5 x 5 tent, led grow light design ????

NugHeuser

NugHeuser

Well-Known Member
eatled said:
Adjust the voltage to the minimum (counter clockwise), fire it up, then slowly increase the voltage.
Monitor the temperature of the strip. You can use your finger.
Increase the voltage until the strip feels somewhere between warm and hot but not burning hot. You should be able to leave your finger on continuously.

You are not using strips with current limiting resistors are you?
Click to expand...
Not sure what the current limiting resistors are.

https://www.cutter.com.au/product/ssk-1560-3590cr/?attribute_pa_led-colour=3500-kelvin&attribute_pa_thermal-tape-length=no-tape&attribute_pa_cri-colour=90-cri

Those are the exact strips being used
 
NugHeuser

NugHeuser

Well-Known Member
So I'm ready to wire these up, my buddy accidentally didnt have the wires come already soldered on so we have to do it. Looking at the 2 terminals on the strip, neither has a plus or minus or anything deciphering which needs the positive or negative wire. Does it matter? If it does how can I know which is which? We have a multimeter if needed
 
welight

welight

Well-Known Member
NugHeuser said:
These are what I'm working with. Are those just poke in's for the wire or do I solder to it? And which is pos or neg?View attachment 4375344 View attachment 4375347
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Hi Nug
sorry the connectors covered the polarity signs, positive + in line with the text, - on the bottom

yes you just poke in wire, the harley davidson foot pedal on the side is to release the wire. Most folks here go solid core wire, Im a stranded wire guy because stranded has nearly twice the current carrying capacity of solid core. We have just released a new version that is wider where cathode and anode are clearly marked

Cheers
Mark
 
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NugHeuser

NugHeuser

Well-Known Member
welight said:
Hi Nug
sorry the connectors covered the polarity signs, positive + in line with the text, - on the bottom

yes you just poke in wire, the harley davidson foot pedal on the side is to release the wire. Most folks here go solid core wire, Im a stranded wire guy because stranded has nearly twice the current carrying capacity of solid core. We have just released a new version that is wider where cathode and anode are clearly marked

Cheers
Mark
Click to expand...
Awesome, I appreciate your help! Should have the light going in no time.
 
Snuff-a-Puff-agus

Snuff-a-Puff-agus

Member
welight said:
Hi Nug
sorry the connectors covered the polarity signs, positive + in line with the text, - on the bottom

yes you just poke in wire, the harley davidson foot pedal on the side is to release the wire. Most folks here go solid core wire, Im a stranded wire guy because stranded has nearly twice the current carrying capacity of solid core. We have just released a new version that is wider where cathode and anode are clearly marked

Cheers
Mark
Click to expand...
On those LED strips if the connectors broke off are you able to solder the wire directly to the spot and work just fine?
 
eatled

eatled

Active Member
welight said:
Im a stranded wire guy because stranded has nearly twice the current carrying capacity of solid core.
Click to expand...
Where did this gem of a fact come from?
Are you saying 18 ga stranded can handle nearly twice the current of solid 18 ga?
I don't think so. See the wire amp table.
Amperage table for single and mulitcore wire: https://www.engineeringtoolbox.com/wire-gauges-d_419.html

I use solid 20 ga "Bell Wire". It's what the Telcos used to wire land lines indoors. $11 at Home Depot. It dual so it's actually 200' of wire. Can be purchased 23¢ per foot.
It works perfect with the Bridgelux poke in terminals.
It will handle about the same current (6 amp) as 16 ga. stranded (5-7 amp).

 
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welight

welight

Well-Known Member
geez I must have been on the sauce when I wrote that, ok not double, 'solid wire of same length resistance of that wire is higher than stranded wire. hence stranded wire carries more current than solid wire due to lower resistance' is more accurate
Cheers
 
eatled

eatled

Active Member
welight said:
geez I must have been on the sauce when I wrote that, ok not double, 'solid wire of same length resistance of that wire is higher than stranded wire. hence stranded wire carries more current than solid wire due to lower resistance' is more accurate
Cheers
Click to expand...
I understand, I need a keyboard with a breathalyzer.

The previous table showed that stranded wire carries LESS current than solid.
It also shows the resistance is the same. It is about the same, not exactly. Some stranded has higher resistance and some lower.

The resistance of stranded (bunched) is typically higher than solid. When the strands are concentric the resistance is lower.
The difference in resistance is negligible.
This table lists the resistance based on number of strands: https://www.calmont.com/wp-content/uploads/calmont-eng-wire-gauge.pdf
 
eatled

eatled

Active Member
NugHeuser said:
Not sure what the current limiting resistors are.
Click to expand...
There are strips that are designed to be powered from a constant voltage supply.
They use on board resistors to set the current limit. That is not the case with your boards.

Your boards are designed to work with a constant current source.
Although if you are VERY careful you can save some money (with risk) and power them with a voltage source.
The key to doing this is the temperature and not exceeding the max voltage.
If the LEDs get too hot they will draw more current. As they draw more current they get hotter and on and on until the board burns up.
This thermal runaway process can take hours so you need to check the temperature of the strip occasionally for a couple of hours.

