Awesome job!
Sounds like a great idea for controlling thermal runaway. Just out of interest, does the circuit have a way of setting the max amps the circuit will put through the cell?
Awesome job!
Sounds like a great idea for controlling thermal runaway. Just out of interest, does the circuit have a way of setting the max amps the circuit will put through the cell?
Painless,
No there is no amp limiting.
What I intend to do is set the startup current with my electrolyte. It will be about twice the current that I normally run my generator.
The circuit will drive the gen hard until it gets to setpoint temperature, then it will go into feedback pwm to maintain the temp..
That way, the generator will put out max until setpoint, then will put out max it can without overheating the generator.
Will start on the winter circuit tomorrow.
Ridelong, Thanks for sharing your time and knowledge with us. It is much appreciated.
All,
Took a break, now I'm back.
Cleaned up the bench, fired up the temp circuit. The lm34 output was way high.
Took the probe out of the electrolyte. The hot melt keeping the electrolyte off the wiring in the ss tube fell off in my hand. Start tomorrow to find something to seal the end of the probe.
I'm thinking of posting only the temperature feedback pwm portion of this project. When I finish, will post the winter heater circuit with the temp pwm combo with relay switching between the circuits.
All,
Here is the link to the temperature feedback pwm.
http://www.mikecramer.com/images/temp-pwm800.jpg
This circuit oscillates about 1400 Hz.
Will post the system with winter circuit when I finish it.
B/M for this circuit:
All Electronics parts:
LM34 Cat# LM34DZ $2.50
1 uf Cat# RM105 $1.00/4
Digi-Key parts:
5k pot CT2264-ND $1.51
49.9k 49.9KXBK-ND .49/5
5.11K 5.11KXBK-ND .49/5
(2)25.5K 25.5KXBK-ND .49/5
4.99K 4.99KXBK-ND .49/5
200 OHM 200XBK-ND .49/5
10 VOLT ZEN 1N5327BTPMSCT-ND $3.90/10
FET IRL1404ZPBF-ND $3.67
so how hard would it be to add current limiting to the temp feedback.
that way, you set your max amps, then run them until heat becomes an issue. My alternator is weak and I would like to see a pwm that implements both.
resago,
It wouldn't be that hard to add current limiting, but it seems redundant. You can adjust the electrolyte to set the max amps. Then let it run until the gen reaches set point temp. Then it will adjust the pwm to hold the gen at that temp.
All,
Just finished testing the temperature feeedback with the winter circuit that turns on a heating element when the gen electrolyte gets below 39 deg F.
Works exactly as designed, turns on heating element at 38.8 deg, and off at around 39.4.
Now I have to find a heating device. Am looking at the USB cup heaters on EBAY. Anyone have a suggestion?
Will post the circuit and a picture of my unit soon.