How long will a 9V batt last for 0.07A useage?

**|squee|** · 13th Mar 2006, 18:19

Is there any way to estimate or calculate how long a 9V battery will last when it's attached to a device that runs 24/7 on a 12V 0.07A rating?

**tawauboy** · 13th Mar 2006, 18:49

these 9v batteries have a typical capacity of 550-500mah.
when supplying 0.07a, the battery will last only 8.5 hours.

and 9v battery not be able to operate a 12v device.

**aqualover** · 13th Mar 2006, 18:59

i personally won't even consider it, if it's drawing current at 70 milliamps, your Duracell battery probably won't last a day. Too costly to do so and it's a hassle having to change it frequently. Use AD/DC adaptor lah

**|squee|** · 13th Mar 2006, 21:19

Darn!

Thomas (Liew), the device I'm talking about is a DC fan, and primitive testing by touching the contacts of the battery on the bare wires of the fan has yielding movement, only at a slower spin rate.

Of course this is not true for other devices.

I guess there goes my plan. I want to setup a slow-circulating fan in my terrarium where air circulation is poor, but the power point is just too far away.

Thanks though!

**tawauboy** · 13th Mar 2006, 21:43

Terrence, forget the idea of using battery to power a fan.
use a ac/dc adaptor for the fan.

you can use an extension cable to bring power to your terrarium. get those ac/dc adaptor with variable output voltages. adjust the output voltage to control the fan speed.