Nite Ize D/C cell Mag Lite replacement bulb problem

Hello,

I just purchased 2 of the Nite Ize D/C cell Mag Lite LED replacement bulbs. One of them works great in my 3 D cell Mag Lite. I installed the other in my 4 C cell Energizer "Hard Case" lantern, and it will not light. I have checked the continuity on the various connections and contacts, tried reversing the polarity of the batteries and cleaned various contacts, all to no avail. I tried the bulb in the Mag Lite and it works fine. The Energizer battery voltage is 5.5VDC, and I verified the bulb would light at just 3V by testing it with two C cells on their own.

Does anyone have any ideas why it would work in the Mag Lite but not in the Energizer lantern? I tried the original incandesent bulb again and it works fine.

I'm mystified. Any ideas? Is there some difference between D and C cells that would cause this?

Thanks,

John Browett.

If you've confirmed that the bulb is working, and you've confirmed that the contacts are functional, it would seem that the most likely problem is that the contacts are not touching the bulb areas where they are suppose to make contact. That bulb draws so little power, I would doubt that AAA batteries would make any difference let alone, Cs instead of Ds.

jbrowett said:

Does anyone have any ideas why it would work in the Mag Lite but not in the Energizer lantern? I tried the original incandesent bulb again and it works fine..

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The Energizer "Hard Case" lantern is wired in reverse polarity, as are most of the less expensive lanterns. AN LED drop-in won't work in them. I've had several lights in which I was able to switch polarity with relative ease, but the Hardcase looks like it would be a PITA. I believe the Hardcase flashlight is also wired backwards. I've got an Energizer rotating head worklight that was bass ackwards, but it was easy to fix.

It's a mystery to me why they wire lights in reverse polarity. Anybody know?

If you tried to install the Nite Ize module in a reverse polarity light, you may have fried it. I know this from personal experience. I once tried to install one of these units in a Rayovac 6 volt lantern that without really evaluating the polarity beforehand. It got never lit up but it got hot rather quickly and emitted a burnt smell. Needless to say, it never worked in any other light after that. Apparently these modules have NO REVERSE POLARITY PROTECTION. Luckily, Target (where you probably purchased the Nite-Ize module) has a very lenient return/exchange policy.

Thanks for the suggestions. I luckily seem to have avoided damaging the device; when I tried it again in the Mag Lite it still worked, so I know it's OK.

I wondered about reverse polarity. I know a LED is still a diode, hence it only works one way. However, I removed the batteries and inserted them all in the opposite direction to that indicated in the compartment, in theory reversing the supply, but the LED still didn't light. Is it more complicated than that to reverse the polarity?

I guess that if nothing else, I have a spare bulb now if I can't return it.

Thanks!

I think you were on the right track, as nikon said, it's reverse polarity. I don't have one but most battery compartments have some form of "ledge" at the positive end that the nub on the battery sticks past. A reversed battery negative end, which is flat, won't make contact where the positive had - a form of "reverse polarity protection" within the device. The prefered way to reverse the device is between the batteries and the bulb contacts, but if nikon says this one is a PITA (pain in the keister) I would believe it. My experience is with the Ray-O-Vac lanterns, the old ones with wires to the battery are a snap, the new ones with a plate that swings over the battery springs I haven't even bothered to try to reverse.

jbrowett said:

Thanks for the suggestions. I luckily seem to have avoided damaging the device; when I tried it again in the Mag Lite it still worked, so I know it's OK.

I wondered about reverse polarity. I know a LED is still a diode, hence it only works one way. However, I removed the batteries and inserted them all in the opposite direction to that indicated in the compartment, in theory reversing the supply, but the LED still didn't light. Is it more complicated than that to reverse the polarity?

I guess that if nothing else, I have a spare bulb now if I can't return it.

Thanks!

Click to expand...

Many battery compartments are setup in such that connection won't be made if you insert the batteries backward.

My guess is that they've designed the battery carrier with at least one contact recessed, to insure proper cell polarity.

Whilst the LED is a diode and would on its own have protection against a certain level of reverse voltage, there are other bits and peices in the drop-in bulbs. They need boost circuits to run the LED at the desired voltage. So reversing some of them may fry the boost circuit. The LED may be unaffected.

Cheers

linerlock said:

If you tried to install the Nite Ize module in a reverse polarity light, you may have fried it. I know this from personal experience. I once tried to install one of these units in a Rayovac 6 volt lantern that without really evaluating the polarity beforehand.

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Same sad experience - reverse polarity fried my Nite Ize C-D bulb. Afterwards a voltmeter confirmed that the 6-volt Rayovac lantern in question (not flashlight, but lantern) was designed with the contacts reversed. No problem for the stock incandescent bulb, but it killed the Nite Ize.

If you like that lantern style, Dorcy makes a similar one with conventional (correct) polarity.