Upgrade a Mag85

[eyeeatingfish]

I dont want to make a mag 85, i want to make my mag 85 into something better. When i first made my light i didnt want to use lithium batteries because of the dangers. Now with the more safe PCB lithiums i am wondering if i could go back and make soemthing better. Its a fine light as is but the Nimh batteries dont keep a good charge past... 4 months i think and I use this for duty and recharging the light is kind of a hastle. Lithiums would be more convenient and could get a lot more juice going. 6x3.7v would be a nice...21 volts or so. Is this possible or do the PCBs pose a problem? I never understood whether the PCBs limited the voltage or not, or exactly how it worked to have 2 or more PCB lithium batteries together.

 

[VegasF6]

The thing with the most common lithiums most of us are using (ones with PCB protection) is they don't limit voltage, they limit current, or amperage through the cell. I guess it is only safe to pull about twice the rated capacity through the battery at once. So, if you have 1, or 2, or however many batteries stacked together in series, you can still only pull about that same amount of current at once. In addition, the quality of that PCB depends on the maker of the battery.

So, if you are using for instance an ultrafire 18650 rated at 2400 mAh, you could theoriticly draw 4.8 amps at once. A 6 volt bulb * 4.8 amps = 28.8 watts. But, there is more to consider. When we overdrive the bulbs at higher voltages, the effective wattage is also raised, hence the current used is higher as well. In addition, the ultrafire being a "budget" cell odds are the PCB is going to be of lower quality and just not allow that amount of current out. And, the way they work, they seem to limit it even more so from a sudden rush of power going through them, I guess because to the PCB it appears to be a possible short circuit. So, you see people talking about "soft starts" and "NTC's" and such, because they allow a gentler start on the batteries, less voltage to begin with that ramps up. (I don't know exactly how long, but I am thinking less than a second) There are other reason's they work as well, having to do with heat generated and the resistance caused by that heat, thereby actually allowing less current to pass. So you see people talking about a light that may not start on the first click starting after 3 or 4 clicks.

Now in the case of safe lithium cells, the lower voltage ones, there is no protection circuit so you don't have those same problems. But, even with the safe chemistry cells you should still follow the 2C rule for the sake of the battery itself. If you don't, it isn't as dangerous because if a safe chemistry cell vents, it doesn't vent with flames and cause your light to explode and vent poison fumes. But, you still run the risk of venting.

Now in the case of other types of cells, the emolis, and A123's, those rules don't apply. They are perfectly safe to use at very high current levels, I don't know the exact specs, but over 40C in a lot of cases, probably more. In fact, they are designed for it.

So, in the case of very high voltage cells, like the 6x3.7 volt setups you are talking about, you would have to find a bulb that is high voltage, but low wattage, and no examples come to mind for me except HID's. Or, use emoli cells or A123's. Or, you could use 6 cells but in series parralel configuration. So for instance, you have 6 cells, but only 2 of them in series. Now you have doubled your voltage, to 7.4 volts. But, because you have 2 stacks of 3, you have tripled your capacity from 2400 mAh's to 7200 mAh's.

Those are the basics of the batteries, but to get answers from someone who REALLY nows what they are talking about, unlike me, you might be better off posting in the battery forum. As for a light choice, best off finding a combination someone has already made and following there recipe exactly. One light you may enjoy reading about is the mag623. Apparently it is quite a step up from the mag85.

 

[eyeeatingfish]

Thanks for all the info, yeah i though the lithiums might pose a problem. Didnt give the high voltage/amperage going through the chemicals a thought. I guess im just looking for other options. wondering if some other better bulb has come out too. The reason is that with some new lights like... the lumapower MVP and possibilities for the P7, the 800 some odd lumens out of a Mag85 just isnt all that amazing anymore.

The thing with the most common lithiums most of us are using (ones with PCB protection) is they don't limit voltage, they limit current, or amperage through the cell. I guess it is only safe to pull about twice the rated capacity through the battery at once. So, if you have 1, or 2, or however many batteries stacked together in series, you can still only pull about that same amount of current at once. In addition, the quality of that PCB depends on the maker of the battery.

