ROP Idea

Would it be possible to do a ROP mod in the old 12V lantern format using SLA batteries instead of the 12V alkaline's.

It would require a battery case with attached handle, an attachment point for a maglite head, a charging port & circuitry for running the ROP head and charging the battery/s.

Do you think that this is possible to do?

I created the "Roar of the Big Jim" a year ago.

Replaced the stock bulb with a 6.4V 30W 4515 sealed beam, and put 7 sub-C cells plus a 1-ohm NTC into a dead 731 battery shell.

You can use a H4515, too.

Out-throws the RoP by a mile, literally.

Another ROP Idea

My local Interstate Batteries carries lithium thionyl chloride C-cells. These guys have an operating voltage about the same as li-ions, and double to triple the energy density. While thoroughly nasty, they seem to have the sort of grunt one would need to make a fire-and-forget 2c ROP for a bail-out bag or other emergency kit with some truly insane runtime.

Funny a lot of stuff on these old style sealed beam lanterns recently in the forms. Well the thing is making a Mag / stile swivel head lantern, sort of defects the purpose of a sealed beam light. You use a small Mag as a base to make a powerful compact light, once you go in to the big lantern realm the trade off of compatibility comes with the ability to use sealed beam bulbs, Not using them is sort of defeating the purpose. A 24 watt ROP bulb will not have a chance in the world at out throwing something like a 30 watt shielded filament bulb like the 4515. And the option to use more demanding bulbs with large batteries is now an option, like 100+ watt Par36. Sealed beam lights are not the most popular on CPF because of their very old technology, however they can be extremely powerful when built right. The light you talk about building is not impossible in any way but would take some fabrication. Oh and what were you talking about using a 12 volt SLA with a ROP bulb? The high bulb can be driven at max by 8.4 volts while the low by 10.5 volts, so a 12 volt SLA is to much power. Also the link you posted is of a 6 volt light I have yet to see a 12 volt lantern "what are those HD 12 volt batteries for any way?

Juggernaut said:

...I have yet to see a 12 volt lantern...

Click to expand...

OT, but neither have I.

Funny thing is, Eveready 8F 732 (12V) lantern batteries were once just as common as the similar-looking 8F 731 (6V) ones, and they were always clearly labelled as "lantern batteries". I do know they were commonly used as backup batteries for burglar alarms in the days before gel cells & SLAs, but calling them "lantern batteries" must have meant there was a lantern that used them.

On the other hand, I have never heard of a 9.6V PAR36, so these lanterns must have been bulb-based. Intriguing.

Oh, and back on-topic, my next step up is currently "The Tractor Beam", which drives a 12.8v 50W H7604 halogen PAR36 with 14 Sub-C cells via a 2.2 ohm NTC. This blows even my 64610 6D Mag out of the water, and on celing bounce, gives double the lux of the room lights.

My 100W "AeroJim" is currently in development, with a 250W "JumboJim" in the distant pipeline. There's life in the old Jim yet.

Please forgive a very childish post:

The Tractor Beam starts fires. Easily. And makes smoke in less than 10 seconds.

There. I'm done. I promise I'll act my age now.

ROP is a 6V bulb? Driving it with 12V SLA seems... not wise.

The WA1166 or the CL-809 seem like good candidates though.

Dr Jekell said:

Would it be possible to do a ROP mod in the old 12V lantern format using SLA batteries instead of the 12V alkaline's.

It would require a battery case with attached handle, an attachment point for a maglite head, a charging port & circuitry for running the ROP head and charging the battery/s.

Do you think that this is possible to do?

Click to expand...

well... considering that a ROP is a 6V lamp....being driven at 9V at start with fresh batteries in conventional ROP standards [6AA]...12V will surely knock it out.

If your 12V battery has enough juice I suppose its possible to give the mag85 concept a try instead

There's something funny going on here.

I clicked on the link labelled "old 12V lantern" and it took me to the new, current-model 6V lantern.

