Sunday, February 26, 2006

Taking things down - removing the extras





I took alot of the hardware off the chair. Pretty much everything I was going to take off it that was bolted down is off. I have not decided yet if I am going to chop and modify the frame. The X bars give it some rigidity but bring the center of mass up for anything I would put on it. The batteries do keep the center of mass low and take alot of space underneath, so it might not be possible to make space lower anyway. I may just try making a enclosure or more likely use a old appliance case, maybee a old flat under monitor pc case.

The Anderson SB 50 connectors work but the new ones are a little hard to connect/disconnect. I think that they are only designed for cold battery connect/disconnect.

The battery tray is 8" wide by 12.5" Long. It takes two 12 v sealed gel cell batteries, connected in series so the motor controller sees the full 24 volts. The batteries that came with it were dead so to test it, I put in two old batteries from a ferrups ups. They hold a charge but I am pretty sure that they are near the end of their useful life. I am going to try to find some decent sealed gel cell motion application batteries. I don't know a whole lot about what makes a decent battery but within brand and type I will be looking for the best cost/ah. There appears to be a big jump in cost as you go up in size, probably because of the extra shipping costs of large/heavy items.

Their rating is 12v 17 ah/20hr. That is less than half the OEM battery, which is rated at 12v 40ah. I don't plan on doing a lot of hard running anyway.

Sunday, February 19, 2006

Preparation

The first thing I have to do is clean up the chair. It was in storage for a few years and is pretty dirty. After that I will make connectors for the battery. I purchased 2 new sets of SB50 Anderson Power Systems Connectors. They are rated at 50 amps and are pretty nice. The connectors are interesting in that they are hermaphroditic. They are not male and female plugs. That is to say the plug at the vehicle and the plug at the battery are identical.

 
 
 
 


I am going to scavange a pair of batteries from a surplus ups that I bought over the summer. The batteries are working but I don't know how much life is in them. They should do fine for the testing and save me the immediate expense of new batteries. Besides they are just sitting in the UPS unused, though it functions I really could not stand to use it since it makes an objectionable hum and fan noise. If I change my mind I can always get new batteries for that I suppose.

Motor and Joystick

 
 
 
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Joystick

 
 
 
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Battery Charger and Connector

 
 
 
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Battery Connect SB50

 
 
 
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Pictures before disassembly

 
 
 
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Beginnings

Plan
Make a robot platform that will carry hardware to run remotely under control that also has the capacity to do useful work.

The base platform will be a action 9000 electric wheelchair.