Running LED bar in series

[natticus]

Hey all,

I'm not sure if I'm over thinking this, but I can't seem to find the answer to what I believe should be a simple question. I picked up two 12VDC 5W 108 LED light bars. I'll be attaching both to the same power supply. My question is can I run them in series? Each light has a switch, as well as some on board circuitry. On the opposite end from the switch there are + and - contact points. For a simple strip of LEDs I wouldn't really be worried and would just connect it to those contact points, but with it having the circuitry on board, I'm not so confident. Again I may be overthinking it.
I've attached pictures of one of the lights to help you understand my rambling.

Thanks for any advice,

Nat

 

[Avo Mk8]

Not sure I understand. Are you assuming that the + and - contacts at the far end of a unit are connected to its incoming 12V red (and/black?) wires, and proposing to connect the wires of the second unit to those + and - tabs?
I think that's probably a bad idea, as I would be concerned the tabs might be supplied from the on-board regulator/driver components, and doubling the load current could kill that. Also that's still electrically a parallel connection, not 'series' though I know what you mean!
I suggest you wire each of your two units directly to the 12V supply - surely a lower risk option!

 

[natticus]

Sounds like you understood the question well enough, or at least understand the way this type of set up works. It was my assumption that the tabs were indeed supplied from the onboard components, but wasn't sure if attaching another light set up the same way would foul things up. Couldn't find the answer I needed searching the web and didn't want to screw up the lights by making an easily avoidable mistake.
After more research on LEDs in general I see what you mean about it still being a parallel connection.
Anyway, I was just hoping for a slightly cleaner install since the lights will be physically mounted end to end with the power supply coming in from one end.
Thanks for the advice!

 

[Avo Mk8]

Anyway, I was just hoping for a slightly cleaner install since the lights will be physically mounted end to end with the power supply coming in from one end.

I did wonder if that was the reason for asking!
Can you run the second lights cable behind the first, or even inside through the first light and attach the wires to the incoming leads of the first?
I don't think it is wise to use the tabs at the far end unless you can verify they are definitely connected to the 'power in' wires.
If you are prepared to disassemble one light you might be able to follow the pcb tracks, though that might not be do-able if multilayer.

Personally I would just do it the 'safe' way and wire it as the manufacturer intended, however inconvenient!

Good luck.

 

[natticus]

In fact, I was just thinking about running the wires through the underside of the first light assembly. It's two screws on each cap and the aluminum body of the assembly is hollow, so that will work just as well.

 

[natticus]

Just one more thing, for clarification. If I had a strip of LEDs with the same power rating but no regulator/driver components, just a simple led strip, could that be safely attached? I don't plan on doing so for these lights, but in case I run into a similar situation in the future.

 

[Avo Mk8]

Just one more thing, for clarification. If I had a strip of LEDs with the same power rating but no regulator/driver components, just a simple led strip, could that be safely attached? I don't plan on doing so for these lights, but in case I run into a similar situation in the future.

LED strips generally run from a fixed voltage (as opposed to fixed current), so as long as the fixed output voltage of your power supply is the same as the strip, and the current demand of all the strips (connected in parallel) added together is less than the current rating of the power supply, then you are OK to attach them.

 

[natticus]

Good to know. Thanks again!