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Old 08-19-2010, 03:56 PM   #185 (permalink)
MN Driver
2000 Honda Insight
 
Join Date: Jul 2010
Location: Minneapolis, MN
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Quote:
Originally Posted by RobertSmalls View Post
While I had the battery out, I wanted to see how well some 40Ah LFP cells would fit in place of the stock 6.5Ah NiMH. I think LFP are more appropriate for a PHEV, and (removed link since it doesn't let me quote it due to having under 5 posts, shakes fist), their cells will last until well after you're bored with them.

Anyway, each of these boxes represents two 40Ah cells, so I'd need 25 boxes, 50 cells, to reach the required voltage to replace the IMA battery. The boxes are a little taller than the cells, which will allow room for wiring and a BMS slave.

32 out of the 50 cells fit in place of the IMA battery module with no problem. An additional 8-10 cells would fit where the inverter cooling fan duct is. I'd have no qualms about using cabin air to cool the inverter. Maybe in the winter, I could recirculate that air through the cabin for heat.

There's room for a dozen or so cells to the left of the driver's side frame rail, perhaps 6 cells under the fuel filler pipe, and a few cells in front of the IMA box.

I've been thinking about an Insight-bodied EV conversion. But to do it right would be at least $10,000. The results would be nice, though. I'd put the batteries where the gas tank is right now (in addition to in the engine bay and exhaust tunnel?), and get rid of that damned IMA box. I'd finally have the cargo space of a CRX.
How many more cells can fit to the left and right of the spare tire area where they packed in the styrofoam inserts for the cd changer option and the gap of nothing on the opposite side? It would be a pain to wire them there but might be worth it if you are trying to keep the spare tire where it is and not loose as much useful cargo room.

I see you have run into my little thought tunnel about going either EV, extended NiMh or Lithium PHEV. It's proving to be a very difficult decision for me to make. If I go with upgrading my capacity using NiMh by using an extra Insight parallel set or two using a pack of our familiar 5 cell 5.5Ah sticks(hopefully they would fit in a decent fashion), I could be up to a little over 15Ah if I'm really lucky(if I get the capacities matched up well enough and the cells are in decent shape) but with a fair amount of added weight and lost space, I would be inclined to remove the cells if I went on an extended trip to lose the weight and gain the space back.

My suggestion is if you go with 40Ah LiFePO4 cells, to go with the CALB cells (formally Sky Energy cells), they will provide you with less voltage sag than the Thunder Sky cells or Hi Power cells. People on DIYelectricCar using these have said that their capacity is higher than what their ratings are and those using Thunder Sky don't see as much of an advantage. With less voltage sag, this demonstrates less internal resistance which means they should also work better at lower temperatures and withstand the 100 amp discharge and 50 amp charges with less internal stress. I think they would likely provide you with more life with this application even though their spec sheet doesn't say so. It seems to be a bit of a wash though because there are more distributors for Thunder Sky out there now and the best one for Sky Energy had a serious issue recently where nobody got their Thunder Sky cells that they paid for while they 'liquidated' them to others in 'bankruptcy'. If I see a killer deal for Thunder Sky or Sky Energy cells, I'll probably take the killer deal and run with it and install a bigger pack. Until then, I might just have a parallel pack or two of NiMh and call it good knowing that I can keep my spare tire where it is.

The more that I think about it, the less I think that I'm going to go with turning my car into an EV. I did a cost analysis recently and it might be best to wait until I can get a used Leaf, Volt, or a different EV for peanuts at the 10 year mark. I'd enjoy the project of converting but if I go PHEV and even going with MIMA, that is extra money that I will feel was wasted if I end up going EV later. If I were to go with EV, I'd have to do it ASAP for it to be cost effective versus continuing to burn gas and buy things that only work with the gas components, IMA, and stock systems in the car.

"Peter Perkins has his on the steering column, between the wheel and the wiper stalk I believe. It has a 6" handle, and you can operate it with both hands on the wheel. "

I'm not entirely sure that is the case, that may have been his second Insight that he said he wife was driving(the one that he was installing the 8Ah LifeBatt cells into, and now it is the 20Ah cell_man cells, brand removed due to possible issue with that 123 company that starts with an A, not being too happy about us having those cells). He has installed a simple two-way switch where one way controls the clutch switch, the other the brake switch to prevent assist or to allow for regen without using the brake pedal.
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