4Sevens rubber tailswitch issue -- seeking assistance

I've had my 4Sevens Quark AA2 Turbo for several years now and it's worked well and never gave me problems.

It does display a strange quirk (quark?) in that the rubber tailswitch starts to inflate when run on Turbo mode for a longer length of time. It grows larger and larger until I twist the entire light open to release the buildup of pressure.

Anyone have this happen to their rubber tailswitch lights? Is it a heatsink problem or is my light just well-sealed from the elements? I wondered if I should put a pinprick in the tailcap to let hot air escape, but haven't done so yet and I'm not sure if I will.

BTW, I am using Tenergy Premium 2500mAh Ni-MH rechargeable AA cells only.

Any help?

A friend of mine had that exact model with that exact issue when using Ni-MH.

How old is the battery? Might be a heat issue. Im not sure about poking a hole in anything...

I did that pin prick with one of my early HDS flat top switch's, and have had no problems over the years.

Bill

Before pricking any holes anywhere, I would really recommend testing with a new set of decent LSD NiMH's.

That's a battery issue. Dump the ones you are using ASAP and get some Eneloops.

I'll give them a shot. Thanks.

What is it that causes rechargeables to give off heat like that?

PB Wilson said:

I'll give them a shot. Thanks.

What is it that causes rechargeables to give off heat like that?

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No expert but I think they might be venting something. Lets toss um out!

Woods Walker said:

No expert but I think they might be venting something. Lets toss um out!

Click to expand...

I concur. NiMH cells are not very likely to vent, but it's by no means uncommon. Haven't had this issue yet with any of my many Eneloops. Happened to a few of my older non-LSD NiMH's, though.

Man, if my light switch cover started swelling due to heat for the first time (after never having it happen before) I'd be tossing that sucker away from me quick thinking "kill it before it breeds"... later I'd certainly be checking it with different batteries. If it continued with different cells I'd do what BullzeyeBill suggested.

I finally got around to testing the light with different batteries. The Tenergy Ni-MH rechargeables were the culprit.

What would make batteries heat up like that?

As for danger, are Ni-MH batteries hazardous? I didn't think so and am not sure they are.

Increased internal resistance from age can heat up batteries. As has been mentioned, it's also possible that the batteries were venting. I wouldn't say AA NiMH's are normally hazardous, but it would hurt to avoid directly breathing the fumes the may vent.