Wow Jaunmadg, I appreciate your effort in your research. This is a little too complicated for me at my knowledge level. I'm a band dad that drew the shortest straw for this project 
:D. I think the "buck converter" and battery is an easier idea. it removes the double AC/DC conversion and makes it strictly a DC power input.
Well, 20 A at 24 V - it just scrapes in!
It does so do you think the will be alright Paul__B? I respect your opinion because you have been more than helpful in answering all of my questions to a guy that has hardly any experience in the subject but I have definitely learned a lot from all of you.
Well, if you have to buy the 20V battery and the DC-to-DC converter, you might want to first try the incandescent light bulb current limiter between the inverter and the PS you already bought...
This is just a standard incandescent (not LED) light bulb in series between the two of them... and a switch in parallel to the light bulb to short it afterwards... (have a cable as if it were no light bulb in the line)
BR
juanmadg:
You can use a conventional light bulb rated to the same voltage as the inverter's output AC voltage (110VAC) and a power rating lower than that of the inverter (100W or lower can do the trick).
Ummm, nope!
Suggestion is entirely arse-about! 
Paul__B:
Ummm, nope!Suggestion is entirely arse-about!
Hi Paul__B,
The way you answered to my suggestion is completely out of place: I'll forgive you as I think you don't understand what I suggested and you just expressed yourself bluntly.
Incandescent light bulb current limiting has been used for decades for many different uses; it's usual name is a ballast (yes, the ballast in your traditional fluorescent light is an incandescent light bulb inside a plastic tube); it has also been used in electronics equipment to compensate for oscillators drift (Hewlett Packard had a patent on this) and so many more uses.
In summary, you are introducing a (temperature variable) resistor in series in your circuit so therefore you are limiting the maximum current that can flow through it (I think it was you who, at the beginning of this thread, suggested about that old somebody's electrical law from high school, right?). Think about it: if you insert a 120VAC/100W light bulb at the output of the inverter, the maximum current through the bulb will be below 1A (0,833A)... now, insert the PS in series with the bulb in the same circuit (maximum current still the same as the PS will have a much lower ESR (Equivalent Series Resistor) at startup - this is why the inrush current is so high in the beginning). Once you've got your PS stabilised (no inrush current), the circuit will still be consuming a max. current of 0,8333A, so, in order to let the PS alone, we connect a switch across the incandescent light bulb so we can short its terminals - thereby bypassing the light bulb and leaving just the PS connected to the inverter, this time without the inrush current surge.
I think this SHOULD work...
Furthermore, it is cheap to implement and the components are common so they are easy to find at home or at any nearby hardware store.
Best regards
In summary, you are introducing a (temperature variable) resistor in series in your circuit so therefore you are limiting the maximum current that can flow through it
Yes but an incandescent light bulb when cold has a low resistance, as it warms up the resistance increases, so it can’t limit the current until it is hot. Therefore it can’t limit the inrush current until after it has peaked.
Grumpy_Mike:
Yes but an incandescent light bulb when cold has a low resistance, as it warms up the resistance increases, so it can’t limit the current until it is hot. Therefore it can’t limit the inrush current until after it has peaked.
Hi Grumpy_Mike:
Yes, but the change in resistance is in the milliseconds range... so, yes, it will limit the inrush current...
Say Goodbye to the Incandescent Lightbulb (as we know it) | Fluke.
Best regards
Grumpy_Mike:
Yes but an incandescent light bulb when cold has a low resistance, as it warms up the resistance increases, so it can’t limit the current until it is hot. Therefore it can’t limit the inrush current until after it has peaked.
Which is as - as i said - exactly the opposite of what would be required for inrush current limiting which is a NTC thermistor.
A light bulb is in fact, a PTC thermistor. Dead wrong!
Sorry Juan, you are not helping here! 
Paul__B:
Which is as - as i said - exactly the opposite of what would be required for inrush current limiting which is a NTC thermistor.A light bulb is in fact, a PTC thermistor. Dead wrong!
Sorry Juan, you are not helping here!
