Best Voltage for HID ballast?

[worldedit]

I got my HID conversion kit and now its time to make a battery pack. Specs on the ballast:
voltage: 9 - 32 V
normal voltage: 12V
How does the input voltage affect the efficiency? I plan to use 18650 cells, so i can have almost any voltage between 9 and 32. Another questions is what happens if the voltage drops below 9V. Will it just turn of or might the bulb get stressed?

I know the answers highly depend on the specific ballast. But someone might have enough experience with HIDs to guestimate a bit for me.

Thanks for reading!

 

[VidPro]

geesh can you really go to 32V, man i got the wrong ballast.

they dont like it when its low, and the more limited ones dont like it when its high. but obviously your doesnt have that limitation.
probably best to ask in the HID section, about its range, but something about the salts forming, or the ballast struggling or something, and it being able to strike at low voltage??

you could almost get away with an 10.8 3X li-ion mabey, but when OTHER li-ion systems try and be 12V (car like), they go for 14.4, or 14.4 with a simple linear voltage regulation to clip it to exactally 12v.
14.4 would get as high as 16.4 and as low as about 13.2 (all loose figures) and you would want the li-ion to cut off about there or before. which it wont do, so 4x not so good for battery and unattentive user.

the 3xli-ion would want to cut out at about 9.9 or before , and so that would be a good choice if the hid could handle the lower voltage, without causing it problems. so the 3x would not only make a small package, but it could be "best" for the battery, stopping before deeper discharges
IF the hid will really not have problems just above 10V, which i doubt, but dont know.

oops, dont we have to know the Load on the batteries? how do we know your not trying to run a tank light off 18650s? what is the HID actual wattage including the ballast?

mabey this thing already has the voltage regulator or current limiter or something in it, but that wouldnt explain how it gets so Low TOO.

weird, i donno, i was just interested

 

[worldedit]

Its a 55W ballast. Im not at home for at least a week so i cant give much more information. The kit is from this auction:
http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&rd=1&item=310125687792&ssPageName=STRK:MEWN:IT&ih=021
Drain wont be a problem, ill simple wire enough cells in parallel. The unit is pretty big, you might have the right ballast for your aplication after all.
Are you suggesting to just try and run it at low voltage?
If i really ran that thing in a car, voltage might get down to 10.5V or up to 14V when the car is running. It must be able to handle that.

 

[VidPro]

i was suggeting i wouldnt Trust that it will run and run properly at 9V.
a car battery is pretty far gone at 10.5 anybody using a light till that happened , wouldnt they be looking for a jump to leave again

on the 14v, yup a modern well regulated car , is about 14.5 when running, and up, as high as 16v for some, the autos seem to be more regulated now than before.

i would ASK in HID forum, what the damage is from low voltage, and about how long to occur. the importance of that would set some parameters.

then i would test it on power supply thing, starting at 11V and go down, till it started flickering or dimming. that would be the max low and your good to go. if it wont re-strike or ignite or whatever you want to call it, after the flickering, then that is the low setting by default and not re-igniting then would be good, if it shouldnt run at that voltage anyway (via both balast and battery).

 

[worldedit]

Flickering and not reigniting are things i woulndt want. Seems like i have to go with the higher Voltage. Whats an eigth cell charger good for if you only charge 3 cell packs...
I thought this woult be the right forum to ask my questions. There should really be a sticky thread about HIDs like those on batteries, chargers, ....

Thanks for your help!

 

[VidPro]

but remember i was trying to formulate paramaters for BOTH items.

in the higher voltage setup, the li-ions will not have a (automagic) low voltage cutoff, which they should have, this could be deemed to be not desirable for the li-ions over the long run. the HID should be loving it.

with the low voltage setup, DEPENDING on how it works on the lower voltage, the li-ions would have relief from excessive discharge, by the balast not functioning below some set voltage, but then mabey the ballast and bulb dont like that.

these are good things just need to . . . accentuate the postives , eliminate the negatives , without Knowing the actual reality way it works , i am just guessing . . . till somone who knows what they are doing comes along .

i was just playing with this before (and hid), and had the same Quandry, do i 3 or 4, when 4 was (for me) to high, and 3 was to low.

someone around here has been messing with a very similar thing just rescentally http://www.candlepowerforums.com/vb/showthread.php?t=223571 i bet he would certannly have more ideas. that is if he didnt take the EASY way out and use a leetel car battery