Max current for horizontal power connectors
Hi, I am powering a large number of LEDs, lighting effects, and some small video screens through the 2 channel horizontal power connectors. The build is only about half done and it's drawing about 1040 mA. I may tap the power for a 9v motor off of the Brickstuff components with a step up converter, which I'd guesstimate would draw another 250 mA (I haven't built any of the motorized components so I can't measure the current draw). I'd also expect the current from LEDs to potentially double. So the question is, how much current can those horizontal power connectors take per channel?
Thanks,
Blake
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Hi Blake , great question. I'd be less concerned about the amount of current those connectors can carry than I'd be about the resistance of the wires. Most elements in our system are designed to support around 1A (1000mA) of current, though we've tested slightly above that without issue. In general that supports the largest lighting setups our customers are likely to create. What you're working on is somewhat at a different level in terms of power needs.
When looking at the entire system, the wires we and most other companies use are 32 gauge (32AWG), which has a higher internal resistance than wires of a smaller gauge. More resistance = less current delivery capability at the extremities. All of this is to say that even if the horizontal connectors could handle the load (I'm not concerned about that part), you're still likely to face high resistance when pulling currents like motors though the system-- especially if you're trying to step the voltage up to 9V to run the motor.
If you're comfortable soldering (sounds like you might be), then my recommendation would be to use our thicker connecting wires (labeled "heavy duty" on our website) and expansion boards with large connecting plugs for your main power trunk, then use these connectors for the magnetic connections-- the wires are much thicker (smaller gauge) so the overall current-carrying capacity would be larger.
If possible, the ideal setup is to use a main "trunk" power line with thick cables and large connecting plugs that branches out into smaller lines at each building/major connecting spot. Just like the power setup in our neighborhoods:
Hopefully this helps. Let me know if it makes sense, if you think it will work for you, or if you have any additional questions.
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Rob Klingberg Thanks for the tips! This is my latest New Hashima contribution if that explains anything about the crazy number of lights. Those magnetic connectors look super useful. I've built my share of electronics. so soldering won't be a problem. I have the wires doubled up to get some extra headroom, but I am still measuring only 4 volts at the end of the chain. A lot of that is over the length of the USB cable, so replacing that with one that can handle a bit more current should help.
It looks like the motor may wind up an a completely isolated power supply, as I noticed it makes all the lights flicker every time it changes direction even when it's not directly connected to the Brickstuff components. I put the biggest capacitor in my collection of spare parts across the power to the motor and it didn't help much. I might do better with the capacitor across the supply to the LEDs with a diode to prevent current from flowing backwards when the motor causes spikes. I'll have to tinker with it a bit.
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Blake Foster Ah, ok, so cool that you are still iterating on the incredible NH builds. For the motor, yes, definitely a flyback diode would be necessary. Keep us posted on your progress!
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Rob Klingberg Will do, thanks!
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Rob Klingberg Another question--I'm using these things in a tower with multiple stacking modules, with the horizontal power connectors making the connections between them. I am considering running a higher voltage--maybe 20 volts--up through the horizontal power connectors, and stepping down within each module with the Universal 7-30V AC/DC Power Supply. The current usage by each individual module is within its capabilities, and that should ensure that they are all getting 5 volts in. I don't think there should be any issues running the higher voltage through the power connectors, except possibly frying the LEDs. And I measured 1.5 kOhms on the onboard resistors, which based on typical LED current usage should give me some headroom anyway. I am expecting the motor to need its own power regardless, but I was wondering if you'd foresee any issues with the higher voltage? Thanks!
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Blake Foster Hi Blake, I don't see any issues with the higher voltage, though of course we aren't able to test the scenario you're describing. Keep us posted on results!