# HID ballast low voltage warning, dont do this!



## roopeseta (Jun 19, 2011)

I just want to warn everyone that do not run your DIY flashlights HID ballast under 9v. If it starts to flicker, stop use immediately (if your battery is low and its flickering because of that).

I bought an ebay 55w hid kit, installed it, and then I stupid left it on with one old broken 12v sla that I resurrected and at 9v it started to flicker for 2 minutes and after that one semi-bright flash and it was dead.

I opened the ballast, scraped the silicone thing stuff away so I can look with multimeter if electicity goes from main ballast to the 23000v mini ballast when hooked with electicity. This was a so called slim ballast that has 2 parts. I gave it 12v from li-ion pack (9x 18650 2600 sanyo mah from laptop battery) and it didnt go on. Just an hour before, it went on with the same batteries for many minutes. 

So now its broken.

This is just a tip for all of you who might want to test what happens to the ballast if you let it go very low. Im pretty sure it was the ballast and not the lamp. 
I cant find the marking on this ballast but most of these ballasts say 9v-32v and you should believe it.


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## kramer5150 (Jun 19, 2011)

thanks for the heads-up warning.
Sounds like a poorly designed ballast. Car batteries die all the time around the world. A decent design should be able to withstand such a common occurrence. I have been meaning to add an inexpensive 12V volt meter to my DIY build.


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## BVH (Jun 19, 2011)

kramer5150 said:


> I have been meaning to add an inexpensive 12V volt meter to my DIY build.



Most on ebay are approx 3" wide and require a separate 5V supply to work. Look here for 1 7/8" wide, self-powered (2-wire and good from 4.5 to 30V) meters for $10.

//stores.ebay.com/Elite-element/_i.html?_fsub=2337321012


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## 2100 (Jun 20, 2011)

I ran my 55W ballast to cut off on the SLA, no issues at all despite repeated restrikes (never thought that the battery was flat, though it was instead the ballast or bulb LOL!). But not sure if its below 9V.


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## roopeseta (Jun 20, 2011)

2100 said:


> I ran my 55W ballast to cut off on the SLA, no issues at all despite repeated restrikes (never thought that the battery was flat, though it was instead the ballast or bulb LOL!). But not sure if its below 9V.


 

Now when I clarify my first message, im not sure what the voltage was.

After it shut down, i took my multimeter, battery was something 10v. But, when I hit the lamp on, the voltage went down to 3-4V.

After 15min I tried to put it back on again and then the voltage was 10.08 and 10.01 when I hit power on.

So, in reality its somewhere there what the voltage was. This SLA is old and not in 100% health. It was broken for 2 years and I added water to it and got something of it back.

Actually if I clarify even more, I left it on untill it shut down. After that I let the SLA rest for 5 min and I hit the switch back on. It flickered something 20 seconds and went off.

I didnt write this in the first message because I was tired or something but this is was a detailed version of what happened.

I ordered a new hid ballast (1x) because this one was also a single kit and not a 2 kit.


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## 2100 (Jun 21, 2011)

No problem, thanks for clarifying. The impt thing is not voltage, but "what will happen when you run a SLA to cut off", ie depleted SLA which cannot provide the juice. My ballast are ok, so is the Amondotech 3128 35W original ballast. In fact for the Amondotech it will provide a very beautiful arc which is not bright and it sustains for about 5-10 seconds. You can see the arc jumping around esp on the hotspot of the light on the wall. Pretty fun. But i can play with it, coz i have more than enough spare ballasts. (ATM i have 2 spare 75W. 1 spare 55W and 1 spare 35W mini ballast)


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## Morepower! (Jun 23, 2011)

Hey, one thing I have found out just recently is the ballasts I have modded definately run cooler and smoother with more voltage. If I run them at 12v they get hotter over the same time period than if I run them at 15v. Im not surprised the ballast died from too low a voltage as that seems to over-heat the Mosfets. U can also hear the "tone" from the ballast go from crisp to more like static as the voltage is decreased.


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## 2100 (Jun 23, 2011)

Probably something to do with efficiency, lower as the voltage goes down.


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## Morepower! (Jun 23, 2011)

I think what needs to be understood here is if a ballast dosn't have a safety cut off the Mosfets are not being switched cleanly(fast) the longer it takes to complete the switching the longer current is being put through them heating them up. Its also like running an amp into clipping, it dosn't produce a nices sine wave but more a square wave which destroys speakers because they are not getting a quick pulse, but an extended one which heates up the voice coils. Similar to cranking a starter motor with a low battery the windings are subject to current being passed through them for longer periods of time heating them up more than if they where spinning faster. I hope this makes sense. Also note that this is only a theory I have. But the fact is all my ballasts run cooler on higher voltages. So don't use 11.1v packs, use 14.8v.


