Flat battery on a hybrid Toyota
Discussion
Had an interesting one this eve, what to do when you get a flat car battery when parked with a hybrid.
I just picked up a little Toyota HCR from the bodyshop this eve, it started ok drove it less than a mile stopped at a shop and when I got back in it wouldn't start after a couple of go's the normal battery was so flat could not even put the hazards on. Stuck in a parking space facing the kerb with no jump leads or starter pack.
Its a hybrid auto so you cant push it.
I asked around and luckily found a lady with jump leads and she kingly parked next to me so I could connect the jump leads and I had ignition and lights...
But then what?
When you switch it on it does not start up it will only start the engine when you drive off in D or R. But I was still connected to the lady's car via jump leads.
So I got going with my flat battery but then once moving if I came to traffic lights or a roundabout it was going to switch off again as soon as I stopped, at which point I'd be stuck again. It also had zero fuel so I had to get petrol sooner than the time it would take to charge the car battery enough to re-start.
Probably there is a button to press to keep the engine on but I didnt know if there was such a feature.
My first experience of a flat battery in a hybrid!
I just picked up a little Toyota HCR from the bodyshop this eve, it started ok drove it less than a mile stopped at a shop and when I got back in it wouldn't start after a couple of go's the normal battery was so flat could not even put the hazards on. Stuck in a parking space facing the kerb with no jump leads or starter pack.
Its a hybrid auto so you cant push it.
I asked around and luckily found a lady with jump leads and she kingly parked next to me so I could connect the jump leads and I had ignition and lights...
But then what?
When you switch it on it does not start up it will only start the engine when you drive off in D or R. But I was still connected to the lady's car via jump leads.
So I got going with my flat battery but then once moving if I came to traffic lights or a roundabout it was going to switch off again as soon as I stopped, at which point I'd be stuck again. It also had zero fuel so I had to get petrol sooner than the time it would take to charge the car battery enough to re-start.
Probably there is a button to press to keep the engine on but I didnt know if there was such a feature.
My first experience of a flat battery in a hybrid!
the bms should see low battery voltage and keep the engine running in links with the smart charging system to boost the battery up. Load shedding will be happening to reduce the amount of load on the battery to also help charge it back up. However the battery could well be too dead to do anything with and require replacing.
Once the car is 'started', - this is just booting up the electronics and closing the contactors for the HV battery. The 12v battery is then charged by the HV traction battery regardless of the engine running or not.
12v battery issues on Toyota hybrids (and probably others) are usually as a result of leaving doors or hatch open for prolonged periods, or repeatedly opening the driver's door without starting the car. The car preps for being driven, boots up multiple ECUs and the brake pressure priming pump and then takes some time to fully 'sleep'. This is a significant drain on the small 12v in most hybrids. Any car that shows the open door warning on the dash before it is started or without the ignition being on is doing this.
12v battery issues on Toyota hybrids (and probably others) are usually as a result of leaving doors or hatch open for prolonged periods, or repeatedly opening the driver's door without starting the car. The car preps for being driven, boots up multiple ECUs and the brake pressure priming pump and then takes some time to fully 'sleep'. This is a significant drain on the small 12v in most hybrids. Any car that shows the open door warning on the dash before it is started or without the ignition being on is doing this.
Wife’s Ioniq has a button by the drivers knee to use the hybrid battery to jumpstart the 12v. Very clever!
As others have said, once you got it started, the BMS will keep it running if the 12v is showing low battery voltage. There’s presumably also a button somewhere to disable stop/ start?
As others have said, once you got it started, the BMS will keep it running if the 12v is showing low battery voltage. There’s presumably also a button somewhere to disable stop/ start?
5s Alive said:
Once the car is 'started', - this is just booting up the electronics and closing the contactors for the HV battery. The 12v battery is then charged by the HV traction battery regardless of the engine running or not.
12v battery issues on Toyota hybrids (and probably others) are usually as a result of leaving doors or hatch open for prolonged periods, or repeatedly opening the driver's door without starting the car. The car preps for being driven, boots up multiple ECUs and the brake pressure priming pump and then takes some time to fully 'sleep'. This is a significant drain on the small 12v in most hybrids. Any car that shows the open door warning on the dash before it is started or without the ignition being on is doing this.