Post after post have pondered 12V lanterns since...

well, the battery type most certainly isn't 6V....I've seen 12V cells like that sold at ratshack...

The link was only meant to be for people who had not seen the style of light before

The SLA's could be of any voltage needed to operate it correctly I just chose them as I remember that the circuitry needed to charge them is a lot less complicated than that needed for a Lithium Ion Battery pack.

The idea was to create a ROP build that could be operated for longer periods than a normal ROP mod and could be recharged without removing the batteries from the light.

The build would also be a lot smaller than the 12v lantern's shape.

It could also be possible to add in a soft start circuit to reduce the chance of the bulb going.

I suppose you could change it to whatever Mag mod you wanted to use be it Mag85, USL, ROP high or Low, Mag65 etc

Hmmm...if I understand your principle correctly, the answer is a flat-out NO.
The essence of the ROP is to take a bulb, and gradually increase the applied voltage volt by volt, to dramatically increase the light output, greatly increase the amps sucked up, and greatly decrease bulb life. SLA's come in discrete values of 6 or 12 volts: you would need a bulb that, by coincidence, will take 6 or 12 volts as the perfect over-drive level.
I understand the idea of: the form of the old 6/12 volt car emergency lantern, a SLA that is easy to charge by plugging it in, and super-bright light that throws like nuts. However, an SLA will not meet this scenario.

Let me ask again:

Has anyone

EVER

seen a 12V lantern?

If so, please post details! I'd love to see one. I have held 12V "lantern batteries" (e.g. Eveready 732) in my hands, so I know such things must have existed...

I share your puzzlement. If you Google EV732 or Rayovac 926, you will get dozens of websites where you can buy one. However, there are NO listings for the associated lantern that uses them. Question: what on earth are people using these things for? I am thinking of things like amateur radio or model rocketry, but I have not a clue. When I was a kid, our family car was robin's egg blue and had fins; we also had one of those emergency lights, that had a big headlight and blinking red rear light. I assumed it was 12 volts, since the car battery was also 12v and this made sense, but in truth, I do not know if this flashlight was 6 or 12 volts.

I absolutely promise you it was 6V.

jerry i h said:

I understand the idea of: the form of the old 6/12 volt car emergency lantern, a SLA that is easy to charge by plugging it in, and super-bright light that throws like nuts. However, an SLA will not meet this scenario.

Click to expand...

Yep you got the idea

what about using a step up or step down transformer or the like?

Or how about what I suggested in Post #2?

Dr Jekell said:

...what about using a step up or step down transformer or the like?

Click to expand...

Now that's an idea. I ain't no EE, but if you stick a pot of sufficient amps on a 12v SLA and a voltmeter, then dial down the voltage to, say, 8v, it should be able to power a 3854HI

jerry i h said:

I share your puzzlement. If you Google EV732 or Rayovac 926, you will get dozens of websites where you can buy one. However, there are NO listings for the associated lantern that uses them. Question: what on earth are people using these things for? I am thinking of things like amateur radio or model rocketry, but I have not a clue. When I was a kid, our family car was robin's egg blue and had fins; we also had one of those emergency lights, that had a big headlight and blinking red rear light. I assumed it was 12 volts, since the car battery was also 12v and this made sense, but in truth, I do not know if this flashlight was 6 or 12 volts.

Click to expand...

To answer the question of who is using 12 Volt primary batteries? To power electric fence chargers is one use. Also to power sailboat running lights and on the small electric outboard motors for fishing at low speeds. Nowadays rechargeable wet cell or gel cell batteries are more common and long term economical for these applications

lctorana said:

Let me ask again:

Has anyone

EVER

seen a 12V lantern?

If so, please post details! I'd love to see one. I have held 12V "lantern batteries" (e.g. Eveready 732) in my hands, so I know such things must have existed...

Click to expand...

Saw one at Big Lots once, and regretted not grabbing it since. Especially after I found out about the Lava Landing modified Volkano.