10 K Service, less than impressed! dealership misery!

Since you to vent either battery just in case, location never dictated the type. The OG VW Bug had the 12V under the rear seat, and that was long before AGM was invented.

Toyota likely went with AGM in the gen 2 & 3(no clue about the gen1) because the rear placement was more difficult to get to for maintenance, and AGM and gel batteries are maintenance free. They can also withstand deeper depth of discharging, which is a concern with the smaller battery chosen.

With under the hood in the gen4, there was easier access to the battery. There is also the big plus of lower cost. Seems they decided to just stay with it for the gen5. I don't recall any major issues in the gen4 with it to deter them.

Using a non-OEM brand won't void the warranty.

 

From the parts guy at my dealership:

The 'technically' OEM battery is something like $1000 USD to order. That's not because it's so good or special or anything, but because it's never meant to be used as a replacement battery. It's like the oil filter that comes on a new Toyota. They use one part number for consumables installed during production, and a different number when those parts need to be replaced in the destination market.

So the G5 comes from the factory with a Japanese-made GS Yuasa 345LN-MF rated for 45Ah and 285 CCA. If you want one of these new through Toyota, you're going to pay through the nose($1k USD) because it needs to be shipped from Japan.

The Toyota-specified replacement battery for a G5 in the US(and Canada?) is a USA or Mexican-made TrueStart H4(00544-H4052-470) rated for 470 CCA. Looks like the base US MSRP for this battery for Toyota is $206.00. Normally I say to search around for a dealership with the lowest price, but that doesn't really work with batteries. Most dealerships either require you to pick it up yourself, or will maybe deliver within a 15mi radius. So you're kinda stuck with whatever markup your local dealerships want to charge.

Option 3 is to just find an H4* sized battery with a vent tube port on the side. My local Walmart has one for about $160, although most other stores are right around the Toyota price.


*Matching Size Codes
DIN: H4
EN: LN1
BCI: 140R

 

If I had my battery tested twice, and it passed, what have I to gain by changing the battery?
Three times, actually, by an independent shop.

 

Nothing, but that doesn't mean it will void your warranty.

 

if it really is flooded lead/acid, it sounds like toyota is just trying to reduce costs

 

Of course. Can't think of any other reason.
Besides cost, AGM is a better battery. It just isn't required when a battery is placed in the cabin.

 

Exactly! The problem wasn’t your battery, so changing it is just responding to the reoccurring fear mongering that pops up here every so often concerning the 12 volt batteries in Priuses.

AGM is not necessarily a “better” battery. It has its advantages in certain situations but not all situations.

Sure! They had to engineer and test a vent system to use the lead acid battery in the Gen 5, but by your reasoning, that’s cheaper than simply buying a AGM battery from an established manufacturer that is ALREADY producing one for the Gen 3’s and early Gen 4’s. Remind me never to ask you for financial advice!

 

Good grief, @bisco.

Dennis Williams
Is this a [sic] AGM battery?

GS Yuasa HKG
Dennis Williams—Thank you for the question. The 345LN1-MF is a calcium base superior MF battery enabled by the patented double lid structure. It employs a central degassing structure and therefore can be used in vehicles in which battery is installed in the cabin or in the engine compartment. It is not a [sic] AGM battery.
​

GS Yuasa | Facebook

 

I posted clearer pictures above.

 

I'd feel like a total moron for changing a battery that has been tested OK 3 times.
I have connected my car to my home wi-fi in hopes that it might be easier on my battery drain.

 

Who knows why they have chosen a calcium battery instead of an AGM battery. We know that some flooded-cell batteries perform better than some AGM batteries and vice versa.

I have never had any problem with this battery in my 2021 Prius Prime Limited. I never trickle-charge it. I even left it undriven for six weeks in hot weather with a full active Toyota Connected Services subscription. Some others have had problems. It is more of an issue with how the car is used than the battery itself. Would an AGM battery solve the issue they had? Probably not.

