Toyota hybrids hidden issues, possible solutions and some other ideas

First let's see about what issues we are talking about, and ideas, and then additional clarification will follow below.


1. 12 V battery discharging problem

The root of this problem is in the lack of information, and solution could be very simple.
In short - drivers know nothing about charging patterns of 12V battery on hybrid cars, and they are convinced that 12V battery are 100% charged after they turn off their vehicle, which is not the case!
The solution, as I said, could be very simple - Every time after turning off power, on dashboard should display next information:

YOUR 12V BATTERY IS ONLY XX% CHARGED, IF NECESSARY PRESS THE 'START' BUTTON AND BRAKE IN ORDER TO RECHARGE IT


2. Temperature monitoring of the battery compartment

It would be very good if a temperature sensor was inserted into the 200V battery compartment, so that we could see the temperature in that compartment on the dashboard... ...and third...


3. All Toyota hybrids, plug-in hybrids...




Clarifications:


1 Discharge of 12V battery

Even before I got my new Toyota, one of my colleagues could not start his Prius after waiting for a longer time at the taxi station. He called the service department and it turned out that the problem was due to a voltage drop on the 12V battery. In addition to other consumers, taxi vehicles also have VHF radio, which (especially in handover) are large consumers of electricity.

This is exactly why I installed a voltmeter on my new car, to monitor the voltage on the 12V batery. With the help of a voltmeter, I immediately noticed some interesting things. Take a look at this short video:

- Unlike other cars, the 12V battery on a hybrid vehicles is charged only from time to time. As a result, I noticed that the next morning the voltage (and that means the charging capacity) of the 12V battery was much lower than it was on the previous car. On the previous car, the voltage would be about 12.8 - 12.9 V, which means that it is 95% charged, while on my new car, the voltage would be between 12.2V and 12.5V, which means that it is maybe 55 - 75% charged.

- The 12V accumulator is recharged only from time to time and it may happen that the driver turns off the car just at the moment when the voltage is the lowest (at the moment when the inverter should start charging it).
When you know, that consumption is 800 mA (while the car is turned off) you can count how much time you have, that you can safely turn on your car if it is charged only 55% after turning OF

This problem does not only happen to taxi drivers!
Someone may go on a winter vacation, park their car in front of the hotel with the alarm on, and when they get back into it after 10 - 14 days, the accumulator will not be able to start the car. The driver will have no idea what it's all about, and the nearest service is maybe 50 km away.

The solution from Toyota is:

"We recommend you put the car in ‘Ready’ mode for about 60 minutes before switching it off again and repeat the process at least once a week"

... but even with that solution we still have two problems:

1. Many drivers know nothing about potential problem, and had never heard of that advice.

2. Even if they know for that potential problem and recommendation, many of them will still be convinced that their battery are 100% charged after they turned off their car, and that they are absolutely safe for maybe next 7 days. But maybe they have turned off car while 12V battery is at the lowest level, a moment before it should start to activate charging process. So, battery is maybe only 55% charged, and alarm, and some other users could discharge battery in next 7 days.

So, after shutting off the car, a dashboard should show information that 12V battery isn't full at 100% but on a xx% (a computer should calculate and display exact value).
The situation in which they might need additional charging will be if car would stand for a longer period, or using a lot off accessories in OFF mode.

If you live your car for a longer period, the best thing to do is to disconect 12V battery, that will do no harm to your battery.

By the way, that will probably lessen the number of calls to Toyota Euro Care roadside assistance.



Allso, beside voltmeter I carry a small jump-starter which I didn't need since I can notice voltage drops on a voltmeter, and if needed I put car in "Ready" mode.



2 Temperature monitoring of the battery compartment.

In addition to the voltmeter, I also installed an indicator of a temperature in the 200V battery compartment (with a suitable sensor) in my car. Monitoring the temperature in that area is very important!
Until I had that instrument, I was guided mostly by the information about the outside temperature and based on that I would adjust the operation of the air conditioner, which is a big mistake.
If the outside temperature is only 20C, and you stand for a long time in a queue on a sunny day, the temperature in the cabin and battery compartment will be much higher than while driving during night at the same 20C.

