Yaris Hybrid 12 volt auxiliary battery

[Anthony Poli]

Not only you can’t start it, you can’t push it since you can’t select neutral. If you are unable to get ready to show then the car requires a recovery truck with the ability to lift the car onto the back.


Sent from my iPhone using Tapatalk

[Mick F]

14 hours ago, Kingsway said:

Nope - the car can do nothing without the 12v supply.  However, I wonder if the 12v battery might recover a little once you take away the load....  It doesn't have to supply a huge current, like a conventional car battery, so you might just get lucky?

OK, I get that.  Thanks.

Unless the 12v is there, the starting circuit wouldn't be there.  The start key would do nothing.  Obvious really.

I suppose if you had an external 12v supply, you could connect it to the car.  ie not charge the Battery first, but just enable the start circuit to boot up.  The traction Battery would then do the charging once started.

Mick.

[CPN]

Exactly so and as long as your HV Battery was at a nominal state of charge. It's also why there is now a plethora of high capacity (but compact sized) rechargeable Lithium-Ion Battery packs available in the marketplace; some of which are even capable of turning over a conventional starter motor, never mind getting a hybrid going... Untidy jump leads are a thing of the past these days...

[pshawfocus]

My NHW11 Prius suffered a flat aux Battery one winter a few years back, basically because I'd left it parked outside for a few weeks as I hadn't needed to use it.  The AA man turned up in the snow and plugged in a booster to the Battery in the boot and away it went.  Never had a problem with it afterwards.    

[Mick F]

I wonder if you had a 12v Battery connected to an OBD lead, you could plug it in to allow the car to start.

Maybe instead, a lead that plugs into the cigar lighter, though I don't think that would work as the socket wouldn't be live.

[mrpj]

One of these to maintain a trickle charge through the OBD2 socket. Mixed reviews but could be useful for keeping that 12v aux. Battery on hybrids up to scratch,  if left for long intervals.

https://www.amazon.co.uk/gp/product/B00AC1LLQY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

[CPN]

16 hours ago, mrpj said:

One of these to maintain a trickle charge through the OBD2 socket. Mixed reviews but could be useful for keeping that 12v aux. battery on hybrids up to scratch,  if left for long intervals.

https://www.amazon.co.uk/gp/product/B00AC1LLQY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I can thoroughly recommend these as I have one myself and it seems to work extremely well even in low daylight conditions...

[Kingsway]

LATER:  Four months on, my 12v Battery is definitely giving up the ghost. I've had intermittant problems with the warning lights for Brake, ABS and traction control staying on, or coming only shortly after start-up.  It is happening a lot more now, and the 'cure' seems to be to give the Battery a good over-night charge with an AGM charger.  (My Battery tester seems to show it has only 50% state of health when fully charged)

Has anyone actually had a new aux battery from Toyota?  Is it true they only charge £100, fitted??  The cheapest I've seen it elsewhere is £169.00   I'm sort of tempted to just get a £50 conventional, flooded battery  size 54h  - with a 5 year warranty....

Someone suggested that the aux battery should be covered by the car warranty - but surely such a battery is a 'consumable'?? (It's nearly 4 years old)

[Kingsway]

A handy chart showing open-circuit  voltages and state of charge for AGM batteries...

[FROSTYBALLS]

1 hour ago, Kingsway said:

Someone suggested that the aux battery should be covered by the car warranty - but surely such a battery is a 'consumable'?? (It's nearly 4 years old)

Devon Aygo, a moderator on the club and who works for a Toyota dealer, said that the Battery, if failing, should be covered under the new car warranty.

Under Toyota's fixed price repair scheme, a new Battery for a petrol Yaris is £100 - see https://www.toyota.co.uk/owners/service-mot-maintenance/repairs.json

[4Tapbuster]

Ref: Trickle charge OBD2 socket, Yaris hybrid, your Amazon link is no longer working, please let me know the details. Regards Mick

[barry appleby]

Hi changed 2 Prius auxiliary batteries last week cheapest was from Toyota main dealer by about 50 pounds

[funky2nite]

Has anyone tried replacing 12v AGM auxiliary Battery with a regular 12v flooded one? if yes what has been the long term verict? any long terms concerns? Today I asked the parts guy at the local toyota dealer and he confirmed that a flooded Battery would just work just the same as AGM for the car. Am seeking to capture this from any previous experiences here , please? Greatly apprecated.

