# Efficient Sunritek T8-style LED



## naoki (Aug 12, 2015)

There have been LED light bulbs which can be used in place of T8 fluorescent light bubls. Until recently, the efficiencies of these were not so great. But there are quite a few new crops of bulbs with impressive specifications. I recently got one of the most efficient model (147 lm/W and very inexpensive), so here is the test report. I've been mostly using COB-type DIY LEDs (most recent types), which achieve higher efficiency than most commercial products. But this kind of T8-LED could be a game changer. In comparison, efficacy of T5HO and T8 is around 90 lm/W, and T5 (normal output) is around 100 lm/W.

The product is by Sunritek, model# ST-DTA12-12WC (3000K or 4000K) (the info in the website is a bit outdated, but they can send better info if you contact them).

*Background*:
There are mainly 2 (+1) types of T8 LED bulbs.

The first type simply fits to the pre-existing fluorescent T8 fixture (like shop light) without any modification. This types REQUIRES working fluorescent ballast.
The other type requires minor (super-simple) re-wiring of fixture (basically you are disconnecting the ballast).
Then there is something called a "hybrid" type which can be used with or without the fluorescent ballast.
I personally prefer the 2nd type, direct-wiring, ballast-free models. The ballast wastes energy (so overall efficiency is lower with the first type), and if the ballast breaks, you need to replace the ballast. A lot of cheap shop lights have cheap ballasts which breaks over time, and I have 10's of broken shoplights. I'm actually glad I have saved those broken shop lights because I can get rid of the ballast and re-use it with direct-wire type LEDs.

Last week, I saw the first type with a relatively good spec. in HomeDepot (Philips InstaFit 4000K, $25, 1600lumen, 12W, 133lm/W). I'm not familiar with this kind, but this would be a very nice fit for people who doesn't want to do modification.

*False advertisement*:
There are lots of LED companies which advertise bogus performance specifications. Especially, you needs to be careful with those from ebay and Alibaba. But even from these sources, there are some decent companies. The following DoE "Lighting Fact" database contains many products tested by 3rd parties, so one can check the fact from false advertisement.

http://www.lightingfacts.com

By checking the database, Sunritek appears to be an honest company. Sunritek ST-DTA12-12WC(4000K), which we are talking here, is almost at the top efficiency (147.09 lumen/W). This is seriously amazing efficiency. Also, DoE CALiPER report for Linear (T8) LED is a good read, and contains the data from the previous Sunritek model as the top performer.

*Cost*
I initially contacted the company via Alibaba, but I think you can use the email which is listed here. The only way to get these at this time seems to be factory direct. I got 20x 4' bulbs ($10 each), and the shipping was $95 with UPS. Then WesterUnion Transfer fee was $30. So $325 total for 20 bulbs ($16.25 per bulb). It is a whole-saler, but they sent me "samples" (no minimum order quantity). Since the shipping is expensive, it is only cost effective if you place a large quantity order (maybe a group buy?).

*Customization/order options:*
There are several customization options.


Wattage: 12W, 15W, 18W
Case style: Aluminum back (DTA series) or all polycarbonate case (DTP series)
Efficiency range: there are lower efficiency options, but you want to specify the top efficiency 140-150lm/W.
Diffuser: clear (no diffuser) or diffuser (which provide more even light, but reduce the total output)
Wiring: single-ended vs double-ended
Color temp: 3000K, 4000K, 5000K etc.
The person who helped me was really easy to communicate, and helpful to decide which option to tak(PM me if you want to get her email).

Comments about the options:

I went with 12W because it has the maximum efficiency. As you go higher, you'll get more total output, but the efficiency goes down. With 18W, the efficiency goes down to slightly below 140lm/W (still very good).
From my measurement, aluminum back DTA series seems to be slightly better than plastic DTP series.
I chose clear (no diffuser) to get maximum efficiency.
Single-ended is easier to wire than double ended in my opinion.
I went with 3000K (which is probably a slightly better option from my measurement below) and 4000K.