I'm afraid you are not thinking nor reading the links I included; it's right the light bulb is a PTC but it's wrong to assume that it doesn't perform a current limitation as it is after all a resistor. It's true that the perfect / professional / best designed ways to limit the current in these type of circuits is an NTC (as you can also see in the links I attached) BUT that doesn't mean a PTC can't be used (as it can also be read on those same links). I'll explain it step by step.
The test is easy, can the inverter light a 100W or 60W or 40W or 25W incandent light bulb (no PS here for the moment) without tripping due to having reached it maximum allowable current? Of course it can; how would it be an inverter to which I cannot connect a damn light bulb which doesn't exceed its power rating. But how? Why is this happening? The inverter is not triggering its protection? This is because the light bulb is not consuming more than the 1.25A the inverter is capable of providing. It is therefore performing a current limiting action (it is a resistor after all) without triggering the inverter's protection.
Quote from the Fluke link from my last post:
"I observed that the peak current occurred at an rms voltage input of about 55 volts. In today's example, using a new high efficiency halogen lamp (more about that later), the lamp is drawing 0.39 A rms (I used a ten-turn loop through my current clamp jaws, which made the apparent reading 3.9 A.) The peak current in that example was almost 1.2 A.
As I continued to turn up the voltage, the rms current increased, but the peak current became less - about 0.8 A."
So, Fluke's article conclusion (not mine): a 100W halogen lamp (an incandescent lamp after all -> Halogen lamp - Wikipedia) won't have a PEAK current consumption of more than 1.2A and, in fact, this will happen at a lower voltage than its rated working voltage (55VAC), being the peak current at its rated 120VAC voltage LOWER and the RMS current increased (of course to a value lower than the peak and so in the inverter's current capabilities range). Howda!!
Additionally, if you use a lower power incandescent light bulb, the max. current will be even lower as they have more resistance than higher power light bulbs.
So now that we have a working circuit (the incandescent light bulb connected to the inverter), we can open one end and connect the PS in series with the incandescent light bulb. In the first circuit, due to the incandescent light bulb's resistor, the inverter couldn't reach its maximum allowable current. Now, we are ADDING a very low additional equivalent resistance (ESR) corresponding to the PS (so Resistance Light Bulb + Resistance PS) - this is a higher resistance than before... therefore... again, no tripping.
The PS will start charging its ferrite cores, condensers, etc. (very low resistance in the beginning) and, as this happens, it will start to rise its ESR till eventually, the PS's ESR will be the dominant resistance in this two resistors circuit. Therefore, the effect that I was telling you of "the light bulb will light up and dim afterwards"; how much will it dim will depend on the final PS's ESR and the light bulbs own resistance at low current levels (but this time dominated by the PS). At the residual current rate (mostly determined by the higher ESR PS) the light bulb is off or almost off (in terms of light emission) and therefore, the voltage across its terminals will be low (10-30V? this will be dependant on both the light bulb resistance and the PS's ESR); so, to finally cancel the action of the light bulb, I proposed to connect an standard mains light switch in parallel to the incandescent light bulb. When this state is reached, short circuiting the incandescent light bulb finally applies all AC power directly to the PS (no inrush current now, that phase has already passed as all the low resistance paths in the PS have been conveniently fed), thereby ending the process of 'switching on' the power supply without tripping the inverter.
So, there you are, a cheap, readily available PTC piece of hardware at every house or hardware store will make the dirty job of a neaty NTC which is hard to find (you will have to order it online or search at specialized electronics stores to find it).
Believe or not... it's just Ohm's LAW!
Hope this will help you understand why i'm not dead wrong.
Hope this will help you understand why i'm not dead wrong.
No it doesn't.
You said:-
Yes, but the change in resistance is in the milliseconds range... so, yes, it will limit the inrush current..
That simply does not make sense. You admit that there is no current limiting at first, so no matter how long it takes to kick into doing the current limiting the peak current has always reached a maximum before it kicks in. Electronic things designed to trip on excess current would still trip. Only if you have mechanical trips can you get away with sloppiness like this.
