# power on board HID on Li-ion



## kanarie (Oct 16, 2008)

Question:
I want to reduce the weight of my power on board HID.
Is it possible to run this HID on 3 Li-ion cells total 11.1 volt (like 3x 18650 batteries) and will it still run when they are almost empty (8- 9volt)
Or do I need 4 cells (and risk of blowing the balast?)


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## kanarie (Oct 16, 2008)

to give an answer to my own question:
yes you can!
I just had an idea and connected two pretty full 18650's (with a magnet)
The two of them had enough voltage/power to startup the HID (buzzing noise in the beginning though) The lightoutput was reduced with a third.
If I can start it at 7 volt (with two) I guess 8-11 volts (with three li-ions) won't be a problem...

Any ideas for a 3x2 18650 battery holder anyone?


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## jayb79 (Oct 16, 2008)

I was thinking something like this
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4270
Do you know how many amps it draws of the sla battery?
I think the voltage will drop quite a bit so 4 cells should not be a problem.


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## schiesz (Oct 16, 2008)

If anyone gets this working on lithium ion i'd love to hear about it. Maybe a 3sx2p config would be god for runtime? To take this monster and make it so much lighter would be incredible.


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## Patriot (Oct 16, 2008)

Good link jay, and it would probably be good to get something with a bit more capacity. 

Here are many packs to choose from:
http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=1008


*EDIT:
*...and yes kanarie, I'd lean toward the 11V packs with larger capacity than a small pack with higher voltage. It's safer, since I don't know if anyone knows what the voltage range of the ballast is, and the run-time will keep the light practical unlike four 18650's.


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## Flashanator (Oct 16, 2008)

those batts + 4300K bulb would really make the POB the light it should have been all along.

Im gonna get a POB.


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## jayb79 (Oct 17, 2008)

Best bang 4 the buck would be Ni-cd 
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2533
Or Ni-mh
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2052
for around $100 and you can have 7-10 ahs of bright light. Easy to charge and lots of capacity.


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## kanarie (Oct 17, 2008)

> I was thinking something like this
> http://www.batteryspace.com/index.as...OD&ProdID=4270
> Do you know how many amps it draws of the sla battery?
> I think the voltage will drop quite a bit so 4 cells should not be a problem.



a 3 pack would be safer I think also 6 x 18650's at DX will cost $25
So I can make an 11,1V 5000mAh (3s 2p) pack for far less money
and a Cheap dual 18650 charger ($6)
I only need an battery holder for 18650 batteries 
maybe two PVC tubes with magnets between the batteries


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## Dead_Nuts (Nov 28, 2008)

I really like the 12v, 10,000 mAH battery that jayb79 shows above. A separate charging lead allows the battery to be permanently installed in the housing and charged externally. Of course taking a $28 light and modding it with a $100 battery and a $28 charger might be considered a little INSANE. But, hey, I'd love to see someone else do it.


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## mdocod (Nov 29, 2008)

kanarie said:


> a 3 pack would be safer I think also 6 x 18650's at DX will cost $25
> So I can make an 11,1V 5000mAh (3s 2p) pack for far less money
> and a Cheap dual 18650 charger ($6)
> I only need an battery holder for 18650 batteries
> maybe two PVC tubes with magnets between the batteries



Just a few things I want to point out here:

1. Your 2x18650 "test" to see if it would work was probably pulling upwards of 8 amps (give or take a few amps) from the cells. That's not good for them.
2. Using cheap cells with huge variances in true capacity is never a very good idea for building battery packs, especially li-ion packs. 
3. Charging a LiCo pack, especially if you are going to use a bunch of cheap mismatched cells, is going to require some special considerations, I would personally recommend looking into balance chargers and building a pack with balance taps for safety reasons.

doing a 3s2P configurations of Li-Ion cells won't really extend the runtime much if any compared with a good performing SLA, with that in mind, it would be a lot of money to spend, to have not dramatically improved anything accept for weight. I would suggest a 3S3P configuration as bare minimum li-ion conversion to say that it was worth it overall, that should extend runtime to around 2 hours.