*Measurement:*
I measured at 12" from the tube (not from the LED surface) in the very middle of the tube. Each value for the T8LED is the average of two different light bulbs. I measured only once for the T5HO and 2 bulb T8LED setup. I used LX1330B for footcandles, and Li-Cor LI-190A for the Photosynthetic Photon Flux Density (PPFD, unit= micromol/m^2/s). I tested DTA (aluminum) 3000K and 4000K and DTP (plastic) 4000K. Room temp was 69F.


```
watt  PPFD footcandle PPFD/W
DTA(3000K)   13    42.8     275    3.29
DTA(4000K)   13.1  42.0     294    3.21
DTP(4000K)   13.3  38.5     255    2.89
2xDTA(3000K) 25.8  82       485    3.18
T5HO(4100K) ~50    83       590    1.66
T5HO(5000K) ~50    85       625    1.7
```

The T5HO bulbs were brandnew Philips F54T5/841/HO/ALTO (4', 54W, 4100K) and F43T5/850/HO/ALTO (4', 54W, 5000K), which were about $10 from HomeDepot. After the initial output, the output of florescent light decays. I did use a regular 4-bulb T5HO fixture with reflectors. The energy consumption for T5HO is calculated from the consumption from 4-bulb fixture, which consumed 200W with all 4 bulbs in. If you put only 1 bulb in the 4-bulb fixture, the actual wattage is about 70W.

*Interpretation:*

Pretty impressive! Basically a shoplight with 2 of ST-DTA12-12WC(3000K) gives similar intensity as a single bulb of T5HO at 12". Note PPFD is the relevant column, and footcandles doesn't matter much. So 26W of LED is enough to replace 54W T5HO (about 50W energy consumption in reality)! Now from the luminous efficacy number of T5HO (around 90lm/W), T8 LED is about 63% more efficient. The additional advantage of LED comes from the fact that T5HO emits the light in 360-degree and some lights are wasted.

Also the bulbs doesn't heat up at all! When you touch, you can feel slightly warm. This is a great advantage for growing plants.

*Technical spec:*
Each tube consists of 120pcs of Epistar SMD2835, driven each at 35mA/each. 15W version uses same number of LEDs at 41.5mA (so slightly less efficient in theory). I checked the Epistar datasheet, and the efficiency number matches with the datasheet.

*Step-by-step conversion of a shop light*

Well, it is super simple to rewire, but here is how I did it. It actually makes it as if it is a complicated process, though....


Here is how the bulbs are packed.



Remove the 2 (or 3 screws) to open the shoplight.



This is how it look like inside. The box is the ballast, which I need to remove. Left side of the ballast, you can see the "tombstone" (fluorescent lamp holder), the place where bulbs get attached. From the bottom of the fixture, you can see the AC-plug wire coming in. There are 3 wires from this AC-main in. Green is "ground" connected to the pin of the AC plug. Black one is the "Live/Hot", connected to the smaller blade of AC plug. White one is "Neutral", connected to the larger blade of the AC plug.



First cut the Live and Neutral wires from the ballast.



I'm using an Ohm meter to confirm that the black in Live and white is Neutral.




(continue...)


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## naoki (Aug 12, 2015)

(Part 2)


When you look at the end of T8LED, one end has "L" and "N" marks. Basically all you have to do is connect the AC power (Live/Hot) to "L" and AC Power (Neutral) to "N". The other end of the bulb has 2 pins, but these are not electrically connected to anywhere. That end is just to retain the bulb to the fixture. This design is "single-ended" because all of the wiring is done in the tombston of one end of the bulb. Sunritek can make "double-ended" (one end of the bulb is connected to AC Neutral and the other end is to AC Live).



When you look at the tombstone, there are two blade which make the connection to the light bulbs. Below the blade, the two left holes are connected to the left blade, and 2 right holes are connected to the right blade. Currently two blue wires are going into the two outside holes.



