Retrofit Plug-In for a full hybrid car.

[Timmon]

It seems a good idea to be able to remove the batteries and charge overnight away from the car. 

All this is way over my head! But I had a look at what someone did with a Prius back in around 2010, in Bristol, UK, and she had a system where she could charge the batteries in the vehicle, and the charge status and mileage achieved on Battery appeared on the internal display etc. She was able to drive locally around Bristol on batteries only for an extended period.

It seemed to work well, until one evening the power went off in the house, and she went out to the car to find the batteries had melted, and the Prius was written off.

She was going to try doing the same to a Nissan Leaf, but that is where the story ended.

[nuccio]

59 minutes ago, Timmon said:

It seemed to work well, until one evening the power went off in the house, and she went out to the car to find the batteries had melted, and the Prius was written off.

She was going to try doing the same to a Nissan Leaf, but that is where the story ended.

Hi Timmon

The story's over because it all caught fire?

These reports make me a little anxious, because it is true, there's always the danger of something happening.

It happened to a friend of mine while he was riding around on an electric bike.

The controller caught fire, but luckily the Battery was saved and it's still working.

Look what's left of the controller, down here.

I had to redo all the connections because the wires were burned out.

Nuccio

 

[Timmon]

Yes, the story ended because of the fire. The owner said the car was written off. I am not sure if they got all of their insurance money or not. I guess if the insurance company were aware of the modifications, they did. The owner got almost 2 years use from her modification, before the system failed spectacularly.

The risk will always be there when using third party modifications that are not approved or fitted by Toyota.

Whatever you decide to do, I guess you realise that it will be a bit of fun, no worries if you write off the car, or spend money and it doesn't work, or Toyota dealers decide not to offer support for your vehicle any more.

Just a hobby, and happy to buy another car if it goes wrong. That's the only approach you can have.

Yes, if that happened to your friend, there is a good chance it could happen to you. And being a car, it will smoke damage the inside of the car, at best. That's the risk you take. On a bike, I guess you replace the saddle and repaint if needed, then blow any smoke smells away by riding it.

[nuccio]

With this project I have to act very carefully because the value of the car is very high and it is vital that nothing happens to it.
The risks are on two levels: the first one is that the car gets ruined, for example it catches fire. The second level of risk is that the insurance or Toyota does not cover the damage.
But without risking anything, nothing is done.
I've been designing and building electric motorcycles for 10 years and I need this experience to understand where and why these fatal breakdowns happen.
In my project there are 2 sources of risk:
1) - The Battery
2) - The Boost Converter.
Tomorrow we will see how to limit these risks.
Good night.
Nuccio

[nuccio]

Battery DANGER

Modifying a hybrid car puts us at great risk of setting everything on fire (not just the car).
The main source of this risk is the hybrid Battery, in our case lithium-ion Battery.
The heat that develops chemical reactions during normal discharge and charging raises the temperature of the battery.
Sometimes after intensive use or when fully charged we have all noticed that even our mobile phone is hot.
The problem arises when the temperature reaches too high and triggers chain reactions.
But it's not just the heat that creates problems. The voltage or state of charge must also remain within set values.
It's bad enough we have to deal with all these things.
But let's not worry, in all lithium batteries there are electronic circuits that handle everything well.
In our Corolla there is even a computer dedicated only to battery management.

I don't want to alarm you because our cars are safe and well tested, but in case a battery alarm appears on the dashboard it is better to take this seriously and contact Toyota assistance immediately.

But the batteries in my kit are not made by Toyota, what risk do you run with them?
A micropocessor monitors the current, the voltage of each cell and the temperature in various parts of the battery pack and if only one of these values goes out of limit, it immediately breaks the connection with the outside.
The quality of construction and connections is also very high. Using the experience of many years of work on electric motorbikes I have used many tricks that increase the safety and reliability of the batteries.

Then I must say that in this use my batteries are absolutely not stressed because they have to deliver a very low current compared to their capacity.
To give you a better idea when using on an electric bike my batteries deliver 110 amps continuous while reaching over 200 amps peak.
My kit, on the other hand, delivers a maximum of 50 amps of peak current, and this little developed heat is no problem at all.

I'd say the Battery Danger is very limited.
But there is also the danger brought by the Boost Converter's power circuits, which we will talk about tomorrow.
Greetings
Nuccio

 

[nuccio]

Here I am discussing the ...

DANGER FROM THE BOOST_CONVERTER CIRCUIT

I divide the electronic circuits into 2 types:
- The first is made up of all those circuits that I call control and transmission of signals, which by their nature are not at all dangerous because they work with very low voltages and equally low currents. These circuits, if well designed and manufactured, cannot burn out, especially if they are protected by a fuse.
- In the second type I put those circuits that must work with higher currents, from 100 mA up to hundreds of amperes. The Boost-Converter is one of these. 
Mine works with currents up to 40 Amps input, and to raise the output voltage, it has to continuously interrupt the flow through a key component called Power Mosfet.
It is designed to handle up to 160 Amps of current, but even with only 40A it heats up after a while, which is why it has to be mounted on a heat sink.
Any excess heat is dissipated by a fan that ignites when a certain temperature is reached.
If the temperature gets too close to the acceptable limit, the circuit breaks and switches off the entire Power-Bank system.

