Unfortunately I’m doing this all on omg own and with the tips you guys help me on here.
Ive done a new design which is 300x100mm and has a big heatsink in the back.
See photos linked.
I got these drivers from russia. They can run 6-12 volts 4.8 amps so it will be two led in series for every driver. But the seller said that it can burn if i use 12 volts XHP-70 in parallel (2.4 + 2.4 amps).
Should I go option 1 or 2?
Option 1: 2x XHP-70 (12volt) in parallel with 4.8 amps
Option 2: 2x XHP-70 (6 volts) in series with 2.4 amps
I don’t want to use one driver per led. But these are small and seem to what another member her used for his light bar.
I need to order the XHP-70 tonight.
Well, those LDRADJ29s do not seem bad. The seller told you they would burn by driving two in-series XHP70s (12+V) at 4'8A because that driver just cannot handle such a load (60+W), seems to be designed for 30ish watts.
So, you'll need 12 emitters and 6 drivers for efficient 20000 lumens light source, 2 emitters per driver. Wether you set 2 “6V” emitters in series or 2 “12V” in parallel is electrically equivalent, though I would go with the former (simpler emitter baseplate).
Bruno28, how space constrained are you planning to be with regards to driver housing? Bear in mind you'll have to attach those flashlight drivers to a heatsink, or else they'll die rather quickly…
I'd choose stuff like this instead:
As you can see o the attachment photos of the CAD, it will be all aluminium, so its a lot of heat sinking. The drivers will be attached to the casing and i will thermal paste it to help with conduction of heat.
I have one of those boost converters for my 100w COB, but its wayyyy to late for the unit I’m building. Wouldn’t be able to make it fit into that head.
Also i have decided to go with 6volts, as someone reminded me that if one led dies, then the series shuts off and not all the voltage/current goes through one led and burn it. Something I forgot to take into account.
Yeah I’ve seen that. Ive spoken to him and he has given me some assistance with things like the driver and heat sink. It is a bit similar. Mine will be pure flood as it will be a working night light and his is more for 4x4 vehicle with lots more throw.
Latest Design. This is iteration 4. More thought out, groove for glass to sit on and be pressed by the front face.
Also included cable tray for organised arrangement of wires from outside to drivers, to led.
Cycle at the back face is for the driver housing. The main body will also be the heat sink for drivers (3 drivers) and the led.
Material will be aluminium for body and heatsink.
I am going to put the flame suit on here
but for the intended purpose why not grab a couple of cheap light bars from ebay
you can run them straight from a car battery or genny with 12v output.
available in a huge variety of outputs floods and spots.
I realize its not modding or constructing just economic
Reliability….ebay cheap lights are Chinese with low quality control.
I’m creating this to use as a substitute for the current lightening system. At least it will be a massive improvement to what we use at SES. I’m using good materials and electronics. Efficient LED and one of the best Tir lenses for xhp-70.
I want to make a few and sell to local fire and rescue and other rescue agencies.
Also this is only the light you’re looking at it will have a Power bank and be able to run 100% for 3 hours without the need for a generators. Generators are time consuming to setup and very loud, which interferes with communication.
Also as an engineer I wanted to create my own lighting system. Been waiting to do a flashlight for a while and I thought this was an opportunity.
The main goal of this project is:
Provide improved lighting system with Reliable operation
Easy of use and setup (under 60 seconds)
Portability
I actually contacted the supplier in France. The company is called Gaggione.
They have many different models. From narrow to medium to wide beam. I got 6 of each, from 6 different models to try out.
But I think there are a few online stores that would sell buy the unit. Which is what you would like.
I need some help with battery calculation and run times. I might have done something wrong. Please correct me if i did something wrong or forgot to add anything.
So the battery I’m looking to use is a LiFePO4 with specs of 12 volts and 120ah.
The 6 units of XHP-70 will require 192watts (32watt x6)
SO the calculations……
Usable capacity
Considering Li-ions batteries can’t be discharged over 80, that means that 20 of the capacity is non usable.
By having 120AH the battery can only deliver actual:
120ah X 0.8=96AH (of usable capacity)
Battery power delivery
P=VI
P=12x96
P=1152 watts hour
Power of LED used: 192watts
Driver efficiency: is 90%. So that means that 192 watts from LED will require:
192 X 1.10 (10% of wasted energy in heat) = 211.2 watts consumed by LED + Driver
So amount of Hours running at 100% [LED+ Driver (211.2watts)] = Battery Power Delivery every hour / Power of LED+Driver
1152/211.2 = 5.45 hours
You can safely deplete LiFePO4s without issues. I'm guessing the power is going to come out of some sort of hulky truck's battery so, whoever is in charge of the stuff told you to stick with a maximum of 80% depth of discharge for it to be able to crank the lorry afterwards, isn't it?
With 12'8V of 4S LiFePO4 nominal voltage, you won't be able to drive 2S 6V XHP70s off that driver; there's simply not enough input voltage overhead, you'd need at the very least 14V I think.
With regards to those claimed 90% 89'8% efficiency figures, your numbers are somewhat incorrect. Your 192W of output represent that 89'8% so: Pinput = Poutput / efficiency
Redo that calculation and you'll find a slightly higher input figure (213,80846325167 watts).
You'll need a driver for each emitter. Either that, or first you'll have to use one of those DC-DC boost converters to ramp up those LDRADJ29s input voltage to around 15V if you want to stick with 3 drivers. The combined efficiency would probably not be much worse in such a case because of the small voltage differentials.
Cheers ^:)
Original post date: Fri, 09/16/2016 - 15:42; small fixup.
I didn’t know LiFePO4 could be depleteed of all its capacity. I assumed it behaved like the li-ioms. That means ill have even longer runtimes. My initial plan was to run 3.5 hours but It will hit over 6 hour which is even better.
Oh so I won’t be able to drive off a 12v? Unless I use 6 drives?
Maybe I should bump the battery pack up to 24 volts 60AH?
Still, reading this, man what a monster project to start
Wouldn’t you be better off just doing some basic flashlight conversion projects and get to know different drivers and the XHP70 before going for this 6 XHP70 multiple driver monster?
All or nothing….hahah
I have modded a few lights of mine before. One I did mod a mtg2 to a Xhp70. Also did do some fixing on a Niwalker mm15mb that came with a dead XHP70.
In terms of drivers I’m not as familiar. But doing this project will help me. I can learn from failures. But everyone has been helpful here and it seems to slowly be going forward.
So any tips please let me know so I can improve.
I need to create this light. It’s something that will have use for me and will for others at my local rescue volunteer. Which will be awesome to be using something I made.
