Gen 2 Prius 12V Battery - Yuasa (Original Supplied) Vs. Bosch S4

[sushd]

Following a sudden -

"There is a problem with the transmission "P" lock mechanism. Park your car on a flat surface and fully apply the parking break."

- error message today morning, and subsequent checkup by AA mechanic, looks like it may be finally time to replace the 12V Battery in the (09 plate) Gen 2 Prius T-Spirit. The guy said the current Battery is the same that Toyota supplies and since there is no record of Battery change in the Toyota work history sheet for the car, it looks like the original battery has lasted 68 months!

I have checked and the battery in there currently is a GS Yuasa HJ-S46B24R with the following specs. (taken from www.yuasa.co.uk):

Having seen a few posts recommending Bosch S4 155 as a DIY alternative to £95 Toyota-does-it-for-you, I found that there are two types of S4 155 models available in the market, and am unsure which one to buy or if both are suitable:

Bosch S4 155 Option 1:

Bosch S4 155 Option 2:

Correct me if I am wrong but I believe that it is the second one (Bosch S4 155 Option 2) that I should buy for the Prius!

I believe that in the Prius, the way the battery is installed, the +ve terminal is on the left side and towards the inside of the car (closer to you). But in the Bosch S4 155 Option 1 (as shown above), the +ve terminal is to the right and if I were to install it with the +ve terminal on the left then the +ve terminal will be towards the outside the car (away from you) and that might cause issues with the way the battery is secured.

Can anyone who has installed Bosch S4 155 in a Prius correct me or confirm otherwise, please?

TIA.

[Joseph D]

Correct me if I am wrong but I believe that it is the second one (Bosch S4 155 Option 2) that I should buy for the Prius!

I believe that in the Prius, the way the battery is installed, the +ve terminal is on the left side and towards the inside of the car (closer to you). But in the Bosch S4 155 Option 1 (as shown above), the +ve terminal is to the right and if I were to install it with the +ve terminal on the left then the +ve terminal will be towards the outside the car (away from you) and that might cause issues with the way the battery is secured.

Can anyone who has installed Bosch S4 155 in a Prius correct me or confirm otherwise, please?

Yes, you are correct, option 2 with the +ve terminal on the left with the terminals closest to you.

[timberwolf]

Agree with Joseph D. Note the battery's vent port is too small for Toyota's vent tube connector.

[PeteB]

... looks like it is finally time to replace the 12V battery in the (09 plate) Gen 2 Prius. The guy said the current battery is the same that Toyota supplies and since there is no record of battery change in the Toyota work history sheet for the car, it looks like the original battery has lasted 68 months! ...

that's entirely feasible if it's never been abused (allowed to go and stay flat). My last Gen 1 Prius was sold with a 9 year old 12V Battery still in fairly good shape (although that was 3½ years ago - I'd be astonished if it was still going now).

[timberwolf]

I think the word abused is misleading. Lead-acid batteries do not like being left in a not fully charged state for long periods. I believe lead-acid technology is no longer a good fit for modern cars because of the large parasitic standby drain placed on the Battery by modern electronic gadgets. If you don't drive the car everyday to recharge the 12V Battery, the life span of the 12V Battery will be significantly reduced.

[Cyker]

For the Prius and other HSD's, they would deffo benefit from a change to a long-run NiMH or LiIon Battery (The sort that hold their charge over a long term; Normal ones, esp. LiIon, have very high self-discharge rates). TBH I'm surprised they haven't.

Then again I'm not sure why they even have a 12v Battery when everything could be run off the traction Battery!

For normal cars, LiIon can't supply enough amperage to crank the starter motor without being severely damaged (NiMH might, not sure there). This is why you need hundreds of LiIon batteries in parallel to power anything that needs lots of amps.

The other issue is both NiMH and LiIon prefer to be partially charged; If left at 100% charge for a long time they tend to deteriorate faster so some extra battery management would need to be implemented rather than just feeding it from the alternator.

[sushd]

Agree with Joseph D. Note the battery's vent port is too small for Toyota's vent tube connector.

Yup, came across quite a few posts mentioning the fact.

[sushd]

... looks like it is finally time to replace the 12V battery in the (09 plate) Gen 2 Prius. The guy said the current battery is the same that Toyota supplies and since there is no record of battery change in the Toyota work history sheet for the car, it looks like the original battery has lasted 68 months! ...

that's entirely feasible if it's never been abused (allowed to go and stay flat). My last Gen 1 Prius was sold with a 9 year old 12V Battery still in fairly good shape (although that was 3½ years ago - I'd be astonished if it was still going now).

Wow, 9 Years - That's something! :o

[sushd]

Yuasa claims that the HJ - S46B24R is a "AGM" Battery, and refers to it as "Prius AGM".

On the other hand, Bosch S4 155 doesn't appear to be (well, Bosch doesn't advertise it as such or claim it to be). Perhaps a Gel Cell Battery (?)

Have recently purchased Toyota's 2 year extended warranty, so need to make sure from the dealer that replacing a "genuine Toyota auxiliary battery" with Bosch S4 155 will not void / affect the warranty! It should not .... but you never know what Mr T says!

