Condor battery life problems

Started by Noplasticrobots, July 25, 2006, 11:43:29 AM

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Noplasticrobots

I have a two-fold problem (suprised?)   ;D

I built a Condor for a friend. He's had it for a couple weeks and he's noticed that when he inserts a brand new battery, it dies within 24 hours. He's using Duracell 9v. I didn't notice an problems when I was building or playing with it. He's not leaving any cables plugged in, and he's not leaving the on/off switch in the on position. I have absolutely no idea what could have gone wrong with this circuit! My second problem is that he lives over a 100 miles away and this whole diagnostic process has to be done over the internet. He's not electronics savvy, so I can't get any DMM readings or anything. Does anyone have any ideas what could be wrong?
I love the smell of solder in the morning.

MartyMart

Sounds like a short , but a "bad" short will kill a battery in a couple of hours and it will get
very hot, so possibly intermittant short ?
What do you mean by "jacks unplugged" and switched off ?
Do you just use input jack to switch power off, or another power switch too ?
Could have been a small "non permanent" short when it was boxed up, like circuit
against box side/switch etc ... I've had that a couple of times when the build/box is a tight fit.

MM.
"Success is the ability to go from one failure to another with no loss of enthusiasm"
My Website www.martinlister.com

Noplasticrobots

Sorry, should've made that clearer. What I mean by "jacks unlugged" is that he removes the cables from the box when not in use to save battery life. The input jack turns it on but I added the standard DPDT switch so he could bypass it during recording to save on battery life instead of unplugging it constantly. I'll have him search for shorts against the enclosure in the meantime.
I love the smell of solder in the morning.

Noplasticrobots

Ok, my buddy came to visit and I took a look at the circuit. Everything appears fine, no shorts, no wires fell off,a ll voltages are fine. However, I noticed that he wasn't using an alkaline battery. Could this be the culprit?
I love the smell of solder in the morning.

calpolyengineer

I have one of those touch screen universal remotes for my living room and tried rechargeables. They were dead by that evening. Regular alkalines lasted for two weeks. Don't know why, it just did. I think it has something to do with the rate of decay of the voltage. Alkalines are pretty gradual whereas rechargeable hold the initial voltage a little longer but then the voltage drops off steeper after that. Like I said I don't know, but the type of battery could cause some problems.

Did you check the current draw? A regular 9V alkaline has about 675mAh. Divide that by the current draw and you have the approximate battery life. Also note that the circuit comsumes more power while active than when idle so have your buddy play through it while you test to get a minimum battery life approximation.

-Joe