How to open Light Monkey sealed battery pack?

Wtoole

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Hi All

I have 10 year old 5.7 - 21 Watt light monkey HID light with a sealed battery pack and need to replace the batteries. First I need to be able to open/unseal the battery pack. Does anyone know how to open/unseal the battery pack? There seems to be a plug in the middle and O-Ring around the pack. Do I need any special tools and is there any tricks/sequence to opening it up.?

Bill
 

turbodog

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No experience with this pack. From opening some light and motion... I would expect (especially since your light looks like a dive light) for the whole internal assemble to be encased in epoxy/etc of some sort. In short... probably time to buy a new battery or cut the end off the wire itself and fit a whole new pack.
 

DIWdiver

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Hi, Wtoole, and welcome to the forum. I hope we can help you with your problem.

turbodog: No. Rechargeable batteries should not be encased in epoxy or anything like that. In the electronics industry we call this "potting". I have never seen a rechargeable battery pack, diving or other, that was potted, because it's a BAD idea.

In this context, 'sealed' probably means you SHOULDN'T open it during everyday use, not that you CAN'T open it for maintenance. Knowing Light Monkey's reputation, I'm sure they made some allowance to replace either the cells or the entire pack without cutting the cord and fitting a new pack.

Can you post a pic or two? If we can see it, maybe we can make some suggestions.

To post pics, you have to put the pics on a separate site like google drive, dropbox, picasa, etc, and paste a link either in the post or in the 'insert image' dialog box. With the former, readers will have to click the link to see the image, while with the latter the image will appear directly in the thread. Keep in mind that the forum rules state that if you post them directly in the thread, there is a maximum of 800x800 pixels.
 

turbodog

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Hi, Wtoole, and welcome to the forum. I hope we can help you with your problem.

turbodog: No. Rechargeable batteries should not be encased in epoxy or anything like that. In the electronics industry we call this "potting". I have never seen a rechargeable battery pack, diving or other, that was potted, because it's a BAD idea.

In this context, 'sealed' probably means you SHOULDN'T open it during everyday use, not that you CAN'T open it for maintenance. Knowing Light Monkey's reputation, I'm sure they made some allowance to replace either the cells or the entire pack without cutting the cord and fitting a new pack.

Can you post a pic or two? If we can see it, maybe we can make some suggestions.

To post pics, you have to put the pics on a separate site like google drive, dropbox, picasa, etc, and paste a link either in the post or in the 'insert image' dialog box. With the former, readers will have to click the link to see the image, while with the latter the image will appear directly in the thread. Keep in mind that the forum rules state that if you post them directly in the thread, there is a maximum of 800x800 pixels.

Well "should" or "should not" aside, plenty _are_ subjected to this.

Hit the website he mentions. The pack appears to slide down into a tube, then the lid closes up which forces banana plugs into the pack. Nice design.
 

turbodog

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Hi All

I have 10 year old 5.7 - 21 Watt light monkey HID light with a sealed battery pack and need to replace the batteries. First I need to be able to open/unseal the battery pack. Does anyone know how to open/unseal the battery pack? There seems to be a plug in the middle and O-Ring around the pack. Do I need any special tools and is there any tricks/sequence to opening it up.?

Bill

I took a look at the packs you mention. Assuming you can't find a seam to pop the pack apart... you could very carefully dremel the side of the pack open, remove the cells and electronics, then reinsert new cells.

Unless the replacement pack is ridiculously expensive I'd use that as a last resort.

Or you could make your own pack and slide it in. Then attach the wires to the plugs from the lid... might have to cut them off and solder a new connector on.

I'd think carefully before doing any of this. Don't want your dive light going out.
 

Wtoole

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I can’t seem to be able to post any pictures (permission, user error?) so below is a link to a picture that shows the inside of the canister light. The battery is behind the bulkhead with two banana plugs. There is an O-Ring sealing the bulkhead and a centre plug. My light is ten years old so doesn’t owe me. Just wanted to check to see if anyone has opened one up before I gave it a try. Was going to try to pull out the O-Ring but do not know what is providing pressure to keep the banana plug lid tight against the o-ring. A spring?

https://www.lightmonkey.us/10-21-hid?lightbox=image1sax
 

turbodog

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If the pack is made to a certain dimension, then nothing keeps the pack plugged in. Banana plugs have a certain amount of tolerance they will accept.
 

DIWdiver

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Anyone can post a photo. You need to use a photo hosting site.

As I mentioned in post #3. Note that if using dropbox, you have to edit the URL.

It might be that the o-ring is what keeps the bulkhead in place. It isn't needed for waterproofing, as water in that area is already a disaster.
 

Wtoole

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Sorry for the lack of pictures, they really would help. I will see if I can get a Dropbox account or something free to drop the pictures into.

But in the meantime I have figured out how to open up the bulk head.

1. Pull out the centre plug with a pair of long nosed pliers. It is fairly easy to pull out as it is held in by a single O-Ring. The plug is for a finger sized hole in the bulkhead
2. Remove the red external O-Ring around the bulkhead.
3. Stick your finger, if it is long enough, into the hole left by the centre plug and slowly work the bulkhead out of the canister. It turns out, there is another O-Ring around the bulkhead making it a very snug fit.
4. There is a thin hard plastic barrier that then needs to be pulled out before you get to the battery pack
5. The battery pack is wedged into place with various pieces of cardboard. Just remove those and everything then slides out easily.

The battery pack is just 6x18650 Li-Ion batteries with 3 pairs connected in parallel and each pair connect is series to give 11.1 volts with 5.2 A. Unfortunately the pack is assembled to give a bit of a circular shape to it. It looks like a standard 2x3 square shape will not fit. Square peg in a round hole problem.

I was hoping I could just use a standard pack to replace the old batteries. I am an electrical engineer and have decent soldering skills but not sure if I am comfortable about building/soldering Li-Ion batteries. So far I have not been able to find a battery place in Ottawa that will do custom Li-Ion builds.
 
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turbodog

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If you a store called 'interstate battery' they do spot welding of cells. I would NOT solder lithium cells under any circumstances.
 

turbodog

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You've got it apart. Just call up some battery repair shops and ask if they have 18650 cells and can spot weld them together. Compare price against a new factory pack w/ warranty.
 

Wtoole

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You've got it apart. Just call up some battery repair shops and ask if they have 18650 cells and can spot weld them together. Compare price against a new factory pack w/ warranty.

So far none of the battery shops here in Ottawa, Ontario will work with Li-Ion batteries. Still looking though. I did find a battery pack from Batteryspace that is triangle shape that I can work with but shipping is a bit pricey, but still cheaper that I would get from the manufacturer, so will continue the search locally for a bit more.
 

turbodog

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Look at the shops that deal with r/c models. They might have a spot welder. Also... maybe you could buy 18650 cells (parallel) spot welded with tabs... then just solder to the tabs themselves. Is there a fair amount of free space in the compartment?
 

MikeAg03

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For what you'd save over a new canister you could possible even buy a spot welder and replace them yourself...
 

Wtoole

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No, there is not much room. Just a few mm. In the end I was able to find a local shop that was able to rebuild the battery pack.
 
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