Constant battery drain problem

[Corollanutter]

I have had my 2019 1.8 TS Excel since the end of July and it has been used very regularly. However I noticed that my dash cam (with parking mode enabled) was shutting down fairly soon (i.e. a few minutes) after turning off the car - and not the two hours it was programmed for.  On checking the Battery voltage I found that the 12V Battery was at 12.2V - indicating a charge level of around 50% (and this was after some decent runs of over 1 hour each). Switching the car to "Ready" made the voltage jump to approx 14.2 volts - showing the car was charging the Battery OK. So it appears that the low voltage monitor on the dash cam parking power unit was switching off the camera. Firstly I thought the dash cam itself may be to blame for the low battery charge level (event though it was only set for two hours in parking mode). So I set it for zero parking monitor time and charged the battery for over a day. Today, a week after fully charging the battery and driving for over 10 hours during the week, I checked the voltage again and found it to be 12.15V. So, I decided to check the parasitic drain with the dash cam disconnected completely - and found a drain varying between 0.3 and 0.5 Amps (this was 5 minutes after locking the car and making sure everything was switched off). Clearly this is far above the acceptable level of parasitic drain (normally a few 10's of mA at the most) and clearly explains the depleting level of charge. Yes, I do have keyless entry enabled, however I had this system on my Avensis and never had these problems during 8 years of ownership. And in any case no system on the vehicle (if working correctly) should be pulling a load such as this when in sleep mode.
I'm going to give the dealer a call on Monday to get it checked over, however has anyone else on here has similar issues?

[flash22]

Unplug the dash cam, they can do weird and wonderful things like randomly turning them self on and doing nothing but still pull 400-800ma

[Corollanutter]

1 minute ago, flash22 said:

Unplug the dash cam, they can do weird and wonderful things like randomly turning them self on and doing nothing but still pull 400-800ma

Already done that. The parasitic drain was checked the with dash cam fuses pulled!

[flash22]

It's a Dead Battery, not holding its charge then, lockdown has killed plenty - It's likely to be around the £60-100 mark (Battery only) the dealer may screw you £60-80 for a diagnostics fee, or they may do it all under warranty FOC

 

iirc the Rolla hybrid uses a standard Battery (lead acid) under the bonnet - a low state of charge and cold weather will kill it

[camellia30]

0.3 to 0.5 Amps of parasitic drain is way too high, this might explain a lot of those stories of flat batteries during lockdown.

[Roy124]

My dealer swapped out the Battery under warranty and fitted a 52 Amp cf original 45 Amp.  I think the original was nadgered during lockdown and before it was generally known about using Ready mode. 

The Dashcam is irrelevant.  It has its own Battery (Nextbase) and that is not being charged when the car is shut down but will wake up under parking mode. 

[Corollanutter]

50 minutes ago, camellia30 said:

0.3 to 0.5 Amps of parasitic drain is way too high, this might explain a lot of those stories of flat batteries during lockdown.

Exactly. Even at a 300mA drain, a 40Ah Battery will be effectively flat in 4 days. The Hybrid "gets away with it" for longer, as there is no starter motor to power, the biggest draw probably being the brake booster charging up before you go into ready mode. In my past life as an automotive electronics designer, I know that ECUs are designed to have a very low quiescent current draw - ideally 1mA or less. The keyless entry system will probably be a bit higher than this due to it polling the key on a regular basis. But nowhere near 300mA. That sounds like an ECU not going to sleep. 

[Red_Corolla]

I agree that 300mA is way too much, but 5 minutes is nowhere near long enough to give a modern car fair chance of putting everything to sleep for a proper assessment. Get the meter set up outside the car, make sure it's locked up with everything closed and give it half an hour. Don't forget to keep your meter awake and the key fob away from the car.

[Corolla2004]

Chris, you could do a bit of further analysis by pulling some of the other fuses one at a time in order to narrow down which circuit is taking the current. But first I'd check you haven't got something like a luggage compartment light left on. A 5W bulb would take 0.42 A.

[Corollanutter]

17 minutes ago, Red_Corolla said:

I agree that 300mA is way too much, but 5 minutes is nowhere near long enough to give a modern car fair chance of putting everything to sleep for a proper assessment. Get the meter set up outside the car, make sure it's locked up with everything closed and give it half an hour. Don't forget to keep your meter awake and the key fob away from the car.

Good thoughts. I’ll try that tomorrow when I have a charged Battery! 

 

19 minutes ago, Corolla2004 said:

Chris, you could do a bit of further analysis by pulling some of the other fuses one at a time in order to narrow down which circuit is taking the current. But first I'd check you haven't got something like a luggage compartment light left on. A 5W bulb would take 0.42 A.

