3rd Party LED and Power Supply Testing

[AGinVT]

Hello All. I have a quick question that I have been unable to find an answer to on my 101 searches.

Our sign company is tasked with installing 3rd party signage more and more every year and I was hoping for some advice on what piece of equipment would work best to test LEDs and power supplies on illuminated signage. Is there a bench top power unit that others on here have used for this purpose? Any recommendations on the best equipment and procedures would be greatly appreciated.

This question is stemming from a 3rd party company that hired us on to install a simple LED light box back in January, only to reach back out a few months later to survey the sign, because it wasn't lighting. Turns out, as expected, the sign was never connected to the main power supply, (Happens fairly often despite many disclaimers and direct correspondence stating that we do not do the final electrical connection. We always inform clients that they will need to contact a licensed electrician for that step, because it is illegal to make that connection is our state without an electrical license, blah blah.). It got me thinking though that we should probably take a closer look at our pre-installation inspection process. And that's where all of you come in. Any constructive advice would be great.

Thank you in advance.

 

[Texas_Signmaker]

Are you asking about how to test the signage before you leave the site? . I run an extension cord up to the sign and test it, showing the client it lighting before I close it up (or take photos of the LEDs on for your client) I have a small 5' cord with plug on one end and loose wires on the other that I can quickly connect to a power supply. If no power onsite, run it off your truck. If you're going to a service call with an outage, you should be carrying around a 12v and 24v power supply anyway... just plug it up and test. That's what I did here yesterday.. quickly plugged up a new P/S and it fired up the bank of LEDs that were out.

 

[GaSouthpaw]

We test our builds by hooking them up and lighting them for a couple of hours to make sure all of the modules are working, that there's no flicker, etc. No real special equipment required- we use an modified extension cord and wire into it temporarily.

 

[AGinVT]

We test our builds by hooking them up and lighting them for a couple of hours to make sure all of the modules are working, that there's no flicker, etc. No real special equipment required- we use an modified extension cord and wire into it temporarily.

This is the technique we have used in the past. Didn't know if there was a more standard practice out there.

 

[GaSouthpaw]

This is the technique we have used in the past. Didn't know if there was a more standard practice out there.

I'm by no means an authority, that's just how we test 'em. Someone probably has a much more thorough method, but we don't (usually) need more than that. You might want to make it part of your workflow, if you're doing a lot of that type of work. Like, first thing, open the box/crate/whatever to inspect for damage, the light it to make sure it works. As I'm sure you know, there are plenty of companies that will blame the installer for problems that started with them.

 

[JBurton]

That's what I did here yesterday

That's some interesting track, but more to the point, what kinda joint has such a big/expensive sign in the lobby?

I have a small 5' cord with plug on one end and loose wires on the other that I can quickly connect to a power supply.

We call them pigtails, mine has wagos on it, saves the hassle of straightening the wires out every other time with wirenuts.

 

[Gettin'By]

Back when I was working on electronics an extension cord with one end pulled off for wiring on lugs was called a "widow maker". If the cord had both plugs on it we called an "electron hose".

 

[AGinVT]

Ha, the names are great. The extension cord method works fine. I just didn't know if anyone used any equipment that both lit the LEDs and tested the amperage/power levels.

 

[JBurton]

I just didn't know if anyone used any equipment that both lit the LEDs and tested the amperage/power levels.

You could always plug one of these into the extension cord to verify amperage, but I can't say I've ever seen anybody concerned with draw on a signage install.

 

[Texas_Signmaker]

That's some interesting track, but more to the point, what kinda joint has such a big/expensive sign in the lobby?

We call them pigtails, mine has wagos on it, saves the hassle of straightening the wires out every other time with wirenuts.

I can't slide the face out of the track cause there is a shelving unit in the way. Have to make a second trip to remove bottom retainer with a helper. Waiting on them to approve second PO...even though I told them all this before I went out there and looked at the pics.

 

[JBurton]

I can't slide the face out of the track cause there is a shelving unit in the way. Have to make a second trip to remove bottom retainer with a helper. Waiting on them to approve second PO...even though I told them all this before I went out there and looked at the pics.

Just did a survey for national company A, to remake some faces for extra large channel letters. Company A never sends PO for production, says client declined the work. National company B then calls, issues PO for same survey, they won't take the previous measurements, so we have to go down to site, login over the phone, fly up and take some selfies, and resend the dimensions to company B, who will now accept them. Luckily, the f*ckery stopped there, and company B issued the PO for refabricating faces. Only con was all the extra mileage on my bucket truck for no good reason.

 

[AGinVT]

Just did a survey for national company A, to remake some faces for extra large channel letters. Company A never sends PO for production, says client declined the work. National company B then calls, issues PO for same survey, they won't take the previous measurements, so we have to go down to site, login over the phone, fly up and take some selfies, and resend the dimensions to company B, who will now accept them. Luckily, the f*ckery stopped there, and company B issued the PO for refabricating faces. Only con was all the extra mileage on my bucket truck for no good reason.

That sounds about right.

 

[danhayes1188]

when doing this sort of functionality test, where do you plug the extension cord into, a wall outlet? powerbank?(Q1) we bring a generator to every job and ive been told i can use the gen to power the lights to test functionality, but research indicates this could easily damage the leds or driver due to power fluctuations. I am trying to understand the best way to avoid this, especially at jobsites that dont have anywhere for us to pull power from. I assume we need to invest in a powerbank for such occasions but am trying to consider all options and understand why we should not use certain methods. From my understanding, our 60w power supplies are designed to change 120v ac to 12v dc, considering that's what the cigarette lighter in our vehicles produce, could you run a long extension cord from the 12v accessory plug directly to the leds? (q2) In a pinch could i theoretically use 2 wires and alligator clips and bring the car battery directly to the led driver to test in cases which the extension cord isn't long enough?(q3) Would that require a fuse or inverter to assure leds are supplied power without the risk of damage? (q4)The only test ive tried is a drill battery to individual letters, bypassing power supply and this method only verifies the functionality of the leds themselves rather than the entire system which is my goal. and yes i understand i am severely uneducated in this field and need to do more research, i am. Regardless i appreciate your time and feedback, even if its just to tell me i should know this already

 

[JBurton]

but research indicates this could easily damage the leds or driver due to power fluctuations.

My anecdotal research contradicts this statement. I mean to say, we test all of our installs off a miller bobcat welder/generator and haven't damaged any drivers/power supplies yet.
I did hear a story about a shop that was using 12v tool batteries to test the secondary side of installs, but they weren't doing anything to regulate the amperage, so the modules were getting several amps beyond what they were meant to carry pushed through them, which was causing them to fail within months of install.
As far as using a vehicles 12v, you could do it from a cigarette lighter, as it has a fuse to keep it from getting the full draw off the battery, but you're very restricted in how long of a run of wire you can use from the source to the modules. Plus the alternator typically puts out above 12v, so I feel this is an even risky solution compared to the generator, not to mention it won't tell you if you are installing a power supply that is just bad from the factory.

The only test ive tried is a drill battery to individual letters

Oh, yeah, don't do this unless it's for a second or two. This is exactly how they were damaging letters. Same with a car battery. Just grab a 3000 watt generator from harbor freight or tractor supply, or a welder/generator combo. If it damages the power supply, then that is the easiest thing to replace anyway, but again, anecdotally speaking, it shouldn't hurt it.
A power bank would work fine, but it's an additional expense and the battery will eventually wear out and need replacing, or inevitably get to job site and need to be recharged.
So in short:
1. its fine
2. don't do this
3. a fuse or resistor would prevent damage, yes
4. again, don't do this!