the same problems. I don't know what you could possibly have to gain with all the trash above. How is that helpful? It should be obvious by now that you are a negative influence in this forum.

 

It was you who drove everyone in the other two threads nuts, not me. We appreciated you sharing your experience, but when we shared our knowledge, you kept either ignoring us or lashing at us that we were giving you false information and only you had the right answers. You kept doing that relentlessly and in a very improper manner. And every time it was proven that you were wrong, you showed no remorse and doubled down, just like now. It wasn't even me who called you names in those threads.

 

Today, the dealer thought resetting the wireless component of the system might resolve the parasitic drain. The battery replacement was basically an act of good will. Two other dealers were unwilling to replace it. At any rate, I don't presume to know what was the cause of the rapid battery drain was until after I complete my testing.

This particular problem has occurred for many new Prius owners, and I was hoping that relating my experiences might help them. I'll leave it others to form their own conclusions.