Yaris HEV 12V battery issues

[Edithluna]

Hi, I bought my Yaris (excel hybrid 2017 plate) about 6 months ago and am having issues with the 12V Battery. 
It’s not holding its charge. Ive had a couple of scenarios where I’ve gone to set off to work and all the warning lights on the dash flicker then the whole thing dies. I can’t even lock the car, it’s totally flat. I’ve taken the 12V Battery out and charged it until the charger said it was fully charged and it seemed fine, then the next morning it’s flat again.

I’m thinking I need to replace the Battery, but firstly im concerned incase it’s something draining it in the car that I’m not aware of. I’ve no accessories left plugged in etc… and secondly I am struggling to find anywhere I buy a replacement battery. 
 

I’ve read a few cases of people saying that these cars need to be driven very frequently for the battery health. I’m using it for short trips about 4 days a week with the odd longer journey….if this is the case I’m wondering if I’m going to need to look at a different car. 
I’d appreciate any advice ☺️

[Heidfirst]

Hi & welcome,

Do you know if it is the original 12V Battery?

if so, at 7 years old it may simply have come to the end of it's life & not be able to retain charge.

[Trewithy]

Edith,

Its time for a new Battery.  I'm sure this would resolve all your issues.

[Bob66]

Change the Battery, before changing the car.

[Mojo1010]

As everyone say change the Battery it's 7 year old without knowing how it was used previously. Your driving routine should be fine, many do low mileage a year without issue.

[Edithluna]

Thanks so much everyone. Do anyone of you know where I can get one from without going to the dealership? I’m struggling to find one 

[Rhymes with Paris]

If you pop your reg no into the hellfrauds (Halfords) website it will show the correct Battery for your car, price etc.

Then check if your local branch has one in stock,or can get one next day.

I think I would even trust them to fit it for you if like me they are too heavy to lug around.

Edit: I would choose a yuasa over any other makes.

 

[flash22]

1 hour ago, Rhymes with Paris said:

If you pop your reg no into the hellfrauds (Halfords) website it will show the correct battery for your car, price etc.

Then check if your local branch has one in stock,or can get one next day.

I think I would even trust them to fit it for you if like me they are too heavy to lug around.

Edit: I would choose a yuasa over any other makes.

 

It is Hobson's choice the Mk3 uses a Yuasa S34B20R (28800-YZZPC) AGM Battery, only Yuasa make them, and nowhere stocks them on the shelf apart from the main dealer and tbh the price isn't that bad around £150 with discount, other suppliers have them at £175-225

looks like the yearly price hike has happened so it's going to be a bit more

[Bob66]

Plenty of cheaper sites, that sell the Yussa 12 v Battery :

https://www.tayna.co.uk/car-batteries/yuasa/ybx5202/

[hind]

47 minutes ago, Bob66 said:

Plenty of cheaper sites, that sell the Yussa 12 v battery :

https://www.tayna.co.uk/car-batteries/yuasa/ybx5202/

This is NOT the AGM Battery used by Yaris mk3 hybrid! 

[Rhymes with Paris]

1 hour ago, flash22 said:

It is Hobson's choice the Mk3 uses a Yuasa S34B20R (28800-YZZPC) AGM battery, only

Oops,my bad, I didn't realise that the mk3 was only AGM.

People like me with mk1 brains should not offer advice to mk3 owners.

[Hadrian1]

7 yrs is about right for the agm Battery.

If changing yourself, be careful to remove the vent pipe first, to avoid breaking it.

[Bob66]

17 hours ago, hind said:

This is NOT the AGM battery used by Yaris mk3 hybrid! 

Quite obviously, buy the Battery recommended for your car...that was an example of a cheaper Battery source.

[TonyHSD]

AGM Battery the dealer offer best prices and those are Yuassa made. 
For my Auris back in may this year Yuassa from car parts shop was priced at £180 including 10% discount where same Battery from local dealer was £136. 

[hind]

38 minutes ago, Bob66 said:

Quite obviously, buy the battery recommended for your car...

Dangerous assumption 😄 especially when you link directly to the specific Battery model

[Bob66]

On 9/30/2024 at 8:46 AM, hind said:

Dangerous assumption 😄 especially when you link directly to the specific battery model

Woooo very dangerous.....I always take what I read on Forums as gospel !

[hind]

Sure 🙂 not your money and not your car, why would you care?

[PeteChat]

You are not alone EdithLuna, there is an enormous topic about 12volt Battery issues on here. Essential bedtime reading 😂

[hind]

Yet most of the cases there are Y4's

[Al-Kibir2017]

On 9/29/2024 at 9:37 AM, Edithluna said:

Hi, I bought my Yaris (excel hybrid 2017 plate) about 6 months ago and am having issues with the 12V battery. 
It’s not holding its charge. Ive had a couple of scenarios where I’ve gone to set off to work and all the warning lights on the dash flicker then the whole thing dies. I can’t even lock the car, it’s totally flat. I’ve taken the 12V battery out and charged it until the charger said it was fully charged and it seemed fine, then the next morning it’s flat again.

I’m thinking I need to replace the battery, but firstly im concerned in case it’s something draining it in the car that I’m not aware of. I’ve no accessories left plugged in etc… and secondly I am struggling to find anywhere I buy a replacement battery. 
 

I’ve read a few cases of people saying that these cars need to be driven very frequently for the battery health. I’m using it for short trips about 4 days a week with the odd longer journey….if this is the case I’m wondering if I’m going to need to look at a different car. 
I’d appreciate any advice ☺️

Hybrids have the 12 Battery almost always at 12 volt or even above 11 when not constantly driven. As one does not have a starter motor and Alternator, it charges off the Hybrid Battery and one of the MG Electrical Motors. 

At 7 years of age, if it is the original Battery chances are it is dead. get a replacement I would say. Similar Battery is a must to avoid taken too much current off the Hybrid battery. 

There is an App called Hybrid Assistant. It will help you check all this in real time whilst driving. Dr, Prius is also very good. 

[MikeSh]

1 hour ago, Al-Kibir2017 said:

it charges off the Hybrid battery and one of the MG Electrical Motors. 

No. Both the MG machines operate with the HV traction Battery and the 12V is powered off that through a converter.

It'll never take too much current from the HV unless there's a severe fault - which would likely destroy the 12V converter and perhaps the rest of the 12V system since the HV Battery can deliver 5-10kW at around 200V without any bother.

[hind]

14 hours ago, MikeSh said:

the HV battery can deliver 5-10kW

Oh, much more 🙂 it would mean that on EV you can get just around 13 HP. I wouldn't risk saying that the max power of electric engine (62 kW = 83HP in let's say the newest 130HP Yaris) can be achieved just from the HV but still it would be something in that area.

[MikeSh]

1 hour ago, hind said:

Oh, much more 🙂

Almost certainly. I was being conservative, partly to allow for earlier models that have much less EV capability. Basically the 12V system is the mahout on the back of any HEV or BEV (elephant).