WOuld it be possible to make an LPS or an HPS flashlight? I currently only have a dream to go by (no schematics or anything) bu would it be possible to make a practical sodium flashlight?  i know HID flashlights exist but im talking like powering a 35w HPS or a 18W LPS bulb in something that can be somewhat portable (kinda like one of those utility flashlights).

i've actually been wanting to do this since i was 3 or four (first time i started noticing the different lamp types) but i do not know where to start

As kid i experimented with this very idea. I ran into some limitations :

 - The lamps i had at the time were 70W E/I lamp and a bare arctube from such lamp. The E lamp is not suitable for spotlight optics, the bare arctube was ok optically but didnt warm up

 - The gear i had was ordinary magnetic ballast + squarewave output UPS. The gear is huge in terms of flashlights - It basically was a backpack with the UPS/ballast in it, and a "megaphone" shaped device with the lamp, connected with a cable

 - The E/I lamp didnt start on the squarewave power anyway. The arctube (with manual start, i had no ignitor) started though



With a more compact clear lamp + appropriate gear (single ballast with DC input / lamp output) this would work fairly well i think

The HPS lamp is a bit sensitive to impact, but not too badly. It may extinguish if it gets an impact. With LPS lamp this is a show stopper because there is quite a lot of liquid Sodium inside, that splashing around when the flashlight is moved can readily destroy the lamp

Your not alone, I'm not looking at a flashlight but more a temporary area light with internal Li-ion batteries and an 18 watt LPS tube but it won't be moved while it's hot..  For ballast ideas check out this site https://www.repairfaq.org/sam/jshidbal.htm and you can find all the parts fairly easy.. But Ash is correct about the LPS lamp, they really shouldn't be moved much during operation or the sodium will go all over the place and end up damaging the tube in the long run, but HPS while it's shock sensitive they do take a good bit of abuse...

But just throwing this out there, those small Xenon short arc tubes used for automotive headlights are cheap and so are the ballasts and they get to full brightness in a few seconds and for the most part they run on 12VDC, those are what is used in most HID spotlights..

If i were to build the circuit mentioned in that first link, what batteries would possibly hold the most juice, (i want to make this thing reasonably long lasting.... like maybe 6 hours, but also compact.... i think im too much of a dreamer to be honest but maybe im wrong and there is some special battery that could handle such a task? aside from a nuclear reactor (which was an idea that genuinely crossed my mind... foolish i know) what is motivating me to do this is the idea of a high powered HPS flashlight that would last a good amount of time, and be reasonably compact. The battery is whats kind of scaring me at this point lol... like i hope to avoid lugging around a car battery  , the circuit mentioned seems compact enough that i could cram it onto a smaller circuit board so thats not an issue,but I'm also a little scared of winding up a ballast... i've tried winding transformers a few times before and they either did not work... or barely worked, one of them did work decently... but then a mistake i made else where fried it gahhh!...  hmm... I would prefer a 70W lamp but I'm figuring i will have to sacrifice lamp power to make it last long and have it be light weight, maybe im wrong there... im not the best at calculations, but it only seems logical... 35W or 50W may be better options, maybe i could avoid all that mess (aside from figuring out the battery situation) if i used the premade automotive HID kits, like you mentioned Lodge? could one of those Ignite and run an HPS reliably?



sorry if my post seems a bit scatter brained.... It very much is, that is essentially all the raw info pouring out of my head so if i need to clear up any misunderstandings here i can.... I'm tired and i wanna go to bed though so i can go to work and maybe even possibly get some more HID fixtures off my boss lol 

Most of the automotive style ballasts use about 23 kV for ignition,so they will have no problem getting a HPS
lamp going and they might even be able to hot-restike the lamp (no cool down needed) the problem is the HPS lamp, it's not designed to be driven with a 23 kV igniter, now personally I haven't driven a HPS from them, but they will power up small pulse start MH lamps but because the voltage after ignition is low they never get to full brightness.. The lamps they drive are very bright and small, and if you get them from china they are like $20 for set with lamps and ballasts for 35 Watt  plus you can pick your color they do come in orange (3000K with a coating on the outer tube) and they go from about 3000K to 30,000K and you can get red and green as well, They are also available in a higher wattage if needed..

