diy apex lunar string

jjoos99

jjoos99

New member
I was given an old legacy lunar sim and am trying to make my own string of leds? Ive got all the items I need. Has anyone built their own string? I wired the leds like my other tank lighting leds. They are wired in series but wouldnt work with the lunar sim. Does anyone know if they should be wired in series or parallel? Does the the lunar sim use pwm to control the lighting strength?
thanks for any advise
Jeff
 
Got a voltmeter?
measure the no load output of it to start..


If I had to guess I'd bet you simply need to put up to 5 LEDs in parallel each with its own current limiting resistor..
And those would be small indicator LEDs of like 20mA or so if that..
I'd start with them at 10mA set by the resistors..
 
I found an old post on neptune's site that linked to some leds that work out but didnt mention about a resistor. They are 20mA so what size resistor would I use to get it down to the 10mA you mentioned?
thanks
Jeff
 
jjoos99 said:
I found an old post on neptune's site that linked to some leds that work out but didnt mention about a resistor. They are 20mA so what size resistor would I use to get it down to the 10mA you mentioned?
thanks
Jeff
Click to expand...

I'd need to know how much voltage the led drops (its Vf) and what the source voltage is to do the normal calculations for sizing a resistor for an LED..
But the formula is here..http://www.ohmslawcalculator.com/led-resistor-calculator

I'm not sure if that LED simulator is just a outputting 10v PWM or something like that in relation to its lunar cycle...
 
jjoos99 said:
These are the leds that I have.
https://www.rapidled.com/royal-blue-moonlight-led/
do you think these would work with the lunar sim? would I still need to use resistors with these leds? The power supply that plugs into the sim module is 9v.
thanks
Jeff
Click to expand...
Well you have 2 issues sort of
1)is the 9v what you get out to the diodes? What goes in is somewhat irrelevant.
2)do you have enough "headroom" to drive 350mA? (or 350mA x "x" units)
WHAT is the output amps (or watt) rating of the power supply?

since the orig array limits at 5 (5 x20mA = 100mA = .1A )
you may light a 350mA diode but at what brightness?

You want to try one at 20mA..
330Ohms.. 1/4 watt..

Suggest testing it using a 9v DC wall wart b4 adding it to the Neptune unit..

Put an amp meter in line to check actual current..



Solution 0: 1 x 1 array uses 1 LEDs exactly
+9V
+ -|>|- -/\/\/\- + R = 330 ohms
The wizard says: In solution 0:

each 330 ohm resistor dissipates 132 mW
the wizard thinks 1/4W resistors are fine for your application Help
together, all resistors dissipate 132 mW
together, the diodes dissipate 66 mW
total power dissipated by the array is 198 mW
the array draws current of 20 mA from the source.
Click to expand...
 
Last edited:
jjoos99 said:
These are the leds that I have.
https://www.rapidled.com/royal-blue-moonlight-led/
do you think these would work with the lunar sim? would I still need to use resistors with these leds? The power supply that plugs into the sim module is 9v.
thanks
Jeff
Click to expand...

Yes they can work but their typical drive currents (350ma) is WAY..WAY too muc for a moonlight unless you have a very large tank..

And all LEDs need some form of current limiting.. The one to use in this application is a resistor..

You still need to measure the output of the lunar module before you do anything else..

Then plug that value into the formula to choose the proper resistor..
 
I set the apex to manual on for the lunar sim and checked the voltage. Wow it was 26v. I did find that I had the polarity reversed on the plug. I will rewire the plug and try it again.
thanks
Jeff
 
success, after reversing the wiring on the plug it worked fine. I assumed that the center of the plug was positive and the exposed outside was the negative. Not sure if the lsm modules are adjustable for brightness but the legacy sim is adjustable so if it is too bright I will be able to turn it down.
thanks for the help
Jeff
 
I would love to be able to redo the LED string that plugs into the LSM module, I just don't have the necessary knowledge. It has been a constant, albeit minor, source of irritation to me for years that neptune uses blue diodes. News flash: the moon ain't blue. Every night dive I ever did it was a cool white on the reef.
 
I have a string at home that got damaged and I don't use. Popped the cover on the led 'boxes'. There's nothing in there other than the wire soldered to the diode. No resistor, capacitor ...... nothing. Oh, and they're wired in series.

Ok, so I'm ordering a bunch of the cool white diodes. Even though I am the worlds worst solderer, I think even I cannot screw this up :)
 
Last edited:
Cool.. Prob any equiv diode would work..
I was expecting at least a resistor..

Series huh.. unexpected.. 2,3,4 strands would have different voltage needs..

So possibly a constant current driver inside the base unit..
 
ca1ore said:
I have a string at home that got damaged and I don't use. Popped the cover on the led 'boxes'. There's nothing in there other than the wire soldered to the diode. No resistor, capacitor ...... nothing. Oh, and they're wired in series.

Ok, so I'm ordering a bunch of the cool white diodes. Even though I am the worlds worst solderer, I think even I cannot screw this up :)
Click to expand...

just tin your wiring and leds first and they will solder up fine. just keep the parts clean and they will take solder good. The string I made is in series and I do believe the voltage is different for the different stages of the moon.
Jeff
 
I popped open all five of the boxes, no resistor. I wonder if the shorter strings have a resistor to make them equivalent? Jeff, how many LEDs in the string you made?
 
I made a string of 4 leds, no resistors, but I used some moonlight led pucks that I had laying around that I used. dont know if that type would make a difference.
Jeff
 
OK, wired up three cool white LEDs, plopped them back into the little black boxes (hides my crappy soldering efforts) and ..... voila .... worked like a charm. Thx for the idea chaps.
 
ca1ore said:
OK, wired up three cool white LEDs, plopped them back into the little black boxes (hides my crappy soldering efforts) and ..... voila .... worked like a charm. Thx for the idea chaps.
Click to expand...

did you install any resistors? I finally installed mine into my canopy last night. According to the moon cycle they didnt come on till somewhere around 1:30 or so in the mourning. Mine were the blue leds but mounted close to 2 ft above the water and I really couldnt tell what color they were, although they were pretty dim. Will the lsm module allow you to dim the leds? I have an old lunar sim that allows me to change the intensity of the leds.
Jeff
 
No, I just removed the blue ones and soldered in the white ones. The LSM module does dim them based on the seasonal table setting in apex, so we shall see if it works as before.
 
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