yaris Cross awd 12 volt battery performance in cold weather.

[BobHos]

Just had a rather unpleasant surprise this morning when my 2023 yaris Cross awd would not start. For the past couple of weeks the mperatures have been quite low and I have had several short town journeys, generally with the heated seat functions on high for both seats. The past 3 days we have had sub zero night temperatures and this morning the car would not start with a warning of low Battery voltage. I tested the Battery and found that it was, indeed, almost fully discharged. I can only conclude that the 12 volt discharge current exceeds the charge capability when it is used on shortish journeys with seats in high heat mode,  especially at night with lights on, etc. looks like there might be a design fault wrt 12 volt load and charge capability and perhaps Battery performance in sub zero temperatures.  Out of interest can anyone tell me how is the 12 volt battery is charged. I presume there is not a 12 volt generator.

[DJ123]

I'm assuming it's a standard set up, then it'll be charged using the alternator which will be at circa 14.5V.

Short journeys will kill any Battery, especially with high power draw of heated seats, and the like. A longer (time wise, is most important)  journey (at least one a week) is needed to replenish the Battery for it to be charged back to full health without damaging the AGM/cells (assuming you do not have a solid state, or lithium battery). The cold will challenge a Battery that's not at full health causing starting issues. 

A drive of half an hour or so will get it re-charged back to full capacity, and should not incur starting issues the next morning. 

[Rhymes with Paris]

I only know a little about hybrids, and that is only from what I read on here.

AFAIK there is no alternator , and the 12v Battery is charged from the traction Battery.

It seems as though it's crucial with these that they spend enough time in ready mode to charge the 12v sufficiently.

Have a look at the other threads about 12v batteries on here, there are hundreds of posts about them.

But yes, short journeys,cold weather, and heated seats etc , high electrical load will soon see off most 12v batteries .

[Mojo1010]

Consider changing to this higher capacity Battery.

[BobHos]

27 minutes ago, Rhymes with Paris said:

I only know a little about hybrids, and that is only from what I read on here.

AFAIK there is no alternator , and the 12v battery is charged from the traction battery.

It seems as though it's crucial with these that they spend enough time in ready mode to charge the 12v sufficiently.

Have a look at the other threads about 12v batteries on here, there are hundreds of posts about them.

But yes, short journeys,cold weather, and heated seats etc , high electrical load will soon see off most 12v batteries .

Yes I assumed that the Cross Hybrid does not have an alternator and that somehow the 12 volt Battery is charged from the hybrid electric system. Also there is no 12 volt starter motor so there will not be a high value 12 volt cranking current so I was rather surprised that the Battery was discharged as I have described. I really do believe that the 12 volt system is badly designed, perhaps it was designed before they decided to add heated seats. I had a Subaru Forester for 15 years and it had heated seats  but I never encountered the same problem with it. If the 12 volt Battery and charging system are properly designed  there should not be a problem. If the charging system can supply maximum load (including lights and heated seats, etc) then the battery should never discharge.

[BobHos]

31 minutes ago, Mojo1010 said:

Consider changing to this higher capacity battery.

If the charging system does not match the maximum load then the Battery will always discharge during severe weather conditions so even a higher capacity Battery will discharge eventually.

[Mojo1010]

That may be the case, however it will give an extra few days buffer. As well it could be due to the not so good quality of the Mutlu Battery currently in the car, that doesn't charges well or discharge more that a better quality Battery. 

If car isn't use for 3 days in this cold weather, should run it on for 30mins to top up. 

[BobHos]

3 hours ago, Mojo1010 said:

That may be the case, however it will give an extra few days buffer. As well it could be due to the not so good quality of the Mutlu battery currently in the car, that doesn't charges well or discharge more that a better quality battery. 

If car isn't use for 3 days in this cold weather, should run it on for 30mins to top up. 

How much more capacity does the Battery you quoted have and will it fit in the existing Battery space and do you supply them?

[jthspace]

I've fitted this to my Yaris, it's exactly the same size and will fit. Even the vent pipe/connector is identical.

Order from anyone who sells them, I bought from eBay for £71 delivered as Amazon didn't deliver to my area (Cambridge)!

Ebay seller

[BobHos]

3 minutes ago, jthspace said:

I've fitted this to my Yaris, it's exactly the same size and will fit. Even the vent pipe/connector is identical.

Order from anyone who sells them, I bought from eBay for £71 delivered as Amazon didn't deliver to my area (Cambridge)!

Ebay seller

GThanks for that informatio jt. Did you have a flat Battery problem as well?

[BobHos]

5 minutes ago, BobHos said:

GThanks for that informatio jt. Did you have a flat battery problem as well?

As a matter of interest what is the capacity of the original Battery (encourage my laziness - save me lifting the rear seat. etc (not good for my bad back). Unfortunately, it won't adress, what I think is a design load/charging capability, it will only buy a little time before Battery discharges under difficult conditions (including operation of seat heaters).

[jthspace]

9 minutes ago, BobHos said:

GThanks for that informatio jt. Did you have a flat battery problem as well?