The trickiest part of the conversion is to remove the wires from the tombstones. I pushed in something like a paperclip (you need to use a pretty thick paperclip), then pulled the wire out. Sometime, I can get the wires out by twisting and pulling the wires gradually without inserting anything.



After the wires are removed, I'm making sure the right and left blades are not internally connected. This is called a non-shunted tombstone. Most of them which I encountered are the correct non-shunted tombstones. But there are some shunted tombstone, where the two blades are bridged/connected. For the single-ended LED T8 bulbs, we need non-shunted, so you need to check it.



This is how the finished wiring looks like. The AC neutral (white) is connected to one side of the tombstone, and AC Live (black) is connected to the other side of the same tombstone. Then you use the 2 remaining holes to make the connection to the second tombstone. This is basically a parallel circuit. I already removed the ballast in this photo.







```
ASCII wiring diagram
            /----------------\
AC Live ------ L of bulb-1    \--- L of bulb-2
AC neut ------ N of bulb-1    /--- N of bulb-2
            \----------------/
```

SMD2835



Backside (label) of the bulb. The end with this sticker is the one which needs to get connected to AC.



The one on the Left has the aluminum casing (DTA), the one on the right has the plastic casing (DTP).



Comparison of DTA(3000K) (bottom) and DTP(4000K) (top). Note that the DTP has slight frosting.



Because of the slight frosting of DTP (right), it looks brighter in this photo, but it is not the case from the measurement. 






The clear case part appears to function (creating a wider beam angle). This creates the stripy pattern you can see on the carpet here. But you can't see the pattern if the bulb is not too close to a flat surface and this isn't a problem in reality. DTP shows less pattern due to slight frosting.



LX1330B lux/fc meter (left) and Li-Cor Quantum PAR meter (right). I think I was measuring 2 bulb per fixture setup in this reading.


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## KyushuCalanthe (Aug 12, 2015)

Wow Naoki, you need to put this up somewhere online - ever thought of starting a blog, or at least a facebook page? Great information, which would be a waste to lose to attrition and time.


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## naoki (Aug 13, 2015)

Thanks, Tom. I hang out in some orcchid facebook groups, but I guess I could give a blog try. I've never done it, and I'm not sure if I have enough time to post lots, but it could be fun.

Here, these LED T8 tubes are deployed in my spare grow tent for quarantine/acclimation (4 LED tubes on the top and 2 at the bottom).




They are mostly from Bela Vista, Ooi Leng Sun and Malala imports from this spring/summer. I got very nice/healthy Paphs from Ooi (difficult to see but they are at the backside of the right most tray).


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## fibre (Aug 13, 2015)

Thank you Naoki for your most informative thread!
I think there will be similar LED solutions for T5 fixtures some day...


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## valenzino (Aug 13, 2015)

Naoki I am using those + 1 year with good results,i grow a full room of 5 x 4 meters,with about 1000 plants inside(many miniatures and seedlings) from november to may more or less...results are great!!!Obviously you cannot grow everithing with those but nearly...


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## Lanmark (Aug 13, 2015)

This is great!


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## Ray (Aug 13, 2015)

valenzino said:


> Obviously you cannot grow everithing with those but nearly...



What limitations do you perceive?


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## bigleaf (Aug 13, 2015)

Awesome post. Thank you.


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## naoki (Aug 13, 2015)

valenzino said:


> Naoki I am using those + 1 year with good results,i grow a full room of 5 x 4 meters,with about 1000 plants inside(many miniatures and seedlings) from november to may more or less...results are great!!!Obviously you cannot grow everithing with those but nearly...



I'm glad to hear that it is working well for you, Valenino! For a large scale operation, small increase in efficiency makes a big difference. Anyway, with the extra saving, I should have a couple hundred dollars extra every year to buy more plants! 

