# DIY PHEV Prius c?



## Ziggythewiz (May 16, 2010)

Isn't the goal to not spend triple digits at the pump?

It's rediculously easy with electric.

What's your goal exactly? Save money? The environment? Neither of those call for buying a new car. At least get an old Prius to modify...


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## todayican (Jul 31, 2008)

Ive been interested in hybrids for a while now as well as building 2 super high mpg trikes from scratch, they just take so damn long to complete :-(

I live about 40 miles from "civilization" in either direction so any practical ev is going to need a 100 mile range to work for me, also, I put a LOT of miles on my cars.

The Prius c is only 6 weeks old and has almost 5k miles on it already for example...

I personally am interested in saving money mainly while still driving a new car, and also, the various parts will likely become a "mpg kit" for the prius c. I am an entrepreneur and it hasn't escaped me or my partner that the Prius c is currently selling like hotcakes, dealers cant keep them on lots and some (not mine) are commanding 8k premiums over list.

And this is for a car, take it from me, people are clearly not buying for its roominess or acceleration, so me thinks an "aero kit" and a "battery kit" might be a good part time venture


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## Ziggythewiz (May 16, 2010)

The more miles you put on em the more you can save with electric. That 100 mile range you need can be had for half the price of the C.

About the aero kit, have you looked at ecomodder much? I don't know what the market is for those mods, but from what I've seen it seems like most people who are willing to go that overboard are fairly few in numbers and probably enjoy the build at least as much as the results.

As for a phev conversion kit, have you looked to see what's out there? I know there are several kit vendors, even Toyota has done factory plugin conversions for years.


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## Wild (Aug 19, 2011)

You are asking to double the rated fuel economy rating of the Prius C. The only way that will happen is to add battery capacity, modify the computer and rely on electric power as much as possible. The hardest part will be installing the extra batteries and charger.


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## todayican (Jul 31, 2008)

I agree on that one. Although there are guys out there doubling the epa ratings with aero mods alone..

My questions are mainly how to build an extra battery and charger right to make the car a PHEV.


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## rmay635703 (Oct 23, 2008)

todayican said:


> I agree on that one. Although there are guys out there doubling the epa ratings with *aero mods alone*..


That isn't true but does not diminish the need for aero.

Aero allows a driver who knows how to drive to exceed EPA by much more than double but.. you don't double unless you also know how to drive efficiently.


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## Wild (Aug 19, 2011)

todayican said:


> I agree on that one. Although there are guys out there doubling the epa ratings with aero mods alone..
> 
> My questions are mainly how to build an extra battery and charger right to make the car a PHEV.


It's more complicated than that, the tiny NiMH battery pack hidden under the rear seat would need to be supplemented with the same compatible batteries of sufficient capacity to meet your goal plus you would need a custom charger built. That extra weight will place a big dent in any aero mods you may make.


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## rmay635703 (Oct 23, 2008)

Wild said:


> That extra weight will place a big dent in any aero mods you may make.


I don't agree with that statement, aero trumps weight every day. Especially on a hybrid.

His battery business would need to be the same type/qty/voltage OR he would need a custom battery charger to stream in electricity from a large LIPO or LIFE pack.


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## todayican (Jul 31, 2008)

That's what I am thinking too.

I've done some research and apparently the "regular" Prius up-converts a 168v pack to 650v and the Prius C up-converts 144v to 550v going to the electric drive.

So one would think the mission at hand is to add a string of 48 calb 60s say to make 144v for another 8.6 KWH

I (Potentially Nievely) think that since the car is limited to 34mph in ev only mode, that there shouldn't be any problem with c rating on the calbs.

Which would be "upstream" of the up-converter..

So would it be as simple as finding an appropriate 144v charger and adding the calbs to the main pack and (with luck) the main pack would simply think it was at a higher charge state then it really is (Thanks to the Calbs?


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## Ziggythewiz (May 16, 2010)

I didn't think the C had an EV only mode.


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## todayican (Jul 31, 2008)

She does, weirdly though, if you select EV mode with the button, it seems to be limited to 25mph.

If you select ev mode with your foot (by being careful with acceleration) it will go to 34.

lastly, I have seen it as high as 40 on slight downgrades


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## Ziggythewiz (May 16, 2010)

In that case you just need to hack it to allow EV up to 55, or whatever your highest non-highway limit is. 

With the old prius you had to hack it just to add the EV mode button, along with the higher performance.


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## Wild (Aug 19, 2011)

todayican said:


> That's what I am thinking too.
> 
> I've done some research and apparently the "regular" Prius up-converts a 168v pack to 650v and the Prius C up-converts 144v to 550v going to the electric drive.
> 
> ...


