I worked with Tinkercad this morning and couldn’t figure out how to get a less voltage battery. But, tonight I was viewing the series by Ben Finio Ohm’s Law/ Tinkercad Circuits Lab 3 in which he showed how to find, in the menu, other battery voltage sources. Plus, scrolling down you can use a power supply with 0-30volts variable it also has an indicator for the mA or current control.

Hello Mates,
Just adding my two cents,
In my some of my boats that have multiple LED lights (Mt Washington, Seguin) I use boards that step down the voltage. The reason being multiple lights can be powered from one source. if they are of the same voltage.
On my HO train layout, I use boards as I have multiple lights. some boards have three voltage outlets. Some of the boards are adjustable so I can control the output, as in my carnival rides.
The railroad passenger cars that I have installed LED lighting in, I have used resistors because of their cost and size.
I do admit that I have limited knowledge on the subject, although I do find it fascinating.
Trev

I wanted to add two more tips for those who intend to build a circuit themselves and use resistors.

MEASURING RESISTANCE

Resistance measurement (all multimeters, even low-cost ones, have this feature) should be performed on a de-energized circuit.
Be careful if the resistor is not isolated but connected to other components, the measurement may be distorted.
For example, if it is connected in parallel with other resistors, you will have the value in Ohms of the equivalent resistance of the resistors in parallel and not of the individual resistor.

DISPOSITION OF POWER INVOLVED

For small circuits with low currents, this information may be useless, but it's good to know.
When purchasing a resistor, only the resistance value in Ohms is considered.
In reality, we must also check its power, or rather, its ability to dissipate heat in Watts without breaking.

A small resistor, like those used in electronics, is typically 250 mW (1/4 Watt).
Well, to know if it's suitable for our use and won't get damaged, just do a little calculation.
In direct current, according to Ohm's third law, electrical power is given by the product of voltage and current.
P = V x I
For example, if a resistor is subjected to a voltage of 12 volts and a current of 40 mA, it must support a power of at least 0.48 W.
480 mW is greater than 250 mW, so one of the resistors mentioned above cannot be used. The resistor was 300 Ohms, of course.
So, in summary, the advice is: always calculate the power involved based on the voltage and current.

Hi EdW, as I was saying to Dave, everyone has their own needs, interests, and hobbies. I agree with you.
I agree with you about the difficulties of learning Arduino (which requires knowledge of computer science, not just electronics) and building a DC/DC yourself.
I agree that building electronic products, now sold cheaply on Aliexpress, is uneconomical.
Furthermore, people often want to save time. I could have made the anchors myself because I knew how to do it, but I chose to buy pre-made ones.
Some time ago, I started sourcing components to build an ESC myself, just for fun, certainly not to achieve better performance than ESCs sold online. I stopped because I couldn't find everything and didn't have time to finish a time-consuming project. I don't rule out picking it up again in the future, along with many other things.
Personally, I don't need to adjust the brightness of the lights on a boat. Once I've found the right brightness (combined with the right current, thus choosing the right resistor), I don't think it's necessary to change them, but that's my personal opinion.
In any case, I could place a variable resistor in series with a fixed resistor for fine adjustments.
As for me, I respect everyone's opinions and choices, so if anyone needs information on basic electronics, to the extent I can, I'm available and happy to share my limited knowledge.

As I have said before, I was an electronic engineer.
Resistors are ok for a single LED but to vary the brightness you have to change the value of the resistor, de-soldering and re soldering and probably replacing the sleeving. Arduino micro controllers are not for beginners unless you wish to go through a lengthy learning curve as you require electronic and coding knowledge. I see that some of you use Vero board, not the best idea in marine applications due to corrosion.
Designing and etching PC boards is another area requiring a lot of experience and best avoided for beginners.
I am able to design simple to complex electronic circuits, design and make their associated circuit boards as well as building them.
Then why, do you ask, do I use LED drivers and digital switches that I buy from Amazon. The answer is simple, they are cheaper than I can build them for and gives me more time to spend building and running model boats. After all my hobby is model boats, not electronics.
My two pence worth 🤔

Brinkman, you took the words right out of my mouth.
I’ve stayed on the sidelines on this topic since my knowledge is pretty limited, but from what I’ve read while researching out of curiosity, I came across someone online saying exactly what you mentioned—and I’m very inclined to do the same with my Juanita.