Ray, one advantage of T5HO is the high density application. The skinny bulbs of T5HO can be packed to give lots of PPFD. 6-bulb T5HO fixture can fit in a 4'x2' grow tent (area) if the heat issue can be resolved. To get the similar total output, you need 12-bulbs of this 12W T8 LEDs. If you use a 4'x2' plywood as the backboard, and screw the tombstones tightly, you can pack T8LED (because it doesn't need reflectors). But with the modified shop lights, 6 bulbs are the max for 4'x2' grow tent. If you need more output, you could sacrifice the efficiency a little bit and get 18W version of Sunritek.

I'm going to place the T8-LED pretty close to plants, just like how it was with fluorescent T8. But we don't have to worry about burning (from heat). With T5HO, I have to make some distance between plants and the bulbs. So with T5HO, it is easier to water, and it can be easier to accomodate tall and short plants in the same shelf.

From the PPFD values, I'm pretty sure that I can grow most of the orchids by putting 6x 12W bulbs per 4x2' (4x is probably better with lower light plants like Paphs and Phals).


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## TyroneGenade (Aug 13, 2015)

Great info! Thanks.

Did they provide you with spectra?


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## naoki (Aug 13, 2015)

Tyrone, I'm guessing that this data-sheet corresponds to the chip:
http://www.runlite.cn/userfiles/huh7rcihn57e61412846995.pdf

It was linked from this Epistar 2835 product page here (I had a typo saying 2830 in the original post, which I have corrected now):
http://www.runlite.cn/en/product-detail-112.html


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## TyroneGenade (Aug 14, 2015)

Thanks Naoki.

Excellent info.


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## naoki (Aug 14, 2015)

Following Tom's suggestion, I decided to start an orchid blog, and put this info there:
http://orchidborealis.blogspot.com/2015/08/prime-time-for-t8-led-lighting.html
I don't know if I have enough time to post many blog entries, but it might be good to consolidate this kind of info (from my older post about DIY LED etc).


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## Migrant13 (Aug 14, 2015)

You are amazing with this stuff! Thanks for the very helpful info and pictorial guides.


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## Marco (Aug 14, 2015)

Very informative! Thanks Naoki.


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## Happypaphy7 (Aug 18, 2015)

Is there any LED lights that I can just buy and use right out of the box without having to go through all this work?
It might be nothing for some, but for me, it is too much hassle to go through.

By the way, how much distance do you leave between your T5HO and the plants?

Also, is the difference (efficiency on plant growth) between T5 and T5HO significant? 

What is the average life span of the ballast?
Shorter than the light bulbs or longer?
I heard someone saying their T5 light bulbs last over one year and some as long as three even? By then, I would think the efficiency is not too good anymore.

What would you recommend for 48"W x 24"D shelf?
I don't have any yet, but it will most likely be something I will try in the near future and I want to be ready before I get to it, so I don't rush or freak out with my plants not having lights in a new home. lol

Heat is the main concern for T5, hence I'm wanting to use LED.


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## naoki (Aug 18, 2015)

Happypaphy7 said:


> Is there any LED lights that I can just buy and use right out of the box without having to go through all this work?
> It might be nothing for some, but for me, it is too much hassle to go through.



How about Philips InstaFit 4000K, $25, 1600lumen, 12W, 133lm/W, which I mentioned in the original post?
http://www.homedepot.com/p/Philips-...-4000K-Linear-LED-Light-Bulb-453852/205807273

I don't have any experience with this particular T8-LED bulb, but the spec seems to be great (and Philips is a good LED company). To cover 4x2' area, about 4 of them are good (for Paphs). You can probably get a cheap T8 shop light to put them in, and no modification required. Initially it will be similar cost (about $120 total) to 4 bulb T5HO.



Happypaphy7 said:


> By the way, how much distance do you leave between your T5HO and the plants?



I think I keep around 15" with 3-4 bulbs. But I have only the higher light Paphs (P. philippinense, P. druryi) under T5HO now. Cattleya is within 12". For typical Paphs, they seem to be ok with lower amount (less bulbs or more distance).