About the battery if you use a pure sine wave inverter with 85% efficiency and say you go with a 35 watt HPS and magnetic ballast (High power factor) And  a sealed lead acid battery, which you shouldn't go beyond 50 % of the rated AMP hour capacity if you want it to last, and the less you discharge them the longer they will last, but I'll go with 50% and round the Ah up to the next largest size you can buy, you'll need a 12Ah for one hour, and to get 6 hours you'll need 72Ah so I would go with a 100 Ah battery, now keep in mind they are made from LEAD so they will weight about 71 Lbs just for the battery and by the time you add the rest of the gear and box it's 100 lbs... And I'll give you a tip, if you need a nice pure sine wave inverter, just look for a used APC Smart UPS's they for the most part have pure sine wave inverters and they offer cold start power up and are easy to hack, and can often be found for cheap or free on Kijiji, with dead batteries (normally 2 X 12 volt, they need 24 volts to work.) 

Just throwing this out there, two Coleman lanterns will be just about as bright, and only use a quart of fuel (or less) in six hours and you can get both Red and Amber globes for them, and if you find them at garage sales you can pick them up for like $5 and most only need to be cleaned and the pump gasket oiled and they are good to go, and if your lucky you might even find one made the same month and year as you where born, and they are easy to carry, also on the plus side you can put them behind your chair when the night gets cold and they keep your backside nice and warm.. 

I will have to look on the automotive HID lights websites-some of the HID foglights are the sodium yellow color.Figure it would be possible to "convert" a halogen portable lantern to use the HID bulb by installing the HID lamp and ballast in the halogen lanterns case-then a portable amber foglight.This has been done on the "Candlepower Forums" site.

The main problem with battery power is the voltage range the ballast must cover: 6 cell lead acid drifts fron nearly 15V (full charge) down to about 9V (flat), 3(4) cell LiIon goes from 12.6V(16.8V) down to about 8.7V(11.5V), 10 cell NiCd/NiMh/alkaline/Zinc Carbon goes from 15 down to 9V (yes, that is valid for all of these).

The simple Royer circuit (on that link) does vary its output according to the actual input voltage, so given the voltage ranges it is usable only with either MV or HPS, but not suitable at all for neither LPS nor MH.
Don't be fooled, the author is not any idiot, but that circuit was designed mainly for boat use with an engine running - then the voltage is in the range of 13..14V, so narrow enough to become usable even with LPS or MH, but you expressed the use mainly from the battery and that is a significant difference.

The automotive ballast is the cheapest thing to get to  aintain the correct power over the whole voltage ranges (usually 8..16V), but these endto feature power boost at startup(designed to provide the minimum required output just after ignition, with onlythe inefficient Xenon being the radiating plasma), whichwill dedstroy lamps not designed for it (it needs way heavier electrodes, the power starts from 90W expecting about 40V arc after ignition, only afterwards, when the halides evaporate, it goes back to the rated 35W).

For the LPS you wouldneed to build some properly regulated ballast (could be the Royer, but with a switching voltage regulator between the battery and the main ballast; that is simple to get on e-bay, but means extra losses).
For not too high complexity I would use something around the resonant controlled fluorescent like circuit (push pull input, secondary goes via an inductor to the lamp, parallel capacitor facilitates the resonance voltage boost for the start; the current is controlled by varying the frequency by a feedback loop).

Most of the automotive style ballasts use about 23 kV for ignition,so they will have no problem getting a HPS
lamp going and they might even be able to hot-restike the lamp (no cool down needed) the problem is the HPS lamp, it's not designed to be driven with a 23 kV igniter, now personally I haven't driven a HPS from them, but they will power up small pulse start MH lamps but because the voltage after ignition is low they never get to full brightness.. The lamps they drive are very bright and small, and if you get them from china they are like $20 for set with lamps and ballasts for 35 Watt  plus you can pick your color they do come in orange (3000K with a coating on the outer tube) and they go from about 3000K to 30,000K and you can get red and green as well, They are also available in a higher wattage if needed..

About the battery if you use a pure sine wave inverter with 85% efficiency and say you go with a 35 watt HPS and magnetic ballast (High power factor) And  a sealed lead acid battery, which you shouldn't go beyond 50 % of the rated AMP hour capacity if you want it to last, and the less you discharge them the longer they will last, but I'll go with 50% and round the Ah up to the next largest size you can buy, you'll need a 12Ah for one hour, and to get 6 hours you'll need 72Ah so I would go with a 100 Ah battery, now keep in mind they are made from LEAD so they will weight about 71 Lbs just for the battery and by the time you add the rest of the gear and box it's 100 lbs... And I'll give you a tip, if you need a nice pure sine wave inverter, just look for a used APC Smart UPS's they for the most part have pure sine wave inverters and they offer cold start power up and are easy to hack, and can often be found for cheap or free on Kijiji, with dead batteries (normally 2 X 12 volt, they need 24 volts to work.) 

