wildstar87
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So is this module safe to use for a 6V input? The description says it doesn't want more than 4.5v, but it looks like from the datasheet for the chip, and the posts here that it could do 6v ok?
DealExtreme AMC7135 1050mA new design
- Thread starter JuanMijangos
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TorchBoy
Flashlight Enthusiast
Link please.
From memory DX's description for the similar board but with the 5 mode controller on it says 4.5V, while KD's description of that 5 mode board says 6V. But any description for this board, with no 5 mode controller, should say 6V.
wildstar87
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This is the one I saw the 4.5v limit on. It's using the same controller, it seems it would support the same voltage limit, other than the 5-mode stuff..
http://www.dealextreme.com/details.dx/sku.6190
http://www.dealextreme.com/details.dx/sku.6190
TorchBoy
Flashlight Enthusiast
If you want a 5 mode board, it's rather similar to http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2958 wouldn't you say? "Operates from 2.6V to 6V" and as a bonus it's in stock.
wildstar87
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So I got my one driver the other day from KD, he shorted me one am still waiting for him to reply, but I digress.
I soldered the output wires exactly as pictured, on the Q3, and the D1+
I'm assuming that on the flip side, the big gold circle is the + and the ring around the outside is negative.
From reading the posts, it looks like the circuit is actually regulating on the negative? I guess I'm used to ground always being connected. So when I use a continuity tester, I'm getting continuity on the positive (since those are all shared), but not on the negative, but that sounds correct, right?
As far as the diode that people have been talking about, which piece would I need to remove on the circuit board? I'm guessing the "chip" at D1, or C1? As pictured in post #11 on the 1st page of the thread.. :thinking:
I soldered the output wires exactly as pictured, on the Q3, and the D1+
I'm assuming that on the flip side, the big gold circle is the + and the ring around the outside is negative.
From reading the posts, it looks like the circuit is actually regulating on the negative? I guess I'm used to ground always being connected. So when I use a continuity tester, I'm getting continuity on the positive (since those are all shared), but not on the negative, but that sounds correct, right?
As far as the diode that people have been talking about, which piece would I need to remove on the circuit board? I'm guessing the "chip" at D1, or C1? As pictured in post #11 on the 1st page of the thread.. :thinking:
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TorchBoy
Flashlight Enthusiast
Yes.
TorchBoy
Flashlight Enthusiast
Yes. Have you had a look at the spec sheet?
You don't want to remove the diode. Do you? There's no point unless you have a very unusual use for it.
D1 would be "diode 1" while C1 would be "capacitor 1".
wildstar87
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Thx Torchboy, I looked at the spec sheet, but I'm no EE so wasn't sure exactly what it was telling me. I'm more used to looking at circuits in cars for connecting up stereos and alarms, or working on PCs.. All the grounds are shared, not positives.. 
As far as the diode was concerned, just wanted to know if I decide to try it out for some reason, that's all.
As far as the diode was concerned, just wanted to know if I decide to try it out for some reason, that's all.
freedom2000
Newly Enlightened
Both the AMC7135 and the µcontroler 12F629 are able to run at 6V.
12F629 datasheet says that max VDD is 6,5 V (page 85)
AMC7135 datasheet says that VDD max is 6V (and 7V absolute max)
So it seems to be safe to use it at 6V max
And my question is :
I would like to test this board with a 14500 battery (3.7V nominal and 4.2V max)
I know that this board has a drop out of 0,12V
To have a pretty good regulation Vin should be more than VF+0.12.
With a Cree Q5 driven at 1A VF = 3.7V (datasheet here see page 7)
So Vin > 3,82 V which is above the typical value for a Li Ion bat....
And the question is... as I have a Utrafire C3 with extension tube I can put into this flashlight 2 AA cells or ... 1AA + 1 LiIon 14500 ...
Do you think that I should dare to mix in the same flaslight a protected LiIon and a 1AA ...
Such a combination could give : 1.2 + 3.7 = 4.9 V which should be in the "high efficiency" zone of the AMC7135 chip (77% and more when the bat will decrease)... see here the curves provided be Drewfus2101.
And 1,5 + 4.2 = 5,7V when both bat are fully charged... a value still less than the max 6 V supported by the board...