It’ll be interesting to see what kind of responses you get on this post.

Hi Dave, in electronics, there are many ways to achieve the same result.
I didn't say using resistors is the best solution.
The advantages of a small LED circuit with resistors are these:
You can understand what you're doing, and once you've learned it, you can repeat it over and over again, applying it to various situations.
It's fun to learn and apply the basics of electronics.
In fact, JSS4 is doing it very well with Ronald, congratulations to both of you.
Other systems, like DC-DC Buck Step Down or Arduino, are much more difficult to DIY. Impossible for a novice to learn easily.
There are those who want to learn more, and those who are content to buy what they need and assemble it.
Basically, with discrete components (resistors, capacitors, transistors, etc., etc.), it's simply fun.
This is obviously not a criticism; everyone is free to do as they prefer, and from your point of view, you've certainly made the best choice in achieving the result you wanted.
Furthermore, resistors are very cheap.

Sorry Ron, I'll reply to your PM as soon as possible.

Alesso,
Even someone like me—with zero knowledge about model lighting—can understand your diagram.
Well done!
😎

It is interesting that this conversation is happening right now.
At our local club's meeting last night, one of the members gave a presentation on LED lighting.
He talked about the different LED colors and voltages.
He is a strong proponent of using DC-DC Buck Step Down converters rather than resistors.
There are many types available online at very reasonable prices.
Most are adjustable, and they can be purchased with or without a digital voltage readout.
I myself have used Buck Step Down converters in a couple of boats.
I certainly don't claim to have the detailed knowledge that some of you have.
In fact, parts of this string have my head spinning!
Can somebody please explain why I would want to use resistors as opposed to what seems to me to be a much simpler solution using Buck Step Down converters?
I'm very open to learning the positives and negatives of both.
Dave B

JSS4, your model looks outstanding. The lighting is perfectly scaled — very realistic and beautifully done.
😎

Thanks for the reply Ron, I was really curious. Will you use this power supply (5.88 volts) for the LEDs or directly from the battery (7.2 volts)?

Great work JSS4, the photo with the boat illuminated at night is very suggestive.

Alessandro, the 5.88volts reading was coming off my receiver bec leads.

I've shared this photo with Ron privately but as Alessandro said about routing wires to a resistor board, here's how I handled the LEDs on my Crockett mast. The outputs aren't bussed as I plan to eventually control them individually (anchor lights etc) but for now they're all connected to the BEC to look pretty on the water

That's fine, Ron.
Since there are only two LEDs, there's no chance of confusion.
You need to tidy up when you have a lot of LEDs to manage.
What were you measuring that gives you 5.88 volts?

This is what I have been doing.

Hi Ron, as I was saying, I've added the last three sketches to post number 9 of this topic.

I did the same for the voltage and current measurement sketch.
I preferred to put them all where the main explanation was given.

Anyway, I'm attaching them in this post as well.

The first one is about voltage and current measurements (later I'd like to give you some helpful tips on resistance measurements, which any multimeter can perform). The second, third, and fourth ones show an example of moving from a circuit diagram to practical wiring.
Generally, the connection logic is on a board (as a beginner, it's best to buy a punch board because it's very easy to use). From there, each LED will be connected to two wires, a positive and a negative, which will run through the boat as best as possible.
Some people, in fact, prefer to proceed as follows:
1. Position the LEDs and wiring.
2. Prepare the board with the resistors, connected to the battery with a manual or remote-controlled switch (or, better yet, both).
3. Solder the LED wires in the correct positions on the board.

I like your diagrams, they are very clear and easy to understand. Thank you for sharing your knowledge and insight. You too are a fine teacher!

