Recent content by Factory400

  1. Factory400

    DIY BMS design and reflection

    I have been designing power electronics for a long time and MOSFET selection seems to get a little more challenging for each design since I learn a little more about the FETs every pass. I commend you for writing a summary of decision matrix. It is a very complex topic and it very rarely ends...
  2. Factory400

    Overcharge club- new member 🙋‍♂️

    The same hardware and software is used for extremely consequential tests and experiments. GPIB has been around since the 70's. My Agilent power supplies cost around $5,500 each - mainly because of the crazy focus on reliability. A dedicated disconnect circuit can also fail - especially a...
  3. Factory400

    24v to 12v dc to dc converters, how efficient?

    The aux battery has it's own isolated charger that runs on 120VAC. It is a bit convoluted, but uses the parts I had on hand. It also keeps the little battery tended while the RV (travel trailer) is not being used.
  4. Factory400

    Overcharge club- new member 🙋‍♂️

    I ultimately decided not to make this dedicated disconnect circuit. Fortunately, I have a stack of GPIB programmable power supplies and used Python to manage the charging. I cannot imagine trusting an analog off-brand low-cost power supply with an expensive battery bank.
  5. Factory400

    24v to 12v dc to dc converters, how efficient?

    I have the 40A Victron which is enough to cover most everything. That is on a custom ideal diode in parallel with a small lead-acid battery/charger. That way, if anything goes over the limit of the converter - the battery effectively supplies a boost. This required me to trim the converter to...
  6. Factory400

    Does an AC to DC power brick need pure sine wave or will it be fine on a modified sine wave cheap inverter?

    Lol - Factory400 is not my job. If it was.....I would be crazy hungry. Factory400 is my pet project where I experiment with ideas on how to cram a full suite of design and manufacturing into my garage space at home. It is exiting, and I do sell things sometimes. But it is just a fun thing to...
  7. Factory400

    Does an AC to DC power brick need pure sine wave or will it be fine on a modified sine wave cheap inverter?

    I don't squabble over semantics and all of my successful commercial designs are still successful. :cool: As the business owner and circuit designer - I have to communicate in a way that everyone can pickup on what I am putting down. The engineers around me (that are much better and much more...
  8. Factory400

    Does an AC to DC power brick need pure sine wave or will it be fine on a modified sine wave cheap inverter?

    Fair enough....my wife says the same thing. And no - it is not a threshold. That is why I noted it is expressed in db at a certain frequency - not any fixed threshold. The load will have a certain amount of noise at various frequencies that are considered tolerable. That is different with from...
  9. Factory400

    Does an AC to DC power brick need pure sine wave or will it be fine on a modified sine wave cheap inverter?

    The price difference is indeed rather small - IMHO the modest additional cost of sine wave is worth not needing to worry.
  10. Factory400

    Does an AC to DC power brick need pure sine wave or will it be fine on a modified sine wave cheap inverter?

    The PSRR describes how a signal on the DC input voltage of the regulator system is transmitted to the regulated output. I am not making this up. How much noise on the input vs noise on the output. How much noise the power supply can reject. A power supply will attenuate noise by some...
  11. Factory400

    Does an AC to DC power brick need pure sine wave or will it be fine on a modified sine wave cheap inverter?

    That is not really true. The steps in a modified sine wave are rather difficult on the the front-end components and create a ton of noise that can go beyond the Power Supply Rejection Ratio. The high current and voltage steps along with the noise that bothers the extremely fragile control loops...
  12. Factory400

    Chargery: AH measurements

    That sounds reasonble for that part. I have been using those for many years and really like them. Once they are programmed - they do all of the hard work and just spit out the results. Now - they just started shipping the 20bit version called the INA229 which I think is a drop-in replacement...
  13. Factory400

    My first question - which BMS to choose

    This is a tough one - the BMS market is FLOODED with cheap Chinese stuff that is very difficult to predict. I have an RV system that needs to operate in the cold, be very reliable, and not malfunction in a way that can damage the pack or any individual cell. I examined the usual suspect cheap...
  14. Factory400

    Chargery: AH measurements

    STM32 internal ADC is what I believe is being used. There is a reference on the board, but I don't believe that STM32 has an external reference input - could be wrong on that.
  15. Factory400

    Chargery: AH measurements

    It sounded like a hypothetical expectation for a future product. The current one that uses a 12bit ADC is dismally implemented IMHO.
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