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Retrofit Plug-In for a full hybrid car.


nuccio
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Hello everybody,

I recently purchased a Toyota Corolla 1.8 Hybrid that I was excited about its technology.

I particularly like the fact that, in cities and provincial roads, most of the time you travel with the engine turned off.

Until I checked it out for myself, I didn't think it could go this far.

But the appetite comes eating... and so I said to myself, how nice it would be to be able to go a few more kilometers with just the electric motor !

So I started to study what we could do, to make those extra miles, without buying a plug-in hybrid.

In practice I would need a kit consisting of an additional Battery and a boost-converter that transfers energy from an additional Battery to the hybrid system.

I know there are already retrofit kits on the market, but no one convinced me, so I thought of building it myself.

I have already thought about what features it should have, but before proceeding with its construction I would like to know your opinion.

That is, how would you like it?

Thanks

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I assume you don't intend to maintain any warranty coverage on the car? as any such modification would certainly render any warranty or drive-train, hybrid and electric system invalid.

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Hello Nuccio, sounds interesting what you are suggesting. I am keen to learn more about the technicalities, and if you go ahead with a project as to how it develops. But doing it on a 12 month old car (if that), what if it all goes wrong and you waste a load of money experimenting? Could hurt your wallet seriously.

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Apart from the warranty serious problem, I find it a bit pointless to try making plugin hybrid from a car with such a weak electric motor.

Even you will have enough electricity for lets say 20-30 kilometres, the motor will be still so weak that during acceleration the car will still start the ICE. And trying to keep the driving and acceleration in the EV zone only for such long distances will be a nightmare. Especially with other vehicles around you.

I have the 2.0, it has on paper a bit more powerful motor and bit bigger Battery. But even so, with 7 out of 8 bars of Battery and selected "EV Mode" button, in a parking lot I have experienced starting the ICE on the ramp to the next floor. 

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Gentlemen, thank you for your contribution.
It's this critical spirit I've been looking for.
So for the moment we've collected 3 very important points.

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.

And I would add:
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) ......

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I think it's nearly impossible to make changes to the cars software or Battery management. Lets say you fill the boot with batteries. The car must understand that it's native hybrid Battery has been extented, and now must work as one large unit, even if the voltage is different. 

It's like inserting a SD card in your computer and trying to merge it with the harddrive. 

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2 hours ago, nielshm said:

I think it's nearly impossible to make changes to the cars software or battery management. Lets say you fill the boot with batteries. The car must understand that it's native hybrid battery has been extented, and now must work as one large unit, even if the voltage is different. 

It's like inserting a SD card in your computer and trying to merge it with the harddrive. 

Thank you a lot, Nielshm for you contribution.

Now the list has gotten longer, but I am convinced that there are other issues to consider.
I am waiting for further interventions, and I am trying to resolve those that have already been mentioned.

Issue list:

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) Impossible to modify car and Battery software.

7) .....

 

 

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I have been in to this issue myself but stoped by all those difficulties.

We hav one Prius+ 2017 which would be very nice to konvert to Plug In and one Prius PHEV 2015 Gen 1 which would be nice to be able to ”upgrade” to Prius PHEV 2017 Gen 2 EV range.

Got some topics here

 

Extra Battery power

 

 

Even been in to the possibility to complement with

solarcells

 

 

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Tanks HSDish,

Your experiences will be very useful for the final discussion on the argument.

Issue list:

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) Impossible to modify car and Battery software.

7) Why not use other Kits already on the market

8  ) A solution with a photovoltaic roof ?

 

 

 

 

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I would suggest checking this topics before proceeding:

1. If you convert your car into a PHEV, the electric motors may have a far bigger share in driving your car. Are they suitable for that or will they wear out prematurely?

2. How fast can your car go on electricity alone? My Yaris Hybrid can't go faster than approx. 40 mph on electricity alone. And when I put it into pure EV mode, the IC engine will kick in nevertheless as soon as I try to accelerate just a little bit. So my car simply is too slow and too lame to work sufficiently even in city only traffic.

