Flat Battery issue

[Roy124]

Although my car is a Corolla I think the topic is a general one.  

My car had been parked in the garage and left, doors closed, but not locked.  When I next went to the car the car Battery appeared to be flat.  I think an interior light was on and dim and certainly did not bright up when the door was opened.  The central display did not light up and the car was otherwise dead.

I connected a Ring charger to the Battery and switched it on.  The charger lights then flicked between charging and charged whether the rate was set at fast or slow.  Odd.  After a few minutes, say 5-10, I disconnected the charger and tried again.  It started as if nothing had happened.

Had the Battery recovered by itself after I switched off the light?

Is my charger suitable; it says suitable for lead acid and gel batteries?

Any comments?

[Roy124]

car failed to start again this evening.  AA Man came out diagnosis was a faulty start Battery.  He explained that the small Battery will start the electrics whereupon the mani Battery takes over.  Just sitting with the Ready light on, even if it wont start immediately will allow the main battery to charge the start battery.  The car will start the petrol motor from time to time to keep the main battery charged.

Now the question:

On the main navigation screen new the bluetooth and wifi strength signal is a battery symbol.  What does it signify?  In recovery there was just one bar.  Next time I checked that whole bar, bluetooth, wifi etc was dark.  So what battery does that show as the big battery has the blue bars in the main part of the screen.?

[TonyHSD]

If you want to save your 12v Battery you have to charge it with trickle charger and use the car once or twice a week for 30+ min at a time, or just turn on in ready mode and leave it like that for 1hr, engine will run often now in the cold weather but that’s ok as long as you have petrol in. The hybrid Battery as aa man told you it’s not a main Battery and never takes over, the hybrid battery only propels the car and air conditioning, anything else is powered by the small 12v battery which charges slower than standard car 12v battery and discharges faster. Toyota hybrids requires at least once a week to keep the car in ready mode for 30-60min to keep 12v battery happy. 👍

[Rosgoe]

I doubt the Battery is faulty not on a 2020 model if you leave any lights on the car should power down after 20 minutes this is to stop the 12v Battery going flat as you can’t start the hybrid system with a flat 12v Battery .

as far as I am aware the 12v battery is lead acid ( correct me if I am wrong) as has been mentioned on the forum before are you leaving the key within range of the car as the key is transmitting all the time so the car thinks it wants to start so this is maybe why the battery is going flat disable the signal from the key by pressing and holding the lock button then press the unlock button twice led will flash 4 times.

I think that the battery symbol you are referring to is your phone battery as the hybrid battery state of charge bars are coloured green.

[Rosgoe]

9 minutes ago, TonyHSD said:

If you want to save your 12v battery you have to charge it with trickle charger and use the car once or twice a week for 30+ min at a time, or just turn on in ready mode and leave it like that for 1hr, engine will run often now in the cold weather but that’s ok as long as you have petrol in. The hybrid battery as aa man told you it’s not a main battery and never takes over, the hybrid battery only propels the car and air conditioning, anything else is powered by the small 12v battery which charges slower than standard car 12v battery and discharges faster. Toyota hybrids requires at least once a week to keep the car in ready mode for 30-60min to keep 12v battery happy. 👍

I connect my Battery charger once a week during this lockdown just leave it on normal charge rate 5 amps I think until the Battery charged light comes on. Don’t bother disconnecting the negative terminal doesn’t seem to do any harm done the same with the auris I had.

[Roy124]

Thank you both.  Rosgoe, that explains the blank line.  First time I had my phone with me, second time I didn't hence no bluetooth or Battery.  Keywise the key is well away from the car, thanks for the tip though.

Tony, true, but the AA man said the Battery should charge at a rate of 10 amps per house and it was much slower than that which was why he suggested to Battery be checked.  We use the car for 20-30 miles at least once per week to get to the shops.  We also may do an extra journey 15 miles of so to the doctors so to is getting a run, if not exactly long runs.

[Roy124]

My Battery charger is not the CTK recommended by Honest John but a Ring one.  Its behaviour is rather odd.  Connected but powered off its charge light comes On.  I suspect  it is actually being powered from the small Battery.  When the charger is switched on its power light comes on and its amber charge light goes out.  The green lamp illuminates showing charged.  In this case I suspect it may be the main Battery charging the small battery thus fooling the charger to say the small battery is charged.

What charger do you use?

