Mag 2c Hotwire w/ AW li-ion C cells (best LUMENS and RUNTIME)

[maxspeeds]

Hi All :wave:

I just picked up a 2c host from Delghi and am researching my options. I've done a ton of searches and came up with several awesome bulbs that I can use with 2 AW li-ion C cells (7.2 volts). They are:

WA 5761 (approx 1300 bulb lumens)
Osram 64275 (approx 1300 bulb lumens with a smaller filament than WA 5761)
WA 1111 (approx 880 bulb lumens)

So, what's my question? I'm looking for the best bulb in terms of lumens and runtime. I don't want my light to only be able to work for 20 minutes at extreme output. I'm willing to sacrafice some lumens for added runtime. I want a good combination of output and runtime. Can someone help me with the formula for runtime calculations? I'd like to find a breakdown of lumens and runtime of different bulbs for this 2c mag with 2 AW C li-ions.

Thanks for your help :thumbsup:

 

[mudman cj]

Re: Mag 2c Hotwire (best LUMENS and RUNTIME)

You're working with 3300 mAh cells there, so take the cell capacity divided by the bulb current draw to get hours. Example: 5761 draws 5.5 Amps (at first), and 3.3 Amp-hours/5.5 Amps=0.6 hours, or 36 minutes. Now, in reality the runtime is more like 28 minutes because the cells can't deliver full capacity at such a high rate of C (their capacity), which in this case is close to 2 and as much as the cells can possibly handle. When you push Li-ion cells to 2C expect a runtime of about 30 minutes.

But I digress. Check out the hotrater spreadsheet to be able to calculate current draws for various bulbs as a function of voltage. Some values are also listed in the sticky thread in the incandescent section about popular bulb current draws, and Lux's excellent work to measure bulb characteristics such as these is also a sticky there.

The 5761 sounds like it would have too little runtime for you. The 64275 draws too much current for AW C cells. The 1111 will have a decent runtime, but you can get more runtime and still have a bright light with the likes of a Carley h1499p.

 

[maxspeeds]

Re: Mag 2c Hotwire (best LUMENS and RUNTIME)

Awesome Mudman! That is exactly the equation I was looking for. I've been also reading about the possibility of using emoli cells. However they are a bit long at 70mm (as compared to AW's 53.5mm) and only 2670mAH in capacity (as compared to AW's 3300mAH) . But, their max discharge tolerance is where its a winner! It can tolerate 20A! :twothumbs

 

[mudman cj]

There is talk of Emoli's in 18650 size, but they would have even less capacity. You may want to check out the IIRC *nearly* 18650 sized A123 cells also capable of high currents.

 

[maxspeeds]

Do these A123 cells need a special A123 charging program? If my Tenergy balanced li-ion charger can do the job, I'm game :twothumbs

 

[RickB]

I think if you are willing to go with a less "challenging" (for the cells) bulb than the 5761, you are fine sticking with the AW "C" cells.

Has your host been converted to bipin, or does it still have the PR base socket? If you still have the PR socket, you could go with the trusty old ROP. I have a 2C Mag with 2 AW "C" cells and the ROP high, and it's one of my favorite lights. Going ROP also gives you the option of using the low bulb, which will still kill any stock Mag light, for a bunch more run time.
http://www.candlepowerforums.com/vb/showthread.php?t=120462

If you have a bipin socket, the WA 1111 is one option, or the Carley that Mudman_cj mentioned. Look for litho123's sale threads in CPF Marketplace. Here's the bipin thread.
http://www.cpfmarketplace.com/mp/showthread.php?t=168089

He also lists a WA 1057, which I haven't heard much about, but might be somewhere between ROP high and low for lumens.

-Rick

 

[mudman cj]

Yeah, the A123 cells require a special charging program. They can also be a tight fit in a C sized light even after re-wrapping in kapton tape. Length is slightly longer than an 18650 at 66.5mm compared to 65. Here is a link to a sales thread with more info on A123 and Emoli cells.

I agree with RickB - your best option for long runtimes is to stick with the AW C cells.

In addition to the 1057, which would be a little brighter than the ROP low, you may also want to consider the WA01274 and the Phillips 7388 (similar to 1111). The Phillips 7388 is supposed to be more resistant to instaflashing than the 1111, which could be a problem using those C cells without some sort of soft start.

 

[maxspeeds]

Thanks Rick and Mudman! I do have Kiu's bipin socket, but am still thinking of sticking with the PR base simply for its solidness and simplicity. I may get download's MagCTower to help in heatsinking http://www.candlepowerforums.com/vb/showthread.php?t=168722. The Kiu socket can allow the bulb to come uncentered if bumped around alot, and centering the bulb can be such a pain! The ROP Hi & Lo are still an option. Here are some quick calcs on theoretical bulb lumen output and best case scenerio runtimes if your bulbs are new and run theoretically.
However, as Mudman stated earlier, li-ions don't completely discharge, so the actual times are less. (I'm missing the Lumen output on the ROP Lo, and feel free to correct any of my errors). Here is the bulb run down from what I could gather (in order from dimmest to brightest):

Pelican 3854L (ROP Lo) --- 1.74 Hours ----___ Lumens
Carley 1057 -------------- 1.65 Hours --- 450 Lumens
WA 01274 ---------------- 1.19 Hours --- 553 Lumens
WA 01111 ---------------- 0.99 Hours --- 880 Lumens
Pelican 3854H (ROP Hi) ---- 0.76 Hours --- 1150 Lumens
Philips 5761 ---------------0.6 Hours ---- 1300 Lumens

:thumbsup: