# Can the Magicshine handle a 12V battery?



## Tinier (Apr 13, 2006)

Just curious, because I have access to 12V lithium packs.. Anybody?


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## Outsider (Jan 1, 2007)

The driver handles 5V(tested) - 8.4V (according to the specs). 12 V will probably fry the driver.


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## MtbMacgyver (Jan 23, 2007)

Not without fairly extensive modifications to the driver board. There are capacitors on the board that are only rated for 10 volts.


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## Tinier (Apr 13, 2006)

Hmm thank you for the information. I shall not try plugging my 12.6V battery pack to it then.


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## mtb_robs-x (Dec 13, 2009)

an adapter would be great.
since, it would open the possiblity to use, other batteries,
and larger packs.
currently working on the circuit, but don't have it sealed yet.
now the low battery indicater, would not work with it, since it would receive a constant 
voltage, right now red, but could be green.

For me , I'd like to use a larger / higher voltage battery, so an adapter like that makes sense for me. Would have been nice, if the Magicshine, could take higher voltage, 
but think, that would have made it more expensive, so they choose the easy route.

let me know, if you are interested, or found a solution.


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## lidarman (Jan 12, 2004)

mtb_robs-x said:


> For me , I'd like to use a larger / higher voltage battery, .


Why?

I actually wish the MS was based on a 3.7v volt battery. That would solve the series charging problem with Li-Ion chemistry as well as allow a USB interface.


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## [email protected] (Mar 28, 2007)

I've modded mine to handle higher voltages. Change the input capacitor to something higher than 10 volts (which is pretty marginal for a 7.4 volt power supply anyway), The rest of the parts are rated at around 25 volts, but I wouldn't get anywhere near that. A 11.1 or 12 volt battery should work fine. You might even get away with a 14.4 or 14.8 volt battery. The driver is a buck converter which gets less efficient the further the input voltage gets from the output voltage, and that lost efficiency means the driver gets much hotter.

To help the driver dissipate heat, you can smother the side of the driver with the coil and mosfet with something like Artica Alumina adhesive (special heat conducting, non electrical conducting epoxy, will cost you around $10 to $15 for the 2 tubes you mix together, can be used for heatsinking the rest of the light as well). Spread it out to the edges of the brass driver holder, and after you snap the driver holder back into the aluminum LED holder, pack some more epoxy between the driver and the aluminum holder. You want to provide a path for driver heat to get out of the light. That's almost as important as getting LED heat out to the surface of the light. Regular epoxy would work in a pinch, but it's not as good as the AA. Of course once you do this you will never be able to open up the light again, so be real sure it works before gluing it shut.

You should also change the current sense resistors (labeled R03 and R04 I think) to a larger package, like maybe two 0.16 ohm resistors in a 1210 package: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RHM.16SCT-ND The 1210 package fits if you are real careful soldering the packages.

1206 packages like these: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=RL16R.16FCT-ND fit easier but are a bit more spendy.

While I was at it I put in thicker wires (the 20 gauge stuff they use is pretty lightweight for the current it will carry and pretty easy to break). You'll need to file, mill, or drill the power cable hole to be a bit wider. And when your finished placing the cable, seal up the cable hole as that was never really water tight anyway. RTV silicone will work in a pinch. Something less corrosive would be better if you can get it.

Since it sounds like you don't need the battery pack anymore, sell it to someone who still has the original light. That will help cover your costs.

Oh, and Geoman if I find the factory has made these mods to any future versions of the light I see, you owe me for some engineering consulting time  , should be worth a couple of free lightheads at the least.

Mark


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## mtb_robs-x (Dec 13, 2009)

the 3.7V , would not work, since the circuit usually is down convert, as such, needs higher voltage,... the 3.7V is nominal, it can get down to 2.5V ....
let's assume , do get the 3.7V battery,... 4.4ah x 2 is 8.8ah, , 32whr,
usb gets you 2.5W,... so it be 13-16 hrs charge time, do you like it ?
the circuit needs to work harder, bringing voltage up, where it needs to be,
so more expensive, and less efficient, more heat, shorter run time,
also the battery would need to be multiple in parrallel, cells need to be matched, and charge circuit needs to be more complicated, current would be high, so all the cables need to beefed up,... aka havier and more expensive,....

if you want one, with usb chargeing, thing the mini newt from nightrider, might fit the bill.
do think, USB be great,.... but until 3.0 and real power, it won't be.
if you take a look, on EV electric vehicles,... higher power,... higher voltage,...
for a litle light, be ok,... but most want more, and definitly not 10-20hrs charge time,
just because you can use USB. now firewire, now we are talking a possiblity.


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## lidarman (Jan 12, 2004)

mtb_robs-x said:


> the 3.7V , would not work, since the circuit usually is down convert, as such, needs higher voltage,... the 3.7V is nominal, it can get down to 2.5V ....
> let's assume , do get the 3.7V battery,... 4.4ah x 2 is 8.8ah, , 32whr,
> usb gets you 2.5W,... so it be 13-16 hrs charge time, do you like it ?
> the circuit needs to work harder, bringing voltage up, where it needs to be,
> ...


What are you talking about?

There are plenty of circuits that do this perfectly well. It's not magic.

Yes, the reason electric vehicles use higher voltage is to get the necessary power while keeping the current low so that it doesn't need huge diameter wiring and keeps the losses down at high power draw since P_loss ~ I^2*R. But we are talking k-watts with EV.

These lights are NOT operating anywhere close to that regime.