There is a similar thermal runaway process that takes place when you power two strips in parallel with a constant current source.
The current in one strip increases and the other decreases until most current is going through a single strip.
This type of runaway can take many hours to play out.

The safest way to power strips is with a single string of strips powered by a single constant current source.
Like using an LDD driver with each strip and powering all the LDDs with a single LRS.

I have some Bridgelux Vesta strips powered by 350, 700, and 1000 mA LDDs.
The 350 mA is warm to the touch at about 40° C.
The 1000 mA is almost uncomfortable to touch for an extended period of time at about 50° C.
The 700 mA is in between warmer but not very hot.
Do not exceed 50° C when powering with a voltage source.
 
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1212ham

Well-Known Member
eatled said:
I use solid 20 ga "Bell Wire".
It will handle about the same current (6 amp) as 16 ga. stranded (5-7 amp).
Click to expand...
Sorry, but that's not correct. That chart shows 4.1 ohms per 1000' for 16 gauge solid and 4.15 ohms for 16 gauge, 26 strand. 20 gauge is about 10.5 ohms per 1000', or about 2.5 times higher resistance than 16 gauge, so that 20g will handle about 2.5 times less current than 16g.

welight said:
geez I must have been on the sauce when I wrote that, ok not double, 'solid wire of same length resistance of that wire is higher than stranded wire. hence stranded wire carries more current than solid wire due to lower resistance' is more accurate
Cheers
Click to expand...
What? :confused:

Ampacity is determined by wire gauge, not the number of strands. The number of strands only has an effect when dealing with the higher frequencies of AC, then skin effect comes into play.... but we're not dealing with high frequency AC.
 
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ANC

ANC

Well-Known Member
I actually went with tinned stranded wire this round, it is a bit more pliable and can take being moved without ripping your poke ins off. Which is why you never see solid core cable in a car where the movement can lead to metal fatigue in the wire.,
If you look at the Hinflux datasheet you will see they actually give prefered thread count and gauge if you decide to go stranded...
 
Abiqua

Abiqua

Well-Known Member
eatled said:
There are strips that are designed to be powered from a constant voltage supply.
They use on board resistors to set the current limit. That is not the case with your boards.

Your boards are designed to work with a constant current source.
Although if you are VERY careful you can save some money (with risk) and power them with a voltage source.
The key to doing this is the temperature and not exceeding the max voltage.
If the LEDs get too hot they will draw more current. As they draw more current they get hotter and on and on until the board burns up.
This thermal runaway process can take hours so you need to check the temperature of the strip occasionally for a couple of hours.

There is a similar thermal runaway process that takes place when you power two strips in parallel with a constant current source.
The current in one strip increases and the other decreases until most current is going through a single strip.
This type of runaway can take many hours to play out.

The safest way to power strips is with a single string of strips powered by a single constant current source.
Like using an LDD driver with each strip and powering all the LDDs with a single LRS.

I have some Bridgelux Vesta strips powered by 350, 700, and 1000 mA LDDs.
The 350 mA is warm to the touch at about 40° C.
The 1000 mA is almost uncomfortable to touch for an extended period of time at about 50° C.
The 700 mA is in between warmer but not very hot.
Do not exceed 50° C when powering with a voltage source.
Click to expand...
In slug based diodes, that was a factor for some reason probably just quality control or using drastically different voltages, causing unequal amperage at a certain Tc or Tj, but these new dies are far superior and really dont seem to even start runaway at less than 4A and thats 4x the limit let alone not even supposed to be working aka melted not physically attached to a substrate,lol. Didnt Led gardener put like 8 amps to a strip for a sustained period?
 
eatled

eatled

Active Member
1212ham said:
Ampacity is determined by wire gauge, not the number of strands
Click to expand...
I do agree. There is a small difference plus and minus according to this table: https://www.calmont.com/wp-content/uploads/calmont-eng-wire-gauge.pdf
But these guys are a little anal on the topic, they are supplies to the Space Shuttle Programs, and the Hubble Telescope. The difference does not matter as you say.

1212ham said:
Sorry, but that's not correct
Click to expand...
I based that comment on the numbers circled in the table as shown below.
At the bottom of the table they make a statement regarding ohms.

The reason I brought it up is because I think it is easier to use solid with these poke in connectors and did not want the guy to make his decision to use stranded based on misinformation.
untitled.JPG
 
1

1212ham

Well-Known Member
To anyone that's interested, a couple quotes from the text above the original table.

"The AWG table below is for a single, solid, round conductor."
It says the table is for solid wire, it does not say the table is for stranded wire!

"The table below indicates the current ratings of PVC-insulated single and multicore wiring cables."
"Multicore wiring cables" means cables with multiple wires, not a single wire with multiple strands!

In the partial table posted by eatled, he replaced the original header and changed the word "Multicore" to the word "stranded".

And last but not least, most people here know 20 gauge can't carry the same amps as 16 gauge whether it's solid or stranded!
 
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