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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Hi, does anyone know how to get a CR2032 to output the full 225mAh specified in the datasheet? The information found here suggests that 500uA drain max ensures long life.
This is for a car alarm keyfob which averages about one battery every 2.5 months!
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
I've changed the (sticky) switches, will see if that helps. Also the LED is an orange/blue one poached from a dead HP front panel so adding some sort of light activated blinker with a 100msec flash every 5 minutes when dark/dropped would be doable.
Registered Member #61428
Joined: Sat Jan 14 2017, 12:39PM
Location:
Posts: 50
If the expense is crippling you and the hassle has you at your wits end maybe you could get creative. If the fob has enough free space inside you might try substituting your primary lithium cell for a secondary Li-ion or Li-Po. For all I know, there may even be Li-ion cells available that fit the CR2032 form factor. Typically, simple transmitter circuits not only tolerate slight overvoltage, but even perform a bit stronger. I'm pretty sure the nominal 3.7V won't croak you fob but a full cell can put out up to 4.2, which I am less certain about. You may want to try it with an orphan fob first. Or you could try to find a small solar cell to glue to the back so that you only have to use the battery when it's dark.
Wouldn't it be cool if fobs worked like RFID tags, by obtaining their power from the receiver? If you're a bit more ambitious it might be cool to try to engineer that.
Dollar stores usually have cheap batteries.
So to answer your question, I don't know. haha. Contact the manufacturer maybe.
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