So, if you are using for instance an ultrafire 18650 rated at 2400 mAh, you could theoriticly draw 4.8 amps at once. A 6 volt bulb * 4.8 amps = 28.8 watts. But, there is more to consider. When we overdrive the bulbs at higher voltages, the effective wattage is also raised, hence the current used is higher as well. In addition, the ultrafire being a "budget" cell odds are the PCB is going to be of lower quality and just not allow that amount of current out. And, the way they work, they seem to limit it even more so from a sudden rush of power going through them, I guess because to the PCB it appears to be a possible short circuit. So, you see people talking about "soft starts" and "NTC's" and such, because they allow a gentler start on the batteries, less voltage to begin with that ramps up. (I don't know exactly how long, but I am thinking less than a second) There are other reason's they work as well, having to do with heat generated and the resistance caused by that heat, thereby actually allowing less current to pass. So you see people talking about a light that may not start on the first click starting after 3 or 4 clicks.

Now in the case of safe lithium cells, the lower voltage ones, there is no protection circuit so you don't have those same problems. But, even with the safe chemistry cells you should still follow the 2C rule for the sake of the battery itself. If you don't, it isn't as dangerous because if a safe chemistry cell vents, it doesn't vent with flames and cause your light to explode and vent poison fumes. But, you still run the risk of venting.

Now in the case of other types of cells, the emolis, and A123's, those rules don't apply. They are perfectly safe to use at very high current levels, I don't know the exact specs, but over 40C in a lot of cases, probably more. In fact, they are designed for it.

So, in the case of very high voltage cells, like the 6x3.7 volt setups you are talking about, you would have to find a bulb that is high voltage, but low wattage, and no examples come to mind for me except HID's. Or, use emoli cells or A123's. Or, you could use 6 cells but in series parralel configuration. So for instance, you have 6 cells, but only 2 of them in series. Now you have doubled your voltage, to 7.4 volts. But, because you have 2 stacks of 3, you have tripled your capacity from 2400 mAh's to 7200 mAh's.

Those are the basics of the batteries, but to get answers from someone who REALLY nows what they are talking about, unlike me, you might be better off posting in the battery forum. As for a light choice, best off finding a combination someone has already made and following there recipe exactly. One light you may enjoy reading about is the mag623. Apparently it is quite a step up from the mag85.

 

[VegasF6]

It's not that it can't be done, you just need to be aware of certain safety stuff in advance

The plus's of the lithiums are they hold their voltage quite well under load, very little self discharge, they are light, and dollar for dollar and volt for volt they are pretty reasonable.

According to luxluthors destructive tests, at 10.8V the 1185 should give 1100-1200 bulb lumens. I know mine running on 9 eneloops is my brightest light, out flooding and out throwing my P7's. But, I would love to see a well driven D bin P7. Maybe soon

Have you read up on the mag 35 on 8 cells? Rather on old build now, but a 6V bulb overdriven that high sound interesting and the bulbs are less than 5 bucks apiece It is a 35 watt bulb driven to nearly 70 watts, should be interesting.

Here is a link that recently surfaced again:
http://candlepowerforums.com/vb/showthread.php?t=107571&highlight=mag35-8

Otherwise, I guess there is always HID or a 6 emitter R2 build.

 

[eyeeatingfish]

I dont have a 6D maglight though. I havent done a bypass on the switch to reduce the resistance but i could do that to get a few more lumens.
The 3xQ5 thing from terralux just looks like such an easy drop in compared to all the work. Probably still doesnt throw as far though.
I would love to get into LED modding but im rather dumb when it comes to electronics like that. Plus when i tried to upgrade a streamlight TL-2 i just ended up destroying the whole thing. Ironically streamlight replaced it for free... go figure.

It's not that it can't be done, you just need to be aware of certain safety stuff in advance
The plus's of the lithiums are they hold their voltage quite well under load, very little self discharge, they are light, and dollar for dollar and volt for volt they are pretty reasonable.
According to luxluthors destructive tests, at 10.8V the 1185 should give 1100-1200 bulb lumens. I know mine running on 9 eneloops is my brightest light, out flooding and out throwing my P7's. But, I would love to see a well driven D bin P7. Maybe soon
Have you read up on the mag 35 on 8 cells? Rather on old build now, but a 6V bulb overdriven that high sound interesting and the bulbs are less than 5 bucks apiece It is a 35 watt bulb driven to nearly 70 watts, should be interesting.
Here is a link that recently surfaced again:
http://candlepowerforums.com/vb/showthread.php?t=107571&highlight=mag35-8

Otherwise, I guess there is always HID or a 6 emitter R2 build.

