thank you. How did you calculate the resistors' values?

R1 determines the current limit.
It's ap;prox. 0.7V/I where I is the desired current limit.

R2 supplies the base current to Q2.
I just selected a value that seemed to work well in the simulation.

 

R1 determines the current limit.
It's ap;prox. 0.7V/I where I is the desired current limit.

R2 supplies the base current to Q2.
I just selected a value that seemed to work well in the simulation.

what is 0.7? why is it a constant value?

 

These may be a starting place. But, it may need cutting your LED strip into shorter lengths as it does not appear these boards will output 60+ volts.
Having 2 or 3 shorter lenghts is a good idea as then only the part needed will be used, extending the run time, or all together if you want.
http://store3.sure-electronics.com/...er-board-dc-sepic-buck-boost-5-32v-wide-input

 

Why not just buy a ready made step up converter such as this. It has an adjustable output current limit but I don't know if it is a constant current design or just over current shutdown. Another option is to use 4 x 5 watt 12 volt MR16 lamps. Last time I bought them in the UK they were about £1.30 each. This was from a shop not ebay.

Les.

 

Fair do's. I would probably say take the cover off the light. See if there's resistors in there. I grow tropical plants so have 12v strip light led tape in some fixtures.

Have a standard wall adapter. All you have to make sure is that you work out the wattage of your LEDs . So 60v times 0.3 = 18watts times 4 lights in parallel 72w.

72w ÷ 12v = 6A. So a 10a boost converter would run all 4 in parallel.

24v=3a

36v = 2a.

48v = 1.5A

So at 1.5a, with a 2 pound BMS. And showing you have the 60v of lithium cells. Some of them could be used in parrarel to get more run time.

 

If the bulbs can run on 60 volts DC, is the package to run them from 120 AC separate?
Really, though, you can buy 5 of those 12 volt gell cells which are nominally 12 volts but deliver a bit more. Just use a series resistor for each bulb, and select the resistor value to drop the difference between the light voltage and the battery voltage at 300 mA current. I am guessing either 39 ohms of 47 ohms will work.

 

Are you sure you need that much lighting? 2400 lumens is bright, and 6000k cool white isn't as pleasant as warm (2700k).

I've made 12V lights by wiring three COB LED panels (from dollar store "switch lights") in series. Each one already had a resistor (sized to run from three alkaline cells), so no additional parts were required. They can be dimmed with a cheap PWM dimmer (aka motor speed controller) module from ebay. For more power, I'd consider harvesting SMD LED panels from dollar store "utility lights" or order 10W COB modules from eBay. The COBs have the disadvantage of needing a heat sink, and don't include a resistor.

Anyway, 12V DC power seems like a good choice: you can run other stuff like a car radio, USB adapters for phone chargers from it, an, there are cheap solar charge controllers if you want to power your gym from solar panels. Higher DC voltages introduce greater risk of shock or arcing; you'll find a limited choice of switches that are rated to interrupt more than 28V DC. It shouldn't be hard to scrounge one or more old car batteries that still have enough life to run lighting; if you have two, one could always be trickle charging at the house.

 

what is 0.7? why is it a constant value?

It's the approximate base-emitter voltage to turn on Q1 which reduces the base drive to Q2 to limit the current.

 

i couldn't find any led drivers like that on the internet

https://www.ledsupply.com/led-drivers/mean-well-ldh-series-cc-step-up-boost-mode

The LDH 45A-350 fits the bill.

Bob

 

Fair do's. I would probably say take the cover off the light. See if there's resistors in there. I grow tropical plants so have 12v strip light led tape in some fixtures.

Have a standard wall adapter. All you have to make sure is that you work out the wattage of your LEDs . So 60v times 0.3 = 18watts times 4 lights in parallel 72w.

72w ÷ 12v = 6A. So a 10a boost converter would run all 4 in parallel.

24v=3a

36v = 2a.

48v = 1.5A

So at 1.5a, with a 2 pound BMS. And showing you have the 60v of lithium cells. Some of them could be used in parrarel to get more run time.

what i'm afraid of is that the current on each "branch" would be different due to structural diffrences in the lights, thats why i asked for a current control circuit, so that i use one for each parallel to maintain the current at 300mA.

because the led strips inside the lights don't have any resistors

 

That is why I suggested using a separate resistor for each one.
And I am sure that you mentioned that the location has no mains power available, so why do folks keep suggesting things that require mains power??
Consider that in many parts of the world running mains power to another structure is a big deal. And I have no clue as to what part of the world the TS is located in.

 

what i'm afraid of is that the current on each "branch" would be different due to structural diffrences in the lights, thats why i asked for a current control circuit, so that i use one for each parallel to maintain the current at 300mA

That is why I suggested using a separate resistor for each one.
And I am sure that you mentioned that the location has no mains power available, so why do folks keep suggesting things that require mains power??
Consider that in many parts of the world running mains power to another structure is a big deal. And I have no clue as to what part of the world the TS is located in.

I live in italy, the garage is just separated from the houses that's why there is no main power.

The problem with resistors is that I would have to buy a battery pack higher than 60v to account for the resistors' losses and that can be more expensive than say 4 current control circuits

I do not intend to use ac current to run the lights as I said in a previous reply

 

I live in italy, the garage is just separated from the houses that's why there is no main power.

The problem with resistors is that I would have to buy a battery pack higher than 60v to account for the resistors' losses and that can be more expensive than say 4 current control circuits

I do not intend to use ac current to run the lights as I said in a previous reply

You will NOT need to bu a battery pack with a higher voltage than the 60 volts because the batteries called "12 volt" batteries always deliver a bit more than 12.0 volts. And just a little bit over is all that would be needed.
If you can borrow a power supply that can provide a bit more than 60.0 volts, and if you already own one of those lights, and a voltmeter, then you can do an experiment and verify this for yourself. Or you may have already done it. Start with a lower voltage and then increase the voltage and see at what point the LEDs start to light. Then with a small increase in voltage they will get much brighter. You will probably see that at 58 volts the light is quite bright. Probably the resistor to use for a 60 volt battery pack will not be over 20 ohms, probably less than ten ohms, but it is better to start a bit higher resistance first. There does not need to be much voltage drop on that series resistor that limits the current.