Happypaphy7 said:


> Also, is the difference (efficiency on plant growth) between T5 and T5HO significant?


T5 normal output can be around 100lm/W while T5HO is about 10% less. But the total output of T5HO is about 2x of T5. T8 has the similar efficiency as T5HO, but the total output is similar to T5. The tricky thing about T5 type vs T8 is that they respond differently to the temperature. Under cooler condition, the efficiency of T5-type decreases more rapidly. Since all of them are fluorescent bulbs, effects on plants should be similar.



Happypaphy7 said:


> What is the average life span of the ballast?
> Shorter than the light bulbs or longer?
> I heard someone saying their T5 light bulbs last over one year and some as long as three even? By then, I would think the efficiency is not too good anymore.



The ballast longevity somewhat depends on the quality of ballasts. For example, there are quite a bit of variation in quality of electrolytic capacitors and resisters. When I disassembled broken ballasts, I saw these components blown. But the ballast longevity is definitely much longer than the longevity of fluorescent bulbs. I have used T5HO for only 3-4 years, and there is no failure in 3 units. With cheap T8, some fails early (like 2-3 years), but many survives for a long time. I guess Exponential probability distribution in action.

I think I posted a thread about fluorescent bulb longevity where I found out that the decay of T5HO output was faster than what I have expected. Now, I've been following the decay more closely. It appears that some of them decay much quicker than others. Or the operating environment may have a major impact. For example, Odyssea 24W plant bulbs appeared to have lost the output (in terms of PPFD) by 22% in 3-5 months. Agrobrite 6400K 24W lost output by 44% in 2 years. But these 24W bulbs were operating at a higher temp because it was sitting on a glass of the enclosure directly (not much air flow around the bulbs). I'm following with Philips F54T5/841 now, and it has lost 10% or so in a half year (I don't have the exact number now). This one is operating with free air flow around the bulbs. I'll eventually post the detail next winter or so.

But maybe 1-2 year is reasonable for T5HO bulbs.



Happypaphy7 said:


> What would you recommend for 48"W x 24"D shelf?
> I don't have any yet, but it will most likely be something I will try in the near future and I want to be ready before I get to it, so I don't rush or freak out with my plants not having lights in a new home. lol
> 
> Heat is the main concern for T5, hence I'm wanting to use LED.



To be honest, most anything will work as long as you give sufficient amount of light (PAR). 4 bulbs of T8, T5, or T8-LED, or 2 bulbs of T5HO, etc. Some geeks (including me) like to discuss small details , but you probably don't have to over-think too much! Heat is an issue if you have lots of fixtures, or if you have them in an enclosure like a grow tent. For Paphs, I don't think you have to worry too much about the heat if you are growing on the open shelves. I personally like to minimize my environmental impact, but for a few fixtures, you might not need to worry too much about the efficiency. Also the LED technology is advancing pretty rapidly, so there will be always better efficiency stuff for the next couple years.


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## Happypaphy7 (Aug 19, 2015)

Thank you for nice detailed answer.
I love geeks because they do the thinking for me. hahaha

It is great to know that I could buy those lights at HD, and we have two here. 

Regarding the distance between the plants and the light source, that is measured from the top of the plants to the light, not from the base of the pots to the light, correct?
I heard people saying 6", but that distance sounds great because for one, I don't like the appearance when the plants are too close to the light, and two I want space for the spikes and all.

I did not know about the impact of temperature on the light bulbs. 
When you say cool, how cool are we talking?

For LEDs, I wouldn't have to worry about heat, and the longevity of them should be longer than T5, right?


