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Picking host - Battery life for high power, heatsinking

BodhiSci

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Hey everyone,

Trying to determine if 2x18350 would be last long enough for my high power build. Anyone know how long these would last? Don't feel like u need to answer every detail here to be helpful.


Using a Nichia NDB7875 9mm 445 that goes 2.5-3W. I'll be using the setting DTR recommends, 2.4A (if I can find an Adj X-drive I might adjust it a bit lower depending). I'm having Ehgemus build the Al host.I want to be able to go from two batteries to one (with an X-drive and this diode it will put out ~200mA with one battery), so it needs to be for 2x18650 or 2x18350 (or I think even 3x18350, which would be a bit more life without being as long as 2x18350).I also have to decide if I want to have a diameter of ~1" or ~1.25. I was thinking that it might be a lot better having the bigger host for additional heatsinking, but I had some wooden dowels of those diameter and length combinations cut and they get pretty big.


Wondering what kind of duty cycle I could expect for a 1" diameter host about 6" long and also the 1.25" diameter, 6 or 8.5". There is no large heatsinking head, just the whole aixiz module w/ heatsinking back inside the Al host. Driver is separate. It is the high power that makes me think I might need the extra metal\size. Will usually just be used for bursts but want to be able to have continuous also.

Thank you!

BodhiSci
 
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Pi R Squared

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The duty cycle will be less than 45 seconds with the 1 inch host. I have one in a stainless steel host that is 0.96 inch diameter, driven at 2.2A. Go with the 1.25 inch host, that should be much better. I suggest a host using two 18650 otherwise your battery life will be short.

Alan
 

BodhiSci

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Thx. Hmm, 45 seconds... So it sounds like it would be more than adequate for short and medium length bursts. I guess the real question would be then how much more time would be addedwith the 1.25" diameter and the extra 2.5" from the second 18650's length.

I am drilling a CPU heatsink for sustained labby lasers in my backyard or indoors. Maybe the answer is getting smaller for walks and using that for longer.

It may be worth the size though if it is much much larger run times.

Any idea how much longer it would go for? Thinking that the increased surface area might really help dissapation though I don't know how long that takes to begin with. If it dissipates way slower than it builds up still then it may not matter that much.

How long do your batteries last in your 2.2 A? If 2x18350 are good for an evening then that is probably fine for me.
 
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Pi R Squared

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I don't think the length would make a big difference in heat dissipation, that's for the larger batteries. I have no idea how much difference the extra 0.25" would make, just that it would be better. My laser that I was referring to is this one: http://laserpointerforums.com/f65/assembled-445nm-9mm-stainless-steel-host-pic-heavy-85997.html it is so powerful I can't meter it with my LPM without smoking the sensor. The battery life is great with two 18650, I have better batteries now but even with those Ultrafire in the photo it was OK. I have a 1.5W M140 that you can see in one of the photos, the small black C6 next to it, that one runs on two 16340 and they run down fast although I have been using some very cheap batteries in that one from the start so that would make a difference but there is a power drop after less than 10 minutes run time with two 16340. You can use two 18350 if you really want something small and it will work, just don't count on batteries lasting long at that power level. With two 18650 you may be able to go for days or weeks before recharging depending on how much you use it.

Alan
 

BodhiSci

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OK. You know what. I think that I will do that. Go with the bigger diameter and size. This is to be my #1 and all you said is good, I also think that it will look better with the style of mod I'm doing. Kind of saber ish and just fits it, plus it will likely be a bit smaller than 1.25 anyways, he clarified that it'd be 1 1/8- 1 1/4. Plus I have HQ 18650's. Thanks Pr^2
 

Pman

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As far as batteries go, I use my AW IMR (all sizes) and Panasonic B and PD cells in applications that require over an Amp or units that were significant in $ and all kinds of other cells in my "regular" units. Same thing goes for my flashlights. Have accumulated plenty of 18650 cells from replacing laptop batteries. Usually find that there's 1 or 2 cells that kill the battery life in the pack. If they will charge up you can still use them for quick tests on things.
When I go to Walmart I sometimes look through all their clearance junk and every once in awhile you find a cheap battery pack for something that you can take apart. I've found that you can usually look up the numbers on the batteries to see what they really are. Don't often find something though as I think other people have the same idea.
 
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