[Rosgoe]

17 minutes ago, Roy124 said:

My battery charger is not the CTK recommended by Honest John but a Ring one.  Its behaviour is rather odd.  Connected but powered off its charge light comes On.  I suspect  it is actually being powered from the small battery.  When the charger is switched on its power light comes on and its amber charge light goes out.  The green lamp illuminates showing charged.  In this case I suspect it may be the main battery charging the small battery thus fooling the charger to say the small battery is charged.

What charger do you use?

I use a ring charger probably the same as yours but obviously when I connect I make sure the car is powered down ie: ignition off and not in accessory mode also I make sure the boot and all doors are shut, pretty sure the 12v Battery does not receive a charge from the hybrid Battery until the ready light is on.

[Roy124]

Rosgoe, that is worth checking, I will try tomorrow.  My decades old charger, 1960s vintage, had a charge rate dial which was far better than a simple light system.  Maths was simple - 50 A/hr Battery, 5 amp charge, then down to 2 amp trickle 🙂

[Devon Aygo]

On 10/29/2020 at 3:13 PM, Roy124 said:

My car had been parked in the garage and left, doors closed, but not locked. 

The car relies on being locked to reduce power consumption, after you lock the car it slowly powers down various systems to prevent excessive current drain, leaving the car unlocked will prevent this and the car will sit in a higher state of readiness and consume more power.

[Roy124]

DA, I must get into that habit, especially as I don't need to lock it.  The AA Man did say to ensure the keys are out of range.  I might check that too.

[TonyHSD]

All correct here, however even when you leave your car unlocked the car bms will turn off all power consumption accessories automatically to preserve the 12v Battery, done experiments myself. I think the combination of all mentioned together has drained your Battery and pretty much to all people who has same things happened to them. One more idea: make sure you lock the car and take away the key and store it in a can of Pepsi or similar, even no lid on top the can completely blocks any signal to and from the key fob, it is also a great theft prevention and Battery saver. 👍

[Roy124]

Tony, thank you.  I tried a range check.  My garage is attached to the house.  My keys are near my front door and on a direct line about 20 feet away.  On a diagonal the direct path passes through a double thermalite block wall.  The key works.  Rather than your pepsi can idea I think we can go one better.  We have a small drawer in our hall table.  It is the exact size of a Marks and Spencer Belgian chocolate biscuit tin*.  I will try that.

*I must declare an interest, we have M&S shares so please try their biscuit tin 🙂

[TonyHSD]

Not just a biscuits, but an M&S biscuits 🙂 I will thanks for that., I do my shopping mostly from them, like their food the best of all shops.👌

When inside the car and hold the key, car on ready mode , put the key in the can or biscuits box and see if you get a message on display “key not detected “, just to make sure works. 👍

[Roy124]

Tony, thank you.  I tried a range check.  My garage is attached to the house.  My keys are near my front door and on a direct line about 20 feet away.  On a diagonal the direct path passes through a double thermalite block wall.  The key works.  Rather than your pepsi can idea I think we can go one better.  We have a small drawer in our hall table.  It is the exact size of a Marks and Spencer Belgian chocolate biscuit tin*.  I will try that.

*I must declare an interest, we have M&S shares so please try their biscuit tin 🙂

[Roy124]

A peripheral tips, flat key Battery,  Open car with emergency key, hold keyfob up to Start button, press start.

[Gerg]

17 hours ago, Roy124 said:

Tony, true, but the AA man said the battery should charge at a rate of 10 amps

It would seem that the AA man is not correct on this - you were right.  The technical dept at Yuasa UK advised that on any AGM type Battery (Corolla has an AGM Battery as per the Auris hybrid, no?), their recommended charge rate is 10% of the rated capacity of the Battery.  Charging faster than that can be done, but risks damaging the battery through overheating it.  At around 10+ amps charge rate, they advised that the battery would have to be constantly monitored to check its temperature, but that this sort of charging is generally not recommended if it can be avoided.

[flash22]

AGM batteries like it low and slow circa 2-5 amps the lower the better

Gerg, i have been caught out by this  some hybrids don't use the AGM batteries

 

ps. I do like the M&S Belgian curls aka biscuit Curls, they are very morish

[Roy124]

18 hours ago, Rosgoe said:

I use a ring charger probably the same as yours but obviously when I connect I make sure the car is powered down ie: ignition off and not in accessory mode also I make sure the boot and all doors are shut, pretty sure the 12v battery does not receive a charge from the hybrid battery until the ready light is on.

