Jump to content
Electronics-Lab.com Community


  • Posts

  • Joined

  • Last visited


Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

loribennms's Achievements

  1. The chokes may actually be making things worse. CEMF by definition is of reverse polarity so the first thing to try is simply diodes across the batteries, wired so normally not conducting of course. I would suggest fast Schottky diodes rated at 1A or more. You may find it best to physically connect them to the wires "pulse 1" and "pulse 2" rather than across the battery terminals to reduce the CEMF path length to ground, you want to trap the pulse at the earliest opportunity as it reaches the circuit.
  2. If you get a "for parts or not working" power supply from certain reputable manufacturers you should be able to fix it. Make sure you can find the service manual and check it that the device does not have proprietary parts. Certain power supplies are so common repair parts are also common. I found a triple Sorensen XT power supply that already was 2/3 working units so I just fixed the part that wasnt and now I have a really solid triple supply. Apart from a hum (a physical hum, the DC output is incredibly quiet, as quiet as a battery) its perfect. But it weighs maybe 30 or 40 lbs. Its a real boat anchor. If it was bought 100% working it would have cost me at least $250 even used and >35 yrs old.
  3. I have gone over 54K miles on my two electric assist bikes. One of the halls started acting up on my mid-drive MAC bike at 8K miles. At 9K it stopped working all together. I replaced the cheap sensored controller with a cheap sensorless, and rode another 21K miles. It sort of worked, but was never as efficient, and growled unhappily on startup much of the time. My big DD cargo bike worked perfectly for 22K miles, but has now started acting up intermittently over the last 1,200 miles. Being a very high power DD, when one of the halls quits, it is like one of my old 4 cylinder cars when a plug would fail...rough running, noisy, low torque. As with the MAC, the problem is happening more frequently, for longer, and I eventually will have to give up,and do something. Here is my dilemma. I am old, with the failing eyesight, and shaky hands that come with age. I don't feel confident to replace the halls, and understand that there is a good chance of ruining them with static from my hands when doing the installation. I searched around and found someone who had put external halls on a skateboard outrunner motor. Getting halls near the magnets on a hubmotor would probably be impossible with the spokes in the way, but what about a simple magnet ring, like people use for pedelec? It seems like an external encoder would be a great aftermarket product for somebody....Justin?
  4. I used Lm386 as an audio amplifier, 9V , and when I check the output waveform it amplifies but it was clipped. I just copied the circuit diagram on its datasheet. How to fix this? Any advice there in making an audio amplifier with good sound quality ?
  5. Hi everyone! One question: How do I proof the reliability or validity of the automatic calibration I do with the analytical balance? I never questioned it, but now I am being told that the only calibration is the one done by the certified metrologist every six months because he presents the whole set of statistical data and everything. Apparently I can only do verifications.... Any advice? Thanks! thanks in advance for any help
  6. One voltage step is typically more efficient than additional steps, i.e., use one converter for each desired output stepping down once form the source voltage, 14-12, 14-9 and 14-5. Worth noting that your 4S LFP won't be at 14V for very long. You'll rapidly drop into the low to mid 13s under load. 2-3) don't know. 4) No, but % efficiency is more related to the power being converted. Very low power tends to be very inefficient. Moderate power tends to be efficient (92% "max"), max power tends to be a little less efficient. "Power" is relative to rated power, i.e., 0.5W on a 50W unit would be very inefficient, but 0.5W on 1W unit would be very efficient. 5) I suspect they may drift slightly with temperature. I'd put a small LED voltmeter on each output for fun.
  • Create New...