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## lennin (Nov 30, 2008)

My low-budget project. 4x3 18650 cells to my HID


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## kanarie (Dec 20, 2008)

NICE!
did you do the wires already?


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## Wattnot (Dec 20, 2008)

If I'm not mistaken there's a 12v 7000ma SLA in the stock POB. If you want to use 18650's, you would probably be better off with a 3S4P config. That should give you enough current draw and runtime from protected 18650s. The stock light claims 70 minutes of continuous operation so you should be able to do your rough runtime math from that.

However, this would be a good application for lithium POLYMER cells. You can buy them in almost any configuration from hobby shops online (I can hook you up). I know I recommended against these in a flashlight previously but that guy wanted to shove a lipo into a mag body. Nice flare if you drop it the right way! But in the POB, it would do fine and save a LOT of weight and current draw is not a consideration since most of these allow 50 or more amps easy. They would be terrible in the cold though. Just throwing out some ideas here.


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## Patriot (Dec 21, 2008)

It would be one high performance POB but a good li-po would sure be light.

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6322

too expensive?


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## jayb79 (Dec 22, 2008)

I would think a 4s pack would be ok. Here is a 3s, http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3871

And a 4s with built in protection circuit, http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4032


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## Patriot (Dec 22, 2008)

The 4S will peak at 16.8V. I'm not really sure how much those ballasts will handle.


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## plasmaman (Dec 22, 2008)

My PoB runs a 50w 4200k D2 lamp on 4 x Li D in series.
Very light, very good output. A great lantern all round.
:twothumbs


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## worldedit (Dec 22, 2008)

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7346
Very cheap, light and can supply 50W no problem.


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## Richie086 (Dec 22, 2008)

From what I've observed in my stock POB, removed from the charger (already on float mode) the SLA battery voltage is about 13v. When turned on, the battery immediately falls to 12 volts and stays there even after the HID bulb has warmed up to full brightness. This HID requires 3.5 amps of power from the battery to run at full power and runs for easily 90 minutes on a single charge. That's as far as I went with the SLA battery. 

I'd love to upgrade it on both of mine as well, so I watching this thread carefully.


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## Patriot (Dec 23, 2008)

worldedit said:


> http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7346
> Very cheap, light and can supply 50W no problem.




Those Rhino brand batteries are very good quality and I fly them in large 1500 Watt RC planes. That said, I personally think the 2600mah capacity is too small. The largest Rhino that Hobby City sells is a 4900mah but it only comes in a 20C which drives the price up to $65. Still a great price for those willing to sacrifice run-time but I'd still want more capacity.


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## D-Dog (Dec 23, 2008)

Patriot36 said:


> Those Rhino brand batteries are very good quality and I fly them in large 1500 Watt RC planes. That said, I personally think the 2600mah capacity is too small. The largest Rhino that Hobby City sells is a 4900mah but it only comes in a 20C which drives the price up to $65. Still a great price for those willing to sacrifice run-time but I'd still want more capacity.



Could you take two of the cheaper packs and run them parallel? 5200 claimed mah at a good voltage... as long as they would fit that is


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## worldedit (Dec 23, 2008)

D-Dog said:


> Could you take two of the cheaper packs and run them parallel? 5200 claimed mah at a good voltage... as long as they would fit that is



That would work. I got some cells from that manufactor and they have the stated capacity. The problem is you cant run them down completely or they are dead.


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## Patriot (Dec 23, 2008)

Sure it would work great but I'd probably start with a pair of 3500mah batteries. Why not have at least equal capacity to the SLA right?


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## FredM (Dec 23, 2008)

I ran mine for a test on 4 Li-Ions in series, the ballast did not instantly explode. But i think the best without a protection circuit woud be 3S so the ballast will drop before your cells get drained to low.

3S3P 18650's would destroy the stock runtime, possibly by 2 fold. 
The weight reduction would be insane.