Rosgoe, did that.  Locked the car then connected the charger.  This time only the power and charging lamps lit.  Previously there was obviously a contest between the charger and the main Battery both connected,  I left it on fast, before reading Gerg's advice but I think 'fast' with this charger is 5 amps.  Anyway 15-20 minutes later the lights changed to fully charged.  Unlike my 60's charger this one switched off.  It is a lead acid/gel Battery charger.  I might add we also went for a 30 minute drive earlier so it would have been nearer full anyway.

Oh for an ammeter or even a volt meter.  I used to have a volt meter, might get one again.

[Rosgoe]

8 minutes ago, Roy124 said:

Rosgoe, did that.  Locked the car then connected the charger.  This time only the power and charging lamps lit.  Previously there was obviously a contest between the charger and the main battery both connected,  I left it on fast, before reading Gerg's advice but I think 'fast' with this charger is 5 amps.  Anyway 15-20 minutes later the lights changed to fully charged.  Unlike my 60's charger this one switched off.  It is a lead acid/gel battery charger.  I might add we also went for a 30 minute drive earlier so it would have been nearer full anyway.

Oh for an ammeter or even a volt meter.  I used to have a volt meter, might get one again.

Just charged mine up again just in case, as Gerg said I think it Maybe it is an agm Battery so I stand corrected. Your car 12v Battery should now stay fully charged but I would check at least once a week or drive the car at least 5 miles or leave it in ready mode for an hour as has been suggested by Toyota during the last lockdown.

I read in a car mechanics magazine on batteries that an alternator will not charge a Battery to full capacity from flat but once it has been charged with a battery charger the alternator will then maintain the charge, I don’t know if this applies to hybrid cars such as ours as I believe they are charged from the traction battery. I agree with you about ammeters and volt meters.

[Gerg]

9 minutes ago, Rosgoe said:

Maybe it is an agm battery so I stand corrected.

Hi Rosgoe, I hadn't spotted that you'd said anything different - this wasn't meant to contradict anything you'd said.  It would be interesting to see if your battery is an AGM - I was only guessing!

11 minutes ago, Rosgoe said:

that an alternator will not charge a battery to full capacity from flat

I wonder if this particularly relates to the more recent 'smart' (brake energy recovery) alternators that have become popular.  These ones, which often only charge when you are braking or on the overrun, seem to change plenty of what you thought you knew about the workings of alternators of old. (well, for me, anyway)! 

Perhaps, with these new charging systems, some Battery capacity is left unused so that the alternator has something to charge into, when you brake etc?  If that is the case, then the hybrid is already doing that into the traction Battery, I suppose, so it will charge the Battery to capacity.  I've never seen any mention of deliberately not charging the 12v battery up

 

18 minutes ago, Rosgoe said:

I agree with you about ammeters and volt meters.

If you  were ever looking into getting a meter for more than 'emergency' use (I appreciate that you were talking about dash meters!), then this one is quite useful:-

https://www.ebay.co.uk/itm/UNI-T-DIGITAL-UT210E-100Amp-600V-AC-DC-CLAMP-METER-Multimeter-True-RMS-VFC-diode/283882488770?hash=item4218b703c2:g:CWgAAOSwXHhdkA1E

It's sadly gone up a chunk, strangely this is since Brexit.  I have had one for a few years (£30 back then).  It's claim to fame is that it has a clamp-on DC current meter, which used to be a very expensive feature a while back. Great for automotive charge/discharge problems - no dismantling needed. But the rest of the meter is fairly ordinary.

Perhaps you are aware; there are simple, but functioning, digital voltmeters available from China for £2.80 upwards, that's including (pretty slow) delivery.  Not an item to remotely be proud of, but the value is there!

 

[Rosgoe]

5 minutes ago, Gerg said:

Hi Rosgoe, I hadn't spotted that you'd said anything different - this wasn't meant to contradict anything you'd said.  It would be interesting to see if your battery is an AGM - I was only guessing!

I wonder if this particularly relates to the more recent 'smart' (brake energy recovery) alternators that have become popular.  These ones, which often only charge when you are braking or on the overrun, seem to change plenty of what you thought you knew about the workings of alternators of old. (well, for me, anyway)! 

