I ran across LM334 current source IC's (TO-92 package) on sale at Electronic Goldmine:
https://theelectronicgoldmine.com/products/g27186
It seemed to me that I ought to be able to use an LM334 and a thermistor to sense when a NiCd or NiMh battery hits a certain temperature that indicates "full charge" of the battery.
When that temperature is reached, couldn't the LM334 or maybe the LM334 and a comparator reduce the current to something tiny, like microamps, to "cut off" the charge?
I found a circuit idea at bristolwatch.com (Mr. Lewis Loflin's website) that had a circuit I thought might work:
https://www.bristolwatch.com/ccs/LM334_sensors.htm
If you have been reading my other posts in this forum, you know that I have been breadboarding a very simple constant current (low current) NiCd/NiMh battery charger using the LM317 and LM350 voltage regulators.
But even at low current, at the "full battery" point, I want the charge to stop.
Any circuit ideas are welcomed!
I want to use some secondhand NiCd 12V batteries and a secondhand 10.8V NiMh battery as the launch power source for LPR rocket launches.
I guess the circuit would need a “latch” feature or some sort of hysteresis when the temperature level is sensed.
Hmm. Maybe this circuit using thermistors and an LM311 comparator is better way to go. It is pretty complicated.
https://www.electronicsmaker.com/em...on/TEMPERATURE CONTROLLED BATTERY CHARGER.pdf
Once an analog circuit gets this complicated maybe it means I should learn how to use a microcontroller? I have been resisting.
- Brock
https://theelectronicgoldmine.com/products/g27186
It seemed to me that I ought to be able to use an LM334 and a thermistor to sense when a NiCd or NiMh battery hits a certain temperature that indicates "full charge" of the battery.
When that temperature is reached, couldn't the LM334 or maybe the LM334 and a comparator reduce the current to something tiny, like microamps, to "cut off" the charge?
I found a circuit idea at bristolwatch.com (Mr. Lewis Loflin's website) that had a circuit I thought might work:
https://www.bristolwatch.com/ccs/LM334_sensors.htm
If you have been reading my other posts in this forum, you know that I have been breadboarding a very simple constant current (low current) NiCd/NiMh battery charger using the LM317 and LM350 voltage regulators.
But even at low current, at the "full battery" point, I want the charge to stop.
Any circuit ideas are welcomed!
I want to use some secondhand NiCd 12V batteries and a secondhand 10.8V NiMh battery as the launch power source for LPR rocket launches.
I guess the circuit would need a “latch” feature or some sort of hysteresis when the temperature level is sensed.
Hmm. Maybe this circuit using thermistors and an LM311 comparator is better way to go. It is pretty complicated.
https://www.electronicsmaker.com/em...on/TEMPERATURE CONTROLLED BATTERY CHARGER.pdf
Once an analog circuit gets this complicated maybe it means I should learn how to use a microcontroller? I have been resisting.
- Brock
Last edited: