Capacitor Pack Recommendation

Its 2013 now and it looks like supercaps have come a long way and are also more afforadable. Check out pricing for maxwell supercaps. Search "tecategroup maxwell"

I am thinking of doing this because frankly I am getting tired of the slow acceleration on my 2007 Prius. Its been driven 80K miles and gets me about 48mpg+. I do not want to spend the money to make it a plugin but I could spend some to get the oomph.

I came across the UC Davis paper where they tested Civic Hybrid with and without supercaps in different configuration and they found upto 2-3 secs improvement in 0-60mph time.

Google "simulations of plug-in hybrid vehicles with ultracapacitors"

 

A different architecture, the Civic Hybrid has long been light on electric energy. But you might want to gather some data before going further:

• record maximum acceleration
  • traction battery drain (current and voltage)
  • MG2 power (torque and rpm)

To accelerate faster, MG2 would have to absorb the extra power. There would need to be some indication that there is 'head room' to absorb any extra power.

A better solution might be to look at a 5th, powered wheel. Install a receiver holding a 5th, electric powered wheel driven by an independent power source, the ultracaps. When not in use, the wheel can be retracted for efficiency. But when you want additional acceleration, the wheel lowers with enough down-force, to not slip when the additional power is added.

Alternatively, you might look at how to couple one or more electric motors to the rear wheels and again use an independent electric source to provide the additional motive force. Heck, you might even look at hydraulic motors and an accumulator:

Perhaps some sort of motorcycle gear with a belt drive connected to an electric or hydraulic motor.

But before engaging in the project, figure out how much power or energy you are going to need to achieve any given reduction in acceleration time. First benchmark what the car is doing today and get the weight. Then calculate the change in energy from say 0 to 60. Then start adding to the model different additional acceleration forces and figure out what sort of system you're going to need:

• motor rating (either electric or hydraulic)
• power power controller
• energy storage

GOOD LUCK!
Bob Wilson

 

Thats an interesting idea but I dont think I have the guts to take on a project that fundamentally changes the mechanics of my car.

Here are some of my thoughts but please feel free to call out my BS .

1. My understanding is that the extra battery pack in Prius PHEV acts as a primary source of energy in EV mode. If I could use supercaps instead of the battery pack I could potentially replace the high-energy system with a high-power system coupled with a control circuit to get the acceleration without blowing up anything.
2. I probably do not need total power comparable to a plugin battery pack to get the improvement in acceleration. Some extra Amps added to Prius's 100Amps for about 10-20 secs should be enough I guess. (Any help to figure out the type and number of supercaps in different configurations is appreciated.)
3. Is it possible to connect supercaps in parallel with existing batteries with a control circuit to ensure the power surge does not do any damage.
4. I am assuming the weight of supercaps should be much less than the battery packs for plugins.

 

Here is a presentation about combining ultracapacitors with batteries.

 

slideshare net /slideshow/embed_code/15522863