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## naoki (Aug 19, 2015)

Actually, the distance (between the top of the leaves and the bulbs) with T5HO was about 12" or less with 4 bulbs, and Cattleyas were more like 8-10" (I think they became taller). So it is probably around 180 micromol/m^2/s at 12". I usually try to get around 100 micromol/m^2/s (or slightly more) for typical Paphs. With around 12 hours of day light (I use a little longer), the cumulative amount of light (Daily Light Integral) is roughly 750-1000fc of "noon" time peak intensity in a greenhouse (you multiply micromol/m^2/s by 7.5-10). So to get 100 micromol/m^2/s with 4 bulb T5HO, you'll need to reduce the number of bulbs and use 12" or you need to give more distance. One of the reasons why I'm using 100 micromol/m^2/s is posted in this thread. But you can give more light before the leaf "burn" or something called "photo-inhibition" starts to occur.

With the temperature and T5 effieciency, this page might be helpful. I realized this when one student was doing a growth chamber experiment at relatively low (i.e. Alaskan temperature, I think it was 15-20C). The T8 system in the chamber broke, so I told her to put a couple T5HO fixture in it. But the total output became extremely low. With Paph conditions, I don't think you have to worry about it. But with high altitude cool-cold growing orchids, this could be an issue.

In theory, (well designed) LEDs should have much better lumen maintenance than fluorescent bulbs. But the fixtures driving LEDs hard (i.e. cheap crap) may fail earlier than expected, though.


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## Lightguy (Aug 21, 2015)

Happypaphy7 said:


> Is there any LED lights that I can just buy and use right out of the box without having to go through all this work?
> It might be nothing for some, but for me, it is too much hassle to go through.]
> 
> I came across this forum while searching the Sunritek tubes. I sell LED lights and was pleased to see you guys interested in them. I'm not sure why you are looking at the regular LED tubes when much research (with a lot more still needed) has already been done with LED grow lights. I have a power point if anyone would want me to email it to them.
> ...


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## TyroneGenade (Aug 21, 2015)

No offense Lightguy but those grow lamps make our eyes hurt and the plants look ugly. We like looking at our plants.  We like the idea of the Sunritek lamps because they produce lighting that is aesthetically pleasing. People interested in Planted Aquaria also want aesthetically pleasing lighting.


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## naoki (Aug 22, 2015)

Lightguy, many people are interested in white light as Tyrone said, but some people including me prefer whatever the most efficient. What kind of efficiency does it have in terms of PAR micromol/J? Any link to the product?


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## Happypaphy7 (Aug 22, 2015)

Thanks, Naoki. 

Now I have found a place that I really like, but it has northwestern exposure (windows), the worst exposure possible for growing plants. 
I will definitely have to build light set up. Three big ones. 

Now the big problem is I have some dendrobiums that are over 2' tall. 
They have leaves all along the cane. 
Do I have to let go of them or is it possible to grow such tall plants under light?
If yes, what kind of light? Would I need HID sort??
I'm thinking only the top portion ( perhaps like 1/3 of the plant ) might get enough light under light? 

I'm sad to think that I can no longer grow certain orchids that I enjoy.
I mean I will be happy with more Paphs, but you know.


Light guy- Thanks, but as Tyrone says most people do not like such LED for aesthetic reason. The plants under these lights simply look horrifying. No offense, just honest opinion. I have a small set up with these creepy LED bulbs in my kitchen. I have no desire to take it with me to my new place. lol


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## Linus_Cello (Aug 22, 2015)

Happypaphy7 said:


> Now the big problem is I have some dendrobiums that are over 2' tall.
> They have leaves all along the cane.
> Do I have to let go of them or is it possible to grow such tall plants under light?
> If yes, what kind of light? Would I need HID sort??
> I'm thinking only the top portion ( perhaps like 1/3 of the plant ) might get enough light under light?



Maybe you could mount the light fixture flush with the wall for your dendrobiums?


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## Happypaphy7 (Aug 22, 2015)

I don't understand what you mean by flush?

Install multiple light bulbs on vertical layers along the wall??


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## troy (Aug 22, 2015)

Thank you naoki!!! Very informative!!!! You are an asset to the orchid growing community!!!