No, but I bought second hand and didn't know the Battery history, and after reading 60-odd pages on the Battery thread (at the time), I thought £70 to eleviate a potential issue was money well spent.  Longest I've left the Yaris unused was 7 days with the new Battery and no issues experienced.

When fitting the battery I installed a charger socket in the battery cover panel at the same time.

[BobHos]

1 minute ago, jthspace said:

No, but I bought second hand and didn't know the battery history, and after reading 60-odd pages on the battery thread (at the time), I thought £70 to eleviate a potential issue was money well spent.  Longest I've left the Yaris unused was 7 days with the new battery and no issues experienced.

When fitting the battery I installed a charger socket in the battery cover panel at the same time.

Neat jt... you are a capable fellow. I have a charger in my garage and just hooked it up to the jump start terminals in the fuse box under the bonnet. When you say there are about 60 pages on Battery issue topics are they similar to what I have been saying and do you have a link to them? I think I will just soldier on in the meantime without the over-use of the seat heaters. Conditions are quite bad here just now. I have told my wife we will just use reinforced hot water bottles on the seats meantime but I think I may have to get a stronger bottle for my wife (hope she doesn't read this).Charge/discharge issue aside I still love my Cross which I am sure (after extensive testing this time last year) will never leave me stranded in severe winter conditions. I posted rigorous testing in severe winter conditions this time last year.

[jthspace]

1 hour ago, BobHos said:

Neat jt... you are a capable fellow. I have a charger in my garage and just hooked it up to the jump start terminals in the fuse box under the bonnet. When you say there are about 60 pages on battery issue topics are they similar to what I have been saying and do you have a link to them? I think I will just soldier on in the meantime without the over-use of the seat heaters. Conditions are quite bad here just now. I have told my wife we will just use reinforced hot water bottles on the seats meantime but I think I may have to get a stronger bottle for my wife (hope she doesn't read this).Charge/discharge issue aside I still love my Cross which I am sure (after extensive testing this time last year) will never leave me stranded in severe winter conditions. I posted rigorous testing in severe winter conditions this time last year.

See the very top thread in this section, now 80 pages! I read somewhere driving with the lights on gives a bigger charge than driving without, i.e. more efficient, for example drive normal = charge normal; drive normal + lights = charge normal+ lights + extra.  Does that make sense?

[hind]

15 hours ago, DJ123 said:

Short journeys will kill any battery, especially with high power draw of heated seats,

The heated seats are only a problem IF they cause the charging voltage drop. 

If the DC/DC converter provides, let's say 50 amps max and the Battery takes no more than 15 amps (because it reaches max voltage quickly as it has low capacity) then it doesn't matter how many energy consuming devices you have connected. If the heated seats cause the overall voltage to drop then they might slower down the charging but unless the installation voltage is over 12.6V the Battery IS charged. 

9 hours ago, BobHos said:

As a matter of interest what is the capacity of the original battery

35Ah

7 hours ago, jthspace said:

I read somewhere driving with the lights on gives a bigger charge than driving without

Someone checked that and the voltage was lower with the lights on which means the charging current was lower

[BobHos]

7 hours ago, jthspace said:

See the very top thread in this section, now 80 pages! I read somewhere driving with the lights on gives a bigger charge than driving without, i.e. more efficient, for example drive normal = charge normal; drive normal + lights = charge normal+ lights + extra.  Does that make sense?

That may or may not be the case. In older generation cars with dynamo or rectified output alternators then increased load meant lower output voltage from the generator and, consequentially a lower voltage at the Battery resulting in lower Battery charge. In modern cars like hybrids I suspect that the voltage may be better regulated with more sophisticated electronic controls, etc. The way to check it, if you are interested, would be to connect a voltmeter across the Battery terminals and monitor gthe voltyage under low load and heavy load conditions. The battery terminal voltage will be directly proportional to the battery charge current. The actual value of battery charge or float current is also dependent on the actual state of charge in the battery at the time but the simple voltyage tests I have suggested will give you the answer. Connect the voltmeter and run the car on light load (no lights, heaters, fans, etc) then switch on lights, heaters, etc and if this indicates a higher voltage then the statement is correct. 

[anchorman]

On 1/17/2024 at 8:31 AM, BobHos said:

That may or may not be the case. In older generation cars with dynamo or rectified output alternators then increased load meant lower output voltage from the generator and, consequentially a lower voltage at the battery resulting in lower battery charge. In modern cars like hybrids I suspect that the voltage may be better regulated with more sophisticated electronic controls, etc. The way to check it, if you are interested, would be to connect a voltmeter across the battery terminals and monitor gthe voltyage under low load and heavy load conditions. The battery terminal voltage will be directly proportional to the battery charge current. The actual value of battery charge or float current is also dependent on the actual state of charge in the battery at the time but the simple voltyage tests I have suggested will give you the answer. Connect the voltmeter and run the car on light load (no lights, heaters, fans, etc) then switch on lights, heaters, etc and if this indicates a higher voltage then the statement is correct. 