3. How do you want to put the charge of the additional Battery into your original Battery? Or do you want to connect both batteries in parallel mode and treat them as one Battery?

4. Your car recharges its battery on its own. How do you want to recharge the second battery? Do you want to treat it apart?

One serious question from a guy with two left hands: don't you think it would be cheaper to sell your Corolla Hybrid and buy a Prius PHEV?

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SampleMan you nailed it !

your arguments are very strong, they make me think a lot.
I add everything to the list and then when the time comes we will have to find solutions to these too. Thank you.

Issue list:

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) Impossible to modify car and Battery software.

7) Why not use other Kits already on the market

8  ) A solution with a photovoltaic roof ?

9) The electric motors have a far bigger share in driving your car. Are they suitable for that or will they wear out prematurely?
10) How fast can your car go on electricity alone? Can't go faster than approx. 40 mph on electricity alone. When I put it into pure EV mode, the IC engine will kick in nevertheless as soon as I try to accelerate just a little bit. So my car simply is too slow and too lame to work sufficiently even in city only traffic.
11) How do you want to put the charge of the additional Battery into your original Battery? Or do you want to connect both batteries in parallel mode and treat them as one battery?
12) Your car recharges its battery on its own. How do you want to recharge the second battery? Do you want to treat it apart?
13) Don't you think it would be cheaper to sell your Corolla Hybrid and buy a Prius PHEV?

I'm sure there are other issues to resolve. What are they?

 

 

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I doubt all the extra weight from the new batteries would make it worth it. The reason (well, one of them) the 2 ltr has a meatier motor is because the batteries are heavier, so the issue of the ICE cutting in would probably be enhanced as the system would detect the additional load and fire up the ICE earlier.

The extra batteries may change handling of the car. And I presume you would carry out all servicing yourself, as the dealer would be looking at a changed spec car, which may no longer be within their remit to service or resolve any problems to make it road worthy?

You probably have enough issues already to scrap the idea. Doing it would just be turning your Corolla into a hobby car, a bit of fun, that might work, or might wreck it. It certainly is unlikely to be a money saver. It is the sort of thing to do for fun, and you would look at changing out the electric motors for more powerful ones.

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Thanks Timmon, The extra weight problem is serious. It certainly affects performance.
Even turning the car into a hobby banger has to be taken seriously.

New Issue list:

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) Impossible to modify car and Battery software.

7) Why not use other Kits already on the market

8  ) A solution with a photovoltaic roof ?

9) The electric motors have a far bigger share in driving your car. Are they suitable for that or will they wear out prematurely?
10) How fast can your car go on electricity alone? Can't go faster than approx. 40 mph on electricity alone. When I put it into pure EV mode, the IC engine will kick in nevertheless as soon as I try to accelerate just a little bit. So my car simply is too slow and too lame to work sufficiently even in city only traffic.
11) How do you want to put the charge of the additional Battery into your original Battery? Or do you want to connect both batteries in parallel mode and treat them as one battery?
12) Your car recharges its battery on its own. How do you want to recharge the second battery? Do you want to treat it apart?
13) Don't you think it would be cheaper to sell your Corolla Hybrid and buy a Prius PHEV?

14) The extra weight problem certainly affects performance.

15) You would carry out all servicing yourself, as the dealer would be looking at a changed spec car, which may no longer be within their remit to service or resolve any problems to make it road worthy?

16) Doing it would just be turning your Corolla into a hobby car, a bit of fun, that might work, or might wreck it. It certainly is unlikely to be a money saver. It is the sort of thing to do for fun.

Any other possible problems ? Thanks.

 

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Toyota and other car manufacturers have spent millions of $s £s on Research & Development to bring a new model through all its stages of testing etc into production, let it be a fully plugin electric, a self charging hybrid or a plugin hybrid, using the best automotive brains and technology available to them. Therefore I think its highly unlikely that an individual would be able to improve on that, no disrespect intended. Enjoy your new lovely Toyota Corrolla.