My ONLY doubt is this "good idea" which could be dangerous for the LiIon or the NIMh I can imagine that the regulation of the LiIon will cut hte bat when the voltage will drop under 3V... and could prevent to damage the LiIon... But for the NiMh ???
As the driver is also there to limit the current to 1A in the led... what could happen to the two batteries in serie ???
Please confirm that this is safe:wave:... or not :devil:
Thanks
JP
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TorchBoy
Flashlight Enthusiast
3.7V is the nominal operating voltage for 1A, and the actual operating voltage for any particular Cree will vary. I've had Cree P4s as low as 3.3V @ 1A. Pick a Cree to suit, and save the higher voltage ones for projects where a low Vf isn't as important.
Most definitely not. Never mix capacities, and NEVER mix chemistries.
Yep.
freedom2000
Newly Enlightened
Thanks Torchboy for this answer.
I keep the idea of selecting a low VF LED.
However I would like to argue again a bit ... just for the sake of art !
Never mix capacities : this is clearly understandable. If we mix capacities, the result is that we can destroy the weaker cell. BUT in my case, if I choose a high capacity NIMh and the regular 800 mAH Li Ion 14500 with a protection circuit, can we cope that the LiIon will empty first and then trigger the protection at 3V level and then shut the flashlight regulation ?
So a safe situation no ?? (if I am sure that the both cells will be charged when used the first time)
Never mix chemistries : well this was my most important doubt.
However I cannot understand why it is so dangerous as the cells are fully separated and will not mix their internal chemistry... Fot sure the cells will not be paired, the internal resistances will not be the same... But is it really dangerous ???
Basically they will only throw electrons into the circuit...
Please if you have more information why mixing cells in a serie is so dangerous, reply again to this thread :welcome:
In any case, I would of course charge the bats with separate chargers...
JP
I keep the idea of selecting a low VF LED.
However I would like to argue again a bit ... just for the sake of art !
Never mix capacities : this is clearly understandable. If we mix capacities, the result is that we can destroy the weaker cell. BUT in my case, if I choose a high capacity NIMh and the regular 800 mAH Li Ion 14500 with a protection circuit, can we cope that the LiIon will empty first and then trigger the protection at 3V level and then shut the flashlight regulation ?
So a safe situation no ?? (if I am sure that the both cells will be charged when used the first time)
Never mix chemistries : well this was my most important doubt.
However I cannot understand why it is so dangerous as the cells are fully separated and will not mix their internal chemistry... Fot sure the cells will not be paired, the internal resistances will not be the same... But is it really dangerous ???
Basically they will only throw electrons into the circuit...
Please if you have more information why mixing cells in a serie is so dangerous, reply again to this thread :welcome:
In any case, I would of course charge the bats with separate chargers...
JP
TorchBoy
Flashlight Enthusiast
I can't give you an answer about the protection circuit on a Li-ion cell shutting the whole thing down. Someone with more knowledge would have to answer.
Basically, mixing cells in series is dangerous because one could reverse charge the other. Some chemistries just die if this happens (which is a waste of the cell), some leak (which is a waste of the device), some explode (which might be a waste of whoever is nearby).
Basically, mixing cells in series is dangerous because one could reverse charge the other. Some chemistries just die if this happens (which is a waste of the cell), some leak (which is a waste of the device), some explode (which might be a waste of whoever is nearby).
freedom2000
Newly Enlightened
Thanks again TorchBoy,
I can understand that reverse charging can be extremely dangerous. But I am still hoping that the protection circuit of the LiIon will cut the cell when under 3V...
Is there a specialist here who could give me evidence of this danger ?
I really like CPF --> very very interesting forum :thumbsup:
I was a newbie in led stuff one month ago. I have learned so much with this forum. Thanks guys
JP
I can understand that reverse charging can be extremely dangerous. But I am still hoping that the protection circuit of the LiIon will cut the cell when under 3V...
Is there a specialist here who could give me evidence of this danger ?
I really like CPF --> very very interesting forum :thumbsup:
I was a newbie in led stuff one month ago. I have learned so much with this forum. Thanks guys
JP
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freedom2000
Newly Enlightened
Ok, I have searched the net for batteries packs design.
Here is the best link that I have found : batteries pack
The most important thing to respect is to avoid overdischarge (or over charge) of any cell in the pack.
