Well, I started writing out a long explanation of my story, but I had a power flash and my UPS backup sucks so here we go again. Scroll to the bottom if you just want to see my pictures!
Preview:
The Story:
I installed MIMA and found that my battery was nearly dead all the time, due to my extreme hypermiling style (I hardly ever use the brakes and override the parasitic charging as it is extremely inefficient).
I tried to read through the entire grid charger article, but my OCD and ADHD combination isn't always conducive to learning. I got a good amount of help from Mike Dabrowski, who I scared a couple of times. Thanks again, Mike - you rule!
I settled on the basic 350ma charger/balancer design.
I ordered four RS-25-48's on eBay for $25 shipped, took a trip to Radio Shack for about $10 in parts and followed it up with an order from Jameco for the CCV 350ma supply. All in all I spent around $65 on parts that guys like us wouldn't already have lying around their garage. I used a 12v wall wart for the fan.
I had a lucky break when a friend ran into computer problems. I'm no longer a PC tech, but no one else seems to think so...
Anyway, their power supply was bad, so I swapped in a spare. Inspiration hit, and I started tearing it apart to see if my components would fit. Luckily it was almost perfect! This was great, as it gave me a built in switch, ability to use the fan, and is a decent size, as well as some LED action.
I measured carefully, drilled, and used some old PC screws to mount the power supplies. I ended up using very sticky double sided adhesive like Mike gives for the MIMA joystick mounts for the CC PSU. I mounted all four of the 48v power supplies in there even though I'm not using the last one - so I can put a 12v one in there later and make it all cleaner.
I decided that I was going to keep the 120mm fan to cool the charger (even though it probably won't need it, but I live in FL and may be charging on hot days). I ended up pulling a small daughter board from the power supply to split the current between that fan and the one in the car. I played around with it, and found out how to make it output about 9.6v to both fans, also giving me a couple of LEDs lit when it's on (in addition to the bright blue fan). It sat on top of the constant current supply with some more of the double sided super-sticky tape, just clearing the fan.
After giving Mike a call because I wasn't getting any voltage, I found the 1A fuse had blown. This had continuously been giving me problems. I ended up switching to a slow blow fuse today and it's working wonderfully. I adjusted the power supplies to 177v on the bench per Mike's instruction.
After sorting that all out, I had to get the terminals set for the battery. I crimped ring terminals to the diodes in the appropriate direction (with some solder for good measure), also soldering on a ceramic fuse on the positive end and covering them with heat shrink tubing. I connected them to some spare decent speaker wire that I had lying around. Next, I used some ULTRA fluorescent green wires from a modular computer power supply to pretty up the connection in the power supply and provide the molex connector to attach to the battery. This is similar to the trailer connection that many use, and is also keyed.
In the back of the Insight, connecting to the negative terminal of the battery was easy, but the positive was tough. I see from the solarvan.co.uk site, that he must supply some type of an extender for the spade connection. I didn't have anything to fashion that out of, so I talked to Mike, and he suggested what I was thinking - tracing the wire, unscrewing the other end, and putting a ring terminal there. But unfortunately, it's a tight fit. He suggested actually removing the battery but I thought NOOO WAY! So I used a philips head bit and some vice grips to undo it from the side. A 1/4" racheting open-ended wrench would have made it a lot easier, but it wasn't terrible. I had to work hard to get it tightly back on there.
I connected the two wires for for the fan connector with some taps. I had to cut back the covering a bit, but it's in an inconspicuous place, for if I ever need to go back to stock. I then connected all four to another green wire from the ULTRA computer power supply to run out of the battery box. I decided to use the holes on the bottom of the box, which the wire fit through exactly. I used a zip tie to not allow it to be pulled any further than necessary and others in strategic places to make sure that there would never be any strain on the connections that I had made to the fan and battery.
I was able to connect and charge my quite low battery overnight without any real problems in the process. I didn't do a full balance, as I got up early to get some things done, but it did charge up to around 168v and showed a full charge on the gauge after driving for a few miles.
I used assist liberally, and was able to get around 105MPG without much effort for over 50 miles and six stops, with a decent amount of city driving. I used most of it about a third of the way into the trip or less, but it seemed to stay at three bars and not force charge for a very very long time... so I'm assuming it simply wasn't reading the charge properly. I did almost totally drain the battery on the way home.
After the maiden voyage, seeing that everything is set, I put things back together. I'm running the wire currently through the left hand side, squished in-between the styrofoam and between the velcro into the storage compartment for now. It's doing great, with my only real problems being the stupid fast-acting fuse blowing on power up. Does anyone else have this problem?
After exhausting all of my fuses, I went to Radio Shack and picked up a handful of slow blow ones at the same rating and it's charging happily!
Check out my pics below. This is before I put all of the pieces back together. I'm not sure how I'm going to permanently mount the charger in there. It will stay with the car, as I'm hoping to do some charging at work as well. 9 hours there will give me over 3AH - most of the usable charge. There is a great amount of space to the right of the cubby for storage, but i'm getting some leakage and the last thing I want is a wet charger.
I'm currently charging, pulling around 72 watts last I checked (including about 6w from the wall wart side pushing the LEDs and fans). I figure it costs me less than a penny per hour to charge, and should pay off by raising my MPG, but moreso just in sanity by letting me have a decent amount of charge at my disposal.
I never take pics as I'm working on something but always wish I had. I'll disassemble and snap a few of the innards a little later. I also plan on taking out the dummy PSU and swapping in the 12v one, cleaning it up, and also allowing the LEDs to tell me that the unit is getting power and doing it's job (vs now, just telling me that the fans are working).
If anyone has any questions or comments, please post! I'd be happy to help anyone who is a novice like me. Anyone who has patience and is very thorough and careful can do this. But as Mike pointed out time and time again, it can be very dangerous, so be careful!
And now, the pics:
Link to pics on Flickr (for larger view)
[pics on next post due to forum restriction]
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