Thanks interesting.12v battery issues on Toyota hybrids (and probably others) are usually as a result of leaving doors or hatch open for prolonged periods, or repeatedly opening the driver's door without starting the car. The car preps for being driven, boots up multiple ECUs and the brake pressure priming pump and then takes some time to fully 'sleep'. This is a significant drain on the small 12v in most hybrids. Any car that shows the open door warning on the dash before it is started or without the ignition being on is doing this.
Its been at the bodyshop for 7 days so probably had doors open for long periods making the battery weak.
So once I got it going I needed to get fuel, but wanted to drive around for a bit to charge up the battery with the alternator while driving.
I was in central Watford where there are loads of temporary road works, load of traffic lights and loads of roundabouts and I didnt want to come to a stop thinking it would shut down and not re-start.
So I set off driving round the estates of Watford trying not to come to a complete stop in case it would not start, but not going far enough that it would run out of petrol (range indicator said 0 miles).
I can vouch its quite tricky to go very far in Watford without coming to a set of lights, luckily there are plenty of roundabouts to go around (and around again!)
I stopped for fuel at asda and left it on (not running) when filling it up and was fine and got back to Hampshire with no issues (apart from the engine and cvt gearbox sounds like a hairdryer on full throttle).
Based on comments above Id guess the car has a fault in the charging system and will get it checked out.
rallycross said:
5s Alive said:
Once the car is 'started', - this is just booting up the electronics and closing the contactors for the HV battery. The 12v battery is then charged by the HV traction battery regardless of the engine running or not.
12v battery issues on Toyota hybrids (and probably others) are usually as a result of leaving doors or hatch open for prolonged periods, or repeatedly opening the driver's door without starting the car. The car preps for being driven, boots up multiple ECUs and the brake pressure priming pump and then takes some time to fully 'sleep'. This is a significant drain on the small 12v in most hybrids. Any car that shows the open door warning on the dash before it is started or without the ignition being on is doing this.
Thanks interesting.12v battery issues on Toyota hybrids (and probably others) are usually as a result of leaving doors or hatch open for prolonged periods, or repeatedly opening the driver's door without starting the car. The car preps for being driven, boots up multiple ECUs and the brake pressure priming pump and then takes some time to fully 'sleep'. This is a significant drain on the small 12v in most hybrids. Any car that shows the open door warning on the dash before it is started or without the ignition being on is doing this.
Its been at the bodyshop for 7 days so probably had doors open for long periods making the battery weak.
So once I got it going I needed to get fuel, but wanted to drive around for a bit to charge up the battery with the alternator while driving.
I was in central Watford where there are loads of temporary road works, load of traffic lights and loads of roundabouts and I didnt want to come to a stop thinking it would shut down and not re-start.
So I set off driving round the estates of Watford trying not to come to a complete stop in case it would not start, but not going far enough that it would run out of petrol (range indicator said 0 miles).
I can vouch its quite tricky to go very far in Watford without coming to a set of lights, luckily there are plenty of roundabouts to go around (and around again!)
I stopped for fuel at asda and left it on (not running) when filling it up and was fine and got back to Hampshire with no issues (apart from the engine and cvt gearbox sounds like a hairdryer on full throttle).
Based on comments above Id guess the car has a fault in the charging system and will get it checked out.
Unlike Lithium batteries lead acid batteries are healthiest sitting at high states of charge. Persistent low charge levels degrade them quickly. Fully flat 12v batteries are reported to lose at least 5% of their original capacity with each such event.
The charging algorithms of many hybrids and BEVs do not appear to keep the the 12v as happy as the humble old alternator. In the early days Tesla were replacing 12v batteries routinely every 12 months.
It’s fairly common to have 12V battery failures in Toyotas unfortunately as they are usually very small batteries.
Some of them are a type that can be damaged by running flat so need to be replaced as they’ll never recover full capacity.
There’s no need to drive around, as long as you have the ready indicator on the dash the 12V is being charged. During lockdown I’d sit in the car for 30-60 minutes with the car in ready mode to charge up the 12V battery.
All the 12V does to start the car is power up the computers and close a relay to the big battery, I’ve heard you can jump start one with a tiny battery that fits in your pocket.
I bought a small jump pack for mine, it doesn’t need to be a big/heavy one.
Some of them are a type that can be damaged by running flat so need to be replaced as they’ll never recover full capacity.
There’s no need to drive around, as long as you have the ready indicator on the dash the 12V is being charged. During lockdown I’d sit in the car for 30-60 minutes with the car in ready mode to charge up the 12V battery.