Just throwing this out there, two Coleman lanterns will be just about as bright, and only use a quart of fuel (or less) in six hours and you can get both Red and Amber globes for them, and if you find them at garage sales you can pick them up for like $5 and most only need to be cleaned and the pump gasket oiled and they are good to go, and if your lucky you might even find one made the same month and year as you where born, and they are easy to carry, also on the plus side you can put them behind your chair when the night gets cold and they keep your backside nice and warm.. 

LOL 100Lb..... that is more than half my weight (135 lb) .... lmao... that would be very unpleasant to carry... i do like coleman lanterns, prob will look into one someday... as for this flashlight thing, after hearing that, I dont know if i want to go through with  it.... however maybe when i get a car i can make some overpowered Fog lights... after all thats what sodium is good at 

The main weight in the project is the battery. Now do a fast evaluation : The average 6 cell laptop battery (containing 6 18650's) is about 55 Wh. Think how much of them it would take to run the HPS you want for the length of time you want

Ash is correct Lithium ion batteries are much lighter, but there is a cost to the weight savings, they need electronics to control the charging and discharging, they do not like to be over discharged and may explode when recharged if over discharged, there is also charging requirements, and balancing cells, and temperature requirements and while laptop packs are nice, and contain most of the needed control electronics, to actually get the 55Wh from a pack you need to get a name brand pack not some off brand cheap pack, so Lead acid is cheaper a single group 27 deep cycle recon is about the same cost as single factory original laptop pack, if not cheaper and Lead acids will tolerate a fair amount of abuse, and offer a longer service life if taken care of, which is why they are the choice for off grid solar..

The other thing to look at is do you really need six hours of run time, I have a 35 watt HID spot light with a 7 amp hour 12 SLA battery and the amount of time I actually use it while camping for a long weekend doesn't kill the battery, even my 3 cell maglight with D size Duracell batteries only gets changed like one a year.. You could go with a smaller battery and run it less or add a cord with alligator clips/cigarette lighter socket and for longer run times just borrow power from a car battery and run the engine as needed.. Or keep an eye out at the junk yard for a 600 Watt Honda generator, they are old,  light and light on fuel as well or a Power-it 1000 watt inverter generator (on sale in walsmart they are under $90) or you can covert an old chainsaw into a generator..     

Some thing for you to check out :>  http://www.instructables.com/id/Chainsaw-flashlight-gas-engine-powered-spotlight/ The guy even has video of it running...

Ash is correct Lithium ion batteries are much lighter, but there is a cost to the weight savings, they need electronics to control the charging and discharging, they do not like to be over discharged and may explode when recharged if over discharged, there is also charging requirements, and balancing cells, and temperature requirements and while laptop packs are nice, and contain most of the needed control electronics, to actually get the 55Wh from a pack you need to get a name brand pack not some off brand cheap pack, so Lead acid is cheaper a single group 27 deep cycle recon is about the same cost as single factory original laptop pack, if not cheaper and Lead acids will tolerate a fair amount of abuse, and offer a longer service life if taken care of, which is why they are the choice for off grid solar..

The other thing to look at is do you really need six hours of run time, I have a 35 watt HID spot light with a 7 amp hour 12 SLA battery and the amount of time I actually use it while camping for a long weekend doesn't kill the battery, even my 3 cell maglight with D size Duracell batteries only gets changed like one a year.. You could go with a smaller battery and run it less or add a cord with alligator clips/cigarette lighter socket and for longer run times just borrow power from a car battery and run the engine as needed.. Or keep an eye out at the junk yard for a 600 Watt Honda generator, they are old,  light and light on fuel as well or a Power-it 1000 watt inverter generator (on sale in walsmart they are under $90) or you can covert an old chainsaw into a generator..     

Some thing for you to check out :>  http://www.instructables.com/id/Chainsaw-flashlight-gas-engine-powered-spotlight/ The guy even has video of it running...