Hi Ron, I've added the last three sketches to post number 9 of this topic.

After addressing the issue of voltage and current measurements, there's another aspect to consider:
Transitioning from an electrical diagram to a real circuit with actual connections and wiring isn't easy for all beginners.

So I've considered a practical example.
Let's say a modeler wants to position the regulation position lights on a boat over 50 meters (according to COLREG).
I've included both the electrical diagram and the possible practical connection.
In practice, there are many possible approaches; the one illustrated is one of many.

Oh, okay, this connection is very nice.

I added the seventh diagram in message #9. It's for current and voltage measurements.

I hope it's clear, but if you're not sure about something, just ask.

Alesandro

Jss4 is my brother in Christ and though he lives 2 hours away and we only message via the iPhone, he is a great guy. We see each other at various times throughout the year at our club events and occasionally at his work place, Little Canada.

JSS4 was tasked with the job to make the cars on the ferry and retrofit the lobster boats so that whey would float appropriately in the promotional video.

Ron, you're lucky to have a guide like JSS4.
I agree with him on resistors and LEDs.

If I understand correctly, you live nearby and can meet in person. Is that right?
Well, that's the best thing; explaining things remotely isn't always easy.


P.S. Sorry I haven't posted all the schematics yet, but I'll do it soon (it's one thing to write on your cell phone while standing, but it's another to find a surface to draw on. So far, I've had a few opportunities).

EdW:
Man, you get my award for being the LED Nikola Tesla. Your knowledge level is up in the clouds.

I don't actually know how to use an led driver but have gotten comfortable with using resistors to control brightness. Is it fairly basic? Yes but it also works.

There is a TLC5940 kicking around my spares box, I need to learn how to use it. It would allow me to use more than the limited PWM outputs on any given microcontroller, my usual ATTiny85 gives me only 2 PWM outputs

Even when I use PWM on a mosfet for a remotely dimmable circuit I still assume it's like a regular circuit and set resistors to the maximum brightness then dial it back from there

Hi Edw, you're absolutely right, but with an LED driver, beginners and those just starting out with electronics wouldn't understand much.
They'd just buy the pre-built circuit and connect it.
With basic circuits, you learn to do something yourself by thinking.
You're an electronics engineer and don't need to learn things you've known for a long time and very well, but imagine that many modelers buy kits and circuits (for lighting, sound, or other things) without fully understanding how they work.
Of course, you're right about efficiency and speed (and that's not a criticism); buying an LED driver saves you time doing calculations and soldering.
For those who've never done them before, it can be a lot of fun and satisfying.

Ron, if at 76 you want to learn some basic electronics, you have all my admiration, you're great.

I was an electronics engineer and avoid using resistors to supply LEDs. The reason that I use driver boards is that they supply pulsed (PWM) supply to the LEDs and by varying the pulse width, you change the brightness. The input voltage is anything from 6 to 24 volts and the brightness is as easy as turning a preset potentiometer. No worries about V=IR and it’s derivatives.🤣

LED know how… yes I know there is a OHM’s Law, but math and I have not always been the best of friends.

I recall one night after my History of Mathematics class at university I asked my professor, “Eli, why do you do this?” As I waved my hand at three blackboards full of equations as they wrapped around the four walls of the classroom. Eli responded to me with a big smile. “ Because it’s FUN !”

I said, “ I can think of a lot more things than this that are Fun”, and he said. “ That’s because you aren’t a mathematician!”

He said for me to come every week to class, take the tests and exam and he would be sure to pass me. I got a mark of 51 a pass, my credit, my degree is a BA of Fine Arts Music

That was 40+ years ago. Now, at 76, I am learning about Ohms, Amperage, Volts and enjoying it.

Hi Chugalone, thanks for the compliments.

I think that to understand electronics, you have to start with the simple things.
There were many more things to say, but I risked confusing Ron.
Maybe I'll add them later.
By applying Ohm's law, you can manage LEDs well. Mathematically, they are very simple operations.

