Dual wire canister light

[mtrhead03]

I'm building a canister light for 2 loads, I'm hoping for some helpful comments and that maybe I could drum up some interest in the left over materials I'll be left with and maybe help someone else. I totally understand why these cost so much now. Anyway I'm trying to figure out which tap to use for the sealing gland holes in the top cover, it looks to have a strait thread with O-ring seal, yet a 1/4 by 18 NPT tap lines up pretty good?

I found that when I dove with 2 canisters, one for the light and one for the vest, I couldn't tighten my harness all the way, this was in doubles I'll bet it would be the same in my rEvo, so I want one can.

The goal is to build a canister with 2 wires, one for the HID light and the other, with EO end, for the 60W heated drysuit vest, and no unplugging and replugging underwater. I didn't want to hack up my LightMonkey 21W HID for parts, so I decided to source a totally separate light. I'm waiting for a used Sartek 21W HID head with integral ballast that I bought from a another board to arrive. I had enough to deal with making the canister, so I went for the store-bought head. I see on their site, Sartek has a really nice trade in deal on a 35w head, if the 21w ever craps the bed.

The can will be 3" schedule 80 PVC, I had to buy a 5' length, so there's plenty left over, wink. The bottom end cap will be 3/4" thick pvc with the step cut to half the thickness, 3/8". The picture shows the first attempt at the cut, the cut was started with a circle cutter and then I got impatient and tried to cut the step by eye, with a router and slipped and nicked the peice. The next attempt will be with a trim router, I've drilled the foot to accept a centering pin, shown in pic, which should allow a nice cut, I'll add a second and third hole for the next 2 cuts.

The top will be 1" PVC, I calculated that 1" could be dug out to provide a switch boot protector built in to the cover, similar to commericial units.

I went way over what I envisioned the budget would be on this, but I'm going cabin crazy anyway so at least I'm doing something diving related. This project will still come in at less then half what it would cost retail, including equipment I'll still have when it's done. I paid retail for the glands, switches, latches and such. The 21w head will come with an EO cable attached, I plan on running a regular cord permanently attached to the canister and head. A separate EO cord will power the vest.

The battery is 23AH, 11V, which should power the head for a very long time and the vest for 4 hours, I'm curious to see the performance and run time running both at the same time. It should work OK since the ballast is in the head. I'm concerned about losing the battery with a leak and was wondering if I could just wrap the battery in epoxy resin fiberglass? This way who cares if it leaks! I don't know if the battery needs to breathe though, comments? I think a thin wrap of fiberglass matt and resin will seal it.

It was too easy to square and flatten the ends of the canister with a DA sander!

The O-ring isn't shown but it is a .210" thick Buna o-ring that has to be streched .1" to fit over the step in the cover, the next size up would have flopped around.

The will be a lot of 3/4" and 1" flat pvc left over and 3" pvc pipe.

If there is interest I'll post followup status and pics.

 

[mtrhead03]

I found a chart, THREAD IDENTIFICATION CHART
according to it, the gland has 5/8 x 18 thread.


Any cautions against sealing the battery in fiberglass?

 

[Dusty2]

OK guys, from one who knows much about doin your own light..... The cable glands shown in your pic are agro brand and unfortunately come in a lot of different sizes but I'm pretty sure they are the ones I use. If so they are metric.
M16x1.5, this is an aircraft fitting size and you won't find it in your local hardware store. I would contact who ever you bought the glands from (oxyceq?)and verify that that is correct as they do come in other sizes but that is the most common one I have seen for sale on the open market. If so these taps are available on ebay most of the time.

I have to say you are brave indeed to attempt this with basic tools. Be careful routers and such love fingers and other body parts. Oh and those switch boots.... I wouldn't put a lot of faith in them. If they are the type I started out with they are pretty fragile. APM Hexseals are the best. N10301 - APM HEXSEAL - SWITCH BOOT | Newark

I would not advise sealing your battery. Under heavy load batteries can get pretty hot and sealing them would just compound that. Especially with LI-po batteries. This is whats happening with the Boeing dream liner right now

Good luck

 

[mtrhead03]

It's a bigger project than I thought it was going to be, I'm getting the hang of it though.

 

[andrewy]

I built something like this from 1 ft of 3" schedule 40 pipe, 2 couplers go over it, and two flat caps, one glues and another served as lid with 2 dive right latches. two glands from mcmaster 69915K61, and two switches. one has light head connected to it, 35wt sartek, another Marshall Underwater female connector cable for a heater. battery is made from 36 x 18650 LiIo batteries. 30AH total. very warm. Cheers., dont forget the BMS for batteries, it is a lot of power.

 

[lucca brassi]

I have mine in final steps - have to rewire all parts together ...2x12V (11Ah NiMH)

 

[mtrhead03]

Dusty2 was right, gland thread is 16mmX1.5, I'm getting away with 5/8 x 18, (diameter of the tap I used is same, pitch of the 5/8 -18 tap in metric is 1.44 so the gland gets tight just as it bottoms).
AndrewY, what is BMS for batteries?
I bought the hardware from AddHelium, I wanted the same stuff that LightMonkey uses.
Careful with routers in PVC, the vibration tends to loosen the bit, I ruined some peices. I'm temped to get a rotary table with chuck for the drill press, but I have managed workable peices with the router. Multiple shallow cuts and then cleanup with abrasive has worked.

 

[andrewy]

BMS is a Battery Management System. it is aboard that will take care of balancing liio cells, prevent over discharging and overcharging and shorts. I assumed you use regular liio 18650 cells. you dont want overcharge protection built in on each cell, (the little board at - minus terminal, take them off if equipped), the put N cells in parallel, this will be treated as single battery by the board i have 3 series of 12 parallel cells..

here the board i used: Protection Circuit Module (PCB) for 11.1V Li-Ion Battery Pack (10A +/-1A limit ) with Fuel Gauge Socket

 

[mtrhead03]

35 hours in it, if I had to do another i could half that easy.
I saved even including the extra materials, tools and drill press.
I'd probably by a Light Monkey from the Scuba Connection next time, too much time in the basement.
Quality pretty good, some things obviously home made, switch guard off to one side a bit.
Passes tub test, I got to get it the water at Dutch springs to declare victory.
It's a little tricky getting the top on, I went with the absolute shortest height I could. I used marine 5200 sealer for a sealant and shock absorber, including the battery.
I believe the battery has a PCB built in, (store bought).

 

[gbm]

What are the tools you bought to build it? And did you build the lighthead too or it was bought?
I trying to assemble all the material for building a canister light but I still don't know what type of light I'll use since I'm unsure if I can build the light head (ie. test tube, LED, MR16, etc.)
Do you have suggestion ?