Possible source of CHEAP HID bulbs/ballasts?

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Well, again, I'm basically treating the bulb and ballast as a closed system. The kits available on Ebay include that wiring, and I don't see a need to change it. I also don't see a need to be concerned with the voltages the ballast outputs because that is part of the closed system that I do not want to modify. As long as the bulb and ballast are designed to work together, I only need to keep the ballast happy, and it will keep the bulb happy (I hope). Am I incorrect in thinking this?

Thanks,

Mike
 
You will probably find that the factory wiring harness is two short, so you will need to get the correct type of wire to lengthen it. You will probably have to cut the harness anyways so you can get the cables through whatever hose you are going to use to seal it.
 
3W (9W) LED - Cave Diver's Forums

Here is a link to a thread that has pictures of an array of three of the LED's that I mentioned earlier. As you can see in the third picture there is no problem with the beam spreading out.
 
3W (9W) LED - Cave Diver's Forums

Here is a link to a thread that has pictures of an array of three of the LED's that I mentioned earlier. As you can see in the third picture there is no problem with the beam spreading out.

I don't mean to be rude, but you keep trying to derail this thread. The merits of LEDs have been argued many times in other threads, and that is not where I want to take this thread. I'm merely trying to get more information on automotive HIDs. NOT LEDS. I've done my homework on LEDs and decided that they do not suit my needs for a primary light. I have even tested a few high intensity emitters (inluding Cree), but that is not what this thread is about. Please keep this thread on topic.

You will probably find that the factory wiring harness is two short, so you will need to get the correct type of wire to lengthen it. You will probably have to cut the harness anyways so you can get the cables through whatever hose you are going to use to seal it.

Finding the appropriate type of wire should not be a problem. As I said, I'm a college student and have access to a lot of materials. Failing that, I'm sure Google will work wonders. If that is my only concern (besides the high voltage/hot start of the ballast that I can't control), then I don't see a reason not to spend $80 and give them a shot. If there is something that will prevent an automotive HID from working in a dive light environment, I'd prefer to know it before spending that money.

Earlier you mentioned something about certain bulbs only working in certain positions. I have not been able to find any substantion to this claim. Can you provide a source for that information?

Thanks,

Mike
 
First - you might have better luck in the DIY dive light forum over at Yahoo - hiddivelights : HID Dive discussion group. Parts, plans, Ideas for building or upgrading will get you there, and people are generally helpful.

Second - automotive lights are definitely designed for a very rugged environment, and can work well in this application, but, as others mentions, some are sensitive to positioning. There are a few examples out there (and more always on the way) using them to make DIY dive lights. Google will be your friend on that one.

Now, for the nitty-gritty...the cheap ballasts you're pointing out are generally unsuitable due to size. HID systems are three parts - the bulb, the ballast, and the ignitor. The bulbs take high voltage (anywhere from 5kV up through 20kV) at very low current to begin the ionization process in the bulb. Once the gas has ionized and is glowing, the amount of voltage to sustain the burn drops off to a more reasonable level (80-90V, typically).

The function of the ignitor is to get the bulb started, the ballast is to turn the DC into moderate voltage AC to both power the ignitor and keep the bulb burning. That "kick" at startup is why the most common failure mode of an HID is when turning it on (...well, second most common...the first is being an idiot and dropping your light...) and why it's bad practice to turn your light off underwater during the dive.

Most of these cheap ballasts from eBay and the like use an integrated ballast and ignitor, and to function, the unit must be VERY close to the bulb, as the high voltage requires extremely specialized wiring with insulation capable of sustaining the voltage without shorting, and longer runs of wire, even if you found the right type, induce enough stray capacitance in the cable that the ignitor is not able to step the voltage up to the appropriate level, anyway.

The 80-90V is easily handled by just about any electrical cable - many are suitable for use under water, but try to find something that's a solid-core, not a paper or hollow core cable, as it is hard to waterproof the latter.