 

[mudman cj]

Well, I know what you mean about the loss of amazement over a light that only puts out less than 1000 lumens. :devil: But especially for a duty light you have to weight that against size, weight and runtime. It's hard to beat the 1185 bulb overall in these categories. However, you could certainly get more runtime and even a smaller size with the 1185 by switching to AW Li-ion C cells. They fit in an extended 3C or a cut down 4C (or you could use a spacer instead of cutting it down) and provide about 50 minutes of light. Less runtime than that gets into the realm of questionable practicality IMHO. And you could use your 3D host that you already have as well (with appropriate spacer), I just prefer the smaller size and weight of the C bodies.

For improved throw you could look into Fivemega's alternative reflector options such as the 2" deep version and various larger diameter ones that require replacing the head as well. These cells should be charged one at a time or in parallel or in series with balance taps controlled by a balancing charger. Do not charge them as a series pack.

The reason I recommend C cells instead of D cells is because D cells cross the threshold for instaflashing the 1185 without soft starting. Also, there are still no protected D cells of a quality that I feel comfortable recommending. A cheaper option is using 3 protected 18650 cells (again, I recommend AW cells) in a 4C host to make a great 1185 with just over 30 minutes of runtime.

If you really want brighter than the 1185, then I suggest stating another requirement such as maximum size or minimum runtime to help narrow the field of candidates.

 

[VegasF6]

You don't have to have a 6D for the mag 35, you can run it on 8AA's + a dummy in your 3d. However, runtime would be pretty bad. I don't think Eneloops would hold up to the draw, you would probably need Elite cells or something designed for high current. Possibly the Titanium Power Max or other cells. But, that is beside the point since I don't think you could get 15 minutes run time in that setup.

People have found some amazing bulbs on this site, but the fact is, incandescent lighting pulls a lot of power and there is no way around it. So, you need a lot of battery. Or, something more efficient.

I really don't know anything about it, but perhaps AW's Incan driver is the answer you are looking for? That way you could have a light with decent runtime, and the power is there if you really need it. You could have a high quality battery pack made by luxluthor, for the most runtime. Might as well build/buy a host with a charging port as well and you will always be ready to go. Now it is getting expensive, but hey, I guess you can drive a Cadillac or a Chevette

 

[eyeeatingfish]

I like the idea of running the 3 Li Ion cells, that way at least there is less self discharge. Is it safe to run the three protected cells through each other? Just for utility id rather run the batteries seperate than in a battery pack, that way i can run other items if i need to. For example i used the AAs in my mag85 to run a digital camera one time. If they were 18650s then i could use it in my MRV.
I use the Mag85 as a extra light in my car when i really need to search beaches or in an ify situation where a badguy might need to get a quick strike.

Well, I know what you mean about the loss of amazement over a light that only puts out less than 1000 lumens. :devil: But especially for a duty light you have to weight that against size, weight and runtime. It's hard to beat the 1185 bulb overall in these categories. However, you could certainly get more runtime and even a smaller size with the 1185 by switching to AW Li-ion C cells. They fit in an extended 3C or a cut down 4C (or you could use a spacer instead of cutting it down) and provide about 50 minutes of light. Less runtime than that gets into the realm of questionable practicality IMHO. And you could use your 3D host that you already have as well (with appropriate spacer), I just prefer the smaller size and weight of the C bodies.

For improved throw you could look into Fivemega's alternative reflector options such as the 2" deep version and various larger diameter ones that require replacing the head as well. These cells should be charged one at a time or in parallel or in series with balance taps controlled by a balancing charger. Do not charge them as a series pack.

The reason I recommend C cells instead of D cells is because D cells cross the threshold for instaflashing the 1185 without soft starting. Also, there are still no protected D cells of a quality that I feel comfortable recommending. A cheaper option is using 3 protected 18650 cells (again, I recommend AW cells) in a 4C host to make a great 1185 with just over 30 minutes of runtime.

If you really want brighter than the 1185, then I suggest stating another requirement such as maximum size or minimum runtime to help narrow the field of candidates.