Can you explain how you will succeed in finding a charger that will successfully charge two different types of batteries? Not to mention how you will prevent burning up the original Prius battery pack.


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## todayican (Jul 31, 2008)

No idea, thats why I asked 

My vague understanding of charging is that the charger charges to a certain (set) voltage then shuts off.

If the charge voltage on pack 2 is within the "safe zone" of the main pack (IE lower then fully charged so as to not even be in danger of frying the main pack)

What I dont know (among other things) is what the operating voltage of the main pack cells are?


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## Wild (Aug 19, 2011)

todayican said:


> No idea, thats why I asked
> 
> My vague understanding of charging is that the charger charges to a certain (set) voltage then shuts off.
> 
> ...


Yes, well the simple answer is you can't. You are dealing with two different battery types.


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## lottos (Jun 22, 2008)

With Hymotion ( http://www.hymotion.com/ ) no longer selling their kits, the market is ready for a new player.


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## Xringer (Oct 12, 2008)

Ziggythewiz said:


> In that case you just need to hack it to allow EV up to 55, or whatever your highest non-highway limit is.
> 
> With the old prius you had to hack it just to add the EV mode button, along with the higher performance.


The 'C' stands for *C*ity.. That's where the C does it's best work. 
If you look at your average speed around a congested city, it's not that fast.
My wife's 'C' can easily stay in EV up to 44 MPH (slightly downhill).










I can go get a pizza over in Lexington (it's close by) and get 70 MPG roundtrip.

My idea of a simple upgrade would be an 8A 144vdc nimh charger built in.

Topping off a half-drained pack might help the MPG.?.
We always park the 'C' in the garage between trips during the day.
If it was charging during those breaks between (mostly very short) trips,
it seems like our MPG would be improved..
Since a high percentage of those trips are in EV mode..


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## EVPowers (May 17, 2012)

It certainly is possible to make a C into a Plug in Prius.

There are aftermarket kits, such as the one from Enginer, that use a separate LiFePo4 battery pack to slowly charge up the Prius' main pack.

I have done many of these kinds of conversions on Insights, Gen1, Gen 2 and Gen 3 Prius. Should work on a Prius C as well. Would take up a bit of the storage space room though.

There are also other people I know who have made a "Universal Grid Charger" that you can use to directly charge the main hybrid pack. Wouyld just need to set it for the Prius C pack voltage.


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## Xringer (Oct 12, 2008)

EVPowers said:


> It certainly is possible to make a C into a Plug in Prius.
> 
> There are aftermarket kits, such as the one from Enginer, that use a separate LiFePo4 battery pack to slowly charge up the Prius' main pack.
> 
> ...


The pack voltage is 144v. It seems like it would be pretty simple to make a 120vac to 144vdc smart charger for topping off the pack.
A regular 120vac outlet is rated for 15A, so it could raise the SOC, if left on charge overnight. 

I read the early Insight had a 144v pack, so maybe there are some chargers out there.?.


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## EVPowers (May 17, 2012)

Xringer said:


> The pack voltage is 144v. It seems like it would be pretty simple to make a 120vac to 144vdc smart charger for topping off the pack.
> A regular 120vac outlet is rated for 15A, so it could raise the SOC, if left on charge overnight.
> 
> I read the early Insight had a 144v pack, so maybe there are some chargers out there.?.


I own several Insight and can tell you that, yes, there are chargers for the 144v Insight pack. The Insight community has been working with chargers like this for years. They call these "grid chargers", "overnight chargers" or trickle chargers

A member of the Insight community build a super high tech version that can be used on almost any hybrid and has plenty of built-in safeties, for a base price of $675
http://99mpg.com/Projectcars/gridcharger/
Is is the coolest thing ever!

You can also build a super low tech version yourself using small power supplies for under $100. http://www.insightcentral.net/forum...issues/22663-grid-charger-power-supplies.html

And there are plenty of variations inbetween, such as this one with variacs.
http://www.insightcentral.net/forum...sues/15103-how-trickle-charge-hv-battery.html

Plenty of schematics in the middle of this page under the heading "Grid Charger stuff"
http://99mpg.com/resources/downloads/

Enjoy!


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## Cliff Douglas (Sep 13, 2012)

Plug-In Supply makes a 3KW plugin kit for the C. It is listed at $4,329 on their diy.pluginsupply.com website. I called and they said the first one will be displayed at the Green Drive Expo Sept 15 in Richmond CA. Cliff.