Believe or not... it's just Ohm's LAW!
Well no. Ohm's law only deals with idealised constant resistances which in the real word do not exist. The fact that you have a temperature / current dependant component means you can't apply Ohm's law.
There seem to be two camps here,
- Ohms law is always true.
- Ohms law is not always true.
In fact the actual truth is:-
Ohms law is NEVER true
First off think what Ohm was trying to do. He was wanting some way of characterising the voltage / current relationship in a circuit. In other words for a given circuit how many amps per volt characterised the circuit. He did this by saying that "voltage is proportional to current" and anything that is proportional can be made into a equivalence by using a constant of proportionality. Hence
E = kI
Where E is the electro motive force measured in volts, and I is the current measured in Amps. The constant of proportionality k he gave to a constant which was called resistance, but it is just a constant of proportionality.
Where this is fundamentally wrong for ALL materials is that k is not a constant, meaning that resistance is NEVER a constant.
Sure for some materials it is close to a constant but it never is a constant. The truth is that what we call resistance is a function of many things, these things include, but are not exclusively limited to, temperature, voltage, current, frequency, atomic structure, and time.
Let's look at a case where most people think ohms law works. Take a lump of carbon, at low voltages and currents it is constant enough but it has a temperature coefficient, as does most materials. So it is only a constant at a fixed temperature. As you increase the current through it, it heats up and so the resistance changes. Therefore ohms law is not obeyed because the temperature change introduces a deviation from what would have been predicted at a lower current. Sure it is pretty dam good and well good enough for working with electronics, but it is not a fundamental law of physics and it does not hold.
The problem is that all real materials do not have a linear relationship between voltage and current. Take a gas for example, that has a very high resistance for small voltages. As the voltage increases the resistance stays quite constant until it reaches a point where the voltage is sufficient to start to remove electrons from the outer orbits of the gas molecules. This doesn't happen at a single voltage but is spread over a very small range. What happens is the normal thermal energy in the gas is added to the pull by the electric field it is in caused by the voltage. Sometimes this thermal force is in the opposite direction of the electric field and sometimes in the same direction. When it is in the same direction it combines with the electric field to detach an electron. When enough of these events happen electrons can pick up enough energy from the electric field to be involved in collisions with other molecules and help to dislodge them. All the time the resistance of the gas is dropping. A point will be reached when the gas breaks down and these collisions form a continuous discharge and the quantity we call resistance has dropped to a very low point. Clearly the voltage / current relationship is not constant and is very non linear.
So in conclusion for any situation you can think about resistance is never constant so ohms law is never true.
But for something that is never true it is very useful because it's deviation from true is so small it is not important, especially if it is applied correctly. That is for materials that exhibit a near constant resistance OR over a small enough section of the restive function that equates to a straight line.
Paul__B, Grumpy_Mike,
Quick question, how long does it take for these 1000uf capacitors in the schematic to discharge when we cut the power? Wanting to provide the band directors some safety info.
Quick question, how long does it take for these 1000uf capacitors in the schematic to discharge when we cut the power?
It depends on the load, that is if the LEDs are on when the plug is pulled. Other wise it will just discharge after about half a second as it tries to power everything.
Wanting to provide the band directors some safety info.
Nothing to provide, it is not dangerous. You only have 5V. Think of a kids electric train set. Those fully exposed rails have 12V on them all the time, they are not a safety risk, so why should a charged capacitor at 5V be?
Ok, thank you for the information!
Grumpy_Mike:
No it doesn't.
You said:-That simply does not make sense. You admit that there is no current limiting at first, so no matter how long it takes to kick into doing the current limiting the peak current has always reached a maximum before it kicks in. Electronic things designed to trip on excess current would still trip. Only if you have mechanical trips can you get away with sloppiness like this.
Well no. Ohm's law only deals with idealised constant resistances which in the real word do not exist. The fact that you have a temperature / current dependant component means you can't apply Ohm's law.There seem to be two camps here,
- Ohms law is always true.
