external battery pack for photon xt

I am tired of buying energizer lithium's to run my photon xt. Yes I know I can buy cheaper batteries, but their life isn't as long so it defeats the purpose for me...

Anyway I thought I'd share it with you.

Started thinking about an external battery pack that I could use rechargeables on with extended battery life. I already have a bunch of 18650's laying around for the IR illuminator.

Nothing fancy but working. Going to mount it to a weaver/picatinny adapter so it can connect to the rail on the side of the scope. Haven't gotten that part in yet. Anyway drop it in and powers it just fine. Let it run for over an hours last night. Haven't field tested it yet, hopefully this evening if the pigs show back up.

How is that working our for you?

So far so good. I have had it lazily thrown together for about a month. I just got the case in to make it a permanent housing. I can and will update with some time.

Awesome...care to share how you make the connection on the cap and what you are using in the battery compartment?

Disclosure: Not responsible for any issues...

The black cylinders are simply a dowel rod that was similar size to a double AA. Ran a wire down the side of it connected to a small screw. The small screw acts as the button on the top of a AA. Had heat shrink tubing laying around to keep the wires nice an tidy. Also took up the remainder space to make up for the size difference of the dowel rod. I drilled a hole through the cab big enough to run the wire through. That battery box is from China for next to nothing. Note: I had to rewire the box. It was in Series not in Parallel.

Total it cost me less than $5. Had everything except the box.

All I need to finish is a small adapter so I can connect to the weaver mount on the side of the Photon.

The positive side goes on the same side of the scope as the weaver mount. Just like the regular batteries do...pay attn there as well.

Im sure I could have made a fancy connection, but I was concerned with the way the cap connects in the center. I didnt want to jeopardize the integrity of the cap closing properly so I just hard wired it in. If I want to undo it I can simply put the stock cap back on and batteries.

I didnt do this to my stock cap. Had an extra. wanted to be clear.

I

Shot it a couple time last night, worked like a champ.

So are the wires run all the way to the bottom and nothing is being done with the top contacts under the cap?

Dogg - That is correct.

What type of run time does it get you?

Good question,. I haven't tested that, yet.

Things I do know.
I know the numbers on 18650's are generally lies. Example ones in picture say 5800mah. I would bet they are roughly only 2500mah a piece. So 5000mah by running them parallel.
Energizer Lithium's are roughly 3000mah and are run in series to increase voltage only.

I believe Sightmark advertises 4 hours of run time on batteries using the IR, which I would have to assume would be with lithiums.

A simple proportion would suggest life on a pair being roughly 6 2/3 hours.

I am no engineer. Good at figuring things out, yes. Good at math, yes.

I will run a test on it this weekend and report back on life on the 18650's.

Any conclusion on the runtime?

Did it fry your photon?

Did it blow up and injure you?

Don't you just love it when people say they will report back.

Easy guys. Been on vacation for 2 weeks. Haven't looked at the forum..

Had to wait on the weaver mount to come from who knows where. Had a few dry runs, hunting.

I will make it a point to test actual battery life. I can say its been on non stop for over 3 hours and still running on what says a full battery.

I just got some live footage of shooting a pig this evening with it. Stays on like it should. I am happy.

Looks good, thanks for checking back. Hope you had a good vacation.

Were you able to buy another cap from Sightmark. I'm interested in how you got an extra one to experiment with.

I thought I had a problem with mine cutting off when I shot. They assumed it was a bad cap. With the replacement cap it did it still. They finally asked me what batteries I was using and said that was my problem. Basically the negative on the off-brand batteries didn't stick up enough...Kudos to them for taking care of me.

One of my buddies lost the center cap on his and called them. They sent him a complete replacement cap at no cost. I'm super impressed with their customer service.

I've heard good things about their customer service as well. Welcome back.

Running the test on battery life now.

For the test I am using the green panasonics 18650s. Labeled 3400mah. I have the internal IRs off to simulate how I hunt.

I started it a 5:45 central time. Going on 3 hours now. The battery meter shows full. Not sure if it will go down or not. Will update that if I can.

I will be checking the battery's at least every 15 minutes.

It is right at 7 hours and still running. I'm beat. Shut it off and will start back up tomm to see how much longer it will run.

No matter how long much longer it runs at this point I'm satisfied. Battery still shows full on the scope.

