By Muwarrior21
#4920555
Hey guys. I have the gbfans wand light kit and i purchases a separate higher powered led board that seems to run well on 9 volts. My question is this how can i get vent light switched power to this light and still have functionality of the gbfans board for the vent light functions?

It looks like the gbfans board puts out about 5v to the vent light leads but its not enough to power my led light board?

Any ideas on how to wire this up?
User avatar
By csullivan1980
#4920556
I think I have the same board as you, I bought a bunch off of eBay for cheap. I wired mine up, crimped the ends of the wires and hooked it into the board the same way as the original vent light. However, like you, I’m sure you are seeing the LEDS are not producing as much brightness when connected to a 9V.

I read about this online, but haven’t been able to figure it out yet. You might need some kind of resistor added to help power up the LED. There is some kind of equation or formula to help determine what kind of resistor you need if you look online. I can’t begin to understand it unfortunately.
User avatar
By bishopdonmiguel
Supporting Member
#4920572
A boost converter will step up voltage while reducing amps. I’m not sure how much current the board supplies to the vent circuit but I’d doubt more than 500mA. If your LEDs draw more than the available, they won’t light even with the higher voltage. Drawing more than available might also interrupt the function of the main board.

A “relay” circuit with a separate power supply is probably your best bet.
By Muwarrior21
#4921857
Hey guys so i got an update

I went with a smaller 12 led panel that says its designed to run on 5 volts.

I get about 5 volts when i put a meter on the cut vent light leads but when i attach the board they do light but are not very intense. I also measure only about 2-3 volts at the solder joint to the board. I tried to re solder etc and no improvement? When i hook the board direct to the battery 9v its super bright. Any ideas on what to try?

My main question is why is the voltage measured so much less with the board connected? Is it just trying to draw too much. I have basic electronic understanding so not sure if a higher amp capacity power source would help or not. Thanks for any help
User avatar
By bishopdonmiguel
Supporting Member
#4921859
Just to baseline, when you connect the board to 3 AA batteries (~5v), what do the LEDs look like? You said it’s designed for 5v but you’re connecting to 9v to test. Higher voltage will increase LED brightness to the saturation point, after which the LEDs will fizzle. Since it’s working with 9v, perhaps it’s designed for that and the reduced brightness is what it normally looks like at 5v.
By Muwarrior21
#4921861
Its a 5 volt designed board but i believe it can “handle a wider range. These are super bright white leds and look quite dim with only measuring around 2-3 when i turn them on and put alligators on the solder joint.



I guess i was trying to figure out why the led voltage drops when the bare leads supply 5 volts when a 9v batt is connected to the board? I assume just trying to draw too much and thus drop in voltage? Or could this be remedied with a different resistor. Perhaps i will try a 9 led and a 6 led panel to see if those work better. When connected to thr 9 volt the board is enough to melt your face. I dont have the skills to wire a small relay / booster in so i just gotta find something like this that works on the ability of the board to supply the necessary current.

On a side note i hooked up a 12 volt supply box that just uses aa batts and not much difference. Im too lazy to dismantle my othet pack that has a li on blue battery pack to see id that helps byt my gut is saying something with the board itself is not allowing enough juice to get there


I wish somebody smarter than me here can explain to me the drop in voltage measured when connected vs when i just measure across the two leads that go to whatever vent light you have
User avatar
By bishopdonmiguel
Supporting Member
#4921864
Seems that LED board is trying pull more current than the vent light run is designed to supply. I looked through the documents but didn’t see a rating for that run. BUT the AUX circuit says it is rated for 100ma max. So current looks to be the limiting factor.

If you have extra room in your wand for a small board and 9v battery, you can use a MOSFET driver.
User avatar
By bishopdonmiguel
Supporting Member
#4921911
I’ve not used that particular driver but it looks like it should work (there are no specs, just the picture). I’ll say I don’t like that they cut the heat sink off but at least they soldered it to the board.

At that price, I’d guess it’s coming from China. Might consider paying more for a US seller or you’ll be waiting 2-3 weeks for it to arrive.

You can optionally reduce the size of the board by removing (desoldering) the screw connectors and just attaching wires straight to the board. Be sure you isolate the board when you install it so you avoid shorting anything.
By Muwarrior21
#4921921
I know a lot of guys that build robots / rc stuff for this use computer code to run the signal input but should a constant 3-5 volt signal that is switched "open the gate" then. It says it works from like 2 - 30 volts or something like that , Id have to check the specs but I was just wondering how exactly the gate "knows" when to open based on the input port?
User avatar
By bishopdonmiguel
Supporting Member
#4921931
Yes. It’s like a digital relay. 3-5 v input signal saturates the MOSFET and current flows through the higher voltage output circuit.
User avatar
By bishopdonmiguel
Supporting Member
#4922261
Nice job.
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