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## naoki (Aug 23, 2015)

I think Linus is suggesting side lighting, which might work.

Yes, tall plant could be a problem with a wide angle light source. Since the intensity of light follows an inverse-square law, 2 feet of plant height makes a big difference when the light source is close to the plant. The sun is far away, so it doesn't create so much difference in the intensity between the top and bottom leaves of the plants (if the bottom leaf is not shadowed by top leaves). So to avoid this problem, you can use light with narrow beam angle, and place it far from the plants. This approach does have an issue that the bottom leaves could be shadowed by the top leaves.

I'm not sure what would be a good option for non-DIY. Cree does have a house-hold PAR38 Spot (27 degree), but it's not so efficient. I haven't looked into this type of LEDs for a long time, but I haven't found any efficient white LED PAR38.


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## TyroneGenade (Aug 23, 2015)

Good reflectors, with the lamps sitting deep in them, will cancel out a great deal of the inverse square law. With normal t8 lamps, reflectors can increase the PPFD almost 3 times.


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## Brabantia (Oct 15, 2015)

I wish to add some additional light to my orchids during this winter. I found on this online sales company (Ali...ess) a T8 which like the one you described: Can you assure me that it is indeed an equivalent to the Sunritek tubes about which you speak?
Ref: *Here*.
Thank you in advance for your help.


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## naoki (Oct 15, 2015)

Brabantia, the one you linked has quite a bit lower efficacy (100lm/W vs 140lm/W). This is because the linked model uses only 54 LEDs (Epistar SMD2835) for 12W while Sunritek uses 120pcs for 12W. So when each LED is driven harder, the efficacy goes down. Manufacturers want reduce the cost of production, so some companies use less diodes and sacrifice the efficiency, others use more diodes to get high efficiency, but the price will goes up. This is the reason why we have to carefully shop LEDs.

However, 100lm/W is better than T8 or T5HO, and it is better than the previous generation which had less than 90lm/W. The total output (1200 lm) is at a bit low end. 32W T8 fluorescent produces initially about 3000 lumen (but it decays quite a bit with the use). But T8 is emitting the light to 360 degree, so quite a bit of light is wasted unless really good reflectors are used (Tyrone has posted about these reflector issues here before). So I think if you can get >1500lm or so from directional T8 LED, you probably get the similar output as 32W fluorescent bulb in terms of PAR.

If you can use lots of them (20 or more bulbs) or if you can do a group order, then Sunritek can give you 40% more light with the same energy consumption. I converted lots of old T12 and T8 in our house to Sunritek. If interested, I can PM you the contact info.

If you need a smaller quantity, can you get Philips InstaFit like this one in Belgium? This assume that your florescent ballast is working, but it has a pretty good efficacy (133lm/W, total output of 1600lm per bulb). For people in the US, they may want to check local home depot. Ours had this Philips on Clearance section (not a lot of discount, I believe it was around $20 per bulb).


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## gego (Oct 15, 2015)

Wow, I lot of excitement here.

I was using the T8 Philips Naoki mentioned, got them from Home Depo. It really works for me as an additional light. There is also a Cree version, same store, It has more output than Philips. I'm using them now. I flowered my helenaes under these lights. 

Yes, they are uni-directional so if you have tall plants and short plants together, you can use a side mount or an angle mount.

I played with LED bulbs before where I have three timers to control one angled light from one side (morning light), top light (midday light) and one opposite side light (afternoon light). It's kind of fun.

On a healthy plant, these lights could provide more than enough for the plants to grow, they will need the food. So don't let them starve.


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## Brabantia (Oct 15, 2015)

Thank you naoky and gego for your fast responses. I will see if I can find more efficient T8. About the length of the tube I am limited at 60 cm (23") and my goal is to added some light to the natural light the dark and rainy days which occurs some time during the winter.


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## naoki (Oct 15, 2015)

gego, does Cree has a new T8-LED? Last time I checked, their efficacy was pretty low.

