Is wiring these Chinese QB288's in series even possible?

[gfpeezy]

I received a pair of QB288 boards from Shenzhen Bava the other day and hooked it up to my HLG-240H-C2100B driver but am only able to get 125 watts out of them.

I asked the sales rep, and he told me that the engineer confirmed it was wired in series when they sent it over.

I went through a similar kerfuffle with another set of boards that I received from the same company but after much trial and error was able to get it running in series at the full 255 watts (albeit with the potentiometer only being able to go 100% or 3% power).

Unfortunately, these new boards are wired differently than the previous ones. They have been stupefyingly soldered together on one side, thus limiting my options for wiring.

So, under these circumstances, does anyone have any suggestions as to how I could get it wired in series? I've thought about re-soldering the 4 wires on the right but am worried either I will screw something up, or the board will get fried.

As it is, I can still make use of the 125 watts (and they can be dimmed properly), but it's irking me that I am unable to get the full 250 watts out of them.


Also, the sales rep at another Chinese LED company Meijiu claims that their 304 boards are not capable of being run in series but their 288's are. Might this be the case with my board as well?

Thanks for reading and any suggestions you can offer.

[DaveJonesFan]

Hey, looks like a bit of a mess of the wiring and labeling of - and + terminals. Hard to decipher right off, but with some time and effort and probably a multimeter the boards could hopefully be made sense of.

One thing I notice right off is the way the qb288 boards are usually wired in series is one flipped vertically to the one next to it to allow the terminals between the 2 boards to be +>- right next to each other. And only one connection would be needed. This configuration seems to have +>+ terminals and ->- terminals connected between the boards with black and red wires respectively. Having 2 leads coming off of the one board for each Wago is not looking right to be either. Probably wired up in parallel or just in an overall mess.

Wiring in series yourself would mean redoing the wiring job in a simple +>+ from driver's positive lead to one board's positive terminal. Next unscrew and rotate the orientation of the board next to it and do one short run between boards from the ->+ starting with the board that is already wired to the drivers' negative terminal this time out to the next-in-line board's positive terminal. Then finish with a ->- connection between the second board in the series' negative terminal back to the driver's negative lead.

Of course I'm not sure exactly sure the internal wiring in the PCB of the boards at all but it's a start.

[atreum]

That board looks like quite a mess. I haven't seen that style of board before, so you will need to determine the internal wiring of the PCB. You can ask the manufacturer, or you can usually see the traces on the board and try to figure it out. Maybe post up a more detailed photo of the board itself, and someone can decipher it.

Assuming the Meijiu 304 boards are designed the same way as QB's, they operate at ~108V. So it's not that you can't wire them in series, but you will have a harder time finding an LED driver that supplies 216V (...for 2 boards; 324V for 3 boards, etc.)

[gfpeezy]

Of course I'm not sure exactly sure the internal wiring in the PCB of the boards at all but it's a start.

thanks for the explanation. I have yet to attempt to do what you described due to a combination of confusion, fear and laziness but i will keep it on hand for reference when i get around to it.

i can follow the explanation you gave up to a certain point. the part that i'm stuck at is with your description of wiring the 2nd board. it sounds like you're referring to the normal method of wiring for the HLG QB's without taking into account my 2nd board's wires have been soldered together. am i incorrect in that assumption?

or do you mean that the i can use the 2nd board's negative terminal at the bottom of the board rather than the unavailable middle ones? i suppose the only real way to find out is to try...

usually if i leave any leads unconnected, the corresponding section of the board doesn't light up, so they all have to be involved somehow.

That board looks like quite a mess.

tell me about it.

it was sent free to make up for the problem with the previous board (that ended up working fine) but this one is giving me even more difficulty. it was probably a prototype they had lying around... never look a gift horse in the mouth i guess.

apparently the engineer realized his mistake and will be sending a picture of the proper wiring.


you bring up an interesting point about the voltage of the board requiring a higher voltage driver. it made me think that it's possible my board was in fact wired in series but that the driver was the culprit... but if that was the case the board would have no current and barely light up which isn't happening. it lights up nice and bright at 125 watts.

...back the the drawing pcb board

[DaveJonesFan]

Yeah if they can supply you with the board's specs so you know how it's solder pads match up with the internal wiring and all that's probably best.

I was working off the assumption that you could remove the soldered wires and get back to a clean board, and the assumption that all the positive and negative terminals already connected to the boards were configured to be for powering the entire board. If the board requires multiple channels powered then that's even more of mess. None of their marketing material shows more than one positive and negative connected (quick alibab seach), but there are many negative experiences documented with Bava I found on the quick search attempt as well. Do you know the diodes provided for your boards?

Since you have some 'free' stuff to play with and they are going to attempt to provide documentation for wiring corrected, just wait that out. Best of luck.