Changing from metal halide to led for sign lighting


  #1  
Old 02-13-18, 07:18 PM
T
Member
Thread Starter
Join Date: Feb 2018
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Changing from metal halide to led for sign lighting

Hi
I've got two sign lights that are metal halide. I switched them to leds. I bypassed the transformers and wired the bases directly to the screw bases. The leds worked great for a month then they're dead. I checked the wires and the bases and they have power. There's a case with a glass window and ambient temperature averaged 10 degrees Fahrenheit so I don't think they overheated. The leds are 20 watt and 4000k corn cob type. Is there something obvious that I'm missing? Why wouldn't they last. The company says they have never had them burn out so quickly.
 
  #2  
Old 02-13-18, 07:40 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,280
Received 862 Upvotes on 725 Posts
What is the voltage to the sign and what are the LED lamps rated for? Many cases metal halide ballasts are powered by 208 or 277 volts (or even 480) Did you also bypass the capacitor?
 
  #3  
Old 02-14-18, 06:13 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,501
Received 2,108 Upvotes on 1,887 Posts
I have tried corn cob bulbs and did not have good luck. Some had very short lives, a couple lasted a year and I don't think I had any that made it to two years. I think the bulbs have a problem dissipating heat and they got quite hot when operating. Enclosed in a small sealed fixture it is possible they are overheating.
 
  #4  
Old 02-14-18, 06:18 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,058
Received 159 Upvotes on 145 Posts
What is the operating temperature range for the bulbs, could be to cold,
Just a thought
Geo
 
  #5  
Old 02-14-18, 09:04 PM
T
Member
Thread Starter
Join Date: Feb 2018
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
I think the voltage is 120. There's a timer with a regular receptacle where the lights are plugged in then they split into two at a junction box. So I'm assuming the voltage is 120 but I'll check. They sell an led in a box with reflector and everything maybe I should install those instead of corn cobs. Tolyn, I think I also bypassed the capacitor I just tied into the leads coming in the reflector boxes.
 
  #6  
Old 02-15-18, 04:12 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,280
Received 862 Upvotes on 725 Posts
I'm assuming the voltage is 120
sdfsfdsf
Yes, check with a meter or voltage tester.

I just tied into the leads coming in the reflector boxes
sdfsfdsf
Metal halide lamps will have a ballast kit which includes a transformer and a cap. All must be bypassed or damage to the new led lamp can result. In order to bypass the ballast you should have seen both the cap and the transformer in some type of enclosure. The transformer will about 4" x 6" with a copper coil. If you just tied to the leads going to the socket it does not sound like you bypassed anything. Perhaps you could post some pictures.

could be to cold
jkashkajshdkasj
LEDs are not affected by cold. Heat however can damage them.
 
  #7  
Old 02-15-18, 09:24 PM
T
Member
Thread Starter
Join Date: Feb 2018
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Hi Tolyn,
I think you're misunderstanding me. I unhooked the leads coming into the fixture that's where all the guts are. The capacitor is part of the guts I guess. Then I unhooked the leads from the screw bases and tied them into the leads coming into the fixture. Yes I bypassed the transformers and capacitor too. One thing was the contacts at the bottom of the bases needed to be bent up a little. I hear that intermittent contact there can cause leds to burn out.
 
  #8  
Old 02-16-18, 04:58 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,280
Received 862 Upvotes on 725 Posts
Ok, that sounds correct. I have not heard that about intermittent contact but it can stand to reason.

Again, make sure the voltage is correct for what the lamp is designed to use. If it is then I would say they are just crappy lamps.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: