I posed a question a while back about the Prius Plug In Hybrid:
http://ecomodder.com/forum/showthrea...hev-24586.html
This thread is a bit of an offshoot from that.
There has been a lot of talk about PHEVs in the automotive world (and in this forum) lately. Personally, I think they are the ultimate eco-car: an EV most of the time and a gas burner when it needs to be. However, they cost a ridiculous amount of money and for 99% of people, the return on investment will simply never happen. I should say that while ROI is definitely something on my mind when considering a fuel efficient vehicle, I am definitely willing to sacrifice some of that to get a car that is high tech and makes me smile when I drive it.
DIY Approaches
There are a few very intriguing active threads in Ecomodder these days:
http://ecomodder.com/forum/showthrea...uck-22080.html
http://ecomodder.com/forum/showthrea...les-24514.html
I am really rooting for these guys and hope they can build something DIY that we really haven't seen yet.
Old Hybrids - The Originals
I am talking about the original Insight and Prius. Some quick searches in Ecomodder reveal a lot of IMA battery issues in the Civics (not so much with the Priuses). However, these seem relatively easy enough to repair at a DIY level.
Part of me wonders whether these packs can be replaced by home made LiFePO4 versions. And since this type of battery is significantly more dense than the original NiMH packs, I wonder what the effects of increasing the battery capacity three or four times the original would have on overall efficiency.
I really don't know, which is why I need some hybrid owners to chime in.
DIY Replacement PHEV pack
If I were to hypothetically make up a 144V LiFePO4 pack with proper BMS and charger and install it into a first gen Insight, would it act like a proper PHEV? I guess it all depends on when the battery pack is charged by the ICE in these cars.
Example: if I leave home with a fully charged hybrid pack and I cannot get much regenerative braking in, will the hybrid system continuously charge the pack using the ICE or will it only charge the pack once the pack reaches a certain level of discharge?
That's my question.
If hybrid systems allow the pack to remain discharged during a drive (or can be fooled/modified into doing so), then it is a matter of getting an old Prius/Insight/Civic Hybrid for a few thousand bucks and fitting a nice new shiny homemade battery pack and charger for a few thousand bucks. THAT seems like a worthwhile investment to me - much cheaper than a "store bought" PHEV and much cheaper than a good EV conversion.