the chainsaw idea... I like that.... that has renewed my interest... also its not that i need it, most of the things i build were never needed, But they're way cooler than what you can buy (at least in my opinion) .... What if i skipped the chain and just welded the motor to the chainsaws drive shaft? that would save on space, the boiler room at the school i work at has many MANY spare motors... I'm sure some of the motors in storage aren't even compatible with some of the machinery currently in use.... which means free pickins... i have alot to choose from there, and there is more than one building with boiler rooms , with spare parts storage yay (i just have to ask ken which ones are not useful to them anymore)... the chainsaw may be a little harder for me to obtain, maybe not, could this be done with a weedwhacker? does a weedwhacker offer the same amount of HP as a chainsaw or at least a sufficient amount to spin a motor at a decent speed? (the motors in the boiler rooms are large) I have very little experience with engines, does a chainsaw require two stroke fuel like a weed whacker? (I've used a chainsaw  before but it was not mine and i did not have to refuel it) If it does not, I'd weigh the chainsaw once again as a better option (mostly because i would just be able to pour normal gasoline into the thing) what about leaf blowers? how are the engines in those? in terms of HP and the type of fuel they use?

 the ballast and all that goes with i have covered that is quite easy, with this, i could probably up the wattage significantly, like maybe up to 1000W? am i being too dreamy there? If so i have 400W ballasts aswell, I'm kind of veering away from the flashlight idea, and more towards a portable work light, or heck if it were 1000W, a portable false sun (sorta) hehe "El Falso Sol" 2.0 (the original one is only 400W MH/405W Incandescent (pictures in my gallery). its gonna be HPS of course, don't get me wrong, MH and MV are cool, but, over all i think HPS is my favorite, not that i cant modify the device to power other lamps though. are all the previously mentioned ideas possible? is there some thing im missing, like does the motor i use affect the wattage that could be provided?  is the engine a limiting factor to this aswell? (like say i use a certain type of engine and i swap the motor i'm using out, could the new motor provide a different wattage than the original?) Like basically with the same engine (weedwhacker,leafblower or chainsaw), but with different motors could one of those motors provide sufficient output to light a 1000W,400W or whatever watt ballast? (sorry for asking the same question in several different ways, I'm thinking as i type)

Also i just realized, that the chain or belt is probably something i should use,rather than connecting the motor directly to the drive shaft, because i can use the chain to boost the speed/power to the motor, (wrong terms but i'm sure you can piece together what i mean)

I'm not quite sure about how to regulate the power... could i somehow modify the inbuilt controls to whatever engine i may use so that it is at a constant? like for example instead of a trigger on a weedwhacker, in place would be a dial? would this regulation be sufficient or would the electricity outputted still be a bit bumpy and require another form of regulation?

sorry for a million questions....

Of course anything you build is cooler then what you can buy, and your only limited to your imagination not corporate shareholder interests, now about the gas engine, you can use pretty much anything to power a small HID light like a 35 or 70 watt HPS, a half decent chain saw is able to run about 1 kW, a weed whacker (well my cheap $50 Home Depot special is 1 HP) is able to do about 600 watts and leaf blower the handheld type can do about 350 to 450 watts, and for simplicity you would want to normally use a 12 volt alternator from a car or truck, you can use other motors but then you need to get into regulation and RPM control of the gas engine and you can get a one wire alternator at most junk yards and they will be complete with a pulley and mounting holes for bolts, and because it's DC it doesn't really care about the engine speed so long as they rotate fast enough. Now yes you can weld it right to the engine output shaft, if you get it perfectly centered and it has the required bearings, or it will vibrate to death in short order, even if your a pro at welding I would strongly advise against doing that, it's much easier to either to use a belt or a coupler (like a  spider coupler) to go from the engine to the alternator, and both make servicing it later so much simpler then having to get out the cutting torch or saw.

About the fuel, most small two stoke engine or reed engines in chainsaws, weed whackers, and leaf blowers, use mixed fuel, so you need to add oil to the gas, in a ratio of about 32 parts gas to 1 part oil some are 40:1 and even 50:1 check the fuel cap but on the positive side they don't care which position you operate them in, yes you can use a chainsaw upside down, with a four stroke normally they don't like that and don't last long..

But don't overlook used lawnmowers (normally they are 4 stoke engines) they are great for a small DC generator and at a yard sale I've seen go for $5, if they pull easy, normally the carb is gummed up and needs to be cleaned or you just need to add some fuel that is not 20 years old (those are the two most common problems, really fuel today doesn't keep long) About fuel usage a gallon of gas will give you about 4 kWh of power, at a good guess..