 

On 1/16/2024 at 10:07 PM, BobHos said:

How much more capacity does the battery you quoted have and will it fit in the existing battery space and do you supply them?

You're assuming it’s a Battery capacity problem and not a Battery quality problem.  I was dismissive about the Battery being a problem in the early days and that it would definitely be the owner not giving it time but since dealing with several of these things that have failed on the hoof and completely resolving it with the battery Mojo has indicated, you’d do well to take his advice.

[anchorman]

On 12/2/2023 at 12:12 PM, Trewithy said:

Will the updated Yaris with the 115BHP engine have the Mk5 hybrid system?

The current one does so I wouldn’t expect any different.

 

[Chas G]

Pity they don't do a 1.5 petrol only yaris cross

[BobHos]

31 minutes ago, anchorman said:

 

You're assuming it’s a battery capacity problem and not a battery quality problem.  I was dismissive about the battery being a problem in the early days and that it would definitely be the owner not giving it time but since dealing with several of these things that have failed on the hoof and completely resolving it with the battery Mojo has indicated, you’d do well to take his advice.

 

[BobHos]

I think that it may well be a Battery quality problem. I have checked the voltage when the 12 volt Battery is being charged in "READY" mode and it is just over 14volts irrespective of the 12 volt DC load so the 12 volt Battery should be getting plenty charge at that voltage. I had not left the car stationary for any significant period(s) prior to the failure on the morning of 16th. so I was extremely surprised with the failure due to low 12 v supply. The capacity of the battery is 35Ah so there is not a significant difference to the 45Ah Yuasa one so I suspect that it is a quality problem. The car was first registered in September 2022 and I purchased it as a 72 mile showroom model with 72 miles on the clock in December 2022. Surely the battery should be covered by warranty but I may have a problem proving it is "faulty" given that Toyota seem to cover their "ar*e" by saying you should consider leaving the car in "READY" mode occasionally for one hour. Seems like a cheap way to overcome a poor design/quality issue.

[anchorman]

25 minutes ago, Chas G said:

Pity they don't do a 1.5 petrol only yaris cross

If they did I wouldn’t have one because it’s a backward step.  The only problem which is easily resolved is the iffy 12v Battery.   I think it’s only hysteria that comes from a lack of understanding that causes all the panic.  

[anchorman]

3 minutes ago, BobHos said:

I think that it may well be a battery quality problem. I have checked the voltage when the 12 volt battery is being charged in "READY" mode and it is just over 14volts irrespective of the 12 volt DC load so the 12 volt battery should be getting plenty charge at that voltage. I had not left the car stationary for any significant period(s) prior to the failure on the morning of 16th. so I was extremely surprised with the failure due to low 12 v supply. The capacity of the battery is 35Ah so there is not a significant difference to the 45Ah Yuasa one so I suspect that it is a quality problem. The car was first registered in September 2022 and I purchased it as a 72 mile showroom model with 72 miles on the clock in December 2022. Surely the battery should be covered by warranty but I may have a problem proving it is "faulty" given that Toyota seem to cover their "ar*e" by saying you should consider leaving the car in "READY" mode occasionally for one hour. Seems like a cheap way to overcome a poor design/quality issue.

I think they know by now but they will insist on having the vehicle for two days while they charge it day one and test it day two.  I’ve charged very questionable batteries after an overnight charge and they’ve come out fine so at worst it will pass the test and you’ve wasted two days or at even worse, they’ll fail it and fit another crock of you know what.  For £80 it’s not worth the hassle and it then presents the car you expected to enjoy.  

[Chas G]

11 minutes ago, anchorman said:

If they did I wouldn’t have one because it’s a backward step.  The only problem which is easily resolved is the iffy 12v battery.   I think it’s only hysteria that comes from a lack of understanding that causes all the panic.  

Apart from the 12 volt Battery issues, it bothers me that if I park in my garage and a jump pack etc won't boot up the management system I won't be able to put the car in neutral, take the hand brake off and push it out for RAC/AA recovery. 

I am willing to risk driving the car into the garage, letting it charge in ready mode for 2 hours and then i put it back on the road on the basis that it stays with the EMS booted up the whole time. 

Rac were supposed to fit a Bosch S4 202 44ahr Battery today but phoned at 6pm to say they didn't have the Battery.

[BobHos]

4 minutes ago, anchorman said:

I think they know by now but they will insist on having the vehicle for two days while they charge it day one and test it day two.  I’ve charged very questionable batteries after an overnight charge and they’ve come out fine so at worst it will pass the test and you’ve wasted two days or at even worse, they’ll fail it and fit another crock of you know what.  For £80 it’s not worth the hassle and it then presents the car you expected to enjoy.  

Yes I knew that would be how it would be - not good. I was told that there are over 80 pages of posts/comments regarding the batteries. I don't fancy wading through them,  I have a very strong hunch now that the Battery is faulty or of inferior quality - shame on you Toyota.