You can get sets of ignitors and ballasts that are separate pieces - and the ignitor is a very small and compact part. You can then remotely mount the ballast in the canister, run reasonable cabling (anything in a standard can light is more than adequate) to the head, and keep the ignitor and bulb extremely close together (3-4 inches wire, max, is probably okay, and you want to use whatever wire they include.) Many of the new ballasts are very compact; I have an old NiteRider "square" case that handily fits the ballast and some LiPoly packs well. I haven't gotten around to machining a head, yet, that fits the bulb.

WRT the bulb itself, there's really only two types (D1 & D2, of which there are r & s variants) approved for automotive use in the US. Anything else is one that has been cannibalized and "rebased" to retro-fit for use by the type of people who do unsavory things to otherwise fine automobiles... :) However, most of those have a more compact base than the D2 series, which takes a special socket. The H1 and H3 series are particularly small, and make good choices for building a lighthead that will take a standard test tube to protect it. It's also easy to find sockets for them at your local auto parts shop or junkyard.

For power, remember to think about your discharge rate. If your bulb takes 35W, and your ballast takes a few (it's a lossy step up converter), figure on around 40W, which is around 3A from your 13.8-14.4 V pack, depending on technology. Make sure that the batteries you choose to power this can support that kind of a discharge rate...for instance, a "small" canister, like a 4.5A one, needs to support a 2/3C discharge rate, which is pretty stiff, and not all batteries can handle that, while living to see another day.

Finally, heat dissipation is an issue with these systems. 35W is starting to get up there to the point where it becomes a concern... Machining a lighthead out of aluminum instead of delrin or PVC would be helpful, and you might seriously consider just how you machine the canister; there are some pretty spiffy aluminum jobs I've seen on the web, and frankly, it seems like a good idea. I haven't run one of these, yet, long enough to have good performance data. For reference, people using the Trailtech 30W system have overheating issues quite commonly, mostly due to inadequate heat sinking.

As one final point - there are some non-automotive 35W ballasts out there (Auerswald makes one in Germany) which are a lot more compact. They seem reasonably hard to obtain, and I don't know their ruggedness or reliability. Worth a look, though, if you want something tiny.
 
...lots of good info...

Cameraone, thanks for the detailed response. Many of the things you pointed out I've already considered, but you also pointed out several things I was not previously aware of. That's exactly what I was looking for.

My current plan, without having these ballasts in hand, is to keep the ballast (which I asuume to have an integrated ignitor based on the pictures) close to the bulb itself, using the included wiring (back to my closed system idea). I believe that Halcyon does this with a similar sized ballast, but I may be wrong. I'm pretty sure some of the other manufacturers keep the ballast in the lamp assembly. This will make it more difficult to build a good light head, but I don't expect that to be a major problem. As I said, I have access to machine shops, CAD systems, etc.

You also bring up some good points about the power comsumption. I've already done the math for that part, and can get a pack built that will meet my needs. My biggest concern at this point is the heat issue. I was hoping to find some responses from other people who had actually used this type of system before to get a feel for just how serious the heat issue is. As of yet, I haven't been able to find any numbers for the amount of heat this thing generates, so I can't do any calculations on it (I'm a Computer Science and Applied Mathematics double major, so I always try to run the numbers first). I'm also looking at existing light heads to get a baseline for comparison. I've got a few good ideas for various ways to get rid of the heat, but some of them may or may not work. I'll have to have the ballast and bulb in hand to do some tests.

At this point, nobody has said anything that tells me these particular lights are totally unsuitable for dive lights, so I'm planning to order one next month after I get paid and see what I can put together. If you (or anyone else) has some good info that hasn't been stated here, I'd love to hear it!

Thanks,

Mike
 
Most Mfgr will conduct the heat from the ballast drives out through the housing.

I have read some people having issues with the trailtech ballast over heating and shutting down.

That was a close explination of how a ballast operates. One thing the automotive ballasts have over the current market is the hot restike. Automotive bulbs have a 2 second hot restart time limit. You don't want to wait in your driveway for a minute while your head lights warm up. It is this requierment that drives that 20Kv ignition voltage. After the bulb is inonized it is then hit high a short high current high voltage spike to start the arc. When the arc strats the resistance of the bulb drops off to almost zero. The ballast must then regulate the current to the bulb, this is when you see the most current draw from the system. As the bulb warms up it will increase in resistance and the ballast must change over to a power limiting control.