If you go with an automotive alternator you will need a small 12 volt source to start the power generation something like a 7 Amp hour battery SLA works great and also helps to filter the output and provide enough power to start a larger loads, or larger to make it though refueling periods when you need to shut it down,  and then if you go with a solid state ballast you can use a cheap inverter, if you go magnetic you should use a pure sine wave inverter (look for a used APC smart UPS they are cheap, but you have to mod the alternator to 24 volts, not to hard or get a larger truck one already set to 24 volts, and they have enough room for small batteries and you might even be able to remote mount the ballast inside the box)

Here's a good website about building one from a lawnmower, with a nice write up and pictures  https://theepicenter.com/blog/generator-lawn-mower-vertical/

And while the guy in the instructable uses plywood for the frame, if you have access to a welder and some scrap metal I would build a small metal frame and or look for a busted pressure washer so you can use the wheeled cart to mount it on, yes it's still lighter then a huge lead acid battery, but wheels will make it so much easier when your tired and as you get older..     

For the genset idea you need something, where you can find ready made components.
So for lighting that means go for the commercial mains ballasts.
But that means you need pretty exact 60Hz feed.
Because the frequency is directly linked to the engine rpm, you need an engine with a speed governor.
So a chainsaw is out: There is no governor and the engine is primarily designed to be as compact and lightweight as possible, so very hard to make any significant mods in that respect...
But the lawn mower should be fine, you should only respect the designed engine orientation (lawnmowers use to be vertical shaft, which is a bit awkward for a genset, but still possible to use; maybe when integrated into the light pole base you may benefit from it - less ground footprint). The problem is mainly the lubrication - the crank case oil pan and agitating "spoon" design needs to match how the oil will be sitting there.

Otherwise a battery operated lantern is not that far out either: Way simpler maintenance and operation than any genset, true, there is higher purchase cost, but then no running cost.

For a 35W lamp (so power input of about 40W or so) you need 400Wh for a 10hour runtime, that leads to just a plain car battery (the cheapest for the capacity, but degrades quicker when discharged), or better some deep cycle "traction" (golf cart, lighting,...) version would be the best. Usually specialized battery stores do carry these, you just have to ask. In the wet form they use to be still not that much expensive (only slightly more than the "car" version of the same capacity), but can handle the deep discharge quite well (obviously you have to charge it back as soon as possible). Usually is just a bit heavier than the car starter type and are not able to hold the charge for that long (the higher selfdischarge rate is a direct consequence of the deep cycle robustness), so you need to store it on a maintenance charger.
For the 400Wh I would use about 70Ah  battery, just to not discharge it really completely (for better cycle life; the 60% designed discharge is about the cheapest battery, when comparing the battery cost and how long it will last), the weight is about 25kg.
Gell cell is easier to use, but impossible to refill the water, if you manage to overcharge it, so I would not use that in this size, unless you want it to be really spill proof.

LiIon will lead to the smallest and lightest pack, you may design it vit very little margin (let say 500Wh), but you will need about 60 18650's (assume about 2300mAh per cell), so pretty more expensive investment. However for really heavy use (daily discharge/charge cycle,...) it may become cheaper for the long run, as unlike the other chemistries, LiIons practically do not age with the number of cycles (the aging rate depends on temperature and the actual charge state, but the cycle component is very negligible).
But you will need the ballasting and charge control sized for your capacity.

If going high capacity, how about using long series string (up to ~150VDC) and feed that into an "ordinary" electronic HID ballast

If going high capacity, how about using long series string (up to ~150VDC) and feed that into an "ordinary" electronic HID ballast

First the problem of the large relative voltage variation remains (40cell LiIon stack will vary from 116V till nearly 170V, so about +/-20% from a center), the standard ballasts are designed for way narrower voltage range (usually +/-10% or so).
Second problem is with the cell balancing: More cells in series, way more difficult it become to keep them all balanced well. With such high voltages even the "classic" (non-lithium, so both NiMh, as well as lead) technologies need an active balancing as well, severely complicating the stuff. Moreover you need the balancing to work efficiently manly during discharge, which is quite difficult to implement (or as a minimum you need separate minimum voltage monitoring for properly operating overdischarge protection, as no chemistry survives too deep overdischarge or even battery reversal).
If you take the Tesla (now I mean the Elon Musk's "car" maker company) battery packs, they use batteries composed of a group of 18650cells parallel, with no more than 3 or 4 such groups in series form one sub-pack, such sub pack has monitoring, cell balancer and a charge/discharge control with a bypass feature (so if the sub-pack reaches its minimum voltage, it is disconnected from the circuit and its position bypassed, letting the car run on the remaining cells with still more juice in them; same with charging, once fully charged). This makes the complete pack very complicated electronic gadget, where the cost of the cells alone is only half of the total cost for the complete battery pack.
For a 200kW car such approach is necessary just to keep the circuit operating currents reasonable (Read: Below 1kA), but on a 50..100W application such complication does not make any sense (when three LiIon cells in series mean the currents will be barely 12A total or so).