Your thoughts on modding a 70's-era Rayovac #100 6V camping lantern / table lamp?

kentchristopher

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Rayovac100Lantern.jpg


I imagine someone out there is familiar with these Rayovac #100 camping lanterns which run on 6V lantern batteries. Hopefully someone even has one that perhaps they can help with ideas here, since I don't have the lamp in front of me. My dad (who lives in a different state) has a couple in storage for emergencies. I always found them to be clunky old things, and yet here I am, internally conflicted with thoughts of attempting to mod them with an LED and make them relevant for the current century vs. convincing him to sell them or give them away. I guess I've come to see the potential value of having a battery-powered table top style lamp, and especially one with an insanely long runtime if modded with an LED, which is what drove me to keep thinking about this and bring me here for input from you all.

He already has a couple D-powered LED lanterns for emergencies (so it's not like he needs this) and generally keeps a good stockpile of D cells in case of emergency, so an obvious mod would be buying a 4D to 6V lantern-style adapter, which I know I can get reasonably cheap. In an emergency though, wasting D cells on an inefficient incandescent light would be a bad idea.

Which brings us to the big issue: replacing the old incandescent bulb. I've read enough CPF threads prior to writing this to know that many drop-in LEDs are polarity sensitive, and that these 6V lanterns have the negative terminal in the center, which can be an issue. I'm not so worried about this because I feel pretty certain I could rewire things if needed, plus I've found several cheap LED drop-ins that claim to be universal polarity. My greater concern is that most drop-ins are made for flashlights and will be pushing light straight up, not around, creating a rather ineffective table lamp.

So, my main question: Are there any decent drop-in LEDs with side emitters for an application like this? Ideally with a warm white tint? I believe (I'm hoping someone with this lamp can confirm) it uses a PR2 style screw-in bulb, although maybe P13.5S bulbs would work as well (are they sometimes interchangeable?).

Alternatively, I'm open to other ideas. I had the thought that I could buy a 1 meter / 10 LED Christmas light string (under $1 on AliExpress) made to run on 2 x CR2032 batteries (6V), snip the wires and wire it up to the bulb contacts, or through a drilled hole into the base, powered by the 4 D cells in an adapter. There are other battery options as well, like using string lights powered by 3x AA batteries (under $2) or one with a USB connector (under $2), allowing the use of a USB power bank inside the battery compartment. A string lights solution would kind of kill the retro aesthetic, but it may be the only cheap way to get warm white LEDs in there in a way which makes an effective area light, and it would cost practically nothing.

This is all my brain has come up with so far. Maybe yours can add something to the mix. :)
 

Lynx_Arc

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I've modded several lanterns and found that I rarely use them instead I end up using native LED lanterns that have several modes and better designed light delivery. I would go and look around at lanterns before spending a lot of money on modding them.
6v lanterns converted to 4D modded for LED end up being a pretty large light and either have unimpressive output or non optimal output.
I have several 3 and 4AA LED lanterns and never use them and bought a 18650 LED lantern and it is smaller than all the others, brighter and rechargeable via micro USB I think it will end up my most used lantern now.
 

kentchristopher

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I say mod it, but I mod every light I can get my hands on. Lol

Using a drop-in isn't a bad idea & if need be, a ping pong ball makes a great diffuser in lights like those.

Interesting. So just cut a hole in a ping pong ball and mount it on top of the drop-in LED?

I've modded several lanterns and found that I rarely use them instead I end up using native LED lanterns that have several modes and better designed light delivery. I would go and look around at lanterns before spending a lot of money on modding them.
6v lanterns converted to 4D modded for LED end up being a pretty large light and either have unimpressive output or non optimal output.

As stated, he already has better LED lanterns. I'm not trying to make something that will be better than those; just something useful if the power goes out for an extended period, without spending more than a few bucks.
 

captianworkbench

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I haven't been around in a while but this message came through my email digest so I thought I would throw in my two cents.

Personally, I have fond memories of these types of lanterns from many family and scout camping trips as a kid.

So, even though it won't be the most awesome, multi-mode, feature rich, whiz-bang lantern with all the gee-gaws, it will still be very cool, better than it originally was, and you will enjoy doing it and both you and your Dad will probably enjoy using it.

Every time I visit my parents I always do flashlight maintenance and there are a few old favorites my Dad has that I have upgraded to LED.

I would definitely vote for modding it.

I like the ping pong ball idea mentioned previously. Great cheap diffuser.

If I remember correctly, the one we had like this when I was a kid used an 1156 automotive type bulb. There are many of those type made with several SMT LEDs on the front and sides. They should distribute the light quite well also.... that is once you solve the reverse polarity issue.

