So I bought this cheap LED bar from Ebay, claimed to be 240W but it actually draws around 110W. I know the housing wouldn’t be able to handle 240W and probably not the 42 leds either but I would like to make it a bit brighter if possible.
My best bet is to change the (what I think is the) sense resistor and force the driver to push more amps through the leds but I know to little about drivers and such to dare to do it without some help. So based on these pictures do you think the R050 resistor is the sense resistor and what would be a good number instead?
The bar is divided in to two parts that looks basically the same but with different sense resistors. The side with the R050 drives 18 leds and the side with two R075 drives 24 leds. Is this even possible?
Yes its is possible but youll prolly fry the driver out.( especialy on a long term base)
I have some exp with those bars and the first thing that you should do is to put some thermal paste under the leds mcpcb, usualy there is none( it seems that yours have some paste underneath yet swap it, you never know what didthey put in there, prolly a thoothpaste or something, you never know)
Are those XP footprint leds? They look something like Epistar, if you want a true bump in the lumen output swap them with XPG3s, or even XPG2
I'm kinda doing the same thing but im going to start with a solid copper board to solder to then just wire everything in. It will make more heat for sure but I'm not planning on running it till i'm moving anyway. I need to order the parts & get some tests done. I am currently doing some research on 3m sealants to keep things from leaking. Mine will only be run in the desert where there is little to no precipitation. I am looking further into a Gortex membrane so the lights wont trap condensation. I'm glad people are looking into this mod, I think it will be fun.
1 on swapping the emitters. You’d be amazed how bad those emitters might be. Even the high end Ridgid Industries RDS light bars only claim ~70 lm/w efficiency. If you bump that up to an emitter that gets even just 105 lm/w, you’d be giving yourself a 50% increase in total light output! If you figure 110w divided by 42 emitters, you’re pushing about 2.6w through each. The XP-G2 S5 makes about 160 lm/w and the XP-G3 S6 makes about 175 lm/w at that wattage! So, without any other changes, you might be seeing well over double light output compared to stock! Add good thermal paste, and a modest driver boost, and you could be shocked at the outcome!
Thanks for your thoughts.
So… Boosting the driver is out of the question then? I’m afraid changing the emitters might be to much of a hassle to be worth it. I measured the existing emitters and they are 2.5x2.5 mm so quite a bit smaller than both XP-E and XP-G emitters (3.45 x 3.45 mm) so reflowing on the existing board seams like it wont work. My best bet would be to buy 42 XP-E on 16mm stars and wiring them all manually but getting them all to line up with the reflectors seams like a nightmare. And I have to find a driver that fit in the housing…
Those LEDs are probably attempting to compete with the 2.45 x 2.45 emitters from Cree, the XB-D and XB-H. You can buy both right now from Mouser, with the XB-D’s costing you around $1.00-1.50/ea and the XB-H’s costing $1.90-2.50/ea. Specs wise they aren’t even close, you’ll get close to double the output with the XB-D’s…
It will be hard to find leds that could carry more than 1amp in this size.
42x3=126w, what is very close to your 110w.
Changing this board to bigger leds on single boards will be to pricey as I think for this housing.
Didn’t know about the XB-Ds, they look interesting. I might have to order one or two and see if it is possible to mount them on the board. Any tips on how to change leds? Soldering iron on maximum heat on the back of the board?
One good thing about changing leds is that I can choose a more neutral colour, the existing leds are quite nasty blue. Another hint that they are of inferior quality I guess.
Depending on how well the board conducts heat, a soldering iron may not be enough. You may need to use a heat gun or torch, or heat the whole board at once by putting it into an oven. If you use an oven, don’t use one that you cook food in, and only turn the temp up to just above the melting point temp of the solder.
Wow! I just looked at the Cree Product pages for those XB-D and XB-H emitters. Here:
Edit: I just did a little ’math’ exercise using Cree PCT. Just by changing the LEDs to XB-H, you could see up to double the output compared to stock. If you were to bump up the current to the 1.5A each that the XB-H are rated for, your output would be around triple what you have now!
Yeah, the XB-H looks great but I need 42 of them and that’s starting to be expensive.
But I’ve found some XB-D in 4-5000K range at about $1 a peace and that seams OK to put on this cheap housing. Probably the lowest bin but still better than what’s there now. I just might go ahead and order a couple and see if I can make them work.
Putting the whole board in the oven seams like a bad idea though, I still want the driver components in there.
But thanks, I will try the heat gun.
Oh, don’t worry about those driver components. How do you think that thing was built in the first place? The solder has the lowest heat tolerance - by design.
Besides, how can you be sure you’re not overheating those components with a heat gun? I’d think an oven would be easier, since it has a thermostat to set the temp.
Honestly, to do this you’ll likely need a hot air rework station but you can pick those up for under $50 if you look hard enough. As for the XB-D vs. XB-H debate… given the other costs not to mention the effort involved, does an extra ~$0.90 each (for a total of $37.80) for the substantially better XB-H’s matter that much? Cheapest XB-D I see is a 4750K, 75 CRI, Q5 bin (237.5 lm @ 1A, 85C) at $1.10/ea and the cheapest comparable XB-H is a 4500k, 75 CRI, T5 bin (345 lm @ 1A or 463.1 lm @ 1.5A, 85C) for $2/ea. If I were going to that much effort…
If you have a wide tip for the iron you can use that. It needs to be wide enough to span the width of the led on an edge that includes both pads, drop of flux, stick the iron in there, and swipe sideways when the solder melts. You will see that happen at the overflow areas on the adjacent edges. To replace the new LEDs place the iron across both solder pads and when the solder again melts slide the new led in place as you slide the iron away. I think Pilotptk and maybe Vestureofblood both did videos of this technique. Hot air rework is no doubt easier if you have that though. A regular heat gun might be too big a hammer as it doesn’t have accurate temp and airflow controls.
"Honestly, to do this you’ll likely need a hot air rework station (link is external) but you can pick those up for under $50 if you look hard enough. As for the XB-D vs. XB-H debate… given the other costs not to mention the effort involved, does an extra ~$0.90 each (for a total of $37.80) for the substantially better XB-H’s matter that much? Cheapest XB-D I see is a 4750K, 75 CRI, Q5 bin (237.5 lm 1A, 85C) at $1.10/ea and the cheapest comparable XB-H is a 4500k, 75 CRI, T5 bin (345 lm 1A or 463.1 lm @ 1.5A, 85C) for $2/ea. If I were going to that much effort…"
Where do you see the XB-H is a 4500k, 75 CRI, T5 bin for $2/ea? I'd like to get some for my project.
Maybe I’m smoking too much rock, but I think this one at Mouser (part # 941-XBHAWT0000T50C2) would qualify if you’re getting at least 10 pieces like the OP? It’s $2.07/ea if you’re getting <10.