All the 12V does to start the car is power up the computers and close a relay to the big battery, I’ve heard you can jump start one with a tiny battery that fits in your pocket.
I bought a small jump pack for mine, it doesn’t need to be a big/heavy one.
Whataguy said:
It’s fairly common to have 12V battery failures in Toyotas unfortunately as they are usually very small batteries.
Some of them are a type that can be damaged by running flat so need to be replaced as they’ll never recover full capacity.
There’s no need to drive around, as long as you have the ready indicator on the dash the 12V is being charged. During lockdown I’d sit in the car for 30-60 minutes with the car in ready mode to charge up the 12V battery.
All the 12V does to start the car is power up the computers and close a relay to the big battery, I’ve heard you can jump start one with a tiny battery that fits in your pocket.
I bought a small jump pack for mine, it doesn’t need to be a big/heavy one.
I have a hybrid Toyota. The small battery does concern me. Can you get a bigger battery in ? Matt from CarWow flattened the battery in a Toyota that he had on test.Some of them are a type that can be damaged by running flat so need to be replaced as they’ll never recover full capacity.
There’s no need to drive around, as long as you have the ready indicator on the dash the 12V is being charged. During lockdown I’d sit in the car for 30-60 minutes with the car in ready mode to charge up the 12V battery.
All the 12V does to start the car is power up the computers and close a relay to the big battery, I’ve heard you can jump start one with a tiny battery that fits in your pocket.
I bought a small jump pack for mine, it doesn’t need to be a big/heavy one.
Which jump start thing did you get?
rallycross said:
no issues (apart from the engine and cvt gearbox sounds like a hairdryer on full throttle).
I'm currently driving around in a a Yaris Hybrid and have come to the conclusion that this is the first car I've ever driven where it shuts down any attempts to drive it fast (i am pretty sure it would tut if it could!) and while the EV/CVT combination is seamless and super-smooth, the noise it makes on anything beyond light tthrottle is painful and a bit embarrassing!Chris
I have a Corolla hybrid and had the flat 12v battery issue a few times.
Mentioned it to Toyota when it went in for its service and they done a health check on the battery, found it had damaged cells so was replaced under warranty with a higher capacity battery. Never had any issues since.
Toyota's advice is that if the car is sitting unused, to run it in ready mode for an hour a week to keep the battery charged.
Also if you're washing the car, or opening and closing doors its better just to stick it in ready mode. Same if you're just sitting in the car somewhere waiting for someone, leave it in ready mode. Keyless system is a big drain on the battery apparently.
I know some owners also use solar panels or trickle chargers to get around this issue but I think that's overkill IMO.
It's one of these Japanese quirks where they have approached things completely differently from everyone else but makes sense once you understand how the system works and learn to work around it.
Mentioned it to Toyota when it went in for its service and they done a health check on the battery, found it had damaged cells so was replaced under warranty with a higher capacity battery. Never had any issues since.
Toyota's advice is that if the car is sitting unused, to run it in ready mode for an hour a week to keep the battery charged.
Also if you're washing the car, or opening and closing doors its better just to stick it in ready mode. Same if you're just sitting in the car somewhere waiting for someone, leave it in ready mode. Keyless system is a big drain on the battery apparently.
I know some owners also use solar panels or trickle chargers to get around this issue but I think that's overkill IMO.
It's one of these Japanese quirks where they have approached things completely differently from everyone else but makes sense once you understand how the system works and learn to work around it.
MonteCarlos1 said:
I have a Corolla hybrid and had the flat 12v battery issue a few times.
Mentioned it to Toyota when it went in for its service and they done a health check on the battery, found it had damaged cells so was replaced under warranty with a higher capacity battery. Never had any issues since.
Toyota's advice is that if the car is sitting unused, to run it in ready mode for an hour a week to keep the battery charged.
Also if you're washing the car, or opening and closing doors its better just to stick it in ready mode. Same if you're just sitting in the car somewhere waiting for someone, leave it in ready mode. Keyless system is a big drain on the battery apparently.
I know some owners also use solar panels or trickle chargers to get around this issue but I think that's overkill IMO.
It's one of these Japanese quirks where they have approached things completely differently from everyone else but makes sense once you understand how the system works and learn to work around it.
Just sounds like poor system design imo.Mentioned it to Toyota when it went in for its service and they done a health check on the battery, found it had damaged cells so was replaced under warranty with a higher capacity battery. Never had any issues since.