I’ll check the luggage compartment lights tomorrow. However they are LED strips on the TS. But it’s another thing to look for! Thanks. 

[Mooly]

3 hours ago, Chris Nutt said:

I found that the 12V battery was at 12.2V - indicating a charge level of around 50% (and this was after some decent runs of over 1 hour each). Switching the car to "Ready" made the voltage jump to approx 14.2 volts - showing the car was charging the battery OK.

I've no practical experience of this on a Hybrid but if the voltage jumped very quickly from 12.2 to 14.2 in ready mode then that may suggest the Battery is deteriorated. A healthy Battery resting at a lowish charge level would pull many tens of amps if it could from the charging circuit... so the big question for me is what is the maximum charge ability of 'Ready Mode'. A traditional alternator could deliver 70 or more amps by way of comparison. 

So possibly an indication of a deteriorated Battery there. Edit... I say possibly because a limited charge current should see the terminal voltage rise far more slowly. A sudden jump to 14.3 suggests the internal resistance of the battery is very high.  

 

41 minutes ago, Red_Corolla said:

I agree that 300mA is way too much, but 5 minutes is nowhere near long enough to give a modern car fair chance of putting everything to sleep for a proper assessment. Get the meter set up outside the car, make sure it's locked up with everything closed and give it half an hour. Don't forget to keep your meter awake and the key fob away from the car.

I'll second this. You need to give it much longer than 5 minutes.

[Cyker]

I'm no expert in electrics, but isn't the 14v being measured the output of the DC-DC converter and not the Battery? If the Battery was pulling so much current that the DC-DC converters couldn't supply enough current then maybe it would show a voltage sag, but under normal circumstances it should be pretty steady at 14.whatever volts shouldn't it?

Thirded the >5 mins advice - My Mk4 still randomly makes whirring and clunking noises at 5 minutes, esp if I'm still in the car  

 

[Devon Aygo]

6 hours ago, Chris Nutt said:

I have had my 2019 1.8 TS Excel since the end of July and it has been used very regularly. However I noticed that my dash cam (with parking mode enabled) was shutting down fairly soon (i.e. a few minutes) after turning off the car - and not the two hours it was programmed for.  On checking the battery voltage I found that the 12V battery was at 12.2V - indicating a charge level of around 50% (and this was after some decent runs of over 1 hour each). Switching the car to "Ready" made the voltage jump to approx 14.2 volts - showing the car was charging the battery OK. So it appears that the low voltage monitor on the dash cam parking power unit was switching off the camera. Firstly I thought the dash cam itself may be to blame for the low battery charge level (event though it was only set for two hours in parking mode). So I set it for zero parking monitor time and charged the battery for over a day. Today, a week after fully charging the battery and driving for over 10 hours during the week, I checked the voltage again and found it to be 12.15V. So, I decided to check the parasitic drain with the dash cam disconnected completely - and found a drain varying between 0.3 and 0.5 Amps (this was 5 minutes after locking the car and making sure everything was switched off). Clearly this is far above the acceptable level of parasitic drain (normally a few 10's of mA at the most) and clearly explains the depleting level of charge. Yes, I do have keyless entry enabled, however I had this system on my Avensis and never had these problems during 8 years of ownership. And in any case no system on the vehicle (if working correctly) should be pulling a load such as this when in sleep mode.
I'm going to give the dealer a call on Monday to get it checked over, however has anyone else on here has similar issues?

What version of software is your Nav unit (MEU) running? Press "setup" button then scroll down on RH menu to software update.

MM17 cars without Apple carplay/Andriod auto versions lower than 1530 can have a fault where the nav ecu doesn't always power down

MM19 cars with ACP/AA versions lower than 1120 can have a fault where the nav ecu doesn't always power down

[Corollanutter]

10 minutes ago, Cyker said:

I'm no expert in electrics, but isn't the 14v being measured the output of the DC-DC converter and not the battery? If the battery was pulling so much current that the DC-DC converters couldn't supply enough current then maybe it would show a voltage sag, but under normal circumstances it should be pretty steady at 14.whatever volts shouldn't it?

Thirded the >5 mins advice - My Mk4 still randomly makes whirring and clunking noises at 5 minutes, esp if I'm still in the car  

 

AFAIK the DC to DC converter is connected to the Battery. So the voltage at one will be the same as at the other. I’ll post an update after more tests tomorrow. 

[Corollanutter]

1 hour ago, Devon Aygo said:

What version of software is your Nav unit (MEU) running? Press "setup" button then scroll down on RH menu to software update.