[PeteB]

...Then again I'm not sure why they even have a 12v battery when everything could be run off the traction battery!...

It's certainly annoying to have a flat 12v Battery and be unable to start the car knowing there's loads of electricity in the HV Battery!

[Joseph D]

Yuasa claims that the HJ - S46B24R is a "AGM" battery, and refers to it as "Prius AGM".

On the other hand, Bosch S4 155 doesn't appear to be (well, Bosch doesn't advertise it as such or claim it to be). Perhaps a Gel Cell battery (?)

It is more than a claim, it is an AGM Battery. The Bosch S4 is basically a flood lead/acid in the B24 footprint. As such it is a drop in replacement.

Have recently purchased Toyota's 2 year extended warranty, so need to make sure from the dealer that replacing a "genuine Toyota auxiliary battery" with Bosch S4 155 will not void / affect the warranty! It should not .... but you never know what Mr T says!

I would be surprised if it did invalidate the warranty, but you should be aware of the safety implications of having a flooded acid Battery in the passenger compartment. If your car is in a crash and hit in just the wrong way you could have sulphuric acid sprayed over your passengers.

[MEP's Yaris GS]

Then again I'm not sure why they even have a 12v battery when everything could be run off the traction battery!

Because its far easier and cheaper to replace a 12v Battery that has gone flat and been ruined when the sidelights have been left on for a week in the airport carpark than it is for the Traction Battery to be.

The idea of keeping the 12v unit is one which has been well thought out and has more advantages than it does disadvantages financially IMO.

[sushd]

Yuasa claims that the HJ - S46B24R is a "AGM" battery, and refers to it as "Prius AGM".

On the other hand, Bosch S4 155 doesn't appear to be (well, Bosch doesn't advertise it as such or claim it to be). Perhaps a Gel Cell battery (?)

It is more than a claim, it is an AGM Battery. The Bosch S4 is basically a flood lead/acid in the B24 footprint. As such it is a drop in replacement.

Perhaps I should have written "says" rather than "claim". The doubt arose when I saw it retails in UK @ £200+ and was wondering how Toyota manages it in £95 (including labour)! Guess that's how the manufacturer says - if you want this, go to the dealer!!!

Was going through the latest BCI battery replacement data book (for equipment manufactured in or imported to US) and it does state that the OE Battery supplied (in Gen 2) is indeed a AGM but it doesn't mandate that a replacement needs to be (AGM).

On the other hand, it does state a replacement in Gen 3 Prius must be a AGM.

Okay, so if I need to have a AGM fitted then there is no option but to go to Toyota because no aftermarket AGM is available in the UK (at least I could not find one) for under £95, or the other option is to "downgrade" to a flooded acid Battery like Bosch S4.

Aftermarket AGM battery for Gen 2 Prius:

Optima DS46B24R (8171-767)

Exide FP-AGM51JIS

[sushd]

Just received confirmation from the dealer that installing a aftermarket non-AGM 12V Battery in a Gen 2 Prius will not affect the extended warranty T&Cs in any way.

[MEP's Yaris GS]

Just received confirmation from the dealer that installing a aftermarket non-AGM 12V battery will not affect the extended warranty T&Cs in any way.

Even on a Gen 3?

[sushd]

Just received confirmation from the dealer that installing a aftermarket non-AGM 12V battery will not affect the extended warranty T&Cs in any way.

Even on a Gen 3?

Jonathan, I enquired only about Gen 2 Prius!

[MLW2233]

Replaced my GEN 2 with a Bosch S4 2 years ago and never looked back. Car starts first time often after 5-6 days of inactivity, and 'feels strong'. Toyota Battery £99 and 3 year guarantee. Bosch about £55 and 4 year guarantee!!!

It fits in the car easily. You will need to carefully 'shave' the Toyota vent pipe with a Stanley knife to make it about 1 millimetre or so slimmer, but it is easy.

Get the Bosch. That company know batteries and make good ones.

[sushd]

Michael,

I would love to ... install the Bosch S4 ... and save some money!

That said, my concern is how the S4 (cranking / starter) Battery will fare (as compared to the AGM deep-cycle battery) with short distance and infrequent use pattern.

The Prius does 2.5mile run morning and evening on weekdays, 25-30 mile single run on one of the weekend days and (no use on the other weekend day).

There are 6-8 occasions when it is not used for the entire week (when I travel for work).

Not used for 3-4 weeks once a year when we are on a long holiday (never had a problem starting the Prius upon returning with the original AGM Battery in the three years since we bought it).

[Grumpy Cabbie]

My Prius is still on the original 12v and sits for weeks at a time. I have looked after it in that I don't leave my lights on etc etc, but it is happy being left for 10 days at a time.

I'm sure it will need replacing soon as they generally only last about 5 years or so. Personally I'd be very wary having a flooded Battery in the back, especially on the drivers side rear. It really is crammed in in that top corner and just needs a OSR shunt on the motorway at even low speed to potentially shower the passenger compartment in acid. I'd rather pay the £50 extra to have original specification safety. An accident might never happen, but if it does! I had a work colleague who had his face melted by Battery acid (from a Ford Fiesta) in an heavy front end accident. That injury is there for life.