JSS4 mentioned MOSFETs and Arduino, but there things get complicated; it's better to take it one step at a time. It's clear that he has in-depth knowledge of electronics.
For those starting from scratch, it's a bit too difficult.

I recommend proceeding as follows:
1. Determine how many LEDs to use, what type, and how to power them.
2. Then draw a small circuit with resistors and LEDs (choosing the best solution).
3. Reproduce it on a breadboard for verification and possible measurements and tests.
4. Apply it to the model by running the wires and positioning the resistors (even all on one board).

If you need clarification, advice, or help, I'd be happy to help.

Now I still have to upload the other schematics I promised and check for errors. But in the meantime, you can view the videos and photos I took previously on other topics.

With simple, discrete components (small space and minimal cost), you can make a circuit with flashing LEDs instead of solid ones, if you like.

WOW Alessandro, you really know your LEDs.
I’ll need to go through this information slowly, as my knowledge on the subject is quite limited.
The topic you brought up will be enormously appreciated by modelers like me, especially because of the level of detail you provided. Many of us are sometimes hesitant to add lighting to our models simply due to a lack of clear information, and this helps remove a lot of that fear.
When I’m ready to start adding lights to my model, I’ll definitely be sending Ron a PM.
😎

Hi Ron, sorry for the delay, I'll post the text first and then try to attach the diagrams (I'll correct any errors as they arise).
Very good, let's talk about a specific case and make practical assumptions.

With a voltage of 7.2 volts, you can choose from several solutions:

1. PARALLEL CONNECTION (ONE RESISTOR FOR EACH LED)
With one resistor for each LED (and then all the LED-resistor branches connected in parallel to the battery), the calculation is easy (see diagram no. 1).
To find the correct resistance value, simply apply the inverse formula of Ohm's law, and then:
R=V/I
The unknowns are the current intensity and the voltage.

Regarding the current, the value is given by the LED's factory data.
If I remember correctly (but I recommend always checking the datasheet for each component you use, it's important), the values ​​for 3 mm electronic bulb LEDs range from 15 mA to 20 mA (i.e., 0.015 A and 0.018 A). With 15 mA, you'll get a dimmer light but less heat loss and a longer LED lifespan; vice versa, with 20 mA.

The value I'll consider for the following calculations is 18 mA (0.018 A).

Regarding voltage, the value to consider won't be the battery voltage, because the LED voltage drop must be taken into account. So, battery voltage minus LED voltage drop.
Again, the LED voltage drop is a factory setting.
For these types of LEDs, the typical voltage drops are: 2 volts for red, 2.2 volts for yellow and green, and 3 volts for blue. Check the datasheet to be sure before proceeding.

With all the data available, you can apply Ohm's law:
R = (Vbatt - Vled) / I
With a red LED, we have:
R = (7.2 - 2) / 0.018 = 5.2 / 0.018 = 289 Ohms
At this point, you'll need to find the most suitable commercial resistor for this resistance value.

1.1 CHOOSING THE MOST SUITABLE COMMERCIAL RESISTOR FOR THE THEORETICAL VALUE
With the most common commercial series, you have two available values: 270 Ohm and 300 Ohm.
If you choose the 270 Ohm commercial resistor, you will have higher current (19 mA or 0.019 A) almost at the limit, and greater brightness.
If you choose the 300 Ohm commercial resistor, you will have lower current (17 mA or 0.017 A) almost at the limit, and greater brightness.
There are precision series that are much closer to the theoretical value, but I don't think there's any need; you can easily choose between them.

2. PARALLEL CONNECTION (EACH BRANCH HAS TWO LEDS IN SERIES WITH A RESISTOR)
(See diagram number 2).

In this case, the same calculations apply, but since there are two LEDs in series, the voltage drop to be considered will be the sum of the two, so 2 + 2 = 4 Volts.
R = (Vbatt - Vled1 - Vled2) / I
With a red LED, we have:
R = (7.2 - 4) / 0.018 = 3.2 / 0.018 = 178 Ohms
At this point, you'll need to find the most suitable commercial resistor for this resistance value, which, luckily, is 178 Ohms.