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## worldedit (Dec 23, 2008)

Patriot36 said:


> Sure it would work great but I'd probably start with a pair of 3500mah batteries. Why not have at least equal capacity to the SLA right?


You got to take into calculation that the SLA battery drops in capacity under high drain.


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## FredM (Dec 23, 2008)

Mine was good for about 4mah at the POB wattage. 3S2P Li-Ion 18650's should at least match it.


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## D-Dog (Dec 23, 2008)

worldedit said:


> You got to take into calculation that the SLA battery drops in capacity under high drain.



Yea, SLA claimed Ah are some of the best BS in the battery world... the tests are done at some unworldly number of hours... maybe if you put the battery in a smoke detector or clock  I have an 18Ah SLA here which is lucky to get 12 in real-world testing... so even though you may be led to believe you need equal capacity Li-ion, this is in actuality not the case


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## Mugrunty (Dec 24, 2008)

Just some quick info... I had my HF POB (The red one offered once at Harbor Freight) hooked up to my power supply to measure amps and stuff....and I found out you can go as low as 5.8 volts before the Ballast flickers and cuts out. The power was always around 42 Watts. So 12V was drawing about 3.5 Amps (After the initial Warm up). I also drove it at 15v for a few minutes and nothing blew up. The current dropped to about 2.8 Amps when at 15 volts. It's too bad they didn't label the ballast to what it could handle. It's completly blank!

I still love the fact that HID lights are held at constant brightness throughout the life of the battery. I'd like to build a more accurate battery fuel gauge though... That LED gauge on the light is only good for when the light is at rest. I'm thinking Coulomb counter with a Microcontroller and a display! HA! With a "remaining Time", "Amps Drawn", "Voltage", and "Percent power". I have all the parts...just need to write a little Assembly code. Sorry, I went off topic a little.


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## Patriot (Dec 24, 2008)

Mugrunty said:


> Just some quick info... I had my HF POB (The red one offered once at Harbor Freight) hooked up to my power supply to measure amps and stuff....and I found out you can go as low as 5.8 volts before the Ballast flickers and cuts out. The power was always around 42 Watts. So 12V was drawing about 3.5 Amps (After the initial Warm up). I also drove it at 15v for a few minutes and nothing blew up. The current dropped to about 2.8 Amps when at 15 volts. It's too bad they didn't label the ballast to what it could handle. It's completly blank!
> 
> I still love the fact that HID lights are held at constant brightness throughout the life of the battery. I'd like to build a more accurate battery fuel gauge though...




A good reminder as to why a 4s li-po might be risky.


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## D-Dog (Dec 24, 2008)

Mugrunty said:


> Just some quick info... I had my HF POB (The red one offered once at Harbor Freight) hooked up to my power supply to measure amps and stuff....and I found out you can go as low as 5.8 volts before the Ballast flickers and cuts out. The power was always around 42 Watts. So 12V was drawing about 3.5 Amps (After the initial Warm up). I also drove it at 15v for a few minutes and nothing blew up. The current dropped to about 2.8 Amps when at 15 volts. It's too bad they didn't label the ballast to what it could handle. It's completly blank!
> 
> I still love the fact that HID lights are held at constant brightness throughout the life of the battery. I'd like to build a more accurate battery fuel gauge though... That LED gauge on the light is only good for when the light is at rest. I'm thinking Coulomb counter with a Microcontroller and a display! HA! With a "remaining Time", "Amps Drawn", "Voltage", and "Percent power". I have all the parts...just need to write a little Assembly code. Sorry, I went off topic a little.



Wow, correct me if I'm wrong, but 5.8 seems really low for a low-voltage flicker... the pack would definitely have to be protected in some way. Don't most ballasts flicker at like 8.x volts?