So if I have a working cut off circuit in my 14500 800 mAh cell and if I use a fully charged NiMH of 2000 mAh capacity, I think that I can safely put them in serie to increase voltage. The 14500 cell will cut off at 3V. This will be the signal to recharge each battery independently...
I think that I will test this on a breadboard and with a carefull monitoring of voltage of the batteries... Well I am a curious guy :thinking:
I will keep you informed !
JP
Here is the best link that I have found : batteries pack
The most important thing to respect is to avoid overdischarge (or over charge) of any cell in the pack.
So if I have a working cut off circuit in my 14500 800 mAh cell and if I use a fully charged NiMH of 2000 mAh capacity, I think that I can safely put them in serie to increase voltage. The 14500 cell will cut off at 3V. This will be the signal to recharge each battery independently...
I think that I will test this on a breadboard and with a carefull monitoring of voltage of the batteries... Well I am a curious guy :thinking:
I will keep you informed !
JP
freedom2000
Newly Enlightened
Well,
I have dared to test it...
I have used an old NiCD cell + a very old R/C lipo cell 600mAh... and done the following breadboard test :
- the two batteries are in serie
- AMC7135 is driving a P4 at 1040 mA (measured on the left)
- the lipo voltage decreases slowly (measured on the middle : 3.46V)
- the NiCD voltage is decreasing more quickly (measured on the right : 1V)
In conclusion it seems to work
- The current is constant through both cells and never exceeds 1A.
- The voltage drop is quite fast in the NiCD cell (the Lipo is more efficient than the NiCD).
- The AMC7135 is not warm at all and is really in its best condition to drive efficiently the Cree LED (efficiency = 83% and will increase when the voltage decreases).
BUT. This configuration is obviously not "safe" if you don't monitor carefully the voltage of the cells and don't use a protected Li Ion pack.
The only "safe" config would be to use a very good high capacity NiMh (> 1500 mAh) + a 900mAh LiIon. Charge them to full. Use the packs in serie until the LiIon cutoff is activated. Re charge all cells, and replay
Beware also that if you stock the flashlight during months, the self discharge rate of the NiMh is much higher than the LiIon one... so recharge the cells before using the flashlight.
Use it at your own risk
As soon as I get the 14500 LiIon protected cell I go on testing :wave:
JP
I have dared to test it...
I have used an old NiCD cell + a very old R/C lipo cell 600mAh... and done the following breadboard test :
- the two batteries are in serie
- AMC7135 is driving a P4 at 1040 mA (measured on the left)
- the lipo voltage decreases slowly (measured on the middle : 3.46V)
- the NiCD voltage is decreasing more quickly (measured on the right : 1V)
In conclusion it seems to work
- The current is constant through both cells and never exceeds 1A.
- The voltage drop is quite fast in the NiCD cell (the Lipo is more efficient than the NiCD).
- The AMC7135 is not warm at all and is really in its best condition to drive efficiently the Cree LED (efficiency = 83% and will increase when the voltage decreases).
BUT. This configuration is obviously not "safe" if you don't monitor carefully the voltage of the cells and don't use a protected Li Ion pack.
The only "safe" config would be to use a very good high capacity NiMh (> 1500 mAh) + a 900mAh LiIon. Charge them to full. Use the packs in serie until the LiIon cutoff is activated. Re charge all cells, and replay
Beware also that if you stock the flashlight during months, the self discharge rate of the NiMh is much higher than the LiIon one... so recharge the cells before using the flashlight.
Use it at your own risk
As soon as I get the 14500 LiIon protected cell I go on testing :wave:
JP
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freedom2000
Newly Enlightened
Hi again,
I performed the same test with a good 2000 mAh NIMh
I got the full power with my old Lipo + 1 AA NiMh during 16 min.
I noticed that the voltage of the NiMh was around 1.1V and remained almost stable during the 16 min of discharge.
This has to be compared to the 1.2V on the same NiMh when driving the P4 with AMC driver at 1A with 4 AA.
Is it an effect of internal resistance higher for my NiMh compared to the internal resistance of the LiPo ???
JP
I performed the same test with a good 2000 mAh NIMh
I got the full power with my old Lipo + 1 AA NiMh during 16 min.
I noticed that the voltage of the NiMh was around 1.1V and remained almost stable during the 16 min of discharge.
