Flat Battery

Faults and Technical chat for the Toyota Yaris Cross
Cuddles
Posts: 21
Joined: Fri Nov 17, 2023 8:10 pm

Post by Cuddles »

Update,
Went for a good run on Monday and when I got home the battery was at about 12.8v and 98% on the BM2. I thought good, that shows it does need a run. The next morning I got a red warning from BM2 that it was at 65% and 12.1v. In the evening that was 56%.
So, after reading many posts on different sites I decided that I absolutely love the car and would look at upgrading it next year to the new 130hp version but I need to know whether it is simply a crappy battery from the factory or a poor car. I need to change the battery now to a good quality battery.
I went to my dealer and showed them the video of the readings and the fact that I am averaging 160 miles per week. She agreed there is a problem and they are changing batteries weekly. They are also advised to put in the Yuasa shown above. Shame it doesn't have more ah but Yuasa is a quality battery maker.
She said unfortunately they can't change it under warranty untill it has failed and been with them which I am not willing to wait for.
I said I am willing to pay for the battery if they knock a decent amount off and fit it free. She went away and came back with the new Yuasa batter and said they would do that. The new battery was delivered only a few days ago as they are now fitting so many and its test printout showed that and it was fully charged.
She said she could ask the technician to do it now and they knocked about £35 off so I agreed.
Chatting to the technician he said off record there has been a problem with 12v batteries since covid as the suppliers struggled to get the materials. Now they are fitting Yuasa he feels it will improve matters - although they still need using or regularly charging - which I will do once a week with CTEK.
He fit it and when home the BM2 showed 12.78v and 100%.
This morning the same reading.
Yes, it cost me and many will say I should have hung out for the free battery after failures to start but if I decide to upgrade to the new 130hp next spring I will be ordering between Christmas day and new years day to get the 2k discount I got on this. This means I need the new battery to be in for the next 6 months to assure me it was just the battery and not the car.
Another thing I learnt this week after contacting CTEK and their engineer contacted me back was the charger doesn't work properly when using two 2.5 meter extensions. It will light up as though it is working but it may not be charging properly as the low voltage over an additional 5m struggles. The BM2 has to say "charging" to show the CTEK is actually charging. My GR yaris with one extension does shew charging but the Yaris Cross with two extensions joined together only showed the voltage and no charging. So, my mistake. Now set up the CTEK for the Yaris Cross with only one extension and low and behold it shows charging at about 15v for a short period then about 13.5v for the rest of the time so it is maintaing full charge.
You learn from your mistakes. Hope everything is fine and I can enjoy this lovely car and possibly upgrade next year.

JonathanM
Posts: 27
Joined: Fri Jan 13, 2023 3:15 pm

Post by JonathanM »

Interesting post Cuddles. When mine went flat the AA man said that it is the hybrid battery that starts the car not the 12V battery. This makes sense since the car doesn't have a starter motor. It actually only needs enough power to trip the relay in the starter system so a high Ah battery isn't really needed. Of course, once the 12V battery has become 'flat' then sulphates on the plates may not all be removed on recharging so the battery's performance will be affected. If the car sat around for a while before delivery, this may have happened.
Cuddles
Posts: 21
Joined: Fri Nov 17, 2023 8:10 pm

Post by Cuddles »

You are correct Jonathan.
I watched a battery technician and he explained that a 12v battery is technically flat when about 8-9v not zero as I used to think.
It does only switch on all of the relay switches that allow the electronic components to work. It will still open the doors at that lower voltage but the relays won't activate so the car won't go into ready mode.
He also explained the old alternators did a similar job as the CTEK. to clean the sulphor from the plates they need a more aggressive higher charge which the alternator and the first stage on the CTEK does. I have a voltage meter in the cig lighter and it does go to 14.8v for a couple of minutes then 13.5v for the rest of the journey. That first 14.8v isn't long enough for me if doing lots of short journeys.
I expect the battery was made months before I picked it up with a few quick charges and drops below 12v. This new Yuasa battery was newly delivered last week and then I used the CTEK overnight so it should be as healthy as it possibly can be.
I will see how it goes. I will make sure I do a 40-50 mile trip once a week along with two short trips a day for dog walks. Every Monday afternoon when finished it will go onto the CTEK which is now working properly till the following morning. This is easy for me to do and hopefully means it will be 12.78v every Tuesday morning and fully clean. I will see how it goes but I am more optimistic now I know it needs managing and not just leaving and ignoring it.
PS01
Posts: 2
Joined: Tue Mar 26, 2024 5:01 pm

Post by PS01 »

I have been monitoring both mine (YC Excel) delivered March 2024 and my son's Yaris hybrid (2013). His battery fell below optimum in February after 2 years of owning the car. We had this replaced (Yuasa supplied and fitted by dealer) since then I have been monitoring both his car and the YC batteries with a meter from CTEK plugs connected to the battery (pole with negative earthed to a suitable contact). I have largely been charging my son's car with an AA 4.8v solar panel and only occasionally using my CTEK charger. The battery in the Yaris holds it's charge better/gets less depleted than the YC even though he uses his car less and for short journeys. The Yaris charges to 12.8v Full on the meter via the solar panel or the CTEK whereas the YC only charges to 12.7v using the CTEK. The YC tends to fall to 12.3v pretty quickly and then hovers around 12.3v/12.4v after a journey - rarely above this. I always charge if it hits 12.2v. This does suggest that the YC hybrid battery charging set-up could be better......

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JonathanM
Posts: 27
Joined: Fri Jan 13, 2023 3:15 pm

Post by JonathanM »

My Jaguar XF 3.0D always has a low battery. When I bought it I checked the voltage after the car had a few minor electrical gremlins and it was 12.2V. So I bought a new battery (expensive!) which ended up exactly the same. Now I just charge it with the CTEK every couple of weeks and it's been fine. It must be a modern car problem due to so much going on in the background when the car is not used but you would have thought that the manufacturers would have found a solution.
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