Toyota's advice is that if the car is sitting unused, to run it in ready mode for an hour a week to keep the battery charged.
Also if you're washing the car, or opening and closing doors its better just to stick it in ready mode. Same if you're just sitting in the car somewhere waiting for someone, leave it in ready mode. Keyless system is a big drain on the battery apparently.
I know some owners also use solar panels or trickle chargers to get around this issue but I think that's overkill IMO.
It's one of these Japanese quirks where they have approached things completely differently from everyone else but makes sense once you understand how the system works and learn to work around it.
Unless all makes have the same issues.
I assumed being a hybrid, with it being plugged in it would take care of everything!
(Not an EV owner of any flavour)
As mentioned, the 12V battery is charged from the HV battery so keeping the engine running doesn't increas the charge rate of the 12V battery any more than driving it with the engine starting and stopping as you drive or even just parked with it in Ready node (as long as the HV battery has sufficent charge to give to the 12V battery).
If you use the steering wheel buttons on the right hand side to put it in Sport mode it will charge the HV battery more agressively when driving and prevent the engine stopping as much as it does in normal or eco mode, this means the HV battery isn't required to start the engine as often and will therefore maintain a higher level of charge.
https://mag.toyota.co.uk/coronavirus-toyota-hybrid...
If you use the steering wheel buttons on the right hand side to put it in Sport mode it will charge the HV battery more agressively when driving and prevent the engine stopping as much as it does in normal or eco mode, this means the HV battery isn't required to start the engine as often and will therefore maintain a higher level of charge.
https://mag.toyota.co.uk/coronavirus-toyota-hybrid...
119 said:
Just sounds like poor system design imo.
Unless all makes have the same issues.
I assumed being a hybrid, with it being plugged in it would take care of everything!
(Not an EV owner of any flavour)
Most hybrids of varying flavours (self-charging/plug in etc) have small 12v batteries as a big battery is not needed to crank the engine over much like it would in a normal ICE car. The 12v is only really needed to activate the ECU, which then in turn activates the electric motor to crank the engine using the main hybrid battery.Unless all makes have the same issues.
I assumed being a hybrid, with it being plugged in it would take care of everything!
(Not an EV owner of any flavour)
A look on forums for various marques suggest this is a common issue with hybrids. As mentioned above kia/hyundai have thought about it and offered a button that uses the hybrid system to charge the 12v battery in emergency but that can also be dangerous if the hybrid battery is low or flat (assuming its a self charging hybrid and not a plug in).
You would be left with a charged 12v battery and an empty hybrid battery and would be unable to start the engine as a result which is a worse outcome as the car would have to be towed to the garage for the hybrid battery to be charged. I think this is why Toyota (and other marques) have not bothered with an emergency switch.
Also, Toyota have been developing hybrid cars for 25 years now and are obviously very good at it given their reliability record. There is probably a good reason why they have done the 12v battery system this way even though it has some shortcomings.
littleredrooster said:
In Park - Ready, the ICE can be made to run by prodding the throttle, or kept running by holding the throttle open.
Thanks some interesting points coming up here, for anyone new to hybrid flat batteries.It did it again today back at the garage and I tried the above tricks but it would not keep the motor running. Its currently on charge but think we will just put a new battery on it.
rallycross said:
littleredrooster said:
In Park - Ready, the ICE can be made to run by prodding the throttle, or kept running by holding the throttle open.
Thanks some interesting points coming up here, for anyone new to hybrid flat batteries.It did it again today back at the garage and I tried the above tricks but it would not keep the motor running. Its currently on charge but think we will just put a new battery on it.
My Mitsubishi Outlander PHEV has a tiny 12V battery. Unfortunately when it fails it gives no warning as you'd get with a conventional ICE car such as slow starting etc. On the Outie PHEV FB group a fair few people just change the battery every 3-4 years before it fails. Unfortunately because its in the passenger compartment it is a specific battery and not particularly cheap.
The Mitsi can be jump started but must not jump start other cars. The car wakes up at 02:00 and if needed the HV battery charges the 12V battery.
you can force the petrol to run but it needs the 12V healthy in order to start.
The Mitsi can be jump started but must not jump start other cars. The car wakes up at 02:00 and if needed the HV battery charges the 12V battery.
you can force the petrol to run but it needs the 12V healthy in order to start.
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