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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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    Cal's DIY BMS

    Made some improvements to the balancer. https://diysolarforum.com/attachments/bms-balancer-jpg.75766/ The design has a few shortcomings. The input diode (kind of) prevented the dc/dc from exceeding maximum input voltage. Still, the input voltage is scary high. The dc/dc output voltage is...
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    Figure out what you need before you buy damn it.

    You're kind of putting the cart in front of the horse. In order to plan you require knowledge. I've been doing DIY projects all my life. You can read all you want on some topic, but nothing beats hands on experience. There's nothing wrong with purchasing something and then finding out later...
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    Figure out what you need before you buy damn it.

    "Figure out what you need before you buy damn it." Can't say I agree. It's not a perfect world. You're looking at utopia. Usually my DIY projects are a work in progress. They virtually never end up with my original concept or components. Give the guys some slack.
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    The Big Misconception About Electricity

    That his setup requires no inductance is actually my opinion. He needs zero impedance transmission line for the light to turn on. The video with the lamp turning on when switch is closed is not what's going to happen. And it won't stay on. Just a voltage transient occurs when the switch is...
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    Building a CPAP battery backup

    Are you using a ResMed machine? Does the connector have a center pin? If so, you're missing quite a bit. The center pin allows communication between the machine and the power supply.
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    Is my new battery charger defective?

    No, not possible. The OP stated voltage reached 13.67V and stayed there. The charger NEVER got into bulk. And... 13.67 is not a specified float voltage. He also tried AGM mode with no change in output voltage. The charger is defective. I would not trust it. It's highly improbable you'll...
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    Is my new battery charger defective?

    The point is that the charger is defective. How long will it take to charge to 13.7V? The last section will be a trickle charge. It would be insane to do that with a generator.
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    Is my new battery charger defective?

    Don’t know why you want to hang on to a defective charger. Your battery won’t get a full charge at 13.8V. 14.4V bulk is perfect for your battery.
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    Is my new battery charger defective?

    Seems like the charger is defective. You could try the charger on a lead acid battery. Does voltage go higher? Probably not.
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    Is my new battery charger defective?

    Sounds like you have a problem. Are you sure the dip switches (1 & 2) are correctly set? Both should be in the "0" position. I would switch them back and forth a few times to see if that makes a better connection. If not the charger is defective. You can try working the dip switches with...
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    Cal's DIY BMS

    I like the simplicity of this architecture. It's very straight forward. With a current limit resistor of 10 ohms, dc/dc output current is 168 mA. At a dc/dc conversion factor of 0.44, input current is 0.44 * 168 mA = 74 mA. That means the lowest cell gets charged by 94 mA and the other 3...
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    Cal's DIY BMS

    The finished 4-cell dc/dc balancer. The connector to the left are for control signals. Cell connections go to the right connector.
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    Cal's DIY BMS

    The dc/dc cell balancer is working very nicely. Got one balancer wired up and connected to Cell 4. You can see Cell 4 voltage rises while the other cell voltages slightly drop during the first 188 minutes of operation. There was no external load or charging during this time period. At 188...
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    Help in understanding new DIY solar setup - voltage drop from panels to SCC

    It's not a good idea to connect battery last. You are tempting fate. Just because Will didn't see any failures (doing the exact same procedure over and over and expecting a different result) doesn't mean it couldn't happen with other setups.
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    Help in understanding new DIY solar setup - voltage drop from panels to SCC

    I don't know if it has a PWM mode. I made that comment due to the 25.9V reading being close to battery voltage. It could be the CC has a short. In that case a fault should be displayed.
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    Help in understanding new DIY solar setup - voltage drop from panels to SCC

    25.9V is close to what would be seen in PWM mode. With MPPT the voltage at the input to the CC should be close to 3 * 31V = 93V
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    Help in understanding new DIY solar setup - voltage drop from panels to SCC

    Try powering the CC up again. 1. disconnect solar. 2. disconnect battery. 3. connect battery. Does the CC know there's a 24V battery attached? Are there any fault codes displayed? 4. connect solar. You could connect just one of the panels directly to the battery by removing all the wires...
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    Help in understanding new DIY solar setup - voltage drop from panels to SCC

    That's good. You didn't blow it up. The 5415 is rated for 150V PV open circuit. Check your connections. Does the inverter work? Will the inverter output 100W>
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    Help in understanding new DIY solar setup - voltage drop from panels to SCC

    You didn't provide EXACYLY which CC you have. The CC has a model number.
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    Cal's DIY BMS

    Got the dc/dc TBA 1-1211 from Mouser today. I was quite surprised how small the package is, but it works like a champ. As expected, the "5V" output is dependent on the input voltage. The output voltage is exactly 0.443 * Vin for the input range 10.0 to 13.2V. The part is listed as 5V, 1W...
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