Serv-Light First Look

[Evan G]

Thanks Alan,

Mmmm, I was hoping. I think I'll just go head an order one.

E

[adleedy]

I also agree with you on the fact that a main failure point is where the cable enters the housing on any light.

When the passaround stenlight was going around, by the time I recieved it you had to hold your tounge and the cable going into the lamp housing just right to get it to work.

[jharman2]

Then we are thinking along the same lines. I found this battery pack which is 3x18650 already packaged. I figured I would dip it in the liquid rubber for coating tool handles to give it some additional water resistance and bump protection. This battery pack can be had for $20 which I thought is a very good price.

2 or 3 18650s in parallel is a good choice and what I plan to do. One thing that you may want to take into consideration when buying a battery pack is the protection circuitry. Yucca - I believe that the pack you show has regulation circuitry included. This is both good AND bad. The good side is that the regulation circuitry protects against over current (and overheating) in the event that the pack becomes short circuited. The bad side is that the regulation circuitry protects against under voltage. Because the regulator protects against under voltage the lamp will turn off with little to NO warning when the battery becomes low! Imagine your light dying while passing a re-belay or on a nasty exposed traverse. Of course you can always carry a small backup lamp on your helmet at all times but even then loosing light without warning is not really fun.

I plan to use some "virgin" 18650 cells (no regulation circuitry) and use a simple fuse to protect for over current. I suspect that Sten does the same thing on their 18650 packs as the early models would shut off without warning but later models will burn for hours and hours albeit very dim.

I am planning to use a connector similar to these:

http://www.wsdeans.com/products/plugs/ultra_plug.html

I also plan on doing the plasti-dip around the whole pack. I have done this before on other packs and it works well.

[YuccaPatrol]

jharman,

Thanks for the info about the regulation circuitry. I think I may still go with the protected pack and plan to carry a spare pack with me. Since I will always have a backup on my helmet, I'll plan to figure out the run-time of my battery pack and plan to change it before it becomes necessary. I guess I cannot get over my fear of a lithium battery explosion/meltdown on my head (even though I have never once heard of it actually happening to a Sten or other lithium powered headlamp)

A question about your beam shots to help me guesstimate runtime. A photo labeled 2P7 700mA: does this mean that each of the emitters is drawing 700mA for a total of 1400mA, or is each one of them drawing 350mA for a total of 700?

[potholer]

The 350/700/1400mA figures are totals for the 2 P7s, as per:
http://www.serv-light.com/Cavingconfiguration.html

[YuccaPatrol]

Thanks potholer! Amazing that I can drool all over that website for weeks and still miss something!

[jharman2]

Thanks potholer! Amazing that I can drool all over that website for weeks and still miss something!

Yes, potholer is correct.

Yucca - I agree with you I have looked over the site many times and always seem to miss something.

[potholer]

Well, they do change things on the site , so it's possible that *some* 'missed' things weren't previously there.

[YuccaPatrol]

Well, I am ordering my lamp today!

I had promised my wife I would wait until I sell the new caving coveralls I have, but she got so tired of hearing me talk about it that she said to go ahead and order it!

[adleedy]

congratulations

What options are you getting?

[YuccaPatrol]

I am getting it with 2xP7 emitters. I decided that the standard cable is probably good enough for me. I'll be powering it with the 3x18650 battery pack I linked to earlier.

I also ordered two of those batteries and a smart charger so I'll be ready when the lamp shows up. If anyone is ordering those batteries and charger, there are a couple coupon codes available to get either free shipping or 12% discount at all-battery.com . "tenergy2008" gives free shipping and "battery12" gives 12% off the total order.

Battery pack: http://www.all-battery.com/li-ion186503 ... pping.aspx

Smart Charger: http://www.all-battery.com/universalsma ... cells.aspx

The only thing I will need to do now is figure out the sort of connectors I am going to use to connect the battery to the lamp cable. I'll probably take the whole kit and kaboodle down to my local RC/Hobby shop and see what sort of connectors they suggest. . . .

[adleedy]

cool,
I ended up going with this battery charger:

http://www.batteryspace.com/index.asp?P ... rodID=4470

and the same batterys, I almost bought the charger you listed but I wanted a much shorter charge time than the 19 or so hours I calculated. The battery space charger should charge my battery in 3.3 hours, if my math is right.

[YuccaPatrol]

I didn't want to charge these at their max charge rate of 3A, but also didn't calculate just how long it would take to charge this pack at 0.5A. Since I will have two batteries, it shouldn't be a problem to plan ahead and keep both charged and ready to go.

I also plan to build a 3xAA battery box as a backup in case I cannot use one of my lithium packs.

If the slow charging rate becomes an issue, I'll look for a charger that charges somewhere around 1.5A as a happy medium. . . .

[Joe Duxbury]

I know this is a bit off the topic of the Serv-Light itself, but jharman2 wrote that he was planning to use Deans connectors to connect to a battery. (Doesn't the Serv-Light come with its own battery pack?) Unless you've already used Deans connectors, I suggest you don't. I was persuaded to use them on the grounds that they are well-regarded by the model flying community. They (i) have virtually no contact resistance, (ii) can take the large currents needed by model motors, (iii) are small, and (iv) they are easily replaced because they have simple solder connections. Although they are excellent electrically, as a result of (i), they grip so well, and their small size (iii), means that getting them apart (to change over batteries) with wet gloves or muddy hands underground, is very difficult. And if your lamps use leds, (ii) is irrelevant.
Other people in the field of caving lamp construction have recommended Anderson 'Powerpole' connectors. These are still small enough to fit in a helmet-mounted battery box, have simple solder connections, but have more to get hold of.

[potholer]

Personally, I've found the Tamiya race-pack connectors to be pretty durable, though they aren't small.
However, size isn't a problem for me, since they fit neatly inside old Petzl Zoom battery boxes, along with a 3x18650 battery pack.