 

[VegasF6]

Sure, it is safe to run the 3 lion's in series. In fact, even though conventional wisdom had sad so, I still had the same question I posed. It was answered by LuxLuthor in this thread:
http://www.candlepowerforums.com/vb/showthread.php?t=197823

Of course, you want to charge them separately, use quality cells, quality charger, and it is important to keep them in balance. You have a meter, correct? If not, please pick one up, a cheapie will do fine. Check your voltages before running the light and try and get them within .1 or .2 volts of each other. (the closer the better)

So lets say you have a mag85 in a 3D with 3x18650 (which fits great by the way) and you remove one of the cells to run in your MRV for awhile. You wouldn't really want to put that cell back into the series setup before charging everything again. Otherwise the run down cell risks the chance of attempting to reverse charge by the others, and that can lead to venting. I THINK the protection circuit should stop that, as long as it is polarity protected, but it is recomended to follow safe procedures anyways and try not to rely on the PCB as it could fail.

For the mag85 or another hotwire you are surely going to need high quality cells like AW's, and you will need to have a charger with separate charging channels to keep your batteries in balance. (make sure it has 2 leds)

For budget concerns you could probably use a cheaper cell like a Trustfire for your MRV, though many will recomend AW cells for everything. But I can understand being on a budget. Many use the Trustfires and you don't hear about them blowing up every day or anything like that.

In the case of the hotwire you would probably prefer AW C cells anyhow for both better runtime, and the possiblity of a hotter hotwire. You can sustain higher current with the larger cells.

If you have a particular build you want, feel free to post it in this thread. If you still just want to learn more about the batteries I think you are going to be better served posting a new thread in the battery forum and getting the advice of the real experts. I am just regurgitating what I have already learned from the board, but others have done the research and can pass on better information than me.

I look forward to seeing your build whichever you may choose, good luck!
VegasF6

 

[eyeeatingfish]

Thanks for the link, it was very informative. My MRV has an attachment where it can take a second 18650 cell for more runtime and a little more brightness and i was thinking about getting the extender, so i guess I should buy AW batteries if im going to do that, or get the MVP.

I didnt see any mention of a problem of using a larger number like 9 AA size LiIon batteries. Im not sure if i understand exactle how the juice runs throught PCB cells yet. So the voltage of one battery doesnt run through the second one, it runs past it on PCB lights and thats why the battery doesnt have too much juice flowing through it?
The thing about making sure the batteries have a similar charge I dont understand too well. It sounds as if one is a bit lower it will act as if it is being charged by the other batteries or the other batteries will want to charge it or something? Is it not the case that a flashlight will naturally draw energy out of batteries differently? When i charge my mag 85 cells i notie some of the AAs charge quickly as if they aren't all draining at the same exact rate. Cant remember if ive ever gone to measure it yet.
Maybe i should jsut resurect your old thread, or at least link any new thread i make to it.

Thanks for all the info so far, I hope its not a bother.

Sure, it is safe to run the 3 lion's in series. In fact, even though conventional wisdom had sad so, I still had the same question I posed. It was answered by LuxLuthor in this thread:
http://www.candlepowerforums.com/vb/showthread.php?t=197823

Of course, you want to charge them separately, use quality cells, quality charger, and it is important to keep them in balance. You have a meter, correct? If not, please pick one up, a cheapie will do fine. Check your voltages before running the light and try and get them within .1 or .2 volts of each other. (the closer the better)

So lets say you have a mag85 in a 3D with 3x18650 (which fits great by the way) and you remove one of the cells to run in your MRV for awhile. You wouldn't really want to put that cell back into the series setup before charging everything again. Otherwise the run down cell risks the chance of attempting to reverse charge by the others, and that can lead to venting. I THINK the protection circuit should stop that, as long as it is polarity protected, but it is recomended to follow safe procedures anyways and try not to rely on the PCB as it could fail.

For the mag85 or another hotwire you are surely going to need high quality cells like AW's, and you will need to have a charger with separate charging channels to keep your batteries in balance. (make sure it has 2 leds)

For budget concerns you could probably use a cheaper cell like a Trustfire for your MRV, though many will recomend AW cells for everything. But I can understand being on a budget. Many use the Trustfires and you don't hear about them blowing up every day or anything like that.

In the case of the hotwire you would probably prefer AW C cells anyhow for both better runtime, and the possiblity of a hotter hotwire. You can sustain higher current with the larger cells.

