XHP and 14500 help.

Hey guys. Just wondering. When in 6v mode what's sort of current draw should I expect from the XHP-50 and are there any 14500 that's will be up to the job when run in 2s2p?
Thanks guys.

I believe the xhp 50 is 3A in 6V mode. IMR batteries will work. I used two efest 14500s in a mini mag to power an xhp 50. If you use a 2s2p setup you'll get more runtime and less wear on your batteries.
I don't know how current load is divided between batteries in series but in parallel you can divide it by the number of batteries. So you should be able to use batteries rated for 1.5A.

That's good then. I'm looking at some 5A 14500's from torchy hopefully it should stay under 7.5A total current in 6v which should give me some margin of safety at least.

Yes, Cree's datasheet says 3A max at 6V. If you're doing an XHP50 conversion, you might want to be familiar with the datasheet:
http://www.cree.com/~/media/Files/C...d-Modules/XLamp/Data-and-Binning/ds-XHP50.pdf

The specs given are at 1.4A.

You won't need 7.5 unless you're powering multiple XHP's in parallel. Batteries in parallel each should take about half the current (1.5A each for one XHP50). Batteries in series will both see the same current.

2 series 2 parallel should be a good arrangement for a single XHP50 in a TN4A. Most decent 14500's should be able to handle this configuration.

That's good to know. Thanks.

You are going to have a driver in there somewhere aren't you? At 2S2P the LED will be facing 8 volts fresh off the charger, which is 30% over the 6 volt rating. At direct drive don't know what that would do, but it probably won't be nice.

Given a 700-800 mAh rating for the average 14500, at three amps you can expect sometime around a half hour of run time from this setup - 2S gives 6-8v and 2P gives around 1.5 Ah capacity. Also, three amps is about the limit for a protected cell, so you might want to look at some IMR/INR cells instead. If you already have some ICR 14500s you can try them, but don't be surprised if the PTC kicks in. I use Efest IMR 14500 cells (one at a time of course) in my EA11, which uses an XM-L2 LED, which is rated at a 3A max forward current.

So I'm going to use unprotected 700mah imr's from torchy as I trust his ratings. I am using the 26mm FET driver from mountain electronics for electronic momentary switched with LDO mod and 6v LVP. I am aware of the risks involved using unprotected cells in series. I have a series of precautions in place to ensure I am as safe as possible. I am however toying with the idea of getting a sled 3D printed to house 2 16500's in series of space allows as this will give me a similar capacity to 4 14500 in 2s2p with better safety. I am a vaper and have a custom build box that houses 3 18650's in series. This pushes batteries hard (~30A) and I am yet to blow myself up. I am not cocky or complacent, I am very strict and slightly OCD about safety and have a strict battery rotation where my batteries are labelled A,B,C and sled position rotates ABC - charge - BCA - charge - CAB - charge and repeat. This is pretty much what I will do with 4 14500's and capacity and charge time after each discharge/charge cycle will be logged and if there is a discrepancy of more than 5% between cells they will all be replaced.

Timothybil said:

You are going to have a driver in there somewhere aren't you? At 2S2P the LED will be facing 8 volts fresh off the charger, which is 30% over the 6 volt rating. At direct drive don't know what that would do, but it probably won't be nice.

Given a 700-800 mAh rating for the average 14500, at three amps you can expect sometime around a half hour of run time from this setup - 2S gives 6-8v and 2P gives around 1.5 Ah capacity. Also, three amps is about the limit for a protected cell, so you might want to look at some IMR/INR cells instead. If you already have some ICR 14500s you can try them, but don't be surprised if the PTC kicks in. I use Efest IMR 14500 cells (one at a time of course) in my EA11, which uses an XM-L2 LED, which is rated at a 3A max forward current.

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As long as it is properly heatsinked it should handle a FET driver fine. Especially with 14500s which can't push a lot of current anyways.

Cool. Well I have no idea how well the tn4a dissipates heat but the led will be mounted on a DTP copper MCPCB so that should help.

staticx57 said:

As long as it is properly heatsinked it should handle a FET driver fine. Especially with 14500s which can't push a lot of current anyways.

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Even most decent protected 14500's (Keeppower, AW, etc) can push 2A or more. With four of them, that's easily enough juice to provide the maximum rated power to an XHP50. He'll definitely want to ensure the MCPCB has a good thermal path to the body.

I seem to recall reading the TN4A battery holder is a tight fit with some batteries. Protected 14500's might not fit. Not a big deal, but that's something to look into before ordering batteries.

I can assure you that a properly heatsinked XHP50 will be able to take way more than 3A at 6V

iamlucky13 said:

Even most decent protected 14500's (Keeppower, AW, etc) can push 2A or more. With four of them, that's easily enough juice to provide the maximum rated power to an XHP50. He'll definitely want to ensure the MCPCB has a good thermal path to the body.

I seem to recall reading the TN4A battery holder is a tight fit with some batteries. Protected 14500's might not fit. Not a big deal, but that's something to look into before ordering batteries.

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If you use a FET driver the driver will attempt to give the emitter all the power it can and will easily trip the protection circuit. A current regulating buck driver will be required to tame the output from the cells.

Fair point. I wasn't catching on that Thom might be planning to go beyond the official ratings. It will be interesting to see what the driver he found is able to push through the LED, especially if he uses some of the better 14500's.

Anyways, even the rated 18W is no trivial amount of heat get moved from the MCPCB to the body.

iamlucky13 said:

Fair point. I wasn't catching on that Thom might be planning to go beyond the official ratings. It will be interesting to see what the driver he found is able to push through the LED, especially if he uses some of the better 14500's.

Anyways, even the rated 18W is no trivial amount of heat get moved from the MCPCB to the body.

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Post number 7 mentions he is looking at a FET driver. That's where I was going with it.

The mentioned driver is a FET driver compatible with 2S

Also I think worth bearing in mind is I'm using moppydrv firmware which has loads of preset modes and for the most part it will be run at no more than 70%. I just want to know how it will run in DD which I will probably set to a 15-20 second limit. Batteries I am looking at have been tested to 10A in some cases. Most perform well at ~5A with ~15 mins of run time. I've also done some very very fuzzy maths. It's my understanding that an XHP50 is 4 XR emitters in an XM sized footprint. I have an S2+ with 3 XPG2's in parallel and it draws ~8 amps at the tail. That's ~2.66A each. As an XHP is in effect a 2s2p layout of 4 of these then I'm looking at ~5.12A total. 5A capability per cell gives me ~5A(50%) headroom and at an estimated ~2.5A per cell it's on the official limit of the batteries. Also can anyone with an XHP50 light get me a tail current reading on turbo please, it will really help me out.
Oh and any input anyone has would be great.