Wednesday, August 17, 2011

Mounting the Compressor

The last two weeks have been exceedingly busy and it's only been these last two days that I've actually had the opportunity to begin working on the car again.  Very frustrating!  But I've made some progress, and I thought I'd share what's been done. 

I finished building and installing the motor mount, which meant that I could finish making all the connections to the transmission; drive shaft, clutch slave cylinder, gear shift linkage, and reverse light connection.  Incidentally, I was able to find the proper Bosch female connector to go with the male connector used for the reverse light switch mounted to the transmission.  That was not an easy item to locate.  To make it worse, apparently Bosch only manufactures them in lots once every so often because they were unavailable at every place that carried them for months, and then in a weeks time everyone had them. 

At any rate, the drive line is complete, and the motor is safely tied down.  It is resting on and held down to a solid piece of hard rubber designed for motor mounts.  The original cross members that prevent the motor from spinning while under torque are still there, but I've added some rubber cushioning that will absorb shocks from upward travel as well.  So to recap, I have hard rubber pads set to absorb any vertical bumps or vibration, and braces to keep the motor from spinning.  It's not going anywhere, and it should be nicely isolated from any sharp bumps the chassis receives.

The last couple days I finished building the tray and the supports that will hold the MasterFlux A/C compressor.  It's a tricky fit, just like everything else in the car.  It will be suspended from the front battery tray as mentioned in previous posts, but it can't be directly under, or there would be no room to hook the pressurized coolant lines up.  So it has to hang below and slightly behind the rack.  Maybe a video will demonstrate it a bit better.  Take a look.

I'm not sure that the shaky camera and rambling dialogue help clear things up, but hopefully you get an idea of what's involved.  Afterward, I took some careful measurements of where the new hoses needed to run, and disconnected the existing hoses.  I took them down to a local shop and explained what I need.  I was worried that they'd want to finish the hoses on the first visit, and I'd run into problems when tying to put them in the car.  Not only do the hoses need to be the correct length, but the new fittings that I need for the new compressor have to be crimped on at the proper angle so there's no twist in the lines.  Apparently this is not an uncommon problem. 

What they intend to do is cut the old hoses off the fitting end that I need to keep and crimp new hoses on that are a bit longer than I need.  Then they'll call me in and hand me the half completed hoses and the new fittings.  I can then bring the whole lot home and mount it up, cut the hose to length and mark the proper angle to crimp the new fittings on and return it to them for the final crimp.  Of course I still need to find a place to mount the compressor's controller and all the supporting electronics.  Truthfully, that has me worried.  I have an idea of where it might go, but I won't know for certain if it will fit in that space until both battery racks are mounted back in the car. 

With the addition of the new meter, and it's larger shunt, I thought I'd take this opportunity to hook things up in a cleaner way.  The old set up had all of the negative lines from the high voltage side running to one side of the shunt.  There was the 2/0 cable from the controller, the 6 AWG from the charger, a 10 AWG from the heater core, a 12 AWG for the DC to DC converter and a small 18 AWG for the negative lead to the meter.  That's a lot so squeeze onto one terminal.  So instead, I'm adding a bus bar.  The bus bar I got has 4 leads, three of which will hold all those cables and wires mentioned above, and the last remaining one will be reserved for a new cable that will run to the new shunt. 

The only problem is that the bus is only rated for 400 amps.  As we all know, I'm looking to put 1000 amps through it.  Well the reason it's rated at 400 is that there is only one 1/8" thick piece of copper tying all the connectors together.  To over come this, I've made 3 new strips of copper totaling 3/16" to stack on top of the existing one, for a total of 5/16" of copper.  That is more than enough for 1000 amps.  That's nearly twice the thickness of the battery straps. 

Speaking of battery straps, I'm taking out the original copper straps that came with the Sky Energy (CALB) cells and replacing them with the braided copper straps from EV Works.  While I'm at it, I've gotten rid of all the old washers and split ring washers in favor of Nord-Lock washers.  These changes will allow for two things.  First, as the chassis moves around and the batteries jostle about, those braided connections will flex the tiny amount needed and not put any strain on the connection point at each battery.  This will help to ensure that there is always a good connection at each terminal.  To further ensure a good connection, I'm using the Nord-Lock washers.  Once you've tightened down a bolt with one of those washers on it, it does not back off.  Vibration or the usual expansion and contraction due to temperature changes simply won't affect them.  Consequently, no loose connections, no fires. 


Christopher Fisher said...

Wow, Tim! It looks like you are making fantastic progress! You might be on track to bring it to the EVCCON!

kanchana bizconn said...
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