In addition, when I monitor that temperature and see that it has suddenly jumped, I immediately know that some party behind me has closed the ventilation hole and that this is the reason for the temperature jump.

So, based on that data, I decide when I'm going to turn on the air conditioning, whether I should turn it up, and whether I should check that the rear vents are working.

If the temperature is constantly monitored and kept under control, the life of the battery will be extended, and probably the efficiency will increase.


3 All Toyota hybrids, plug-in hybrids

It would be good if all Toyota’s Hybrid cars (at least in areas with cooler climate!) had the option of external recharge of the big batterie (say, inside of a garage overnight, with clever charger!!!)

What are the benefits?

Theoretically, we can start a hybrid vehicle in the morning with either a full or an empty battery. In the first case, a fully-charged battery will revive/unload the engine while warming up, whereas, in the second case, the engine will be additionally burdened with recharging the battery during the warm-up period.

It is when petrol engines are cold that they reach the highest consumption, therefore the first (and less significant) difference will be instantly visible in somewhat lower consumption of fuel.

What is more inportant - relieving the engine during warmup will extend it lifespan

Also, if we empty the battery before reaching home (as much as we could while driving in EV mode), the consumption decrease will be considerable.

Additional idea could be if we maybe had a 230V heater inside the engine block, for the engine to warm up prior to ignition :) .

At the end, just to mention that my average consumption from Aprill till the end of the October is about 3,4l/100km (69 mpg). In May and October it was 3,3l/100km (71 mpg)

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Edit 22.11.2022

An interesting thing happened, and that is, that not long after I posted this text, my 12V battery also failed.

On Sunday morning I drove out and parked the car in front of the garage. Some 8 hours later, I get into the car to park it back, but the hybrid circuit could not be activated because the voltage on the battery was less than 12V. With the jump starter, which I keep in the car, I started the car, put it in the garage and connected the smart charger.

I assume that the reason is in the following: it is likely that the previous day I turned off the car just before the inverter started to charge the battery (when the voltage on it is the lowest), just starting it drew a little more current from it, and in the two minutes it took me to take the car out, the battery could not be replenished sufficiently.

I shared my experience in a Viber group, which also includes a gentleman from Toyota Serbia.
Considering that reliability is the first thing that comes to mind with Toyota, it is a real shame that there is such a banal thing that can be solved very easily.

In the group I wrote what I think Toyota should do:

1 update on the car itself - after turning off the car, information appears on the dashboard - how much the battery is charged (let’s say 74%) and in case the charge is lower (as we said, it is not always the same), an additional warning that it should be topped up in ready mode

2 to explain it in detail and point it out in the book that we all received with the car

3 to instruct all service centers and car dealerships to draw the attention of every driver of a hybrid car to the fact that the 12V battery after turning off the car is not 100% charged as in other cars and to instruct them to carefully read all the instructions in this regard in the book (or on the Internet).

After that, I asked the gentleman from Toyota the following questions:

- What do you think, would there be any benefit if, after switching off, information about the battery charge appears on the hybrid car, let’s say 62% or 78%, and if it is 62%, then also an additional warning that the battery should be topped up?
I turned off the car and I had the problem with starting already after 8 hours, and not after 8 days. If I had received information on the dashboard that I would have to top up the battery, the ignition problem would not have occurred.

- How much do you think it would increase the cost of producing a car, if only the processor, based on the voltage on the battery, calculates how charged it is and displays that information on the dashboard?

- The third question is - if you were to weigh the benefit from it on one side, and the harm (cost) on the other, which side do you think would prevail?
(by the way, the benefit would be at least in fewer calls to the Toyota Eurocare service)

And the last question - if by chance the benefit would be greater than the harm, do you think it would make sense to present this idea to Toyota?


Until Toyota eventually does an update, there are things you could do yourself:

1 You can install an instrument that shows the current voltage and charge of the battery

2 You can also install a temperature monitor in the battery compartment (with a suitable sensor)

3 a slightly better electronics technician could make you a smart charger for a 200V battery

4 You should change all bulbs in cabin and trunk.
I do not understand why did Toyota, instead of LED bulbs of 1W or less, put 8W bulbs in vehicles where there may be problems with the discharge of the 12V battery? .