Recent content by Cal

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    what does low voltage limiter mean in this context?

    I'm trying to wrap my head around why there's no time delay. The time-current chart is all about delays. It appears to me the fuses are rated for wire fusing current in 20 ms. If I got this right, the 35 fuse correlates to about 5 awg wire. The fusing current of 5 awg copper is 800 A. The...
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    Better Way To Handle Reverse Current Flow

    6571A Service Manual pg 72 Edit: pg. 139 is schematic. Might just be able to cut wire to J900-3 (downprogrammer control)
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    Better Way To Handle Reverse Current Flow

    From manual: A6 Output Filter Board 1. Remove the A5 Control Board as described in that procedure. 2. On the Output Filter Board, remove the nut securing the lead from choke L900. 3. Remove the bolt that secures the Output Filter Board + OUT out bus bar to the heat sink. 4. Remove the screws...
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    Better Way To Handle Reverse Current Flow

    Yes, my bad. Paralleling diodes should still work. Just need a slight load resistance in series with each diode. Some length of cable would probably work. The diode with the smallest voltage drop will conduct more current. Cable resistance provides negative feedback. Interesting problem...
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    Better Way To Handle Reverse Current Flow

    Not sure if the 2 supplies in parallel comment is directed to me. I suggested multiple diodes in parallel. That's no different than a solid state relay. Many FETs are in parallel in a SSR. Still, your comment is not accurate. You program both PS's with the same current limit. The...
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    Better Way To Handle Reverse Current Flow

    The simplest solution is to install 4 diodes in parallel. They should share current reasonable well as they have a negative temperature coefficient. Use an infrared thermometer to verify diodes operate at similar temperatures.
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    How to keep Lifepo4 cells balanced without charging to 100%

    Yes, it works perfectly for me. High voltage disconnect is at 3.40V. At this point in time the processor determines the difference between the highest and lowest cell voltage. The lowest cell then gets charged for a time period determined by the delta voltage multiplied by a constant. The...
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    How to keep Lifepo4 cells balanced without charging to 100%

    That may be the case. However the cell is in the knee of the charging curve. Cell voltages have diverged. There's absolutely no problem initiating balancing at this voltage even at high charge rates.
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    How to keep Lifepo4 cells balanced without charging to 100%

    I'm not doubting the principles of LiFePO4 charging. I was questioning you comment that balancing at 3.40V makes no sense. Regardless of charging current, 3.40V is absolutely in the knee. There's no problem using this voltage to initiate balancing.
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    How to keep Lifepo4 cells balanced without charging to 100%

    Is that your graph? Is that data consistent with other cell manufacturers? The charging plot I'm showing has 180 AH CALB cells charging at 3A, or 0.017C.
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    How to keep Lifepo4 cells balanced without charging to 100%

    Why doesn't it make sense to balance at 3.4V? 3.4V is well into the knee. That's what I do and it works great. As the chart shows, high voltage disconnect is at 3.40V. The DIY BMS determines which cell has lowest voltage (in this case Cell 1) and applies the appropriate balance charge...
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    Cal's DIY BMS

    Getting closer to the final product. I'm not much of a packaging guy... A cardboard box will have to do. The box rests on top of the battery. Pictures is the ESP32 board (containing an adc to measure cell voltages, temperature sensor and PCF8574 GPIO expander). Going clockwise to the left...
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    Stuck at first-time 2000W solar setup on boat

    If you install bypass diodes (they may already be installed in each panel) then connecting the panels in series provides more power during partial shading.
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    Figure out what you need before you buy damn it.

    Don't get me wrong. I'm all for planning. However, the folks we're talking about probably never heard of Ohm's Law (or long forgotten about it). They just seen one of Will's videos and want to build a system. It's really difficult to plan when there's no knowledge base. Research might be...
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    Figure out what you need before you buy damn it.

    Don't tell me you and your pipeline layers are perfect. Pipeline oil spills certainly make the news. We had one in Santa Barbara county not too long ago. There's always room to do it again and again... "Do it once , do it right" is a great slogan but shit happens. What happened to the...
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