2nd Gen Prius PHEV Conversion (Enginer plug-in lithium ion battery kit)

[Daox]

I worked on the Prius mounting setup yesterday.

I put the box in and marked where I needed to put the weld nuts in. Fortunately, on the driver's side that spot fell directly between the frame rails.





On the passenger's side I was also very close to the frame rail, within 1".





So, I drilled the holes for the weld nuts.





And then welded them up bit by bit with time to cool between so as not to burn too much paint and not melt the sealant that was fairly close to it.







A little grinding and a few coats of primer finished things off.





I am interested in suggestions on how to reinforce it a little. MrBigh is correct that the sheet metal is thin back there. I do think that it will be okay the way it is unless the trunk area gets smashed and there is a roll over in an accident. I was going to weld in some extra metal, but there is a lot of that sealant around the top and bottom (sorry no pics) that I'd like to avoid. There is also the issue of rust-proofing things after the fact (yay Wisconsin salty winters) that is probably going to be a problem. I was able to prime and paint the passenger side weld nuts, but since the driver's side are between the frame rail sides I can't actually get to them to do anything.

[bennelson]

I did something similar in the back of the Electro-Metro for holding down components.

Winter road salting is a big deal in terms of how corrosion effects the back bottom of cars. I would highly recommend anti-seize on those bolts, and possibly even go to stainless.

Zinc-coated fasteners will NOT hold up for any significant amount of time on our extra salty winter roads.

Grease-up, anti-seize, or otherwise protect those nuts and bolts there.

[nemo]

If there are any tie down holes in that frame rail close enough to the nuts, you may be able to use some spray lithium grease to coat the bottom of the nuts and bolt threads after instillation.

[Daox]

Thanks for the tip Ben. I did actually get stainless fasteners and I do plan on anti-seizing them as well. I'm actually a bit more worried about the body around the weld nut though, where I drilled and welded. I think I am going to have rust problems unless I can get to it from under the car and weld up the overlapping metal that is just going to collect moisture.

Nemo, thats a great idea and I do believe there is a hole in the general area. I'll see if I can spray some grease in there.

[Cobb]

You seem to be going through a lot of trouble to keep the original box for your setup. Any reason? Its rather bulky, freaking heavy and retains heat like a miutha.

Even Enginer has discontinued it in favor of an open designs that allows easy access, better heat management and to and keeping the spare tire.

[Daox]

I have heard of users splitting up their kits, but I wasn't actually aware that enginer had gone that way. Its a great idea and I'd like to do it, but my cells are all individual and connections are exposed. I'd have to do quite a bit of work to get the batteries mounted in the spare tire well. Perhaps this will be an evolution of the kit. For now I'd just like to get it working.

[Daox]

Last night I worked on the batteries. First, I cleaned the cells, their terminals, and connectors. A couple cells look really rough (scorched from heat) but they tested good so I'm using them. Next, I connected all the parallel sets. The strongest cell was connected in parallel with the weakest cell, next strongest with next weakest so on and so forth. This leaves me with a pretty closely balanced pack. My lowest parallel capacity is 64.1Ah and the strongest set is 65.5Ah. By doing this it maximizes the usable capacity of the battery pack.

[Cobb]

Yeah, I can see with those cells you would want to be extra careful.

I had a personal quest to hit 100 mpg and it wasnt til I nearly gutted the car, including the box for the enginer kit and lots of other things before I managed to do so, for 5 miles.

Although I am over that since it took too much work, I am still going to be cautious. I am working on some mods for better interior cooling and venting of heat before I reinstall the rear bumper cover. I think I got a good one for the Enginer kit. Next up is an exterior vent for the IMA system. It generates a hell of a lot of heat and the blower is as powerful as a leaf blower.

Added an exhaust vent to better maintain the interior temp and keep the converter cool.

[flash=200,200]

[Daox]

A little earlier this week I got the box installed along with the batteries. The dc-dc converter, charger, and bms are still not in the car. That is the project for this weekend.

On the front of the box mounting flanges, I added a 1/2" nut. This will allow me to put in threaded rod to lift and set down the box.


Sorry for the blurry pic.




I also threw in some rubber padding between the box and chassis to save the paint and also dampen vibrations a bit.




So, the time has finally come to install the box!




And here is the back row of batteries. I got the rest of them in with the BMS harness connected, but at that point it was pretty dark out and I just wanted to finish up for the night.

[Daox]

This morning I was able to put the dc-dc converter in and the charger.

Before I put the dc-dc back in though, I had open it up and noticed what I believe is a temperature probe was not secured in place. I used some clear silicon and attached it to the mosfet it came off of.





After that, I buttoned up the dc-dc and the charger and installed them into the case.

The only thing left to do is build and install my BMS system now.