Help with my p7 3d mag

Hi, I'm a newb. I tried Stefan's p7 mod for my 3d maglite.

I took my 3d maglite, installed H22a's heatsink with arctica alumina epoxy to a CSXOI P7 LED. Then I wired up Stefan's amc 7135 1 amp multimode driver and the 1.4 amp slave board. So that should be 2.4 amps.

It turns on, and I have all the modes, but when I tested the mA at the tail cap...I am only drawing 1 mA. Not 2.4 mA; only 1 mA.

It's running on new alkaline D cells. Is that the problem? or did I screw up the wiring? Does anyone know what the mA should be with alks using stefan's mod?

I'm planning on buying nimh but I want to make sure there is no problem other then the alkaline batteries. If I get nimh D cells will the mA increase upto 2.4 amps from the 1 amp with alks?

You'll need 4 NiMhs, 3 is not enough for 7xAMC7135s. https://www.candlepowerforums.com/posts/2534867#post2534867

I read stefan's thread and he was discussing 3 vs 4 nimh batts with the amc 7135 boards. He said that they were good upto 4.5 volts and that 4 nimh would be outside the edge of the boards thermal management capapbilities. 3 nimh or 1 LiON was what he recommended.

It seems like 3 nimh for 3.6 volts is a little low, but 4 nimh at 4.8 is a little hot.

I've got two 3 d's so I think I'll stick with 3 for now, but thanks for the tip.

I think it's just the alkaline cells. It draws (on high) 1 amp with 3 alks D's. It goes up to 1.65 amps with 4, then 2.15 amps with 5 alk d cells.

Are you sure it's mA(Milliamp)? Because that would be pretty dim. I'm guessing you mean 1 A(or amp).

Alkaline batteries have a much higher internal resistance then rechargeable batteries so they won't supply as much current as rechargeable batteries.

CaneZMD said:

I read stefan's thread and he was discussing 3 vs 4 nimh batts with the amc 7135 boards. He said that they were good upto 4.5 volts and that 4 nimh would be outside the edge of the boards thermal management capapbilities. 3 nimh or 1 LiON was what he recommended.

It seems like 3 nimh for 3.6 volts is a little low, but 4 nimh at 4.8 is a little hot.

I've got two 3 d's so I think I'll stick with 3 for now, but thanks for the tip.

I think it's just the alkaline cells. It draws (on high) 1 amp with 3 alks D's. It goes up to 1.65 amps with 4, then 2.15 amps with 5 alk d cells.

Click to expand...

I haven't looked at Stefan's boards, but in general the AMC7155's are good up to 6 volts, however, around 4.5 they start getting hot. However I am running a ssc p4 led from 4 C cell rechargables and no problems so far. I did "pot" the board in thermal epoxy and glue it to the heatsink, so that may be helping a little, but probably not much as I am not making good contact to the metal directly.

You will not be able to achieve the brightness you want with alkalines, I suggest you pick up some nimh cells, perhaps the accupower C's, they are quite reasonable. Or your other option would be one C or D size Li-on and a spacer.

I don't know if you are aware of it or not, but you can fit the c's in your 3D mag, you just need to mod the spring and de-annodize or scuff up the inside of the tailcap.

If measuring current from the batteries, it won't tell you exactly what the led is pulling, but it can give you a rough idea, and that is certainly too low.

darkzero said:

You'll need 4 NiMhs, 3 is not enough for 7xAMC7135s. https://www.candlepowerforums.com/posts/2534867#post2534867

Click to expand...

yeah i noticed that each time AMC 7135 is added the input voltage requirement to maintain n*350ma seems to increase as well.

I had 3x7135 driver pushing 950ma to LED with single 18650,by adding fourth AMC 7135 will decrease output to 600mathinking. I have to increase the voltase by about 1v to get ~1.4A result.

darkzero said:

You'll need 4 NiMhs, 3 is not enough for 7xAMC7135s. https://www.candlepowerforums.com/posts/2534867#post2534867

Click to expand...

Are you referring to a sandwich of seven amc7135 boards? I'm running stefan's setup with a single 1.4 amp amc 7135 multimode board and a 1 amp slave board. So a total of two boards.

I ordered 3 10,000 mah nimh D cells so I'll see how that works.

It seems like the best way to drive this p7 is going to be either a 4 d or 4 c maglite with nimh; or a 1 d setup with a li ion.

If you get 1A (1000 mA) instead of the desired 2.4A with your setup mentioned here something is wrong with the driver sandwich. I just checked my remaining 3D Maglites that are driven at 3A. Battery draw with three small and insufficient AA eneloop cells are 2.2A on high with both lights. I have the numbers from my 2.4A 3D Mag (it's sold so I can't recheck them) and I got ~2.3A with AA eneloop and ~2.45A with three 9000mAh NiMH D-cells. Regulation was good with three D NiMH and half decent with three eneloop. Even with three alkaline cells you should get close to 2A.

Stefan