Yes, the nite rider light is a good example of this. You can fast charge it with a special USB supply or slow charge it with your computer.


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## mtb_robs-x (Dec 13, 2009)

well, show me a circuit, that can drive the P7 LED from a single cell ?

it would need to step-up the voltage, since the battery can and will drop,
need to be able to do 2.5 to 3A+, and now you need 4cells in parrallel matched.
doable , but not practical, not for a magicshine 9W, more like for a 3W light, then ok.
but most don't want a 3w light, nor a newt, what can do it.
not to mention, it's less efficient, and cost more. ehm, longer charge time too.

battery wise, it will stay multi cell, even high power LED's are moving multi,
with exeption of lumileds, as such, they are less efficient, circuit is less efficient, cost more too. even high power flashlights have multi cells, since they run into problems,...


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## gmcttr (Oct 7, 2006)

Huh? There are many single 18650 P7 flashlights.


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## mtb_robs-x (Dec 13, 2009)

*ok , give in*

ok, they are few single cell P7 flashlights, still not the norm
because,
- less efficient
- too much load on battery, burn them up
- fading light, with voltage drop from battery, or at least fluctuation
- very limited runtime, due single cell,
- additional heat from battery current

don't disagree, that its not possible,
but as of now, you won't see any decent higher power light, designed around a single cell battery, with all the problems and limitations. that's just common sense.

I'am working on battery power, so for a dual 9w light, aka magicshine, 2x 32w, 62whr,
would be 8p cell 16ahr+ , the light needs right now 5.4V+, so would need additional circuit, / cost, 18% less efficient, cells need to be matched, at 8p gets more dangerous, especially with li-ion, and there are no chargers for that, safty issues too.
even if I want to, would not be able to build something usable , safe , and affordable.
hmm, would take more than 32 hours to charge the battery on USB, definitly wrong direction, I want less than 1hr if possible.
thanks for the input, gotta hit the hey now.


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## pimpbot (Dec 31, 2003)

*I might ask...*



Tinier said:


> Just curious, because I have access to 12V lithium packs.. Anybody?


... uh, why? You get 3+ hours on high, 6 hours on low. Is that not enough for you? Maybe two batteries?


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## mtb_robs-x (Dec 13, 2009)

*why not, reuse*

beeing able to reuse, existing battery, is flexibility.

...
- reuse battery , think green, 
- reuse chargerink 
- faster charging
- better quality
- backup
- different capacity, larger, smaller
- different packaging, waterproof rugged
- mixing, existing/differenti lights

maybe we could compile a list of different batteries, that can be used,...
- RC 7.2V nimh could be used, (need to measure it)

did measure the adapter, going from 14.8V down ,
back of light, stays red,
looks like 13% lost efficiency,
it gets warm, need to test run it, to see, if it needs another heatsink.
need to try running 2x lights, to see if it can handle it.
try a different circuit, now it gets larger,...
------
update:
the cheaper circuit works for 1 light, gets hot
the more expensive circuit , works for 2 lights, needs heatsink, works great, but is larger
so now I can use any battery with larger voltage, and larger capacity, means longer runtime,
other workaround, be getting a expensive lupine battery, to do so. 
but this opens up the possiblity to run the light, from
- car battery
- truck battery
- military battery
- lipo
- nimh
- laptop
- dc power
- pc psu
- etc


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## Shark (Feb 4, 2006)

mtb_robs-x said:


> beeing able to reuse, existing battery, is flexibility.
> 
> but this opens up the possiblity to run the light, from
> - car battery
> ...


I can't fit a truck battery in my camelback.... 

Flexibility would be nice though, be able to use my existing Jet Lite battery/charger with an LED lighthead would get me alot longer burn times.


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## Tinier (Apr 13, 2006)

pimpbot said:


> ... uh, why? You get 3+ hours on high, 6 hours on low. Is that not enough for you? Maybe two batteries?


Because my 12V lipo pack is smaller and lighter than the magicshine's 4x18650 pack.


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## mtb_robs-x (Dec 13, 2009)

*lipo's don't have protection circuit*

lipo's usually don't have protection circuit,

as such, you'd compromise
- safty of the battery
- safty of you
- spending more, by destroying the pack,
- possible ruining your ride, due failure

on top of that , you need a regulator, what is less efficient, additional cable,
what would negate the weight savings.

currently have a design a circuit, to accomodate that.
the benefits would be, to reuse, existing batteries (lipo) and charger.
cost savings would be negative, aka, not cheaper, so for most people not interested.
on the same line, availability and reuse is still a valuabe thing.

that's why those batteries from power tools, seam so interesting.
not that they are cheaper, in contrary, but 95% of the time, they be used in the tools,
and 5% on the bike, utilizing the existing charger, so no new single use charger needed,
and getting an extra battery, even if it is 2-3 times the cost, seams valuable, especially 
because it's available ,.... aka run into home depot, and just get one .

RC batteries reuse,... 7.2V NiMh be the first pick, probably double the weight,
and poor cold weather performance, than again availability/reusability is key...
not just for the guy who is cheap, don't want to spend any money, 
but in principle, for the green thinking ones, who don't want another wallwart in the house,
and for the ones, who don't want a special item, where the have to jump through hoops,
to get a replacement, and rather be able to walk into a local store, and get it done.

this is part of my vendetta of trying to design a new standard mtb/bike light, 
and as you can see more than half of it, is the battery juice.

appriciate feedback / critique / applause



Tinier said:


> Because my 12V lipo pack is smaller and lighter than the magicshine's 4x18650 pack.


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