- Ohms law is not always true.
In fact the actual truth is:-
Ohms law is NEVER trueFirst off think what Ohm was trying to do. He was wanting some way of characterising the voltage / current relationship in a circuit. In other words for a given circuit how many amps per volt characterised the circuit. He did this by saying that "voltage is proportional to current" and anything that is proportional can be made into a equivalence by using a constant of proportionality. Hence
E = kIWhere E is the electro motive force measured in volts, and I is the current measured in Amps. The constant of proportionality k he gave to a constant which was called resistance, but it is just a constant of proportionality.
Where this is fundamentally wrong for ALL materials is that k is not a constant, meaning that resistance is NEVER a constant.Sure for some materials it is close to a constant but it never is a constant. The truth is that what we call resistance is a function of many things, these things include, but are not exclusively limited to, temperature, voltage, current, frequency, atomic structure, and time.
Let's look at a case where most people think ohms law works. Take a lump of carbon, at low voltages and currents it is constant enough but it has a temperature coefficient, as does most materials. So it is only a constant at a fixed temperature. As you increase the current through it, it heats up and so the resistance changes. Therefore ohms law is not obeyed because the temperature change introduces a deviation from what would have been predicted at a lower current. Sure it is pretty dam good and well good enough for working with electronics, but it is not a fundamental law of physics and it does not hold.
The problem is that all real materials do not have a linear relationship between voltage and current. Take a gas for example, that has a very high resistance for small voltages. As the voltage increases the resistance stays quite constant until it reaches a point where the voltage is sufficient to start to remove electrons from the outer orbits of the gas molecules. This doesn't happen at a single voltage but is spread over a very small range. What happens is the normal thermal energy in the gas is added to the pull by the electric field it is in caused by the voltage. Sometimes this thermal force is in the opposite direction of the electric field and sometimes in the same direction. When it is in the same direction it combines with the electric field to detach an electron. When enough of these events happen electrons can pick up enough energy from the electric field to be involved in collisions with other molecules and help to dislodge them. All the time the resistance of the gas is dropping. A point will be reached when the gas breaks down and these collisions form a continuous discharge and the quantity we call resistance has dropped to a very low point. Clearly the voltage / current relationship is not constant and is very non linear.
So in conclusion for any situation you can think about resistance is never constant so ohms law is never true.
But for something that is never true it is very useful because it's deviation from true is so small it is not important, especially if it is applied correctly. That is for materials that exhibit a near constant resistance OR over a small enough section of the restive function that equates to a straight line.
Oh, man! Your reasoning is really flawed... Ohm's law is fundamentally right (it wouldn't have been applied through so much time if it weren't); you are presuming constant current, constant voltage, constant resistance... but when you study electronics you learn that there are many types of signals and materials and these equations still keep being valid. Just say k is not k but r(T), being T the temperature. The resistor will keep being a resistor, I said the change in resistance is in the range of milliseconds, I didn't say the light bulb would not have any resistance when cold, I just said its resistance change from cold to hot is extremelly quick and yes, Ohm's law keeps being valid, the only caveat is that now there is another variable - temperature - playing in the game.
As for the rest of you disertation ... oh, man...
Oh, man! Your reasoning is really flawed... Ohm's law is fundamentally right
Oh man you reading skills are so poor. Go back and read what I said.
but when you study electronics
Have been doing electronics over 50 years. I taught it at University for 21 years.
What is your experience level?
Grumpy_Mike:
It depends on the load, that is if the LEDs are on when the plug is pulled. Other wise it will just discharge after about half a second as it tries to power everything.
Nothing to provide, it is not dangerous. You only have 5V. Think of a kids electric train set. Those fully exposed rails have 12V on them all the time, they are not a safety risk, so why should a charged capacitor at 5V be?