Perhaps, with these new charging systems, some battery capacity is left unused so that the alternator has something to charge into, when you brake etc?  If that is the case, then the hybrid is already doing that into the traction battery, I suppose, so it will charge the battery to capacity.  I've never seen any mention of deliberately not charging the 12v battery up

 

If you  were ever looking into getting a meter for more than 'emergency' use (I appreciate that you were talking about dash meters!), then this one is quite useful:-

https://www.ebay.co.uk/itm/UNI-T-DIGITAL-UT210E-100Amp-600V-AC-DC-CLAMP-METER-Multimeter-True-RMS-VFC-diode/283882488770?hash=item4218b703c2:g:CWgAAOSwXHhdkA1E

It's sadly gone up a chunk, strangely this is since Brexit.  I have had one for a few years (£30 back then).  It's claim to fame is that it has a clamp-on DC current meter, which used to be a very expensive feature a while back. Great for automotive charge/discharge problems - no dismantling needed. But the rest of the meter is fairly ordinary.

Perhaps you are aware; there are simple, but functioning, digital voltmeters available from China for £2.80 upwards, that's including (pretty slow) delivery.  Not an item to remotely be proud of, but the value is there!

 

No that’s fine yes I think you are right that alternator charging about what I said does in fact refer to the alternator’s of old , I will find out if the 12v Battery is in fact an AGM i think they are on all newish cars so you haven’t got all that sulphuric acid sloshing about.

[Mooly]

5 hours ago, Rosgoe said:

............I read in a car mechanics magazine on batteries that an alternator will not charge a battery to full capacity from flat but once it has been charged with a battery charger the alternator will then maintain the charge................

Yes and no is the answer to that one. A flat Battery (as in discharged beyond normal limits) may well need a significantly higher than normal voltage to get current flowing again and for charging to commence normally. An alternator can not do that as its output voltage has strict limits.

So the answer is that 'maybe' the alternator might recover the Battery if you drove for long enough but that could be in the 10 or more hour region and its possible the Battery would just not draw sufficient current to charge and recover. If the battery could be given a high initial charge, even if only for a short time then normal charging would likely recovery.

For example the flat battery draws little current at 14 volts but if you apply say 20 volts then current flows. If the charge current is limited correctly to say 5 or 10 amps then that 20 volts from the current limited charger is actually pulled down as the battery recovers. The charger is working in what is termed constant current mode rather than a constant voltage mode.

You apply as much voltage as needed initially to get that sort of current to flow. The current is limited and the charging battery actually sees a decrease in its terminal voltage as it charges, so you see 20v, 19v, 18v and so on. It may drop quite a way below 12 volts and then start to climb again as it it begins to charge normally.

The current must  always be limited to avoid over heating the battery though. 

 

 

[Roy124]

Going back to a much earlier car designed for winter driving I did a 15 mile trip on snow in the dark with lights on headlamps on dip, front and rear fogs, windscreen and headlight wipers on and seat heaters though they switch off and heater fan on full.  Half a mile from home we stopped at a shop.  The car would not restart.  The alternator had simply not had sufficient capacity for the load and the Battery was depleted.

Moving on to a modern hybrid, the AA Man gave me to understand that the Corolla did not have an alternator to charge the Battery at all.  The AGM Battery was solely to energise the system.  Once on line the main battery would charge the AGM battery.  The main battery in turn would be charged by the ICE or by energy recovery.  Hence the car sitting there with occasional bursts from the engine.  Depending on the static load the ICE might run more frequently.  For instance downloading the map update if you sat with the heater or fan or aircon on the main battery would need topping up more frequently.  All very clever.

All useful knowledge that I would never have learnt without all your inputs.

[Catlover]

Roy, that’s correct, no alternator (nor belts), no starter motor, no clutch...... all of which can cause problems and need attention during the life of a vehicle, costing a lot of money....... then people say it will cost a lot to replace a hybrid Battery. One alternator, one starter motor, and one clutch would cost much more then a new hybrid Battery, which, with Toyotas hybrid Battery warranty provision goes up to 15 years. How cool is that.         
The ICE will also kick in when the computer detects engine has cooled too much. Hence when driving on a cold winter day the ICE may fire up when driving even though you may have hybrid battery bars showing. Very clever, but this technology has been there since Toyota marketed hybrid vehicles in the late 1990’s. Toyota have been the leaders in hybrid technology for a long time and still are IMO.