This applies to all lamps, mine and others, hence a general posting. I feel a need to raise awareness of this issue.
If something is put under stress it will fail.

The picture below shows how this comes about in a lamps fitting and the point of failure. If the cable is flexible rubber sheathed it will be the internal wires that will fail through metal fatigue, if the cable is the harder PVC failure will occur by the splitting of the outer sheath.

🔗116529[linkphoto]116529[/linkphoto][/link]

I changed to the type of gland which provides cable support a while ago for this reason.

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To add a bit on this from stuff I have had to deal with in the day job:

Cable glands like this are a sealing point where a cable goes into an enclosure & they are designed for the cable to exit pretty much in line. They are definitely not suitable for a dynamic use; this is where one with strain relief, as Roy now uses, should be used.

Cables have a minimum bend radius, in the case of the cable Roy uses (just looked it up) this is an inside radius of 6 times the OD which is 6.2mm so 37.2mm. Bear in mind this is a minimum and it is best to keep well above it.

Using cable designed for dynamic use such as energy chains allows for a smaller bend radius.

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Petzl Duo’s are renowned for that.

Leif.

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I think that the gland may be part of the equation. I was originally using the metal type (as shown in the picture) which were of Chinese manufacture and seemed to have more of a 'sharp pinch' that I would have expected.

The ones I use now are from Lapp Kabel.

A while back I met a chap in Ranpgill who had one of the best looking lamps I had ever seen. Of course, I asked him about it.
It was one of a batch of 10 he had manufactured, keeping two for himself and selling the rest to his friends. he would not say how much, but just remarked "expensive"

Getting on to the subject of the glands, I mentioned that I was having a lot of my battery packs returned with cable failure issue and was upgrading the glands with the Lapp ones. His face fell and he confessed that he had every one he sold back with this, so I offered him the Farnell part number for mine.

What Nick says makes a lot of sense, but it should always be remembered that if its possible to do something in a certain way, then sooner or later someone will do it, regardless of printed instructions.

I recently had some queries from a customer.
"Its all in the instructions"
"Oh, I threw them away"
:lol:

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My Duo failed for exactly this reason after well over 10 years good service. A temporary repair allowed me to continue using it, however with a tighter shortened cable, there was probably even more stress on it, so expecting a second failure in due course I have replaced the lamp with one of Roy's.

The problem is balancing the cable being mounted tight against the helmet to avoid snagging and giving it enough bend radius.

Mounting the glands at an angle to closer match the helmet curvature reduces the problem but does make machining the housings rather more awkward & expensive.

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The problem is balancing the cable being mounted tight against the helmet to avoid snagging and giving it enough bend radius.

Mounting the glands at an angle to closer match the helmet curvature reduces the problem but does make machining the housings rather more awkward & expensive.

That's an interesting point and would do well to be taken on board by anyone having battery casings custom made.
I will bear this in mind in the future should I ever do this.

I have been using my own lamps for years with wide loops on the cable and very seldom have any snagging. Remember the Oldham's with the cables hanging down your back like something out of "Dr Who", "Invasion of the Electrons" or whatever.
We don't know how well off we are.
:lol:

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All my lamps still have belt mounted batteries, including the one made by Roy :lol:

Cracking bit of kit though :thumbup:

All my lamps still have belt mounted batteries, including the one made by Roy :lol:

Cracking bit of kit though :thumbup:

yes but my last batcooker does 7K lumens from a helmet mount power bank containing 3 Tesla cells.

Things move fast in technology

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All my lamps still have belt mounted batteries, including the one made by Roy :lol:

Cracking bit of kit though :thumbup:

yes but my last batcooker does 7K lumens from a helmet mount power bank containing 3 Tesla cells.

Things move fast in technology

I tend to buy the best I can and then use it until beyond reasonable hope of repair before repeating the cycle - not only for lamps but in all thing really. The only exception to this is when technology improves to such an extent that I am cutting off my nose to spite my face in persisting with the old stuff.

For some reason this annoys Mrs T and she is oft heard to mutter 'isn't it about time you got a new one of those'.... :lol:

Mounting the glands at an angle to closer match the helmet curvature reduces the problem but does make machining the housings rather more awkward & expensive.

I did exactly that on my 3D printed battery box.

Chris.

The MagnumStar is more of a collector item now really, big issue is its weight.
A real hot rod of a lamp.

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Would something similar to this be suitable if they could be sourced at the correct size?

http://www.directindustry.com/prod/giovenzana-international-bv/product-12319-1925443.html?utm_source=ProductDetail&utm_medium=Web&utm_content=SimilarProduct&utm_campaign=CA 

That is pretty much what Roy is using these days

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That is pretty much what Roy is using these days

A sound bit of engineering, very similar to the belt mounted Oldham cable outlet.

That is pretty much what Roy is using these days

Looks to me an imitation of the Lapp Kabel which is IP68.
IP 65 NG for underground.

Lapp is Farnell part no 1204195

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