[Catlover]

A “regular 12v flooded” Battery will probably work just as well as an AGM Battery, and the Flooded type will be cheaper then an AGM as you probably aware. But why is there an AGM Battery fitted in the first place?             
A Regular 12v flooded battery has acid sloshing around in it. If that battery was split open the acid is the unrestrained, and in the case of an accident could splash about. In an AGM battery, the acid cannot do that as it’s is Absorbed in a Glass Mat. 
So where is the 12v battery in you car? If it is under the bonnet then in case of an accident and the battery gets split the consequences of the acid endangering someone is low. However, if the battery is within the cab area, as in under the rear seat (or in the boot area as with some Toyota hybrid cars) if the 12v battery was the flooded type and an accident occurred where the battery split, this could result in passengers getting acid burns which would not be good. Hence, for those type of vehicles am AGM type battery is fitted for safety reasons.

[funky2nite]

49 minutes ago, Catlover said:

A “regular 12v flooded” battery will probably work just as well as an AGM battery, and the Flooded type will be cheaper then an AGM as you probably aware. But why is there an AGM battery fitted in the first place?             
A Regular 12v flooded battery has acid sloshing around in it. If that battery was split open the acid is the unrestrained, and in the case of an accident could splash about. In an AGM battery, the acid cannot do that as it’s is Absorbed in a Glass Mat. 
So where is the 12v battery in you car? If it is under the bonnet then in case of an accident and the battery gets split the consequences of the acid endangering someone is low. However, if the battery is within the cab area, as in under the rear seat (or in the boot area as with some Toyota hybrid cars) if the 12v battery was the flooded type and an accident occurred where the battery split, this could result in passengers getting acid burns which would not be good. Hence, for those type of vehicles am AGM type battery is fitted for safety reasons.

Thanks Joe for your insightful reply, v v much appreciated. From what I can make it of it, it's exclusively to safety toyota goes for AGM. I asked on doubt whether a flooded Battery would just die too early for being used as an auxiliary. Since AGM are marketed to be slower in losing charge and lasting longer. my current one lasted 9 yrs for example, it's still usable, it did leave my wife stranded but when I got him charged it put it back, its been working for the past week or so, im carrying a spare flooded Battery atm until I narrow down if its due for replacement or not to avoid being left stranded.

 

thanks again

[Catlover]

If you got 9 years out of any Battery you can’t grumble if it stopped working today…… having said that I hope it keeps going. 😄

 there are other benefits to AGM, you mentioned longevity. All depends on how you treat them, you must have done something right over the years. Obviously not letting them get flat is one benefit. With jump starts being not much more the size of a smart phone it sounds sensible to have one for say £60. I also have the. CTEX 5, which I use 3 or 4 times per car! Keep it up on charge as we don’t use our cars a great deal, pre covid 7k, and 5k, maybe we will get back to that soon.

[funky2nite]

On 2/20/2022 at 3:44 PM, Catlover said:

If you got 9 years out of any battery you can’t grumble if it stopped working today…… having said that I hope it keeps going. 😄

 there are other benefits to AGM, you mentioned longevity. All depends on how you treat them, you must have done something right over the years. Obviously not letting them get flat is one benefit. With jump starts being not much more the size of a smart phone it sounds sensible to have one for say £60. I also have the. CTEX 5, which I use 3 or 4 times per car! Keep it up on charge as we don’t use our cars a great deal, pre covid 7k, and 5k, maybe we will get back to that soon.

I never complained about current Battery, 9 yrs is amazing. Although my first car had a flooded-type Battery that lasted 15 years and didn't fully die on me, just gives me one start after every drive, hence unreliable if you stop and start often. I think I'll be going down the path of a flooded Battery for my yaris hybrid and hope for the best that it doesnt drain too quickly for auxiliary usage. someone else was right to post here that toyota do give a discount on the AGM they sell, instead of Eur190 they sell it for Eur150 with 3 year warranty. 

Will keep you guys posted here. thanks again for your input

[IanML]

My wife has just acquired a 2019 Yaris Hybrid.  Unfortunately, she has injured her shoulder, and is currently unable to drive, so it's just sitting parked.  I'm a bit worried about the auxiliary Battery running down, and educating myself about it.

I measured the Battery voltage at the jump terminal in the nearside fusebox at 12.2 V, which seemed low to me, so I used a trickle charger through the same terminal to charge it.  It fully charged in quite a short time (about 6 hr),  I tried to measure the Battery condition with a tester, but it refused to work via the jump terminal (reporting "Check Connection"), so I wonder whether there is some component between the battery and the jump terminal which prevents its use.