Oh man, you really shouldn't give those advices - what is dangerous is current; DC current is dangerous in the sense that if you touch an exposed cable and enough current passes through your muscles, your muscles will contract and you won't be able to let go the cable (this is called tetanus). Two much current will likely produce deep burns due to power dissipation. It doesn't matter if it's 5V, 12V or 1000V; a 1000V source with a very low current won't kill you but a 5, 12V or 20V battery with high amperage can kill you if the circumstances ally against you (low impedance - resistance - path). Damn! Ohm's law! Have you ever touched the terminals of a 9V LR6 battery with the tip of your tongue? It will prickle. Sure you can touch them with your 'dry' fingers and you won't notice anything but a wet connection will do the trick. Now, the LR6 battery doesn't have much power, put it a higher voltage and higher amperage battery and the right conditions (maybe some rain, a spilled coke, etc...).
Physiological effects of electricity:
https://www.allaboutcircuits.com/textbook/direct-current/chpt-3/physiological-effects-electricity/#:~:text=Direct%20current%20(DC)%20is%20more,shocking%20current%20has%20been%20halted.
DC protection is quite similar to AC protection so, as security is A MUST, you should install a similar setup to what an AC electric box has. This would include at least an adequately sized fuse or DC circuit breaker for overcurrent protection, which should be installed as close as possible to the DC power source on the positive wire (so an overcurrent - as a short circuit - between the DC power source and the protection is unlikely to occur) and all wiring is protected. This will also protect your circuit from catching up on fire if there would be a short circuit somewhere and it would also protect your LEDs from blowing up. You know, nothing happens till it happens.
If the setup is going to be installed outdoors you could also want to install a surge protection against lightening (usually due to inducted surge) or ESD.
https://www.littelfuse.com/technical-resources/application-designs/lighting/outdoor-led-lighting.aspx
If it's outdoors and it's going to be outside for some time, you can also install a lightening protection at an adequate height (the typical protected area of a lightening rod is the area inside a 45 degree cone starting at its high tip downwards). This should have sufficient height and a bare copper cable of enough section connected to ground.
Grumpy_Mike:
Oh man you reading skills are so poor. Go back and read what I said.
Have been doing electronics over 50 years. I taught it at University for 21 years.
What is your experience level?
I'm an electronics and telecom engineer with 20+ years of experience in systems and solutions integration. My reading / writing / speaking skills are really good at various languages and well, the point with your dissertation is that it got so off of the topic... if all you can really answer is personal bullying and trying to impose a pretended intellectual status or knowdlege over mine... just leave it alone.
@pfulda Would it be a serious inconvenience for you to test if your inverter can light an incandescent light bulb without tripping its output protection? maybe try with 60W and 100W? So we can close this discussion with some experimental results.
I'm an electronics and telecom engineer with 20+ years of experience in systems and solutions integration.
So no actual understanding. Shown by this comment
Oh man, you really shouldn't give those advices - what is dangerous is current; DC current is dangerous in the sense that if you touch an exposed cable and enough current passes through your muscles, your muscles will contract and you won't be able to let go the cable (this is called tetanus).
Are you some sort of idiot, sure I know it is the current that is the killer. But what you fail to understand is that the current has to be driven through a voltage. And as that voltage is driven from a capacitor it will decrease. It is ohm’s law, remember that?
So 5V is dangerous but 12V on a train set is not? So take two thumb tacks and put one in each wrist, and then accidentally touch one of the thumb tacks with 5V and the other with ground then there might be a danger. But in the real world inhabited by real people that scenario is just as ludicrous as the other advice you are giving.
I think you are way out of your depth on this thread and you would do everyone a service if you stoped posting. Your experience is not in micro electronics and you don’t seem to have picked up any common sense at all.
On the other hand it is alway possible you are a troll.
"Tetanus is an infection caused by bacteria called Clostridium tetani. When the bacteria invade the body, they produce a poison (toxin) that causes painful muscle contractions. Another name for tetanus is “lockjaw”. It often causes a person's neck and jaw muscles to lock, making it hard to open the mouth or swallow."
Nothing to do with electricity.
Well, he actually meant "tetany" which would be a correct interpretation, but this fellow's intrusion into this discussion with suggestions that are simply wrong, is most unwelcome to say the least.