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37 minutes ago, Bernard Foy said:

Toyota and other car manufacturers have spent millions of $s £s on Research & Development to bring a new model through all its stages of testing etc into production, let it be a fully plugin electric, a self charging hybrid or a plugin hybrid, using the best automotive brains and technology available to them. Therefore I think its highly unlikely that an individual would be able to improve on that, no disrespect intended. Enjoy your new lovely Toyota Corrolla.

+1 👍

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I read somewhere that in the very earliest experimental versions of Plug-In Prius Toyota used two 'ordinary' HiMH Hybrid batteries, one on top of the other (half filling the boot).  It was said to be an early attempt to develop the changes to the rest of the Hybrid system to manage the different charging and discharging requirements, and the changes necessary to allow higher cruising speeds and better acceleration in EV mode.  I guess they had other teams working separately on developing the LION Battery technology necessary to make it all work.

I awaited the arrival of the 'official' PiP with eager anticipation, having had occasional use of a company 2007 Gen 2 Prius with a Plug-In conversion by a firm called Amberjac.  It used LION technology and they managed to fit enough juice into it to give almost 40 miles EV.  It still had the problem of needing the engine as a heater, and didn't have the benefit of heated seats.

The clever thing about the conversion was they made no changes to the Hybrid setup - it plugged into the same connector as the old Battery and 'lied' about the state of charge, claiming the Battery was maxed out until the State of Charge got down to (IIRC) about 15% then behaved like a standard Prius.  The maxed out condition made the system use EV mode as much as possible, and with medium acceleration would get up to around 60 mph without bringing in the ICE.

I could get up to about 1½ thousand miles out of a tank of petrol sometimes.  The 40 mile range almost covered my journey to work, and at home I charged it on overnight off-peak electricity, plus daytime recharges at the office.  Even at 70 mph, although the engine would be running, it was only doing 1100 rpm and was assisted by the electric motor while the HV battery had enough charge so used much less petrol than a normal Prius at the same speed.

AND they managed to keep the space saver under the boot floor.

By 2011 Amberjac ceased operations as with the imminent arrival of an official Toyota Plug-in Prius demand had all but gone.  The conversion at the time cost between £8,000 and £10,000 on top of the donor Prius.

Because the conversion was done with no modifications to the core Hybrid systems, apart from the battery swap, all other original parts of the car were still covered by the warranty, although as it happened this car never required any warranty work.  After a few years my old firm sold the car to a chap who worked in the Hybrid industry and had significant skills to support Hybrids.  He ran the car until a few years ago, charging it entirely from his wind turbine.  He also hacked some setting in the ECUs to stop the engine starting to warm up.

[The same chap bought by 2nd Gen 1 2002 Prius saloon when it was 9 years old with 163,000 on the clock.  Last I heard, he had sold the Plug-In conversion Prius and it was still in daily use].

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Thank you Bernard for your wise advice,
I'm in love with my new Corolla and I wouldn't touch a screw.

My first choice was to buy a Plug-in, but the cost was too high for my pockets. However, I am aware of the risks of what I would like to do, I will try to avoid them or at least reduce them to a minimum.
I have a fair amount of electrical retrofit experience (12 years) that you can see in my old blog below.

http://electricmotorcicles.blogspot.com/

New Issue list:

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) Impossible to modify car and Battery software.

7) Why not use other Kits already on the market

8  ) A solution with a photovoltaic roof ?

9) The electric motors have a far bigger share in driving your car. Are they suitable for that or will they wear out prematurely?
10) How fast can your car go on electricity alone? Can't go faster than approx. 40 mph on electricity alone. When I put it into pure EV mode, the IC engine will kick in nevertheless as soon as I try to accelerate just a little bit. So my car simply is too slow and too lame to work sufficiently even in city only traffic.
11) How do you want to put the charge of the additional Battery into your original Battery? Or do you want to connect both batteries in parallel mode and treat them as one battery?
12) Your car recharges its battery on its own. How do you want to recharge the second battery? Do you want to treat it apart?
13) Don't you think it would be cheaper to sell your Corolla Hybrid and buy a Prius PHEV?