Happy tinkering!
 

kentchristopher

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If I remember correctly, the one we had like this when I was a kid used an 1156 automotive type bulb. There are many of those type made with several SMT LEDs on the front and sides. They should distribute the light quite well also.... that is once you solve the reverse polarity issue.
Thank you for mentioning this as I indeed had it wrong about the bulb type. I did some digging through eBay listings and found a photo of the bottom of the lamp which shows print that reads "USE BULB NO. 1651", which is a bulb with a Ba15s base, same as the 1156 automotive bulbs you mentioned, although those are designed for 12V -- not that the incandescent bulbs wouldn't work on 6V, but an important distinction in looking for a 6V LED equivalent.

Now to see if I can find a low-cost version of such a bulb in warm white, ideally without polarity.
 

kentchristopher

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First, thanks to all of you who replied thus far. I'd like to reward you with this video which I stumbled upon yesterday of a guy who modded similar lamps with an LED. You might appreciate the surprise twist. :)

I've found some bulb options, but one question that has come up is: could I use a 12V bulb on 6V? I'm guessing the bulb would just run dim, which may not be bad since the 12V bulbs are designed for cars and may actually be a bit too bright (referencing the video above). Getting something about the same brightness as the incandescent but with a big increase in run-time would make sense for emergency use. I know it's also possible the bulb wouldn't light up at all, so I'm looking for input from you who are more experienced with such matters.

Here are the bulbs of interest I've found so far, which I'm posting for the sake of posterity, but would also be happy to hear your input.

3000K options:

1651 LED 5V in warm white 3000K from ledlight.com - Non polarity, "up to 320 lumen output", "operates from 4.5V to 6V", basically the best option but the $6 price + $8 shipping made me look elsewhere.

1156 LED 6V to 24V in warm white 3000K from ledlight.com - As far as I can tell the exact same bulb as above but with more info in the description. And 70 cents cheaper -- but still expensive.


4300K options:

1156 LED 6V in warm white 4300K from AliExpress - Non polarity, 160 lumens, "about 2W". Seems a very safe and affordable option at a price of $2.33 shipped. (Possibly same bulb on eBay.)

1156 LED 6V in warm white 4300K (2pcs) from AliExpress - I believe the same as the one above (but 2 pieces). This page has more info and better pics, including one that shows .3A draw at 6V.


Wildcard:

1156 LED 12V in warm white from AliExpress - This is where the 12V LED on 6V becomes relevant. The advantage of this listing is it has lots of orders and lots of reviews. It doesn't explicitly state non polarity, but I feel like if they weren't, one of the 200+ reviews would mention a problem with it. They also have a video showing the different colors, and the warm white looks nice. At $0.79 shipped it's the best deal -- IF it works on 6V.
 

Lynx_Arc

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The problem with using a 12v bulb supplying it only 6v is when it has multiple LEDs in it. Typically 12v bulbs with multiple LED emitters have several "groups" of them in series and they expect voltage in a range of perhaps 11-14v and 6v probably won't even light up the LEDs at all. The only case 6v would work on a 12v LED bulb is if it has a buck converter that is dropping the voltage down or has resistors dropping the voltage down that can be replaced. I seriously doubt that you can power a 12V LED bulb off 6v.
After thinking awhile.... it is possible some of these bulbs have linear regulators which will allow them to work but will be a lot less efficient than a buck regulating circuit. A linear regulator is essentially an electronic resistor burning off excess voltage such that a 6v bulb with a 3v LED would burn off (waste) 3v of power.
 
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Poppy

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He already has a couple D-powered LED lanterns for emergencies (so it's not like he needs this) and generally keeps a good stockpile of D cells in case of emergency, so an obvious mod would be buying a 4D to 6V lantern-style adapter, which I know I can get reasonably cheap. In an emergency though, wasting D cells on an inefficient incandescent light would be a bad idea.
When I moved, I threw a couple of similar incan lights out in the trash. Unless you have more time than money, or really like the idea of tinkering with them to upgrade them, I'd toss them, or bring them home to upgrade them and never get around to it.

The main purpose is to get them away from Dad so that he doesn't blow through his battery stash on them during an outage. Especially when he already has better lights.