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## BVH (Jun 23, 2011)

On regulated ballasts, less Voltage means more Amperage and correspondingly more heat from the higher current.


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## Morepower! (Jun 24, 2011)

BVH said:


> On regulated ballasts, less Voltage means more Amperage and correspondingly more heat from the higher current.


 
Hi BVH, been a while. That's true with the way they are regulated it's so the wattage remains the same. Do me a favour and next time you've got a STD ballast hooked up to you PSU run it at ~15v and put your ear near the ballast and take note of the tone it is puttind out, then wind the voltage down to 9 or 10v and see if it dosn't sound more like static. I just want to see if anyone else can confirm what I have noticed with other ballasts. I'm just curious to know if it is just because I have modded them. Thanks.


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## BVH (Jun 25, 2011)

Will do. Guests here this weekend so Monday.


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## 2100 (Jun 25, 2011)

Morepower! said:


> Hi BVH, been a while. That's true with the way they are regulated it's so the wattage remains the same. Do me a favour and next time you've got a STD ballast hooked up to you PSU run it at ~15v and put your ear near the ballast and take note of the tone it is puttind out, then wind the voltage down to 9 or 10v and see if it dosn't sound more like static. I just want to see if anyone else can confirm what I have noticed with other ballasts. I'm just curious to know if it is just because I have modded them. Thanks.


 
I know my slim ballasts turn coarser and louder when i turn down the voltage. I have a 20A 13.6V PSU that's meant for powering VHF/UHF transceivers that has a pot so you can tune from 11V to 14.8V. (so definitely enough juice)


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## Morepower! (Jun 25, 2011)

I tell you one other thing i've noticed so far and that is the electrodes in the cheap bulbs "seem" to be lasting longer when running the ballasts at higher input voltages. Though only more time will determine if this is correct or not. But so far it is looking like it is going to be true.


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## BVH (Jun 25, 2011)

In my testing, when I raise and lower supply/input voltage, output to the bulb (Watts) remain constant but also, Voltage and amperage to the bulb are almost rock-steady throughout the range of voltages I provide (typically 10 to 18V) I'm very interested to see your results when done testing. If this ends up being the case, I'm wondering if Volts and Amps to the bulb are unchanged regardless of input Voltage, what would account for your results.


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## 2100 (Jun 25, 2011)

Morepower! said:


> I tell you one other thing i've noticed so far and that is the electrodes in the cheap bulbs "seem" to be lasting longer when running the ballasts at higher input voltages. Though only more time will determine if this is correct or not. But so far it is looking like it is going to be true.


 
Good info, learned something today....luckily the cheap bulbs are cheap to replace at about 7 bucks a piece shipped for the 55W, I got 2 in special colours too, purple and 30k dark blue. For DISCO...heh heh. So far no issue even when gunning them with the "100W" black finned ballasts. I've got 8 spare bulbs now @ different CT! Sounds expensive, but its really not if you hang out in the LED flashlight forum....or you are modding different LED emitters (except budgetlights forum, but it also gets expensive fast if you are collecting budgetlights! heh heh...


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## Morepower! (Jun 25, 2011)

2100 said:


> Good info, learned something today....luckily the cheap bulbs are cheap to replace at about 7 bucks a piece shipped for the 55W, I got 2 in special colours too, purple and 30k dark blue. For DISCO...heh heh. So far no issue even when gunning them with the "100W" black finned ballasts. I've got 8 spare bulbs now @ different CT! Sounds expensive, but its really not if you hang out in the LED flashlight forum (except budgetlights forum, but it also gets expensive fast if you are collecting budgetlights! heh heh...


 
What sort of hours do you have up on them ?


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## 2100 (Jun 26, 2011)

Morepower! said:


> What sort of hours do you have up on them ?


 
Haha...true to a hobbyist's reputation, not more than 1 hour for each bulb. LOL!
Well ok, perhaps the main 4300K I think maybe 2-3hrs. I have 2 backup 4300s. 
So the arc chamber can deform all they can after 10hrs, i don't care. 

Interestingly my main HID light which i used for long is the Amondotech 3152, 35W. I used it to ceiling bounce at my new apartment, ya know....no lights yet. I think about 10hrs total, and the burning position wasn't optimal and supposed to eat up the electrodes fast. Philips bulb sTill working strong.... (focus need to be fine tuned abour 3mm back from OEM)


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