This has to be compared to the 1.2V on the same NiMh when driving the P4 with AMC driver at 1A with 4 AA.
Is it an effect of internal resistance higher for my NiMh compared to the internal resistance of the LiPo ???
JP
TorchBoy
Flashlight Enthusiast
I've just sent a PM to SilverFox. He has much more experience with Li-ion cells and their protection circuits than I do.
SilverFox
Flashaholic
Hello JP,
As you have discovered, in a series circuit the current from each of the cells is the same. In general, you should never mix chemistries because of the dangers associated with reverse charging, and you should never try to charge a pack made up of mixed chemistry cells.
If I understand your set up correctly, you are adding a 2000 mAh NiMh cell in series with an 900 mAh Li-Ion cell and drawing around 1 amp from them. You plan to charge each cell separately.
If this is correct, then I think you are good to go.
Problems will occur if the NiMh cell becomes completely discharged before the Li-Ion cell. If that happens, the Li-Ion cell will reverse charge the NiMh cell, destroying it.
I would not recommend this combination, but I can see where it would be fun to play with...
Tom
As you have discovered, in a series circuit the current from each of the cells is the same. In general, you should never mix chemistries because of the dangers associated with reverse charging, and you should never try to charge a pack made up of mixed chemistry cells.
If I understand your set up correctly, you are adding a 2000 mAh NiMh cell in series with an 900 mAh Li-Ion cell and drawing around 1 amp from them. You plan to charge each cell separately.
If this is correct, then I think you are good to go.
Problems will occur if the NiMh cell becomes completely discharged before the Li-Ion cell. If that happens, the Li-Ion cell will reverse charge the NiMh cell, destroying it.
I would not recommend this combination, but I can see where it would be fun to play with...
Tom
freedom2000
Newly Enlightened
Hi Tom,
You are right, I plan to draw 1A in the serie until the 900mAh LiIon cut off circuit shuts the light (ie the LiIon is safely empty). Then recharge separately the two cells. I assume that the biggest capacity cell (ie 2000 mAh NIMH) will never empty before the lower one (LI Ion), this must prevent the risk of reverse charging.
BTW, I have already tested the combination and it works well.
My only concern is that the voltage of the NIMh cell when used with the LiIon in serie is 1.1V (when also drawing 1A in the LED)
The same cell put in a serie of 4 NIMH draws 1A in the led but has a voltage of 1.2V...
Can you explain this 0.1V difference on the NiMh in both combinations ?? (same drain current 1A but not same voltage...) ?
Thanks again for your help (and TorchBoy's one also)
JP
You are right, I plan to draw 1A in the serie until the 900mAh LiIon cut off circuit shuts the light (ie the LiIon is safely empty). Then recharge separately the two cells. I assume that the biggest capacity cell (ie 2000 mAh NIMH) will never empty before the lower one (LI Ion), this must prevent the risk of reverse charging.
BTW, I have already tested the combination and it works well.
My only concern is that the voltage of the NIMh cell when used with the LiIon in serie is 1.1V (when also drawing 1A in the LED)
The same cell put in a serie of 4 NIMH draws 1A in the led but has a voltage of 1.2V...
Can you explain this 0.1V difference on the NiMh in both combinations ?? (same drain current 1A but not same voltage...) ?
Thanks again for your help (and TorchBoy's one also)
JP
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SilverFox
Flashaholic
Hello JP,
I believe the difference occurs because of the difference in internal resistance between NiMh and Li-Ion chemistries.
In a series circuit, the current draw will be the same from each cell, so the only way to adjust for differences in internal resistance is with a change in voltage.
I don't work with using multiple chemistries in an application, but I would think that you may see a similar difference in voltage if you apply a 1 amp load to your Li-Ion cell. In this case, you may see the voltage around 0.1 volts lower.
Tom
I believe the difference occurs because of the difference in internal resistance between NiMh and Li-Ion chemistries.
In a series circuit, the current draw will be the same from each cell, so the only way to adjust for differences in internal resistance is with a change in voltage.
I don't work with using multiple chemistries in an application, but I would think that you may see a similar difference in voltage if you apply a 1 amp load to your Li-Ion cell. In this case, you may see the voltage around 0.1 volts lower.
Tom
