Controller for heated gloves/socks

Thread Starter

enveetee

Joined Dec 1, 2009
5
Hi, first post so be gentle!!!


I'm looking to make a controller for some heated garments. I've sorted the garments and heating element fine, it all works off a 3cell Lipo battery.

I need to solve two problems.

1) Heat regulation. Each glove/sock draws between 300 and 700 mAh @ 12V depending on how warm they need to be. I have found a circuit based on a NE555, LM393 and a FET (IRF540) which seems to do the job (I need to build and test it.)

2)Battery protection. I need to protect the battery. Lipos go crazy if discharged below 3V per cell so I need a cut off at around 10V to protect them. I was thinking of using a MAXIM 8211 or 8212 voltage detection IC and a relay to disconnect the circuit at 10V or so.

Does this sound feasible? Should I be taking another approach? Can anyone suggest a circuit or give me some ideas on how to proceed?

Cheers

Nigel
 

SgtWookie

Joined Jul 17, 2007
22,230
I'm looking to make a controller for some heated garments. I've sorted the garments and heating element fine, it all works off a 3cell Lipo battery.
What is the voltage of your 3-cell LIPO battery?

I need to solve two problems.

1) Heat regulation. Each glove/sock draws between 300 and 700 mAh @ 12V depending on how warm they need to be. I have found a circuit based on a NE555, LM393 and a FET (IRF540) which seems to do the job (I need to build and test it.)
It would help a great deal if you would post the circuit diagram (schematic).
IRF540 MOSFETs require a Vgs of 10v (voltage on the gate using the source as a reference). NE555 is a bjt (bipolar junction transistorized) 555 timer, it requires at least 6v to operate, and it's output will not go higher than Vcc-1.3v even under light load.

2) Battery protection. I need to protect the battery. Lipos go crazy if discharged below 3V per cell so I need a cut off at around 10V to protect them. I was thinking of using a MAXIM 8211 or 8212 voltage detection IC and a relay to disconnect the circuit at 10V or so.
Disconnect is not a problem using a MOSFET and some simple circuitry. You really don't want to use a relay, as it will draw a lot of power by itself.

Does this sound feasible? Should I be taking another approach? Can anyone suggest a circuit or give me some ideas on how to proceed?[/QUOTE]

I thought you had a circuit already?
 

Thread Starter

enveetee

Joined Dec 1, 2009
5
Thanks for taking time to responde

What is the voltage of your 3-cell LIPO battery?
10V nominal


It would help a great deal if you would post the circuit diagram.[/QUOTE said:
http://home.mebtel.net/~rbutterfield/Images/dimmer.jpg


Disconnect is not a problem using a MOSFET and some simple circuitry.
Yeah, I *was* thinking of using a MOSFET but have no experience with them. I have used a MAXIM 8211 voltage detector in the past, so maybe I can use one of those as well. How would you driver the power-cutoff MOSFET from a logic output? Could you suggets something

Thanks again

Nigel
 
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