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## Mugrunty (Dec 24, 2008)

Could be...but for some reason I remember it being around 6. I could try it again to see what happens. But yes, It would definitely need some sort of protection. Even the Lead-acid battery wouldn't like being discharged that low. About 10.5V is good for a lead acid...MAYBE 9V if it was under heavy load...but 6? Naaaaa.


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## D-Dog (Dec 24, 2008)

Mugrunty said:


> Could be...but for some reason I remember it being around 6. I could try it again to see what happens. But yes, It would definitely need some sort of protection. Even the Lead-acid battery wouldn't like being discharged that low. About 10.5V is good for a lead acid...MAYBE 9V if it was under heavy load...but 6? Naaaaa.



That's weird, as I would think the cheaper Asian ballasts would have stricter cutoff voltages:thinking: Still, a simple protection circuit is a must... even with the SLA as you stated. If people are running theirs done to blinking, it's gonna really impact the SLA cycle life...


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## Mugrunty (Dec 24, 2008)

Yup, I thought about doing something like that. It's slightly harder because you would have to add a switch of some kind. Either a MOSFET or a RELAY..etc. I would just use an Op-Amp as a comparator and have it switch off the switch when it gets to 10.5V.

I might just head out to the shop and quickly find out for sure what voltage the Ballast stops working. BRB...


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## Mugrunty (Dec 24, 2008)

Ok, I've done a little analysis:

*Lamp starts to dim a little: *about 9V

*Ballast shuts off* (flickers first): 5.25V

*Interestingly, the powersupply I have cannot start the ballast by itself. I needed to use the SLA battery as a starter buffer, then disconnect the battery.
I initially had to voltage at 13.5V but didn't read the current. My power supply has duel 0-30V at 5 amps...but I used the parallel button to achieve 0-30V at about 10 amps. 

Here are some current and voltage readings:

11.99V @ 3.53Amps = *42.3247 watts*

6.63V @ 5.32 Amps = *35.2716 watts* 

5.54V @ 5.62 Amps = *31.1348 watts

*Sorry if they are incomplete, I might go take more measurements. I should have included more in the 11V 10V 9V 8V range. Just from looking at the light output, the light started to dim slightly at 9V. You can see that the power output dropped when running at the lower voltages.

Let me know if you guys want more measurements and I'll just go out there again. It doesn't take long.


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## Norm (Dec 24, 2008)

Might be a handy addition no matter what battery you use.
http://www.jaycar.com.au/productVie...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID=



> *Low Voltage Battery Warning
> *This circuit monitors any battery voltage between 3-15 volts once set. Whenever the voltage falls below a predetermined value a Red LED lamp lights up. It does not, however, automatically disconnect the battery. Uses a tiny amount of power from the battery being monitored. Could save you embarrassment or a fortune by avoiding battery damage.


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## Patriot (Dec 24, 2008)

I think a low voltage power cut off switch would be better, especially if other people besides the owner will be operating it. 

I'm still blown away that the ballast doesn't shut off until 5.2V. It seems like if that were the case a 7A SLA would run longer that 55 minutes.


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## Richie086 (Dec 24, 2008)

Patriot36 said:


> I'm still blown away that the ballast doesn't shut off until 5.2V. It seems like if that were the case a 7A SLA would run longer that 55 minutes.


 
When I tested my POB, I wanted to see if it would run for the rated 70 minutes, which it did easily. I did run it until it reached 90 minutes and then stopped it to recharge the battery. This thing runs much longer than my Thor-X 10 MC Power halogen. Regardless, if you run SLA batteries below 10v - 10.5v, you are really going to destroy them.


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## D-Dog (Dec 24, 2008)

Richie086 said:


> When I tested my POB, I wanted to see if it would run for the rated 70 minutes, which it did easily. I did run it until it reached 90 minutes and then stopped it to recharge the battery. This thing runs much longer than my Thor-X 10 MC Power halogen. Regardless, if you run SLA batteries below 10v - 10.5v, you are really going to destroy them.



