Forklift controller

This entry should pull together all the things in my web site name.Bunch of electronics, code, and some machining to make it fit.
I have a 30+ year old fork lift at my shop that died. It was basically given to us to use for storing it by someone who got it for free.

It was broke when we got it and I got it working whit the original electronics. It has a blown transistor and huge diode that I replaced and it worked for about a year until it finally gave up. The main power section was made up of 16 large PNP transistors (they actually had International Harvester part numbers on them, didn't know they did electronics!) and all of them were dead along with the 16 low ohm high wattage resisters that tied all the sections together and acted as fuses.
Partial picture:

I started looking for replacements and found them at NTE for over $20 each and the resisters were no longer available. So rather than patching it back together for over $300, I decided to design my own.
I found a simple design at http://www.zeva.com.au/speedy/ and up-scaled and modified it for my use. This is the highest power circuit I have ever done, so it was something new for me. Also it is the first time I used an AVR. Using what I could find out about the original control, I determined I wanted about 400 amps at 36 volts. I took this from the original transistor ratings and the fact there is a 3?0 amp main fuse. (couldn't read it) It powers the drive motor as well as the hydrolics. This is probably a bit over kill, but better to be safe. This also worked out well since I spec-ed out reasonably priced FETs that are 50A each, so 8 would give me 400A and an even number to drive.
The first version was built using the heat sinks and other bits form the original control and lasted about 30 seconds.
Pilot error. Looked like mini flash bombs at a rock concert! 8 FETs later and some fine tuning and I got it working for about 6 months. It finally died so I decided to take another whack at it. In the interim I ran across this tread paul-sabrinas-cheap-144v-motor-controller which basically started out the same way I did but took it much further with a lot of community support.
I have tried to do this on the cheap using what I have available, so I started with the heat sink that was salvaged from an old forklift charger. It also worked out since 6"x9" is the largest board I can easily etch. From there I tried to correct the errors I made on the first version.
First, I totally under designed the power supply section. It got upgraded with pass transistors to give me a stable 12v gate supply. This was causing the FETs' gate siginal to be crappy and the main cause of the failures.
Second, the first design had the FETs mounted on the separate heat sinks from the original controller. This gave different gate lengths and added more noise.
Third I had some bad code. After looking at the "Cougar" design I found a few flaws I had.
I ended up with this:

I also added a serial port so I could monitor things real time.
One big difference from the "Cougar" is I am using the original current shunt to measure current. My code is not as sophisticated since I am simply sensing over current or high temp and shutting things down instead of adjusting the output. I am also controlling the reversing solenoids with the micro. I do not have such large ripple caps since I am still using the HUGE ones from the original as well as the freewheel diodes in parallel with the ones on the controller.
So far I got it running pretty smooth. Good power, no noise, staying cool.
I'll see how it goes and report back how it works out.
Here are a few more pics of the work in progress.
A few more pictures

Posted on 6 Dec 2009, 22:36 - Category: Projects
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Front yard landscaping

My front yard has been slowly sliding down hill for years. There is hardly any topsoil left, so the grass looks like crap. I have been wanting to add a small retaining wall along the front then back fill to level out the whole yard and replant new grass. After doing the pool, I had to a lot of dirt left over and figured now was a good time to do it. (hence the "free" pool just got more expensive!)

Of course, there was not quite enough dirt to fill it all the way! Now to get more dirt (or dig another hole in the back yard!) and get some grass growing. I like having nice grass in my yard, of course the best grass I had was right where the pool went!!
I could always start on the garage I wanted to build and use that dirt. Hmmm... another project, but not for a while, I need to rest up for this whole wedding thing.

A few more pictures

Posted on 6 Aug 2009, 15:27 - Category: Projects
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New "free" pool

Earlier this spring we got a complete free pool on freecycle. It was in pretty good shape, we just had to take it down. At the time it was still cold, in fact part of the pool was buried and was frozen into the ground! The liner had a small leak in it but didn't matter since it was still frozen too and got destroyed.The reason "free" is in quotes is it still cost some money to install:
A new liner (duh)
Building permit
Electrical supplies ($45 GFCI breaker!!)
Spray paint for the uprights and rails
Renting tiller
Pavers to go around edge
New filter cartridge
Vermiculite for bottom
Misc. replacement hardware
Food to feed the friends who helped on set up day (Thanks Scott)
All in all, no where near the several thousand a new pool would have cost.
For others who might do this, we found the Vermiculite at Menards in the "insulation" department for insulating block walls, worked out to be cheaper than bags of sand and a whole lot lighter to handle!! It also gives a wonderful bottom. We installed the liner using a shop vac to suck it into place and have no wrinkles!! My family had several pools and I had been though setting them up before, and this method rocked!

Next thing will be to install the solar heater we also got on freecycle. I am not happy with it's cheesy installation though and will be looking into something better. (Oh goody, another project)
You may also notice the home made solar cover roller. It was a quick project that needs some refinement (it bows real bad) When I redo it, probably season, I will try to document it as well.

A few more pictures, during and after

Posted on 6 Aug 2009, 15:11 - Category: Projects
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Rain barrel note

You might have noticed on my main page a note about a rain barrel system. I have to go back and take pictures of each component and put it together. The problem is it is summer and all kinds of other projects have came first (see next posts), and now planning for a wedding to.Here is a quick sneak peek at it and see if you can guess what makes it special.

A few more pictures

Posted on 6 Aug 2009, 14:21 - Category: Projects
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Patio Side Poject

A little side project building a patio enclosure for a friends hot tub.

Patio images

Posted on 2 Jul 2009, 24:45 - Category: Projects
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