[sushd]

Six months on:

The original 12V Battery did not give any starting trouble since January but it wasn't holding charge (charged it fully for 72 hours using ctek -> ran diagnostics -> acc. mode -> defrost, lights. etc. on -> charge ~10V), so decided to replace it.

Installed a new Yuasa YBX5057 flooded Battery (£46 including VAT & delivery).

Used a 5mm-4mm straight hose reducer to connect the (original) vent plug to the vent hole of the Battery. Even a 4mm-4mm straight joiner would do the job with a bit of micropore tape applied on the battery end. Alternatively, one can use a 8mm-4mm elbow reducer to connect the hose (on the 8mm end) to the vent hole of the battery (with a bit of micropore tape applied on the 4mm end) and keep the original vent plug safe for use with Yuasa AGM battery in future.

Sealed the other vent hole (near the -ve terminal) with silicone sealant.

I don't know if it is the new battery or the weather or the tyres that I rotated on the same day or a combination of all these, but there is a definite improvement in MPG ...... me, happy bunny!!

[larry609]

Yuasa claims that the HJ - S46B24R is a "AGM" battery, and refers to it as "Prius AGM".

On the other hand, Bosch S4 155 doesn't appear to be (well, Bosch doesn't advertise it as such or claim it to be). Perhaps a Gel Cell battery (?)

Have recently purchased Toyota's 2 year extended warranty, so need to make sure from the dealer that replacing a "genuine Toyota auxiliary battery" with Bosch S4 155 will not void / affect the warranty! It should not .... but you never know what Mr T says!

I would think that everyone, by now, would know that the Magnuson-Moss Act REQUIRES the manufacturer (or whomever is warranying the product) to PROVE that your modifications caused the damage/malfunction/whatever. I modified my Prius Gen 2 electrical system and then, months later, had a problem with the MFD. (within warranty) Toyota tried to say that my modifying the system voided the warranty; my lawyers called their lawyers, had a 5 minute chat about the Act - and how Toyota already KNEW that they had no claim, and my MFD got replaced for free. https://en.wikipedia.org/wiki/Magnuson%E2%80%93Moss_Warranty_Act

[Devon Aygo]

Yuasa claims that the HJ - S46B24R is a "AGM" battery, and refers to it as "Prius AGM".

On the other hand, Bosch S4 155 doesn't appear to be (well, Bosch doesn't advertise it as such or claim it to be). Perhaps a Gel Cell battery (?)

Have recently purchased Toyota's 2 year extended warranty, so need to make sure from the dealer that replacing a "genuine Toyota auxiliary battery" with Bosch S4 155 will not void / affect the warranty! It should not .... but you never know what Mr T says!

I would think that everyone, by now, would know that the Magnuson-Moss Act REQUIRES the manufacturer (or whomever is warranying the product) to PROVE that your modifications caused the damage/malfunction/whatever. I modified my Prius Gen 2 electrical system and then, months later, had a problem with the MFD. (within warranty) Toyota tried to say that my modifying the system voided the warranty; my lawyers called their lawyers, had a 5 minute chat about the Act - and how Toyota already KNEW that they had no claim, and my MFD got replaced for free. https://en.wikipedia.org/wiki/Magnuson%E2%80%93Moss_Warranty_Act

The poster you have replied to lives in the UK the Act you refer to is law in the US and has no standing in the UK at all.

[larry609]

Yuasa claims that the HJ - S46B24R is a "AGM" battery, and refers to it as "Prius AGM".

On the other hand, Bosch S4 155 doesn't appear to be (well, Bosch doesn't advertise it as such or claim it to be). Perhaps a Gel Cell battery (?)

Have recently purchased Toyota's 2 year extended warranty, so need to make sure from the dealer that replacing a "genuine Toyota auxiliary battery" with Bosch S4 155 will not void / affect the warranty! It should not .... but you never know what Mr T says!

I would think that everyone, by now, would know that the Magnuson-Moss Act REQUIRES the manufacturer (or whomever is warranying the product) to PROVE that your modifications caused the damage/malfunction/whatever. I modified my Prius Gen 2 electrical system and then, months later, had a problem with the MFD. (within warranty) Toyota tried to say that my modifying the system voided the warranty; my lawyers called their lawyers, had a 5 minute chat about the Act - and how Toyota already KNEW that they had no claim, and my MFD got replaced for free. https://en.wikipedia.org/wiki/Magnuson%E2%80%93Moss_Warranty_Act

The poster you have replied to lives in the UK the Act you refer to is law in the US and has no standing in the UK at all.

I didn't notice that - my bad.

[YarisHybrid2016]

What type of Battery is in the Gen 3 Yaris Hybrid?

[Devon Aygo]

What type of battery is in the Gen 3 Yaris Hybrid?

http://www.yuasa.co.uk/batteries/automotive/yuasa-auxilliary-backup-specialist-batteries/hj-s34b20r.html