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Noise on a 12V DC circuit.
tanner0441:
Hi
My other little 60Mhz scope came with two premade leads with the correct plug on rated to 100 Mhz. so if needed they will be used. I bought a cheap probe with the correct plug on, when I say cheap it fell into the cheap sh## class but the lead was good spec so I cut the probe off the end and fitted a flying BNC on the end and I used that with the AC current probe from the HP scope I have in the loft with a dead timebase so no display.
What I've decided to do is split the system back to 24V with 760W of solar and 12V with 200W of solar that for one will isolate the problem to one or the other reducing the variables.
Also when I go to 24V I can go to 1440W of solar and I can buy 370W 36V panels for £115 GBP as long as I collect them.
Brian..
tanner0441:
Hi
I kave myself a suitable kick up the #### and located the problem, located not cured. The constant noise is from the MPPT controller and runs from 66Khz to 78Khz the pulses are from the PWM controller. The two together give a very strange waveform on a scope because it doesnt know which one to lock on. But several runs on single shot I was able to see them and with a ten turn 4in loop I was abble to identify the source.
Tomorrow Im going to clip current transformers round the cables and see if I can isolate things further.
I overcame the LED lighting problem by mounting the light fitting on a strip of wood to isolate it from the aluminised plastic and foam insulation sheeting lining the roof.
Brian
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