Tests done on new driver board for P7

[Drewfus2101]

So I had tried before to wire two of the DX sku 3256 boards together before, and I knew that they would work together that way, so I figured why not try it with a P7.

I've got quite a few laying around, so I grabbed three and spent some time wiring them together. Then just jumpered them to a P7 through a testbed with two multimeters on it so I could get some numbers. Here is what I found:

I'm pretty happy with the results. I think 3 of these boards would work great with 2 x lithium ion batteries. Even with 18650s you would get 2 full hours of runtime.

I plan on using 4 of these boards with my 4 x NiMH build. I can post the same tests on those boards when I get that built. Four should work well in the 5.2V-4.4V range and still give me close to 3.0A output current.

 

[freedom2000]

Hi,

Thanks Drewfus.:thumbsup:

Very interesting results as the P7 could be used to its full power with a 2*18650 configuration.

2 questions for me :
- do you think it could fit into a classical flashlight like this one ?
- how did you wire the 3 boards ? Simply // wiring of the outputs ?

Another thought : with 2 LiIon config all the classical drivers are in "linear configuration" when Vbat> Vf.
How does this driver react ? What is the use of the coil in this "high voltage" configuration ?

Wouldn't it be better to use a 8 AMC7135 config ?
I know that this driver is limited to 6V input voltage... So I am thinking to use an "hybrid" batteries configuration to power it "just above Vf + 0.6V".
I did it for a Cree Q5 and it works really well in high efficiency zone (see here for description and safety warnings)

JP

 

[freedom2000]

I plan on using 4 of these boards with my 4 x NiMH build. I can post the same tests on those boards when I get that built. Four should work well in the 5.2V-4.4V range and still give me close to 3.0A output current.

HI again !

With 4 Nimh you are in the "ideal" configuration for AMC boards.
4 NImh = 4.8V to 6V max --> perfect for the AMC7135 driver AND the µcontroller.
You could use :
- either 2 * 4AMC71635 boards
- or one 4AMC board + one 3AMC+µcontroler board

With the first config you could get real 2.8 A but no modes
with the second one "only" 2.45A AND modes and memory

The only drawback is that we would need to buy 10 pieces of this 4AMC boards... I think that I will do it --> if you are tempted I could share half with you :welcome:

JP

 

[Drewfus2101]

HI again !

With 4 Nimh you are in the "ideal" configuration for AMC boards.
4 NImh = 4.8V to 6V max --> perfect for the AMC7135 driver AND the µcontroller.
You could use :
- either 2 * 4AMC71635 boards
- or one 4AMC board + one 3AMC+µcontroler board

With the first config you could get real 2.8 A but no modes
with the second one "only" 2.45A AND modes and memory

The only drawback is that we would need to buy 10 pieces of this 4AMC boards... I think that I will do it --> if you are tempted I could share half with you :welcome:

JP

I have done a P7 build with those boards, and done quite a bit of testing on the 1400mA, 1050mA and 350mA versions. They're efficiencies are pretty low when you are not exactly at they're Vf+0.6V range, which is impossible to stay at with any battery setup.

From 5.2-4.8V, the 1400mA AMC boards (just for comparison) have a tested efficiency of between 73% and 80%. This board was between 87% and 88%. That means longer runtime. These won't get as hot as the AMCs will also. Those have to burn off the extra power, unlike these which actually convert it.

With my example of 4 x NiMH batteries, with the AMC boards, my current build actually pulls more like 2.6A. So with D size Tenergy batteries with a capacity of 10A, that comes to a runtime of around 3.85 hours. Although it will vary as the driver will output current will sag as it heats up.

With the 4 x DX3256 boards, and 4 x NiMHs, D size Tenergy, at full charge the voltage registered 5.2V. I did some calculations based on test efficiencies. That means the input current would start at 2.44A, giving me a runtime of 4.1 hours. And runtime won't vary at all with these boards like it will with the AMC boards. And this is with a full 3.0A output.

It is all about efficiency, thats why I prefer these boards. And being constant current regulated boost/buck boards. Not linear regulated boards (fancy resistors) like the AMCs.

Thanks for the offer, but I've got a ton of the different AMC boards. I ordered the 1400mA version, and you can just remove the chips to drop the output current down to the 1050mA, 750mA or 350mA level. And I'm not new to CPF

 

[Drewfus2101]

Hi,

Thanks Drewfus.:thumbsup:

Very interesting results as the P7 could be used to its full power with a 2*18650 configuration.

2 questions for me :
- do you think it could fit into a classical flashlight like this one ?
- how did you wire the 3 boards ? Simply // wiring of the outputs ?

Another thought : with 2 LiIon config all the classical drivers are in "linear configuration" when Vbat> Vf.
How does this driver react ? What is the use of the coil in this "high voltage" configuration ?

Wouldn't it be better to use a 8 AMC7135 config ?
I know that this driver is limited to 6V input voltage... So I am thinking to use an "hybrid" batteries configuration to power it "just above Vf + 0.6V".
I did it for a Cree Q5 and it works really well in high efficiency zone (see here for description and safety warnings)

JP

I don't see why they wouldn't fit into a regular style flashlight. They are small enough. I assume you are asking because you want to know if that light is regulated or if it just has a resistor to dull down the extra voltage. I think it is safe to assume that it will be regulated.

Yes, all I did was wire the outputs in parallel.

You lose me with linear configuration. I don't think I've ever heard that before, or coil. No it is not better to use the AMCs, check the post above this. Its all about efficiency. It might be better if your using a single lithium-ion, but thats about it. I know all about those boards:
http://www.candlepowerforums.com/vb/showthread.php?t=192925

 

[freedom2000]

It is all about efficiency, thats why I prefer these boards. And being constant current regulated boost/buck boards. Not linear regulated boards (fancy resistors) like the AMCs.

Thanks for the offer, but I've got a ton of the different AMC boards. I ordered the 1400mA version, and you can just remove the chips to drop the output current down to the 1050mA, 750mA or 350mA level. And I'm not new to CPF

Hi again,
Thanks for this comprehensive answer. You are right, efficiency and constant current are the most important parameters for a driver.

For the moment I haven't bought the 4 AMC board. And BTW, if you have a few to sell... I would be ready to buy one ...

Please don't be offended by the smiley. It was only for me a sign to express that I really like this forum.
And frankly speaking when reviewing all your detailled posts I would never dare to consider that you are a newsbie :wave:

JP

 

[freedom2000]

I don't see why they wouldn't fit into a regular style flashlight. They are small enough. I assume you are asking because you want to know if that light is regulated or if it just has a resistor to dull down the extra voltage. I think it is safe to assume that it will be regulated.

Yes it seems to be regulated but the first review shows that it has a very poor regulation... see here. As I have ordered this flashlight it meens that I will have to change the driver to get the full power of the P7 led.

Thanks again for your posts.
You are right the config you use will give 88.7% effciency at 4.8V compared to 80% with the AMC board... So it is better (but with no modes ?)

JP

 

[Drewfus2101]

Yes it seems to be regulated but the first review shows that it has a very poor regulation... see here. As I have ordered this flashlight it meens that I will have to change the driver to get the full power of the P7 led.

Thanks again for your posts.
You are right the config you use will give 88.7% effciency at 4.8V compared to 80% with the AMC board... So it is better (but with no modes ?)

JP

Wow, those are pretty pathetic results for that light. Those don't make any sense at all. I had a lot of hope for that light. And I hate modes.