Yup, forget that *7Ah* capacity after only a few cycles... SLA's are one of the more resistant battery chemistries too, however, nothing is perfect (Although I have revived SLA batteries from 0 volts before... just not easy to do). A simple low-voltage monitor such as the one listed above would suffice in protecting your POB


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## Mugrunty (Dec 24, 2008)

That would be a lot easier to do (The low voltage monitor). Has anyone ever gotten to the panal where the LEDs are? It's pretty well hidden behind some plastic I think. If you could get to that, It might be possible to drill another whole and make room for an additional LED. I'm not sure how much room there is because I haven't disected the light enough to get there.


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## kanarie (Dec 25, 2008)

> Ok, I've done a little analysis:
> 
> *Lamp starts to dim a little: *about 9V
> 
> ...


Thanks for the info:
amazing it still works @ 5,5 Vollts
I one should use li-ions he better have some cut off protection


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## Patriot (Dec 25, 2008)

Mugrunty said:


> Ok, I've done a little analysis:
> 
> *Lamp starts to dim a little: *about 9V
> 
> ...





Thank you for taking the time to document that. It's very good info and honestly, I never would have guessed.


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## Mugrunty (Dec 26, 2008)

Yup, no problem! I might get some more data later this week or something. I hope everyone had a good Christmas! I didn't get any flashlights, lol, but thats ok. I probably have enough. But then again...for some reason enough is never enough.:twothumbs:sick2:<-- funny face!


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## petrev (Dec 26, 2008)

Hi

Posted this a while back and regularly run my POB on 4p4s Li Pack

*DIY 8800mAh Lithium pack for HID / POB / Thor Mods* 

Lighter weight 4300K POB is just great :wave:

Cheers
Pete


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## Richie086 (Jan 6, 2009)

Mugrunty said:


> It's too bad they didn't label the ballast to what it could handle. It's completly blank!
> 
> I still love the fact that HID lights are held at constant brightness throughout the life of the battery. I'd like to build a more accurate battery fuel gauge though... That LED gauge on the light is only good for when the light is at rest. I'm thinking Coulomb counter with a Microcontroller and a display! HA! With a "remaining Time", "Amps Drawn", "Voltage", and "Percent power". I have all the parts...just need to write a little Assembly code. Sorry, I went off topic a little.


 

Hi Mugrunty,

Removing and examining the POB ballast is about the only thing on this light I haven't gone near yet. I would like to know if anyone can recommend a replacement ballast that would fit correctly in this light in the event it craps out. As far as the input voltage the ballast can handle, I just assume you can run the light between 9-16 volts. 

I'm also glad to see others are looking into doing heavy mods to this light too. The Stinger volt meter I installed on mine is working really well and ensures I don't overly discharge my battery. 

BTW....since the ballast seems to put out about 43 watts, does that mean the 35 watt bulb is actually running at 43 watts? Thanks.


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## Norm (Jan 6, 2009)

Richie086 said:


> BTW....since the ballast seems to put out about 43 watts, does that mean the 35 watt bulb is actually running at 43 watts? Thanks.


Don't forget that the ballast isn't 100% efficent, so it won't be running 43 Watts. Not too sure what the actual figure would be.
Norm


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## Mugrunty (Jan 7, 2009)

Exactly! That ballast is probably around 80%. One way to figure out what the bulb actually uses would be to measure the voltage at the bulb and the current going into the bulb. It would be slightly difficult because they use those insulating connectors at the bulb. Not sure If you have seen my pictures of the ballast and connectors. Plus, you would have to wait for the initial high voltage spike to pass. IIRC, the ballast provides around 16Kv to ionize the gas...then as it begins to conduct electricity, the voltage lowers to around 90ish. I never really took readings, I'm just guessing ballpark figures. I think I remember seeing a post somewhere that actually had readings. The ballast is roughly the size of your palm.


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## Richie086 (Jan 8, 2009)

Hey Norm and Mugrunty,

Thanks for the information. I'm starting to modify my other Power On Board HID at this time. I'll see if I can get any power consumption reading using my volt meter.


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