14) The extra weight problem certainly affects performance.

15) You would carry out all servicing yourself, as the dealer would be looking at a changed spec car, which may no longer be within their remit to service or resolve any problems to make it road worthy?

16) Doing it would just be turning your Corolla into a hobby car, a bit of fun, that might work, or might wreck it. It certainly is unlikely to be a money saver. It is the sort of thing to do for fun.

17) It's highly unlikely that an individual would be able to improve that maked after years of reserch and developing of the best automotive brains and technology available to them. Enjoy your new lovely Toyota Corrolla.

The list has gotten very long, is there anything else ???

 

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Thank you very much PeteB for your positive experience.

This encourages me to move forward with my project.

I'm curious to know if Amberjac in his plug-in has replaced the original toyota Battery or just added lithium batteries.

Thank you again.

Nuccio

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26 minutes ago, nuccio said:

Thank you Bernard for your wise advice,
I'm in love with my new Corolla and I wouldn't touch a screw.

My first choice was to buy a Plug-in, but the cost was too high for my pockets. However, I am aware of the risks of what I would like to do, I will try to avoid them or at least reduce them to a minimum.
I have a fair amount of electrical retrofit experience (12 years) that you can see in my old blog below.

http://electricmotorcicles.blogspot.com/

New Issue list:

1) Invalidate the warranty.
2) You risk destroying something and throw away a lot of money.
3) The electric motor of the Hybrids is not very powerful and does not hold at normal trafic speed.
4) It takes up a lot of space in the luggage.
5) It costs a lot of money and you can't get it back by saving gasoline.
6) Impossible to modify car and battery software.

7) Why not use other Kits already on the market

8  ) A solution with a photovoltaic roof ?

9) The electric motors have a far bigger share in driving your car. Are they suitable for that or will they wear out prematurely?
10) How fast can your car go on electricity alone? Can't go faster than approx. 40 mph on electricity alone. When I put it into pure EV mode, the IC engine will kick in nevertheless as soon as I try to accelerate just a little bit. So my car simply is too slow and too lame to work sufficiently even in city only traffic.
11) How do you want to put the charge of the additional battery into your original battery? Or do you want to connect both batteries in parallel mode and treat them as one battery?
12) Your car recharges its battery on its own. How do you want to recharge the second battery? Do you want to treat it apart?
13) Don't you think it would be cheaper to sell your Corolla Hybrid and buy a Prius PHEV?

14) The extra weight problem certainly affects performance.

15) You would carry out all servicing yourself, as the dealer would be looking at a changed spec car, which may no longer be within their remit to service or resolve any problems to make it road worthy?

16) Doing it would just be turning your Corolla into a hobby car, a bit of fun, that might work, or might wreck it. It certainly is unlikely to be a money saver. It is the sort of thing to do for fun.

17) It's highly unlikely that an individual would be able to improve that maked after years of reserch and developing of the best automotive brains and technology available to them. Enjoy your new lovely Toyota Corrolla.

The list has gotten very long, is there anything else ???

 

26 minutes ago, nuccio said:

Nice compilation.

Have You checked used Prius PHEV gen 2 (2017-19) ? 

 

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51 minutes ago, nuccio said:

...I'm curious to know if Amberjac in his plug-in has replaced the original toyota battery or just added lithium batteries.

The original Battery was replaced.

The Gen 2 Prius has a false boot floor with quite a bit of space under it, with a second floor that housed the standard HV Battery and spare wheel.  After conversion, the whole space under the false floor was used up, and the boot floor was about an inch (25mm) higher, so there was still a fairly usable boot.  The spacesaver spare wheel was still under the slightly higher boot floor.

