So I have recently come into possession of a Professional’s Favorite spotlight. It’s giant, it’s hideous, it has a pretty worn-out lead acid battery, I paid zero dollars for it, and it looks just like the one in this pic snagged from The Google (who found it on CPefffff):
I’ve searched around and it seems they have ample space inside for tossing an HID ballast in there. I’ve done HID conversions in cars/trucks… how different is it with flashlights? Would a (really big) LED be better? Looking for a ton of light that will shine an absurdly long way. Really no idea where to begin with this spotlight except for tearing it down, drinking beers and staring at it until a plan materializes.
Biggest question is probably what to do with the battery situation… I don’t know much about these SLA batteries — they are marked saying max current of 2.1A and I’m assuming I’ll want to exceed that by… a lot. So maybe a battery pack made of laptop-pull 18650’s? Someone more experienced please give me some guidance. I’m at a loss of where to begin with this thing. Also, I don’t want to spend a boatload of money on it. So cheaper plans = better. I think I should mention I can probably put my hands on a 55w HID ballast and bulb or three that are orphaned from past vehicles I modified/unmodified/sold.
that looks like a variant of a popular spotlight whose name eludes me (I’m real helpful, I know…) It has been modded a lot, and with many variations. Try searching “cyclops” into cpf/ google. that might get you somewhere.
I have something similar but know nothing much about HID stuff so I've had it sitting for a couple of months while I wait for inspiration.
Will be following this thread with interest.
I have seen some of these projects before, but at the time they didn't have much relevance so I didn't pay too much attention.
For a power source, the ones I saw made were running from an RC LiPo pack. 3S2P from memory. If you've never looked into these, Hobby King would be a good place to start. These packs do not have any low-voltage protection so be sure to get a low-voltage alarm. This is referred to by some as a screamer or a buzzer. It plugs into the balance lead and will alert you to a low voltage situation.
I've got a similar light and am trying to decide on approach for powering too. I know I want HID (already have 35 and 55 watt balasts and bulbs) and I want 3S or 4S Li-ion power. I'm just trying to decide between on-board battery management or normal pull/replace cells. I prefer pull/replace because I like monitoring cell health and replacing cells when any start showing signs. If I go on-board management, I would like to use a laptop pack (unmodified) as I doubt I could do anything better than that. Just not sure how to do that at this point.
I’m also looking to modify a searchlight. The one I’m working on is a cheapie from Harbor Freight. I was thinking about a MT-G2 or a Luminus SST-90. I already have a couple of the SST-90’s. The Harbor Freight light has two 6-volt SLA’s in series to send 12V to a halogen bulb. The MT-G2 would have an advantage if I were to keep the SLA’s because I could rewire them in parallel to feed the MT-G2’s Vf needs. The driver, then, would not have much extra to dissipate as heat. These 6V SLA’s charge to 7.2V, by the way, so there still is some overhead to feed the driver itself. The SST-90 would be better if converting to NimH or Li-Ion, because the Vf is lower, and would align better with the voltage outputs of those chemistries. One thing a lot of people may not know - there is a 1.2V NimH rechargeable 18650-size cell available. I happen to have 12 of them already that I had bought a while back for some project I ended up not doing. That is probably what I’d use, since it would be simpler for charging in the light and probably a lot safer than a bunch of Li-Ion cells.
The one thing I wonder about is the reflector. Is it going to still work effectively when changed from a halogen bulb to a LED emitter? Would I need to modify it somehow in order to still get good throw? I hadn’t given HID a thought, but it would solve this issue, and still work with the 12V SLA setup as well. It would pretty much be a drop-in solution. But, I really want LED, if I can make it work.
The main issue with SLAs is that they really don't like to be drawn down to less than 50% on a regular basis. Even deep cycle rated lead acid batteries will suffer from premature failure if regularly discharged to a low level. Also, because of self-discharge issues they do need to be topped up every couple of months. There have been many reports of people with these big spotlights complaining that the batteries died when they went to use them. It appears that if you leave these torches sitting around for six months or so and then try to run them you're just asking for problems due to sulfation.
In other words, they need to be properly maintained. I'm not sure that this is spelled-out on the instructions that are supplied, even if the users did bother to read them.
Lead acid batteries will also suffer more voltage drop under load than a LiPo pack. Your 7.2 Volts will not give you a 1.2 V overhead once you start drawing on it.
In this respect LiPo or even NiMH (especially if LSD) are better suited.
I suspect lead acid is used because it's cheap, fairly easily replaceable and relatively safe. LiPo packs are dangerous in the hands of the ignorant in a way that no SLA can hope to match. They can also be made incredibly dangerous if they are discharged to too low a level and left there. Battery management circuitry to prevent over discharge would add extra cost.
None of these issues are probably relevant to those in a forum like this considering making their own modifications, but they are probably major considerations if the light is designed to be sold to the general public.