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## rmay635703 (Oct 23, 2008)

Cliff Douglas said:


> Plug-In Supply makes a 3KW plugin kit for the C. It is listed at $4,329 on their diy.pluginsupply.com website. I called and they said the first one will be displayed at the Green Drive Expo Sept 15 in Richmond CA. Cliff.


Too bad the kit is $1.36 a Wt instead of $1.33 an AHR.


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## johnhlong (Sep 1, 2013)

I have a similar but much less demanding requirement.

I am retired and live in a very small remote town.
I would put on 2 - 3 miles every other day or so around town.
It's more of a show & tell than a gas savings strategy.

Is there a small trickle charger for the stock 2013 Prius C traction battery?
A DIY would be nice.


The speed limit here is a whopping 20 MPH and so EV mode around town would be great. Just want a way to charge the traction battery without using the ICE. Electricity here cost 7 cents a kWH. That calculates out to 1.5 cents per mile or less than 5 cents a day, just to rub it in.



John
East Carbon, Utah


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## rmay635703 (Oct 23, 2008)

johnhlong said:


> I have a similar but much less demanding requirement.
> 
> I am retired and live in a very small remote town.
> I would put on 2 - 3 miles every other day or so around town.
> ...


 yes any that work on a G1 insight will work on the prius C, just understand that prius batteries last longer than G1 insight bats because they do not fully charge and are a different structural style. 

The prius style cells do not tolerate overcharge like the old style insight batteries, so your charger must be more kid gloves than the original insight spec and a pure dumb charger would need to stop before filling the battery completely.



johnhlong said:


> The speed limit here is a whopping 20 MPH and so EV mode around town would be great. Just want a way to charge the traction battery without using the ICE. Electricity here cost 7 cents a kWH. That calculates out to 1.5 cents per mile or less than 5 cents a day, just to rub it in.
> 
> John
> East Carbon, Utah


Your prius battery is really only good for about a mile, though on my test drive I eeked out a little more.

Even still 1 mile is better than nothing and using the prius C's neutral you can pulse and glide the rest of the way without the irritating mandated recharge once the battery level drops.


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## Moltenmetal (Mar 20, 2014)

I own a 2013 Prius C and love it. Thought Toyota switched from NiMH to Li ion in the C? My 2008 Prius base model has NiMH. The C's EV mode is basically useless. It won't allow you to use it on the. Car when cold, even to swap cars in the driveway (where an IC engine start is really wasteful ). You'd need to do some serious hacking and reprogramming of that system to get it to be a useful plug in hybrid. The other downside is that the fuel economy AND fuel economy recording accuracy of the onscreen display both fall off in the winter like a rock. Still better than the 2008 Prius which was a nice surprise, but the summer performance was awesome and would like to exend that into colder weather to the extent I can. Will need to do grille blocking and consider a block heater to prewarm the engine next winter. Found these made some difference with the 2008 but not enough to bother with.


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## TexasCotton (Sep 18, 2008)

Moltenmetal said:


> I own a 2013 Prius C and love it. Thought Toyota switched from NiMH to Li ion in the C? My 2008 Prius base model has NiMH. The C's EV mode is basically useless. It won't allow you to use it on the. Car when cold, even to swap cars in the driveway (where an IC engine start is really wasteful ). You'd need to do some serious hacking and reprogramming of that system to get it to be a useful plug in hybrid. The other downside is that the fuel economy AND fuel economy recording accuracy of the onscreen display both fall off in the winter like a rock. Still better than the 2008 Prius which was a nice surprise, but the summer performance was awesome and would like to exend that into colder weather to the extent I can. Will need to do grille blocking and consider a block heater to prewarm the engine next winter. Found these made some difference with the 2008 but not enough to bother with.


 To clarify my understanding of Toyota Prius HSD Gen 2 and 3.....all currently use the nimh HV traction battery with a limited range less than 2-3miles.....without any addtional modifcation to oem hv pack.. The gen 3 prius is a tiny bit more ev efficent than gen 2 and comes with actual ev switch


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## TexasCotton (Sep 18, 2008)

oh yea toyota tech enginers change up the coolant flow pattern from gen2 to 3 because of cold climate declined performance mpg. I am considering a good thermal hood blanket next winter season almost like the never ending winter here and hope the past ice storms driving did not do any unseen damage to my vehicle


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## petebarchetta (May 15, 2014)

asking the rather obvious question i know, but what is stopping you from obtaining another Prius Battery pack and connecting them in parallel. you then get increased range, charger would take longer as its trying to fill a bigger bucket, if you go for something like a solar roof mod, you can charge as you drive / park 

Just a suggestion..... wiling to take the flack now


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