Brabantia, I believe Sunritek comes in 24" version. Is Philips XF-3535L too much trouble? Here is the step-by-step I posted long time ago:
http://orchidborealis.blogspot.com/2015/09/easy-diy-led-philips-xf-3535l.html
It is pretty easy and takes only slightly more time than T8-LED conversion. One of this can replace 1-2 T5HO in terms of PAR. So it is pretty cost effective.


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## gego (Oct 16, 2015)

naoki, Cree has a 1700 Lumens, 18.5W T8. I also bought a Phillips, 2100 Lumens, 17W T8. This one is priced only for $10. I had doubts but I bought two anyways.

I compared this to my Cree and the output in terms of PAR are indentical.
So it's a good buy. But why so cheap?
I asked one guy there if there was a mistake and he just shook his head, confused because the 1600 Lumens version, 14W is priced for $21

Anyways if you're buying in quantities, it should be worth it.


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## naoki (Oct 16, 2015)

Brabantia said:


> Thank you naoky and gego for your fast responses. I will see if I can find more efficient T8. About the length of the tube I am limited at 60 cm (23") and my goal is to added some light to the natural light the dark and rainy days which occurs some time during the winter.



Oops, you are right, the aliexpress link was for 60cm bulb. So a lot of things I said in the previous reply was wrong. Sorry.

So 1200 lumen is very good total output. If you are using it for supplement and not using it all the time, you can probably sacrifice the efficacy. Just for comparison, Sunritek 2ft (60cm) model is ST-DTA06-9W, the version with 120-140lm/W costs $7 (wholesale).


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## naoki (Oct 16, 2015)

gego said:


> naoki, Cree has a 1700 Lumens, 18.5W T8. I also bought a Phillips, 2100 Lumens, 17W T8. This one is priced only for $10. I had doubts but I bought two anyways.
> 
> I compared this to my Cree and the output in terms of PAR are indentical.
> So it's a good buy. But why so cheap?
> ...



OK, so the cree is the one I looked up which has pretty low efficacy. With their technology, I don't know why they can't make better T8LED. 12W Philips has higher efficacy than 17W, but 17W philips has decent efficacy (123.5lm/W), so it is a great deal for $10!

The similar PAR between the Cree and Phllips is probably from the different beam pattern?

If you still have the PPFD measurement from your Cree and 17W Phlips, I'd love to see the numbers (just for curiosity).


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## gego (Oct 16, 2015)

naoki,

1700 Lumens Cree measured at 40.8 PPFD.
2100 Lumens Phillips measured at 39.6 PPFD

I am using an Apogee sensor probably not as good as Li-Cor. Taken 12" (perpendicular) from the bulb.

I don't think you should trust those numbers they posted. Between Cree and Phillips, I would trust Cree.

But for that price, I would get more of those now. But then you'll never know, technology is moving fast. Cree is looking at using GAN. The price will eventually drop with higher efficiency.


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## naoki (Oct 22, 2015)

Thank you for the info, gego! It is pretty similar to Sunritek which is around 1700-1800 lumen.

With white light, Apogee is very good. I think the error rate is within 5%.


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## naoki (Oct 15, 2017)

I've been using at least 50 bulbs of Sunritek T8-LED bulbs to grow carnivorous plants and orchids for 2 years. I used more bulbs for the household fixtures, but they are not used for a long hours like grow light. Some of them are in high humidity grow tents, but none of them has failed, and I'm pretty happy with this. Now it is not the top efficiency. But compared to T8-LED bulbs or LED shop light commonly available from Lowes etc, it is still at least 20% more efficient.

Anyway, I didn't have any more fixtures/shoplights to convert, so I made a frame with left-over lumber. It's nothing fancy, but I thought that some of you might get some ideas from it.

Here is the link to my Orchid Borealis blog post about this. Instead of adding this info to the original blog post, I made a separate entry.


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