As an aftermarket choice, I would go with the Walmart EverStart Maxx 140R, as it has a larger capacity than the OEM GS Yuasa but it is of identical size. It is of high quality and made in Korea. It has the same central venting system with two holes on the two sides with a red plug in one of them as the OEM GS Yuasa.

Note that the original 345LN1-MF did not have central, exhaustible venting. They changed it to central venting in Gen 5 but did not change the model number.

https://www.gs-yuasa.com/webdata/img/gs160315422530/pdf_gs_160304201730.pdf

And GS Yuasa is not the only company who makes the 345LN1-MF calcium battery for Toyota. Here is a centrally vented one made by the Turkish company Mutlu Akü.

TOYOTA MUTLU BATTERY 12V 45Ah 260A 345LN1MF X00 | eBay

 

They would have to engineer a vent line for an AGM. Just like they did for the gen2's AGM.

 

Same here with our ‘22 battery: I test it every 6 months when I change the oil, and occasionally in between if it’s been extremely cold. Haven’t needed to put a battery tender on it and it still tests like new including internal resistance numbers. Just turned over 7000 miles in 26 1/2 months, with only 77 miles put on it in the last 14 days (pretty much our normal). Started testing it shortly after buying the car in response to the “Chicken Littles” here on PC claiming such low usage would cause “the sky to fall”. Still waiting for it, and the hybrid battery is doing fine and gas mileage is staying consistent.

If this is true, someone forgot to tell Toyota. You’ve apparently had the opportunity to look at your battery several times lately (based on your posts) so tell us, does yours have an AGM? That would certainly put an end to this ridiculous round robin discussion (one would think anyway). Or perhaps there’s another issue here?

 

The link he posted is for Gen 2 and Gen 3 Priuses, which had AGM batteries.

 

Obviously you are implying that all the dealers are lying. I'd say there's an issue.

 

Below the picture of a 2G and 3G Prius, which did have AGM batteries... Do you think it's possible that text doesn't cover 4G and 5G?

The page is definitely older than the 5G - it was first archived in October 2022.

Went to find where this was last discussed - here it is. And there's a link there to earlier discussion too.

And this explains a dimly recalled mystery - you said there you'd "confirmed online" that it was AGM. You didn't answer what you'd found then, but now I know it was from that pre-5G article showing pictures of the 2G and 3G.

I'd agree we still haven't got a 100% definitive answer, but evidence is pointing to not AGM - we had a definite statement from manufacturer (GS Yuasa) about the 4G battery that it's not AGM and is suitable for in-cabin use, and the 5G battery appears to be a member of that family with the lid vents removed.

On the "it's AGM" side we have an article predating the 5G, your dealer who's not very good with batteries, and confused people in this thread who are just making assumptions. Yes, the 2G and 3G had AGM batteries, and that would explain all the assumptions that the 4G and 5G do. But there's no evidence for it - quite the contrary.

 

It has the same model number as the Gen 4 battery.

It says "add distilled water" on the label of the Gen 5 battery. You can't add water to an AGM battery.

The vents have not been removed. A central-vent lid has been installed on them. You can still remove it to add distilled water into each flooded cell.

Interestingly, the AC Delco EN LN1 AGM battery also has a central venting system, making it suitable for trunk installation. You can see the vent hole on the side and a small circular red plug attached to the red cap for the positive terminal to plug the unused vent hole sealed. It has a capacity of 50 Ah, and it is made in Germany; so, it looks like it is of good quality. However, since the battery sensor assumes that it is a flooded-cell battery, I wouldn't use an AGM battery in a Gen 4 or Gen 5. It may result in unexpected behavior due to different voltage-vs.-SOC etc. characteristics.

ACDelco EN LN1 AGM battery

 

Weren’t people prying off the caps of gen 2 batteries and adding water for longevity?

 

No, I am NOT implying that all the dealers are lying: I am pointing out that you are misinformed (no offense intended).
All that aside, is there a reason you aren’t taking a look (and perhaps a picture of) at your battery to answer the question of the battery type?