Effects Pedal Battery Explodes--when Unit is off

heat causes batteries to swell and burst. it can either be from internal heat caused by drawing too much current from the battery (a.k.a. short circuit) or external heat, such as sitting in a car on a hot day ... even if not powering anything. and of course, some batteries are just defective and leak.

Buy one of these and never again worry about batteries. 8)
http://accessories.musiciansfriend.com/product/Visual-Sound-1-Spot-Combo-Pack?sku=150373

But if there's a short in the pedal, the wall wart will also overheat.

Using my extensive knowledge of electronics, I can say with conviction this is a bad thing. Time to replace that pedal if it is cheap and fix it if it's expensive.

But if there's a short in the pedal, the wall wart will also overheat.

good point Doc, i hadn't thought of that.

wouldn't there be some other sort of sign, if the pedal had a short?
i mean some sort of obvious hum or noise that would tell ya right off that something was amiss?
is this type of problem common? i've never heard of it happening till now. i would take Rics observation to heart on this one and check the guts to see if something inside is amiss.

those external power supplies are short circuit protected, especially the newer ones that contain switching supplies (as opposed to the older-design linear supplies)

if the pedal works at all on a battery, it probably doesn't have a power supply "short." Nick may be correct in blaming the pedal if the pedal does not work with a fresh battery or an external supply. if only one battery has ever failed in the pedal, and the next seems to work okay, the most likely culprit is a defective battery. it happens.

True. Thread title implied repeated occurrences, I thought. Short circuit protection in most wall warts is smoke. Lets you know it went. Some sort of short when the switch is off would be the only reasonable explanation for repeated battery overheating or exploding with the pedal turned off. Happening once could be a bad battery.

we seem to be interpreting the same text differently these days. :wink: which is somewhat amusing as we both end up dealing with vague statements of problems in our professions: your patients' symptoms and complaints to customer service about my engineers' product designs.

I get enough battery complaints to know it's usually the battery. but fool me twice ...

God help the person that consults with you two if their pacemaker battery is acting wacky

If it blows up, that'll likely end the discussion.

Lol. I doubt it.

God help the person that consults with you two if their pacemaker battery is acting wacky

no MP insurance here. Ric gets solo honors.

Thanks to everyone for the input. Thankfully I think it was just the battery. I'd been leaving the input jack in, even when not in use--and I'm told that that will continue to draw from the battery (so I think the battery's way of giving out, was to pop). Happily--it hasn't happened since I corrected that practice.

Car batteries can develop shorts internally when getting ready to go to little battery grave-yards. I saw the results of a couple of them doing that in certain minivans's OE units back in the mid-90's. Nasty messes. I wonder if widdle 9 volters can do the same?

But, like TL pointed out, those power supplies are da bomb! (hmmmm...bad choice of words)