buckpack

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tharg

tharg

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i just put together a 3 q5 in sireas setup. using a 1000ml buckpack driver. for a dive light. so my question is will a 12v 5000ml battery pack run this setup. if i am right the etmitters will take 11.1v. so if the battery starts losing charge will the volts drop down below 11.1 v . i don;t know alot about dc power so the help would be great.
 
Hi - welcome to CPF.

The buck puck is a nice driver and very convenient to control with 1 switch - I have some myself (along with drivers from taskled, etc)

http://www.ledsupply.com/buckpuck.php

Almost all buck type drivers need the battery pack voltage to remain about 2 volts higher than the LED Vf, at least on paper. With 3 Cree's in series, you are somewhere near 3 x 3.5 ish = 10.5 - 11.5 volts LED Vf.

To be certain without testing, you would need to add 2 volts to this, so about 13 volts at the battery.

How exactly is your 12V, 5,000 pack made up ? Is it made from 8 NiMH cells in series ?

Take care,

Harry
 
For situations like this where V(LED) is very close to V(batt), I think the following options are the best:


  1. Run your LEDs directly from the battery with a small resistor (google for "LED calculator"). It may provide superior runtime at the expense of consistent output.
  2. Use Buck/Boost circuit (2 MicroPuck drivers from ledsupply). This will give consistent output you are looking for, but typically they are less efficient resulting in shorter runtimes.
 
Last edited:
odessit said:
For situations like this where V(LED) is very close to V(batt), I think the following options are the best:


  1. Run your LEDs directly from the battery with a small resistor (google for "LED calculator"). It may provide superior runtime at the expense of consistent output.
Click to expand...

LOL - It is funny that it is usually me promoting using a resistor - and for once I decided not to. :wave:

I think the micropucks will not handle the 12 volt battery pack setup he has, even in the special buck / boost configuration, at least from the pdf info this seems to be 7 volts max - I think.
 
tharg said:
i just put together a 3 q5 in sireas setup. using a 1000ml buckpack driver. for a dive light. so my question is will a 12v 5000ml battery pack run this setup. if i am right the etmitters will take 11.1v. so if the battery starts losing charge will the volts drop down below 11.1 v . i don;t know alot about dc power so the help would be great.
Click to expand...

I have used the 3021 for over a year with several units. It will work fine.
Runtime with a PS 1229 12 volt 2.9 hour battery has given me over 5 hours of use.

I have one that uses two Duracell 9 volt batteries and have used it over an hour.

The 3021 works with voltage from 5 volts to 32 volts.
 
Hallmc - So, do you think that the spec sheet is being too conservative ?

That would be great if we could use that driver with a narrow Vbat - Vf. I have this driver in the drawer already, I just never tried it in a 12V bat and 3S LED setup.
 
HarryN said:
Hallmcc - So, do you think that the spec sheet is being too conservative ?
Click to expand...

The truth is I am not an expert and am only here to learn. I would have to say the spec sheet is probably accurate or real close. As to the requirement for 2 volts over required vf, for best results it may accurate. I have not had an issue and am not qualified to dispute it.

I can tell you I have 4 of them working with that set up. To date I have converted three Dive-Rite Wreck lights to Tri-Cree Q5's. All three are running at full output which is actually 1100ml, 100% plus 10% using the external trim pot. All three are using the factory 12 volt 2.9ah battery. One is right at a year old, one at 11 months and one at 5 months plus.

I have a 3 C mags running Quad R2's powered using the 3021 at 110% with two 9 volt Duracell's. The usable light output exceeded my desires and needs as far as run times. I am still shocked how long they will run until they become to dim to use.

My post is to let you know my actual experience with the product. I have found that the posters on this board know their stuff. If they suggest something else there is a good reason why.
 
thanks for the input. and yes the battery is 10 c cells in seris. thanks agian
 
the 12v 5amp well run 4 hours.before it starts dropping off .but with still plenty of light. sence this is a dive light thats plenty. thanks for the help
 
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