Paul & Sabrina's cheap DIY 144v motor controller

[bennelson]

Thinking about just changing voltage, but not amperage is also a little weird because there isn't a good way to change voltage on the fly.

Typically, voltage is fixed by how many batteries you have. Amperage is controlled by the motor controller by how far you press down the go pedal.

An exception to this would be a Citicar with an original contactor controller. The go pedal actually controls a series of switches that combine the batteries in in either series or parallel, with "1st gear" being the batteries in parallel, but running through a resistor. Instead of the throttle controlling amperage, it controls whether the batteries give 12, 24, or 48 volts to the motor.

It's also very annoying, as there is a loud click every time you change from one "gear" to another.

[Christ]

Mention of the single cell batteries - I'll check into it, but it's probably not economical for much of anything besides small projects.

Paul/Everyone - how to check a battery that isn't labeled for maH rating? (with ohm-meter, probe? not sure... would love to know though LOL.)

Paul - I'm loving the new modifications to the software.. maybe one of these days I'll get around to building my own controller.

[Christ]

I posted at the same time as bennelson - and now I have a comment on his post as well!

Ben - I thought about something like this, but only using a sort of gear selector for the "speeds" making it seem more like driving a ICE car....

In a manual transmission, 1st gear might be 12VDC, 2nd 18VDC, 3rd, 24VDC, 4th 30VDC, 5th 36VDC (not specifically those voltages, but constantly having a (X number) of amps, still limited by pedal/controller, regardless of number/configuration of batteries.)

It seems like an enormous waste of time though, other than being able to choose your speed/range more accurately than just pushing a pedal...

Sound like something worthwhile?

[MPaulHolmes]

I think you could let the battery sit for a while, check the resting voltage, from that guess at it's state of charge. Run it at a pretty low current (so the Peukert effect doesn't come in to play?) for a specific amount of time, let it rest for a few hours, check the state of charge and figure it out from that. That sounds really annoying.

[MPaulHolmes]

I think you could let the battery sit for a while, check the resting voltage, from that guess at it's state of charge. Run it at a pretty low current (so the Peukert effect doesn't come in to play?) for a specific amount of time, let it rest for a few hours, check the state of charge and figure it out from that. That sounds really annoying.

I tried it with the wax paper. It needs fine tuning. I pressed to hard, and it smooshed the ink all over the place!

[bennelson]

Originally Posted by MPaulHolmes

I tried it with the wax paper. It needs fine tuning. I pressed to hard, and it smooshed the ink all over the place!

A lot of printers have a "quality" setting on them. Often, this simply effects HOW MUCH ink is used.

Try using "draft mode" for less ink. As the ink has no other place to go (such as soaking into the paper) you can use much less.

[Christ]

I think I missed something - Paul, are you trying to make a circuit diagram for etching the copper panel?

If you are - use photolithic film (probably not the correct word). It's a film that allows you to expose the core to a negative image, and the exposed areas are completely immune to this awesome chemical called Cupric Chloride (don't touch) that will eat away the copper under the portions of the film that haven't been exposed.

Afterward, you clean the core off with whatever the manufacturer of your photolihic ( again - probably not the right name) recommends, and you have a perfect circuit line left in the exposed areas.

You'll want your circuit lines in the print several mil thicker than you intend them to be, b/c you'll need to use the "soak/rinse" method to etch your panels if you do it this way.

If you're not trying to use the printer to create the circuit board, mibad - ignore this LOL.

[MPaulHolmes]

The lighter ink amount worked! I don't think it dries, but it's clear on the copper.

I'm sort of ANGRY RIGHT NOW! I was experimenting in the garage, everything going great, and I was switching the voltage around to 36v to look at something, and I accidentally connected my poor little ATMega8 5v input to 36v... Yep, 36v was a bit high. It broke. I have 1 spare for just such an emergency, but I hope I didnt' break anything else hooking it up like that.

Next step, label the wires! hehe.

It's interesting that chips fail very quietly... They don't say, "no! That's too much voltage! Don't do that!" They just quietly die.....

Christ: I am trying to etch PCB. I just wanted to use mechanical means because people I've talked to said its very hard (an all day activity) to etch 4 or 5 ounce PCB with chemicals because it's so thick. You have to keep going back and shake it around, and there are several kids in this house, and my mother in law would get mad.

[Christ]

I loved doing my job at EIT - chemical etch... I could etch BOTH SIDES of a 6oz copper panel in less than 2 mins LOL.

Then again, I used 13 spray bars equally distributing 30-60GPM of Cupric Chloride at 80+PSI. Oh - I had two etch chambers... so that's 26 spray bars... pfffft. :P

The etch machine I used was exactly as large and deadly as Oprah... only it smelled better. (Catch of a whiff of the fumes from Cupric Chloride... you'll see )

[MPaulHolmes]

You sure have had some unusual and interesting jobs! I would invest in that chamber for spraying if I had a place to put it. Maybe the bathtub.