ROP LE vs. Mag85 LE - Output Difference

[RichS]

What is the output difference between the ROP LE and the Mag85 LE? I just built a 2D ROP with 2 AW protected 18650s, and it is bright! I have already ordered all the parts for my Mag85, and I'll be using 3 AW protected 18650s to power it.

I was hoping it would be at least 30% brighter than my ROP for the $$ I put into it, but going by Lux Luthor's lumen ratings for each of these bulbs in his Destructive Incan Bulb Tests post, the ROP is brighter!

It lists the following:

ROP HI 8.0v = 1642 predicted lumens
WA 1185 @11.2v = 1401 predicted lumens

This shows the ROP HI at 241 lumens brighter with two Li-ions vs. three in the Mag85. Is this true? If so, why build the more expensive and bigger Mag85? I am not doing many resistance mods, so I realize my net voltage will be less than both of these, but that being said they will still both drop making the ROP still brighter in theory.

I wish I saw this earlier. I'm just hoping I didn't waste my money on building the Mag85.

 

[who]

I have 4 ROP High (on various batteries, 18650, AA, C Li) and 4 Mag85 (again, on various batteries).
Any of my 1185's are brighter than any ROP High.

 

[RichS]

I have 4 ROP High (on various batteries, 18650, AA, C Li) and 4 Mag85 (again, on various batteries).
Any of my 1185's are brighter than any ROP High.

Good to know, thanks. Are they significantly brighter (25+%)?

 

[Patriot]

This shows the ROP HI at 241 lumens brighter with two Li-ions vs. three in the Mag85. Is this true? If so, why build the more expensive and bigger Mag85?

Because the 85 is brighter than the HI in reality. I'm not sure why the numbers are coming out the way they are, but Lux or mdocod could probably explain it if they see this thread. You could always PM them too.

 

[RoyJ]

Because the 85 is brighter than the HI in reality. I'm not sure why the numbers are coming out the way they are, but Lux or mdocod could probably explain it if they see this thread. You could always PM them too.

Well, the problem is the 8.0V assumption. I don't know what combo in the 2D form can deliver this kind of V-bulb.

A typical AA delivers 1.1V under 4+ amp load. Assume you run 7, that's only 7.7V V-batt. In an unmodded Mag, you'd be lucky to get 7.0V V-bat. 7 CBPs will deliver 1.2V under load, but you have a high risk of insta-flashing.

Same with li-ons. Two 18650, or Cs, will NOT be close to 8.0V v-bulb. Maybe with the Kai 2D setup?

The 1185 is less demanding current wise, which means there's much less voltage sag, v-initial is much closer to v-nominal. You can hold a good operating voltage without causing insta-flashing initially.

 

[RichS]

Well, the problem is the 8.0V assumption. I don't know what combo in the 2D form can deliver this kind of V-bulb.

A typical AA delivers 1.1V under 4+ amp load. Assume you run 7, that's only 7.7V V-batt. In an unmodded Mag, you'd be lucky to get 7.0V V-bat. 7 CBPs will deliver 1.2V under load, but you have a high risk of insta-flashing.

Same with li-ons. Two 18650, or Cs, will NOT be close to 8.0V v-bulb. Maybe with the Kai 2D setup?

The 1185 is less demanding current wise, which means there's much less voltage sag, v-initial is much closer to v-nominal. You can hold a good operating voltage without causing insta-flashing initially.

That makes a lot of sense, thanks. Now I'm looking forward to building my Mag85 again...

Just curious, does anyone know what voltage is actually getting to the bulb with two AW 18650s in a typical setup without the extra low-resistance mods?

 

[mdocod]

Well... I can only make an educated guess, on a mag with minimal resistance, you will be at 7.0-7.4V Vbulb fresh off the charger depending on the brand of cell (I haven't seen an AW 18650 discharge graph, so I can only speculate). The best performing Li Cobalt Oxide cells in the 18650 size will be unprotected cells of good quality like LGs. Protection adds resistance unfortunately.

If you were to say take a pair of cells that drive the ROP bulb at 7.2V fresh off the charger, the same cells could probably drive an 1185 to about 11V. The result would be that the 1185 might be around 20% brighter, which isn't even enough to distinguish unless you spend some time with them side by side. The difference that IS noticeable is that the ROP would probably be running in the realm of 3420K, while the 1185 would be running right at about 3500K, that would show up as a very noticeable difference that would make the 1185 appear to win by a larger margin.

 

[RichS]

Thanks for the info mdocod. Then that puts the ROP lumen output about where I've seen it estimated in other posts. So the Mag85 should be about 200 lumens more potentially. I haven't heard anything mentioned before about the beam color difference between these two bulbs. So even though the difference between the two is only 80K (2%), this will be very noticeable? I'll have to admit I'm new to the incandescent side of the house, but am learning a little more every day. I know some about LED bins and where they fall in the spectrum, but I need to get my mind around the Kelvin color temperature rating system for incandescents. Can someone point me to an informative post?

Well... I can only make an educated guess, on a mag with minimal resistance, you will be at 7.0-7.4V Vbulb fresh off the charger depending on the brand of cell (I haven't seen an AW 18650 discharge graph, so I can only speculate). The best performing Li Cobalt Oxide cells in the 18650 size will be unprotected cells of good quality like LGs. Protection adds resistance unfortunately.

If you were to say take a pair of cells that drive the ROP bulb at 7.2V fresh off the charger, the same cells could probably drive an 1185 to about 11V. The result would be that the 1185 might be around 20% brighter, which isn't even enough to distinguish unless you spend some time with them side by side. The difference that IS noticeable is that the ROP would probably be running in the realm of 3420K, while the 1185 would be running right at about 3500K, that would show up as a very noticeable difference that would make the 1185 appear to win by a larger margin.

 

[mdocod]

even relatively small differences in color temp are surprisingly noticeable when dealing with incandescent bulbs. Actually much more noticeable than small differences in total output, because our eyes constantly adjust to output, but remain sensitive to color changes, especially when things are lit up a LOT. A 50K difference in color temp is distinguishable side by side. A 100K difference is very noticeable.