If you have a particular build you want, feel free to post it in this thread. If you still just want to learn more about the batteries I think you are going to be better served posting a new thread in the battery forum and getting the advice of the real experts. I am just regurgitating what I have already learned from the board, but others have done the research and can pass on better information than me.

I look forward to seeing your build whichever you may choose, good luck!
VegasF6

 

[germanium]

Thanks for the link, it was very informative. My MRV has an attachment where it can take a second 18650 cell for more runtime and a little more brightness and i was thinking about getting the extender, so i guess I should buy AW batteries if im going to do that, or get the MVP.

I didnt see any mention of a problem of using a larger number like 9 AA size LiIon batteries. Im not sure if i understand exactle how the juice runs throught PCB cells yet. So the voltage of one battery doesnt run through the second one, it runs past it on PCB lights and thats why the battery doesnt have too much juice flowing through it?
The thing about making sure the batteries have a similar charge I dont understand too well. It sounds as if one is a bit lower it will act as if it is being charged by the other batteries or the other batteries will want to charge it or something? Is it not the case that a flashlight will naturally draw energy out of batteries differently? When i charge my mag 85 cells i notie some of the AAs charge quickly as if they aren't all draining at the same exact rate. Cant remember if ive ever gone to measure it yet.
Maybe i should jsut resurect your old thread, or at least link any new thread i make to it.

Thanks for all the info so far, I hope its not a bother.

The main concern with high wattahe incandescants is the very low resistance when cold making for very high turn on currents which may exceed the current limit on protected Li-Ion cells.

The cold resistance is typically 1\100th of the resistance of the operating resistance resulting in huge inrush of current when initially turned on.

Note; incandescants get more efficient with higher voltages, not less, so giving an incandescant more voltage does not increase the current draw but actually reduces it. As a result the power draw goes up only minimally. If you increase the voltage 20% the current draw may go down 10% yeilding a 10% increase in power draw but may yield 40% more light, of coarse not for very long as it will burn out much more quickly.

 

[mudman cj]

In response to germanium's comments:
Not exactly.

Increased efficiency at higher power levels comes from the fact that as the filament gets hotter, it emits more light in the visible spectrum and less in infrared, which is invisible to us and therefore not counted towards efficiency calculations.

The resistance of a metallic filament still increases with increasing temperature, and increasing the voltage across a metallic filament will always result in an increased current draw according to V=I*R. Current will not decrease with increasing applied voltage.

eyeeatingfish:
The current does flow through all of the batteries equally when they are in series. Each cell in series just adds more 'push' to the current, which is voltage or potential. If one cell is at a lower potential than the others, it could be depleted before the other ones. But it won't magically stop discharging before damage can occur unless it has a protection circuit. It will continue to discharge even past 0V and can develop a negative voltage because all of the other cells in series are still pushing current that direction. It is a bad idea to run Li-ion cells in series without some sort of protection circuit to prevent this.

 

[M@elstrom]

I think what germanium is hinting at is the higher voltage spec globes can run @ less Amps than the equivalent lower V rated unit

ie. 20w 12v = 1.66A Vs. 20w 6v = 3.33A


Thus a 12v configuration will provide a significantly longer (more efficient) runtime from the same type of capacity cell (ie. 2500mAh multi's)

 

[mudman cj]

Thanks for offering another interpretation. I may have misinterpreted what was being said, but the last statement, "of coarse not for very long as it will burn out much more quickly" still makes me think he meant for a given bulb. Regardless, you do bring up a good point worth considering when designing a hotwire, especially since higher currents are harder on switches and can limit the use of protected Li-ion cells.

 

[germanium]

It is this very point that protects the filiment from burning out instantly. As the filiment gets hotter it's resistance goes up until an equalibrium is reached where the resistance reaches the point where current voltage can no longer increase the current. To what degree the resistance goes up if you go past normal operating voltage I would have to measure it & I don't have the means right now to do so. I may have made a mistake to say it actually goes down but rest assured it can not go up much if any with voltage.

I have burned out solenoid relays on headlights on some cars I've had in the past due to leaving the lights on & having the battery get low. these were 30 amp relays feeding bulbs that totaled 9.16 total amps at normal voltage due to the excessve current that occures as voltage goes down.