Regarding using a large LED emitter, my main problem with this has been thinking about how the heat could be dissipated. I would think the emitter would need to be inserted a fair way into the reflector rather than simply sitting at the base of the reflector like it does with most purpose designed LED lights. You really need to consider where the filament of the regular bulb was and then imagine how you would position the LED that far into the reflector.
I can only imagine some kind of copper bar arrangement extending into a big heatsink behind the reflector but I have no idea how I could fabricate this. Computer CPU heatsinks and cooling fans come to mind.
If its H4 id probably just go with a H4 HID if you already have a ballast and bulb, its probably easier than trying to fit a HIR 9011 bulb and cheaper if you already have the parts.
You would have to decide between some AGM (deep cycle batteries) or 4S (14.8v) from Hobby King, you can buy something to cut it off at low voltage and also voltage monitors are cheap (I really like OLED voltage monitors).
A good chargers for maintenance AGM batteries like the Noco Genius G7200 are about $100 or so, a hobby charger for maintenance of lipo cells like the Accucell 6 is about $30.
I was hoping that wiring the two SLA’s in parallel would assuage some of those issues at least a little. But, like I said, I also have 12 x 1.2V NimH 18650’s that I can use. I don’t know if they are LSD, since I bought them so long ago and I didn’t even know about LSD cells back then. I hope they are, because they’ve been sitting quite a while now unused. If I can’t get them to work, I may default to AA Eneloop Pros I just bought from ChibiM a few weeks ago! Or, I may do Li-Ion cells in parallel for the SST-90. If I go with Lithium cells, I probably won’t do MT-G2, because the cells would have to be in series. I was hoping to keep the ability to charge the light, not have to remove the cells and charge them separately. The light is made with a simple charging circuit for the SLA’s. I think I can figure out how to make it charge two SLA’s in parallel, or some NimH in series or Li-Ion in parallel, but not Li-Ion in series.
As for the large emitter, I’m sure it will have to be raised into the reflector, but I figured it needed a good heat-sink anyway, so I could use the heat-sink to bring it up to the level it needed to be. The back of the reflector is a very wide flat place, so a good sized heat-sink would easily fit there. I just don’t know about the angle of the light coming from the emitter in the very large reflector. Unless it’s a very wide angle, it may miss the reflector altogether and be completely unfocused as it comes out through the lens. That would not do at all for a searchlight which is all about throw! Anybody know where I can get an 8” diameter aspheric lens?
I know little to nothing about HID at this point but was given this light by my nephew who founded it discarded somewhere and thought it might be of interest to "Uncle Torch". It's in pristine condition but came with no batteries or charger.
My initial thought was to go with HID.
I already have a couple of hard case 4S LiPo packs and an icharger 106b+ hobby charger so I'm set in that regard. Have a couple of low voltage screamer alarms to monitor the packs.
As I said, I know very little about this stuff but I'm thinking it might be a good project to try over the Christmas break. That's why this thread caught my interest. I just need to do a lot of reading.
if you know of a good source of suitable parts I'd appreciate any links. Thanks
HID usually works well with these large spotlights and usually gives a better beam in them. It will produce lots of light. You can buy one of the automotive kits off ebay, with bulb, holder and ballast. It's a good choice for 12V, since that's what they are designed for. SLA batteries would be fine if you find one with a good output. Yes, they don't like to be run down too far, but I used mine that way and it worked fine.
The key is being able to find the sweet spot for the bulb. It needs to be adjusted in/out, till it gives the tightest spot and then locked down into place.
LEDs don't work well in spotlights unless you like floody lights, (usually).
After a fair bit of looking about, do you know if Im right in thinking this tech is not available in H1 or H3 despite them being single unshielded filament type bulbs. From what I read, only unshielded bulbs can be (or are) made in HIR. The light housing obviously can have shields, but not the bulb itself so H4s claiming this tech are fake.
Lifepo4 batteries are a good option for automotive HID systems. A 4s lifepo4 will have a range of about 13.6v to 12.8 nominal and then the dropoff at the end is steep. I’ve talked to TRS about their Morimoto 50w ballasts and while they couldn’t confirm for me, they said the electronics in their ballast most likely automatically shuts the ballast off at a critical point, so if the shut off is at 9v this would be 2.25v per cell which is fine for lifepo4. Other auto ballasts may automatically shut off as well since they are all electronically controlled. To make a pack from individual cells I like the big headway cells; for a factory pack I’d just grab one from Hobby King. Alternatively, a 3s lipo would also work fine within the range of 12.6v - 9v.
That may be the ticket there. I haven’t gotten around to tearing mine apart just yet. Been working too much on building 3-XPL Convoy S2+’s and other lights for Christmas gifts. This spotlight is definitely going to be one of a few projects I’m planning on tackling in January though.
Really leaning towards going with an HID bulb and ballast and one of the lifepo4 packs either via making a pack or buying one already made depending on how I end up stuffing everything into the housing.
Y’all reckon it’d get way too hot if it’s direct drive? Lotsa plastic on this thing.