MM17 cars without Apple carplay/Andriod auto versions lower than 1530 can have a fault where the nav ecu doesn't always power down

MM19 cars with ACP/AA versions lower than 1120 can have a fault where the nav ecu doesn't always power down

Thank you - I will check and report back!!

[Mooly]

7 hours ago, Cyker said:

I'm no expert in electrics, but isn't the 14v being measured the output of the DC-DC converter and not the battery? If the battery was pulling so much current that the DC-DC converters couldn't supply enough current then maybe it would show a voltage sag, but under normal circumstances it should be pretty steady at 14.whatever volts shouldn't it?

The DC/DC convertor is essentially a 'constant voltage' output but it will have a defined 'current limit' which means the voltage will reduce once that limit is reached. I've no idea what that limit value (amps) is though.

The op says the voltage jumped from 12.2 volts to 14 volts when put in ready mode. If measured on the Battery terminals then that would need an awful lot of current from the convertor to make that quick step change on the Battery if the Battery were 'new or in as new condition' and you would as you mention expect to see a 'sag' or delay in the time it took to climb from 12.2 to 14v.

   

[Red_Corolla]

From what I've heard, the 12v charging output from the inverter isn't particularly powerful compared with a conventional alternator. That's why a decent amount of run time is necessary to keep the 12v Battery alive, even though it doesn't have a lot of work to do itself.

On my last car, specifying a tow bar added a bigger Battery & alternator, but not so with this one (although the option was about half the price). I'm not sure why VAG do that anyway, because an extra set of tail lights shouldn't pose much of a problem for cars designed to run electrically heated seats etc.

[Corollanutter]

So, an update from today. After charging the Battery for a good 20 hours at 14.1V (via a regulated 5A PSU in constant voltage mode), the off-load Battery voltage has risen to 12.64V -indicating a near fully charged condition. I have checked the NAV unit and it is running 1530 version software (so no problem there). I have also checked luggage space light - and it's off when it's supposed to be off. Doing a longer term parasitic drain test on a locked and fully closed car I found:

1 mins - approx. 750mA

10 mins - approx. 450mA

40 mins - varying between approx 10 and 40mA  (probably caused by the locking and other systems polling)

So, the 40 minute point is not showing any real issue with parasitic drain. At this level a fully charged Battery would be down to ~50% charge after around 2 months, not allowing for any self-discharge.

So, I'm coming to conclusion that it may be a duff (low capacity) battery. Time for a call to the dealer to see if it is covered by the warranty - and then arrange a check.

Thanks to all for the useful tips provided on this thread.

 

[Mooly]

That is the first time I've seen anyone post meaningful figures for quiescent current draw... excellent.  A fluctuating 10 to 40ma is acceptable imo and so I think you have to look at the Battery as being suspect based on this. 

[Corollanutter]

1 hour ago, Mooly said:

That is the first time I've seen anyone post meaningful figures for quiescent current draw... excellent.  A fluctuating 10 to 40ma is acceptable imo and so I think you have to look at the battery as being suspect based on this. 

However, in the background I'm still somewhat confused as to why Toyota recommended a weekly "top-up" during lock down - and there are a LOT of threads on internet forums about flat Toyota Hybrid batteries (whatever the model). With all the cars I have owned over the past 45 years, I have never had a problem with the vehicle starting after a couple of weeks. Agreed, they didn't have all the kit and caboodle that the Corolla has, however this still shouldn't really be a problem with modern low-power electronics. This car is getting a new Battery, covered by the warranty or not!

[Mooly]

The recommend may be just to try and avert problems given that many did not cover much mileage last year. Reducing charge levels on batteries because of quiescent current draw is insidious in nature. You begin with 100% and a few days with a small current draw may see that fall to 90%. You do a few miles and get back to 98% but then it stands a a couple days and drops to say 93%. You go to the supermarket and back and now you are at say 96%. Its a downward trend because of the constant but low continual draw. To get back to 100% might see most of the energy get put back in say 20 minutes but it then takes another hour or two to get back to 100% and that last part is what doesn't happen.

So although something like 40ma draw isn't much at all, its cumulative effect over time on a little used vehicle adds up. The older a Battery gets (higher internal resistance) and the longer time is needed on each charge to put all of that energy back. There is also the other issue of capacity of the Battery falling permanently that is made worse by periods sat at lower charge levels.

[Cyker]

I guess it's partly because so many people have complained to them in the past about Battery drain, so they figured they should put out some advice. That said they do usually use smaller 12v's in their hybrids as they figured why would you need a normal sized Battery when you don't need 500A to start an engine, and a smaller 12v would knock maybe 5-10kg off the weight (And auto makers are always looking for ways to reduce weight as it gives both improved economy and performance!), which likely contributed to the problem. The other being overly sensitive keyless entry systems, which kept pinging the key fob.