3. PARALLEL CONNECTION (EACH BRANCH HAS THREE LEDS IN SERIES WITH A RESISTOR)
(SEE diagram number 3).

In this case, the same calculations apply, but since there are three LEDs in series, the voltage drop to be considered will be the sum of the three, so 2 2 2 = 6 Volts.
R = (Vbatt-Vled1 –Vled2 – Vled3)/I
With a red LED, we have:
R = (7.2 -6) / 0.018 = 1.2/0.018 = 67 Ohms
At this point, you'll need to find the most suitable commercial resistor for this resistance value, which is 68 Ohms.

For obvious reasons, we can't connect four LEDs in series because the sum of their voltage drops is greater (8 Volts) than the supply voltage (7.2).


4. SUMMARY OF RESISTORS TO BE USED

With a single LED per resistor, use a 270 Ohm resistor.
With two LEDs per resistor, use a 178 Ohm resistor.
With three LEDs per resistor, use a 68 Ohm resistor.

There is a slight difference between red and green LEDs.

5. CONSIDERATIONS ON TOTAL CURRENT DRAWN BY THE CIRCUIT

For simplicity's sake, let's assume you want to power twelve LEDs with a 7.2 Volt battery (I'm using twelve LEDs for example only).

If you connect them all in parallel, you'll have a total current draw of 216 mA or 0.216 A (i.e., 0.18 mA x 12).
(See diagram 4.)

If you connect them in groups of two in parallel, you'll have a total current draw of 108 mA or 0.108 A (i.e., 0.18 mA x 6, because there are six branches in parallel).
(See diagram 5.)

If you connect them in groups of four in parallel, you'll have a total current draw of 72 mA or 0.072 A (i.e., 0.18 mA x 4, because there are four branches in parallel).
(See diagram 6.)

When you connect an LED in series with another, one of the two that breaks will prevent the current from flowing to the other, which will therefore appear off even if it's healthy.

Ron, those light setups look great!

I've also dimmed leds with a servo board and a small plane brushed esc (like 2A) can also work. Servo board is kind of a janky solution but in a pinch it can work. It's easiest if you have a programmable radio (I'm really liking the tx16s)

On the Horizon harbour tug I did the deck lights are dimmed from an Arduino on a mosfet. The code basically reads the servo signal from the receiver and maps it to a PWM output 0-255 then the mosfet handles the current. That gave me more control over how it behaved.

Eventually I'll program the crockett light functions but I've been too lazy and it needs more important things right now.

Usually my BEC is 3+ amps so I'm not concerned about LED current draw

If you have the plans for Mary Ann you will see a small light at the bow on a post about head height. This is a fishing light just needs another LED.
Roy

What teachers like is when you listen and then do something for yourself. It means you have learnt something by yourself.

NB I am not a teacher! But have done a little instructing.
Roy

Roy, that makes sense, and it works.

My teacher has said to use a separate resistor for each Diode. Do I question my teacher, yes, and he gives me kind answers without getting annoyed with me😁.

Here I took three of these diodes from a waterproof string of LEDs and used them to add light under the ceiling of the wheelhouse cockpit.

I didn’t ask, I just did it and he was pleased.

Hi Ron, I think your friend JSS4 is right. The best approach is to know how to use resistors (individual components) to operate and understand how an LED circuit works.
As soon as I can, I'll send you some practical instructions applied to the specific case of a 7.2 volt power supply I'm preparing (which you can show to JSS4).

The cheapest way is to use a separate BEC. Ohms law gives you the value of resistor the mWatt value of the LED gives you the current. But a single BEC (5 volts) will drive 2 LEDs in series or maybe 3 and no resistors required.

Forget the mysteries of electronics it is just a simple arithmetic calculation.
Roy

I use LED driver boards that I buy from Amazon.
At 2 for £8 I could not even buy the components to build them myself. The input voltage is 6-24v and the output current variable so changing brightness is easy.