To find out the mounting limits of the bulb you will need to pull the bulb mfgs spec. They will call out what degree of mounting is ok. Some bulbs will melt the base if they are put in a head down config. But it is spec per mfgr, everyone is different.
 
To find out the mounting limits of the bulb you will need to pull the bulb mfgs spec. They will call out what degree of mounting is ok. Some bulbs will melt the base if they are put in a head down config. But it is spec per mfgr, everyone is different.

That's part of the problem, with the ones I've seen on eBay, I have no idea who the manufacturer is, probably generic made in Taiwan models. I know they won't compare to some of the more reputable names, but I'm hoping they'll serve the purpose.

As far as durability of these bulbs go, I haven't been able to get an exact number, but it seems most HID bulbs/ballasts last upwards of 1000 hours, which is plenty for my needs, plus with the automotive kits, I'll have a spare in case somethign goes wrong.

Thanks,

Mike
 
As far as durability of these bulbs go, I haven't been able to get an exact number, but it seems most HID bulbs/ballasts last upwards of 1000 hours, which is plenty for my needs, plus with the automotive kits, I'll have a spare in case somethign goes wrong.
Well, the plus side of auto bulbs is that they're a lot cheaper than the Welch-Allyn or Brightstar bulbs that most of us are using in our off the shelf lamps. Also, the lower wattage bulbs (10W, 18W, etc) are less efficient than the 35W-50W setups with regards to actual conversion of electricity into light - lumens per watt, if you will.

WRT Halcyon - they don't run ballasts that big - their 18W ballast-in-handle-design (of which I have one - rebuilt by Salvo to use Brightstar parts) uses a smaller ballast, which I still find unwieldy. It's a good place to tape deco schedules, though! If you open up the light head, you won't find a heck of a lot of room inside the head to actually fit a whole lot of electronics - you need a reasonable wall thickness. Just think about that carefully as you machine your head.

The more progressive manufacturers, like Salvo, which does have a 35w unit, have moved to a ballast-in-the-can approach. I haven't disassembled one, but the round "blob" at the back of the lighthead is tell-tale for an ignitor in the handle.

FPPF makes a good point - the hot restrike isn't really needed in a dive light, and if you drop the ignitor voltage down from 20k to 7-10k things are a little easier to work with.

One more point on bulbs - there are some sellers (eBay Motors: Xenon HID Conversion Kit H1/H3/H4/H7/H13/9006/9007/H11 (item 200196582344 end time Feb-06-08 18:29:19 PST) as an example - I have no vested interest) that offer "H3C" sized bulbs, which pretty much match up to the brightstar old-style bulbs. I don't know how their brightness compares to the longer, more traditional automotive HID bulbs, but I do know they are extremely rugged and may be a good choice, as they're also very short and stubby.

I'm sure you can do what you're planning with the ballast unit close to the bulb, but you may end up with a pretty bulky handpiece. I'd seriously consider milling it in three pieces - top plate and bottom section of a rectangular block, and a tube for the bulb/test tube/reflector to glom on to. If your shop gear supports it, milling it in just two pieces would be enough (bottom piece can mill out with the reflector tube and spare you from yet another o-ring). I'm usually pretty uncomfortable with rectangular-shaped o-rings, but it's too many years of paranoia of flooding a camera that did it to me...NiteRider canisters have a double seal on their rectangular lids, and they're still prone to flooding. My Salvo frankenlight has a single o-ring and I've never had a problem.

Anyway, good luck, and let us know how it turns out.
 
Some of the mfgrs are putting the ballast in the can and the ignitor in the head.

I was going to do this, however the ballast will generate upto 400 volts during startup or if the bulb goes out. I just don't like the idea of having a 400 volt cable in water that could get pinched. We are still trying to figure out if there is even the remote chance of getting a shock if the light flooded. I have not heard of anyone yet, but there also are not that many floods.
 

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