During the first tests, a display will allow me to monitor the temperature during active driving. 
The most critical moments are accelerations and higher speeds. In fact, the current supplied by the Boost-converter is proportional to that required by the electric motor.

In conclusion we can say that when the car is parked or stopped there is no risk from the electric circuits because they are all off.
Moreover, both when the car is on and when it is off, there is no danger that the current from the hybrid system could flow to the Power-bank kit, so there is no danger of damaging the hybrid system.

To limit the risks as much as possible, the power off systems are duplicated. For example, each Battery has its own BMS which will cut off the current flow when the Battery has run out of power, but so will the Boost-converter if it detects an input voltage below the safety limit.

What do you think?
Greetings
Nuccio

 

[Sampleman]

Hi Nuccio,

you are comparing the use of your project with a powerbank for a smartphone, which enhances the performance of the product. This is the point where I'd like to address my doubts.

I know the problem of keeping my smartphone alive. I need mine for both business and private purposes, and usually one charge covers one day. So there is no need for more Battery capacity, because I can charge it at home. Every now and then I visit an industry fair. Out of various reasons, this increases the power consumption of my phone, so one charge does not cover the entire day. A phone which stops working at 7pm is almost worthless for me when my last meeting ends at 11 pm. So I can buy a small, cheap power bank in order to recharge it once. This helps me to keep the phone alive for one day - and I can charge everything at night in the hotel. Once or twice a year I attend to a motorcycle festival and sleep in a tent for two or three nights. Now I need a solution to keep my phone alive for at least three days. So I bought a bigger power bank (about the size of a video cassette). It not only keeps my USB charged gadgets alive, it also has an integrated torch - and it can jumpstart my motorcycle in case of emergency. Great value for 75 Euro!

Fitting your Corolla Hybrid with a bigger Battery will not be done for 75 Euro. Several thousand Euros seem far more likely to me. But what is the big benefit of it?

But, anyway: It is your car and I would love to see you coming out with a successful solution.


Best regards from Bavaria
Frank

[HSDish]

Still very curious about this prodject. 

Would love to get ideas to be able to increase EV range for our Prius+ 2017 ( a car that suits our needs very well if it only could do some more pure ev driving)

[GG78]

Hi, this project sounds just like something I'd be interested in. Any progress since the last posts?

[roger451152]

If you go through with this project please send me updates as I have been researching the exact same topic for a little while myself on the same car. There are kits out there for the Prius to be converted but yet to see one for the Corolla.  

The designs of the two cars are very similar and should in theory be able to be changed to work slightly to work.  I haven’t looked up the exact specks of the Prius but what little I did look at when buying the car there’s not a whole lot of difference.  You may need to change out the electric motor for a more powerful one if you wanted higher speeds, larger Battery packs, and change some of the cars stock programming.  The Battery pack, wiring harness, and motor swaps should be fairly straightforward.  The most difficult part I’ve run into through research for me is changing or fooling the cars original programming. 

Its possible that there’s already programming chip out there that will let you override the factory’s setting for that and allow you to adjust for the new settings needed but I’ve yet to find anything already out in production, or a legitimate workaround without going full redneck on it and bypassing everything going from scratch. 

Please keep me updated on the project and if you can video it if you do go through with it.  Best of luck if I find anything or do it myself I’ll forward any information I find along the way.  

[Jason key]

Jason key electronics engineer 

Hey guys anybody had any success with this as I'm thinking of doing a modification to mine .  Il go Into it .. mine will have three modes, 

Charge mode

Normal mode 

EV mode 

Each mode will have to fool the Battery ECU to the following states 

 Charge mode 39% soc

Normal mode  60% soc

And EV mode 73 % soc 

Iv found that at 40 percent the vehicle will charge all the time 

At 60 percent will drive normally with low power EV mode 

And over 70 percent there is a higher power EV mode .. so I'm not talking about EV mode button.. I'm talking about in normal or eco mode if the Battery level is nearly at 80 percent the engine doesn't come on as much as further research has found that you can accelerate with more amps on the electric motor (a lot more) with higher speeds and more current before the engine cuts in.. but you rarely see this as you need to have gotten down a big hill to get the Battery to 80 percent and then also be doing 50 to 60 miles per hour to see that it will actually drive at 60 miles per hour on electric only .. it will only do this for a very short period as the small battery goes below the level very quickly so a decent amount of power is available from the electric part of the drive train but the soc level needs to be very high over 73 percent once it gets to 72 it backs off to a slightly lower level still more electric than normal once it goes down to around 64 the engine will cut in after the eco on the dial as nornal