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-  Have You checked used Prius PHEV gen 2 (2017-19) ?   -

Dear HSDish this would have been the best solution.

I know that a used car with a few miles is economically advantageous.

At the time of purchase, I wasn't thinking about a used vehicle.

I preferred to buy a new car so I kept it for at least 15/20 years. 

When I saw it I liked the Corolla, and all my good intentions went up in smoke.

 

 

 

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Thanks PeteB

your information is increasingly convincing me that doing a Plug-In retrofit can be invasive.

So thanks to the arguments read on this forum I think that what can be done without complicating things is a downward compromise.

We can call it  - light Plugin -.

I've drawn a rough sketch that I hope will give an idea of what I'd like to do.
Then we will discuss whether this can solve the long list of issues.

The plugin is drawn in red on an old Prius diagram.

 

 

Schema-Kit-PlugIn.jpg

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Maybe we should do some math (please allow me to use metric dimensions, I am far more familiar with that):

My Yaris Hybrid uses a NiMH Battery which enables the car to run about one kilometer in EV mode. According to the specs I found, the Battery has a capacity of 0.9 kWh. Let's assume that the car needs one full Battery charge for one kilometer, then it would use 9 kWh for 10 kilometers and 90 kWh for 100 km. This would be absolutely hilarious, because a Renault Zoe needs about 15 kWh for 100 km. On the other hand I know that Toyota uses only 60 percent of the technical battery capacity in order to maintain a long battery life. So, normally the battery is never completely charged nor completely discharged. If I take this into consideration and assume that my car may be able to run up to 2 km on electricity only, i get a power consumption of at least 25 kWh per 100 km.

This sounds disappointing, but also reasonable. I have read that the new Mercedes C300de burns more than 40 kWh per 100 km, which makes it cheaper to run on Diesel instead. And people who make a mission out of burning as little fuel as possible with their Toyota Hybrids stay away from running the car on electricity too often, because recharging the battery costs more fuel than driving the car.

The next problem: If I would install a bigger battery and a plugin charger, I would not do that to get my lousy electric range from 1-2 km to still lousy 2-4 km. I would like to have at least 40 km, enough to go electric from my garage into the city and back. That mans that I would have to tenfold (at least) the battery capacity of my car. Now I have a battery pack which is about 30 to 40 liters big (bold assumption) and weights 35 kg. Let's tenfold that, and you get a battery which is 300 to 400 liters big, weights 350 kg and costs 10,000 Euro (when built with used components).

This does not sound promising, I think...


Best regards from Bavaria
Frank

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Dear Frank
Your math is more than right, but we're looking at very different vehicles and the proportions are not linear.
Let me explain in more detail.
Full-hybrids have an electric motor that helps the petrol engine, so both the maximum power of the electric motor and the power and capacity of the hybrid Battery are very small, just enough for that purpose.

On my Corolla hybrid Battery has a capacity of 0.75Kw/h !!! 

Let's assume that both a Toyota Corolla and a Renaul ZOE need the same power of 20 kW to run at the same speed.
The Toyota Battery has to deliver 26 times its capacity, while the Zoe, thanks to its large battery, only needs about 0.5 times.
In these years of activity on electric bikes I have learned that when you overcharge a lithium battery (but maybe it's true for all of them) you lose drastically a good part of its capacity.
This is the only way to explain the poor EV range of Toyota.

As far as Plug In Hybrids are concerned, the ratio is more in line with pure electrics.
In fact they have batteries around 10 Kw/h which are subject to a lower discharge rate.
In my project I refer to the power consumption of the Plug-In and that is about 5 Km every Kw/h of energy.
 

Best regards

Nuccio

 

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Dear Nuccio, I do not think that our calculations are very much different. You want to reach 5 km per kWh, this equals 20 kWh per 100 km. If you want to have a PHEV which provides you an electric range of 40 km, then you need at least 8 kWh of usable Battery capacity. Your Corolla has only 0.75 kWh, so a second barrery of this type will not do the job.

Best regards

Sampleman

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