If possible could you post a specific parts list, and how dud you end up mounting the battery compartment? Thanks again for sharing this.

Sure thing. I will try and work on that this afternoon.

Parts list:

1. Battery box - I got this one it was cheap, but works. I had a hard time finding one that had a cover for the batteries. To each is own. With this one its wired in series. You will need to convert it to parallel for it to work properly. I don't know if the photon can handle the extra volts. If it could, it would also cut the battery life run time in half.
Battery Box

2. Picatinny/weaver rail adapter - The side photon has a weaver mount. You will need to grind this adapter on one side to clear the side of the photon mount.
Weaver rail adpater

3. Dowel rod - Don't remember which size, had it at the house. Lowes/Home depot, etc has it. Take a AA battery with you. It will be a little bit smaller.

4. short/small screws. Had laying around. Size needs to basically mirror what the button on the top of a AA battery looks like.

5. heat shrink tubing - Big enough to go around the dowel rod and wire. and smaller if you want to cover the paracord ends.

6. short chunk of wire. Doesn't need to be be very big diameter. I went small as I has around the house. So the hole through the cap was small. need to be able to identify the + from the - so you put the dowels in the right slot.

7. paracord - if you want it to look a little nicer. To cover the wire.

Cut the dowel rod the length of the battery minus the button on top. Drill a small pilot hole in the end of the dowel rod. Screw the screw in part of the way. Strip each wire long enough you can wrap it around the screw. Finish screwing in the screw. Check length to make sure its the same. Too long and the cap won't close. Too short and it will likely not put enough tension on the spring and cause the scope to turn off on firing. I started a 1/16 to long and used a file to shorten the dowel rod. Add the heat shrink tubing to the dowel with the wire running up the side of the dowel.

I drilled the hole on the wrong side of the cap, does it matter no.... Notice in pictures. You have to drill just outside of the metal insert under the cap. As close as you can get. Has to be there bc of their design on how the cap secures closed. Pull the wires through the cap and get them situated so the lid will securely close.

At this point you can stick a 18650 battery to the ends and test for power. The positive should be on the side that the weaver rail is on.

Rewire the box to be in parallel, however you see fit. Check voltage.

Solder wires between the battery box and the dummy batteries. If you want the paracord cover. You need to remember to slip that on first and also the heat shrink tubing.

The picatinny/weaver mount is to long one side. a flaw in the photon engineering. You will see if you attempt to put it on. No biggie. I grinded one side so it will clear that lip. Hit it will some black paint.

I tried putting JB weld to secure the box to the mount. Worked great. Until I bumped it on something. For the moment, I used a super thin zip tie ran through the holes in the bottom of the box and through the hollow gap on the rail adapter. Still working the finish thought out, but so far its working..

Things I would have done different. One would have been drill the hole on the other side of the cap. Two would have been make the cable shorter. Three would have drilled a new hole in the side of the box where the wire could go straight up and over to the top of the scope. I left mine long bc I wasn't sure where I would be mounting it at the time.

Sorry for the long winded post. Feel free to tweak it however you see fit. If you have a better idea, I would love to see it. If you need a picture of something specifically let me know. And if you need some clarity on some of my rambling let me know.

It's been on almost 13 hours at this point I'm blown away.

I may redo the test and see how long just one of the batteries will last in it.

I am testing just one 18650 battery now.

Currently at 5 1/2 hours. I maybe redoing mine to make it smaller. I will update again.

12 hours in on 1 - 18650 battery and still going. I'm done testing.

Be careful draining the 18650s too low. It ruins them and at some point they become unstable if not circuit protected.

I am aware that's why I ended the test. I ran it that long for you and anyone else that was interested. I bet I wouldn't have one on for more than 8 hours a night.

Plus I should be in the thermal world shortly. But it eliminates me buying energizer lithiums, giving me longer battery life which was all I care about.

I scan with thermal, world of difference. Thanks again for all the info.

hello, is it better to power yukon photon xt 6.5x50 on 1x18650 or on 2x18650 connected in parallel? I am wondering if 4.2V voltage did not burn yukon? Is it safe? I am thinking about one 18650. I turn on the yukon just before the shot, that's why I think about 1x18650. help me what to do? I already have enough weak AA KTORE batteries to fall quickly. I am waiting for a response. greetings. Lukas