Modern cars do tend to draw a lot more standby power tho', esp. ones that are always connected to the internet.

I do wonder why they can't just have an automatic system that engages the traction Battery to charge it when it gets low, as long as the traction battery doesn't get too low (That would be much worse!).

I'm not even sure why we need the 12v battery - Originally I thought it was because there was a rule that the high voltage system can't be on when the car is 'off'/not in use, but Teslas power a lot of their always-on systems from the traction battery, e.g. Sentry mode, so how come they can get away with it if nobody else is allowed to...?

 

[Gerg]

7 hours ago, Chris Nutt said:

Doing a longer term parasitic drain test on a locked and fully closed car I found:

I did something very similar with an couple of Aurises about a year back.  Your figures are very close to what I measured (posted on this forum, somewhere) at the time.  On the Auris, the car is completely 'asleep' after 20 minutes, fwiw.  After this time the parasitic drain was just under 50mA.  If the keyless locking was turned off beforehand (via the dash) , or the car didn't have it fitted from new, then you could subtract 20mA from that drain figure.  I understand (but have never measured myself) that the car turns off the 'keyless' locking itself after being parked, uninterrupted for 5 days, although I've also seen 7 days quoted for that to happen.

I had the impression that the flat 12v Battery problems on the earlier hybrids were aggravated by (as well as that said above) the charge requirements for the AGM batteries fitted to those earlier cars, specifically that those 12v AGM batteries will not accept a high charge current, even if the inverter can supply it. 

Whilst I know very little about this, I guessed that this was down to the gel electrolyte, or similar, of the AGM, being much slower to allow the raised acidity surrounding the plates (created through charging) to dissipate into the rest of the Battery electrolyte, so the Battery 'appears' charged temporarily (by its voltage) when a higher than ideal charging current is used. Although that theory doesnt work so well when high cold cranking amps that can be delivered by an AGM are taken into account.  So, happy to be corrected on all this!  The Yuasa quoted rule-of-thumb for their Toyota-installed AGMs is to charge at 10% of their rated capacity, fwiw.

1 hour ago, Cyker said:

I do wonder why they can't just have an automatic system that engages the traction battery to charge it when it gets low

The system you describe is fitted to the Hyundai Ioniq hybrid.  A dash button kicks this into operation, so driver intervention is required to set this off.  Also on that car, the 12v battery is fitted alongside the traction battery, but it is logically and physically (just) seperate, and its chemistry is slightly different to the 'normal' lithium traction battery, but it is still a variant of the lithium chemistry.  As I understand it, anyway.

[Mooly]

9 hours ago, Gerg said:

I had the impression that the flat 12v battery problems on the earlier hybrids were aggravated by (as well as that said above) the charge requirements for the AGM batteries fitted to those earlier cars, specifically that those 12v AGM batteries will not accept a high charge current, even if the inverter can supply it. 

Whilst I know very little about this, I guessed that this was down to the gel electrolyte, or similar, of the AGM, being much slower to allow the raised acidity surrounding the plates (created through charging) to dissipate into the rest of the battery electrolyte, so the battery 'appears' charged temporarily (by its voltage) when a higher than ideal charging current is used. Although that theory doesnt work so well when high cold cranking amps that can be delivered by an AGM are taken into account.

You are correct in what you say, however the AGM if correctly managed by the charger can be charged at much higher currents for the first part of a charge cycle say up to 75 to 80% full charge but from then on it must be charged much more slowly for the cells to absorb that charge. And that is the problem, that final time period is not be reached by cars doing modest mileage. This is where I keep saying the effect is incremental, you go from 100% to 90% but then only back to 98% and so on. 

Using AGM on a traditional starter actually takes very little from the Battery when you think how quickly a small modern engine starts. Its cranking for only around 1 second at the most in my experience, even from cold so only a percentage point or less discharge of the Battery I would think which is soon put back.  

[Corollanutter]

So just to follow up on this topic. I swapped out the 12v Battery for a slightly higher capacity (52Ah) Bosch S4. I didn't bother about going to the dealer as the diagnostic fee was about the same as the cost of the Battery - and in the case that they didn't "find" anything wrong or that the Battery wasn't covered I would end up effectively paying double. I didn't have the time to mess about sitting in the dealers for hours either. Anyway, one week after the swap, I have just tested the battery voltage again and it is showing about 85-90% charge, compared to around 50% with the old battery over the same time period. Added to that over the past few days I have been using heated seats, rear screen etc a LOT more due to the sudden drop in temperature. So I think the old battery was duff - and had simply gone very low capacity and with a high internal resistance. Thanks to all on here for their inputs!