Does he have a set of 18V power tools? A nice gift for him might be a LED lantern that goes with the set, or LED flashlight that goes with the set. The batteries usually take a pretty quick charge, and he will have other reasons to keep them charged. Also, since usb charged phones are every bit as important as light during an outage, something like the Ryobi P781 is both a lantern and phone charger.
 

broadgage

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A 6 volt incandescent vehicle bulb will not work well in this type of lantern. So called 6 volt vehicle bulbs are actually designed for about 7 volts, this being the voltage when the engine is running and the battery on charge. A 4 cell battery will average about 5 volts on load, working 7volt bulb on a 5 volt supply will produce a very dim light. Also most vehicle bubs are too high powered to work from disposable batteries.

I would either use the original type of bulb, 5 volt 3 watt, or make an adaptor to take a modern multi voltage LED flashlight bulb.
 

kentchristopher

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A 6 volt incandescent vehicle bulb will not work well in this type of lantern. So called 6 volt vehicle bulbs are actually designed for about 7 volts, this being the voltage when the engine is running and the battery on charge. A 4 cell battery will average about 5 volts on load, working 7volt bulb on a 5 volt supply will produce a very dim light. Also most vehicle bubs are too high powered to work from disposable batteries.

I would either use the original type of bulb, 5 volt 3 watt, or make an adaptor to take a modern multi voltage LED flashlight bulb.

Thanks for your reply. Did you watch the video I linked above? Here it is again: https://www.youtube.com/watch?v=UkBN2ntpoIU&t=5m27s

With the standard 6V lantern battery and a 6V 1156 automotive LED bulb (0.3A draw at 6V), it worked very well for that guy. I know that using a 4D adapter I might get closer to 5V resulting in a dimmer bulb (same as a partially used 6V lantern battery?), but if it's even close to the brightness of the incandescent bulb, it will be worth it for the greatly extended runtime.

I will be doing this mod and will post here with the results, though it likely won't be until December of this year (2019). I encourage anyone interested to follow up if I haven't posted the results by then, in case I forget.
 
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broadgage

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A 6 volt automotive LED bulb should be fine. With only about 5 volts applied instead of 7 volts the light will be reduced, but should still be sufficient and the current will also be reduced thereby extending the battery life.
Some 6 volt vehicle bulbs are available that are not polarity sensitive.
 

xxo

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If you get a 6V to 4 D cell adapter, you could use some 3 AA to D cell series adapters to raise the Voltage and use the 12V bulbs, would probably over drive them some especially with fresh alkalines. Eneloops would be better. Down side is that in addition to the adapters, you would need 12 AA cells and runtime with the 12V bulb would be short. Another option would be to convert to take standard PR based bulbs and use a LED drop in - you could probably change the polarity at the same time.
 

kentchristopher

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If you get a 6V to 4 D cell adapter, you could use some 3 AA to D cell series adapters to raise the Voltage and use the 12V bulbs, would probably over drive them some especially with fresh alkalines. Eneloops would be better. Down side is that in addition to the adapters, you would need 12 AA cells and runtime with the 12V bulb would be short. Another option would be to convert to take standard PR based bulbs and use a LED drop in - you could probably change the polarity at the same time.

Interesting idea, running 12 Eneloops in series through adapters... but I think my modest stock of Eneloops will be better used elsewhere if there's ever occasion to use this lamp.

I am open to the idea of using an adapter to allow a PR2 drop-in, but I'm assuming I'd need to make that myself -- I'd guess using an old 1156 bulb base and a PR2/P13.5s socket? The thing is, I've searched online for "PR2 bulb socket" and "P13.5s bulb socket" and I only find bulbs -- no sockets. Even if I do find one, I'd be back to the problem of using a unidirectional bulb in flood light settings, though I could use the ping pong ball diffuser idea mentioned above.

For now, I'm thinking I'll try out one of the 6V 1156 bulbs I listed above.
 

kentchristopher

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The results:

First, a photo of the lamp with the original incandescent bulb for comparison:

Lantern-Incandescent.jpg



Below, with this 1156 6V LED bulb from eBay for $3 shipped.

Lantern-LED.jpg


About the same brightness, maybe a bit brighter than the incandescent, though clearly not as warm. It draws about 12% of the current though, which should translate to about 8x longer run-time, which is exactly what I was going for since this lantern would likely only be used at length in an emergency.
 
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Lynx_Arc

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About the same brightness, maybe a brighter than the incandescent, though clearly not as warm. It draws about 12% of the current though, which should translate to about 8x longer run-time, which is exactly what I was going for since this lantern would likely only be used at length in an emergency.
Most likely the runtime will be a lot longer than 8x as LEDs can give out usable light at current levels pretty low and voltages sometimes half that incans operate at. I prefer less warm in lights myself as even though warmer white is more relaxing it makes it harder to read than more neutral white tints are for me especially as the output drops over time.
 
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