Several days later, without the car being used, the voltage is back at 12.2 V.  It occurs to me that there may be some limitation on charging through the jump terminal to prevent the possibility of the battery gassing hydrogen into the passenger compartment.  Any views?

My next step will be to lift the rear seat, and attempt the condition measurement at the battery terminals.

[Mojo1010]

My car Battery only go upto about 12.77v max after a few hours of use - 2023 car. There is a draw of current from modern car so I don't see anything is wrong with your 5 year old car, in fact it's in pretty good condition.

[Cyker]

Some newer chargers go into a cyclic charging mode when it senses the Battery is fully charged, rather than a constant trickle charge, so it may be that...?

 

[MikeSh]

3 hours ago, IanML said:

I measured the battery voltage at the jump terminal in the nearside fusebox at 12.2 V, which seemed low to me, so I used a trickle charger through the same terminal to charge it.  It fully charged in quite a short time (about 6 hr),  I tried to measure the battery condition with a tester, but it refused to work via the jump terminal (reporting "Check Connection"), so I wonder whether there is some component between the battery and the jump terminal which prevents its use.

That's suitably vague. What kind of 'trickle charger'? How was 'fully charged' decided/defined? What kind of condition tester? 

12.2V is about 60-70% charge by most accounts. Our non-Toyota does short journeys a lot so I monitor the voltage before starting and give it a boost charge when it gets down to 12V. After giving it a charge to FUL with an 'intelligent' charger the voltage next day is about 12.6. It then falls over a few days to about 12 1/4 where it seems to stick for weeks before eventually drifting down to 12. So I suspect that for whatever reasons (of Battery and/or charging profile) 12.2-12.3 may be a natural plateau for these systems. So I'd monitor it and maybe charge when it gets to 12.

[IanML]

Thanks for the replies.  The charger is a CTEK MSX-5 (shows a green lamp when fully charged, and does cycle thereafter if left on).  The Battery tester is a TOPDON ArtiBattery 101.

I took the car for a short trip (maybe 2 miles, but hilly) this morning, including a stationary powered-up period in the carwash.  I then lifted the rear seat squab, measured the Battery volts direct (12.5) and then tested with the TOPDON, setting the type to AGM and the CCA to 270 A (the TOPDON only does increments of 5 A, but that should be close enough to 272).  Results were SOH 60% and SOC 95%.

The TOPDON recommends replacement at less then 62% SOH, but that logic may be dictated by requirement to start an ICE, so perhaps still ok for the hybrid?

 

[hind]

If you want to be sure, you should measure the capacity. Charge the Battery fully, wait for 30 minutes and then discharge it with known load (car bulb for the headlights should be good choice as the H7 bulb are rated at 55W IIRC which equal to 4.58A). Measure the voltage when discharging and disconnect when it falls to 11V. Then multiply the counted hours by the current of your load. Let's say it reached 11V after 3.5h. This would mean that your Battery capacity equals 3.5 x 4.58 = around 16Ah.

Then compare this value with what is on the label of the Battery (eg. 44Ah) and this would mean that yours keeps only 35% of designed capacity thus probably should be replaced or at least charged regularly (like once a week) when the car is not used. 

Of course be very cautious when connecting stuff directly to the battery as touching the bare + and - wires together will cause them to stick and it will damage the battery, melt the wires and possibly set everything on fire!!! 

[MikeSh]

1 hour ago, IanML said:

The battery tester is a TOPDON ArtiBattery 101.

It's a conductance tester, so the extra resistance of the wires and ground paths from the engine bay to the rear seat will have thrown it. As you found, connecting direct to the Battery worked. 

1 hour ago, IanML said:

Results were SOH 60% and SOC 95%.

For a 5yo Battery that's been through COVID lockdowns that seems reasonable, though I'm not sure these are AGMs.

Although it doesn't have to crank, the brake power assist is 12V. When you open the driver's door it starts the pump to pressurise the brake reservoir (which drains over an hour or two). I don't know the current consumption but I'd think it will be significant, which may be the last straw for marginal batteries, so they then fail to start the car. 

If the Battery failing isn't going to be a big issue then I'd say keep it topped up weekly until it's back in regular use and wait till it lets her down. But if failure isn't an option then just get a new one so you know where you are.

 

[flash22]

be aware that the Mk3 hybrid uses an AGM Battery and charging system when on a charge they like it low and slow <4a @ 14.4v - 15.2v charge directly at the Battery only or  Just run the car for 30-45 mins every 10-14 days