will a ROP run on 5 1.2v cells

[Barrie]

Hi
i have got my hands on 30 sub-c cells for very little money and have found 5 cells fit very snug in my 2D mag with the tail spring removed
i am waiting on delivery of ROP hi and lo bulbs which i intend on running on 2 18650s in my own light
i was just wondering if 5x1.2v would be sufficient to run the hi or lo bulbs as my partner would also like a good bright light but she is not keen on the Li-ions with all the stores of

 

[copperfox]

Yes it will power up. Fully charged that should be approximately 7v. The bulbs are rated at 6v.

 

[Mjolnir]

The cells will be under 7 volts when under load; probably more like 6. The original ROP had 6 sub-c cells, so 5 should be fine.

 

[^^Nova^^]

Are you sure you have full length Sub-C cells? I have a stick of 6 and they only just fit in my 4D with the spring removed and a piece of rubber in the tailcap. IIRC there is a 4/5 Sub-C that is shorter.

Back on topic though, as others have said, it will run fine, although it may be a little dull and orange.

Cheers,
Nova

 

[Barrie]

thanks for the replies guys
did not want to tell my good lady i could give here a decent light and then it not be any better than the mag she is using
would the lo-bulb work better than the hi with the reduced power of only 5 cells
as for the size of the cells i don't know what variant of sub-c they are i got them from a work colleague who is in to radio controlled trucks
he uses them to make battery packs all i know is they aren't much bigger than half the length of a normal c-cell
Barrie

 

[gswitter]

The standard ROP hi and low bulbs are 6V bulbs, so not only will they work fine on 5x 1.2V cells, you'll be driving the bulbs at spec. The output won't be nearly as bright as with 6x 1.2V or 2x 3.7V cells, but the bulb life will be much longer.

 

[Outdoors Fanatic]

thanks for the replies guys
did not want to tell my good lady i could give here a decent light and then it not be any better than the mag she is using
would the lo-bulb work better than the hi with the reduced power of only 5 cells
as for the size of the cells i don't know what variant of sub-c they are i got them from a work colleague who is in to radio controlled trucks
he uses them to make battery packs all i know is they aren't much bigger than half the length of a normal c-cell
Barrie

It will definitely be a heck alot brighter than a stock 2D mag! A ROP Low @spec 6V delivers around 300 lumens.

 

[Howecollc]

Barrie

I assume the ROP bulbs you ordered are the 3854 SLA (sealed lead acid) bulbs, which are rated at 6.0 volts. These are the more common ones and will be running at spec, nice and white and bright with your 5 ni-cads. They won't be under-driven or orange, they'll be just right.

Lately it has become necessary to differentiate the 3854s from the until recently unheard of 3853 NiMH bulbs. The 3853s are rated for operation at 7.2 volts. They would indeed be under-driven and orange if run with either 5 ni-cads or 5 NiMH cells instead of the required 6.

After looking over this post, it seems that some people now consider the 3853 to be the "standard ROP bulb". The only situation that calls for the 3853 is when using IMR26500 cells, and there is a large trade-off in that the bulb is not being overdriven.

For your 18650 overdrive set-up and for the ladyfriend's 5 cell set-up, the 3854 SLA is the model you need.

 

[Barrie]

thank you
to all of you for the information you have given
it is the 6v 3854 bulbs i have ordered from light hound i look forward to there arrival

 

[Linger]

The low is indeed very nice with 5 cells. I have a cateye halogen bike light that I was waiting on a replacement bulb for when my first Rop cells arrived with a bi-pin 8aa Mag. Well, what is a person to do with a pr base bulb and a 5nicd bike light with an empty pr socket?

It's fantastically bright, highly effective combo. I've kept run-times low as I didn't want to push the batteries hard, and the case isn't designed for heat.
Interestingly, it's a clear plastic through-out so wires and cells visible through the case - with the Rop low the entire unit lights up and my whole hand glows.

So yes indeed your Rop low is great for 5 cells.