diy solar

diy solar

Recent content by natec

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    Battery not balancing well.

    It does. Thanks.
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    Battery not balancing well.

    @toms, I'm about to introduce an alternator that will push rates closer to 0.5C. Would you still recommend the same settings based on the new firmware? Specifically curious about BMIN, BMAX, CHAR, and MAXC.
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    Battery not balancing well.

    This depends on the firmware version (now at least). REC made some significant changes, IMO, to their charging algorithm in version 2.7 and 2.8. From the latest manual for the REC Q/Victron Compatible BMS: What can mean in practice (for me at least) is that you will get hard cutoffs...
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    Pre Charge using REC unit - Surprising Results

    I just fired up my Van electrical system for the first time and was very surprised by the size of the transient in spite of using the REC BMS Precharge unit set to 11 seconds. System: 24V 16 EVE 280AH cells in a 2P-8S configuration. Inverter is Multiplus 3000. The yellow trace is a probe...
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    Pairing Cells for a 2P 8S battery

    Thanks so much for getting back to me! The adventure begins...
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    Pairing Cells for a 2P 8S battery

    Steve, Thanks for the reply. Data from the supplier is now attached (mobile mishap). These are cells and data from Luyuan. I'm planning to assemble (electrically at least) in the 2P8S configuration shown at the bottom of page 10 of Luyuan Assembly Guide you pointed to, managed by a REC Q...
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    Pairing Cells for a 2P 8S battery

    I just received my 16 EVE 280AH cells and accompanying data. I plan to bulk charge in the 2P8S arrangement and the shift to 16P for top valence. My question is on the best way to pair up the cells based on the test data I have. Should I focus on matching resistances? Resistances at low SOC...
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    Pack / Cell compression Optimized By Using Springs.

    That was concept C for me. It's not a bad idea. It's a little more difficult to find springs with the right characteristics, but they are out there.
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    Pack / Cell compression Optimized By Using Springs.

    This was the whole basis for my final design. When you account for the flex of the compression plates, which will act as two springs in series with the compression attempted by the springs, you will find that the flex of fairly thick plates (3/16 steel) is substantial. If you choose the plate...
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    REC Q (Victron Firmware) CANBUS Communication Schema

    Wondering if anyone on here has details on this subject. I just got my REC BMS powered on yesterday and started monitoring its CAN communication. I got a few surprises in what I was seeing coming across the channel. Its all documented here...
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    Pack / Cell compression Optimized By Using Springs.

    I ended up going with 3/16 steel, but not exactly for the rigidity. Based on some math, I can rely on the flex of the steel instead of using springs to provide compression in the general range we are looking for. Current design is here...
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    Cinergi's 28 kWh / 4 kW Solar / 10 kW inverter RV build

    Amazing! Tell me about this mini-split!
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    Cinergi's 28 kWh / 4 kW Solar / 10 kW inverter RV build

    The siglints look really good and have a good reputation. Thats what I'm saving for.
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    Cinergi's 28 kWh / 4 kW Solar / 10 kW inverter RV build

    Just thinking out loud, I would have assumed that the AC content seen on the DC side would have been 2xFoutput (ie the product of AC output Voltage in phase with AC output current, which would be appear a twice output frequency cyclical power draw). That frequency shouldn't have a dramatic skin...
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    Cinergi's 28 kWh / 4 kW Solar / 10 kW inverter RV build

    Skin effect is an AC effect. It results from induced an EMF that opposes primary current flow. Inducing that EMF requires a changing magnetic field, which in turn requires an AC current (the higher the frequency, the greater the effect). What ever you are seeing is likely due to something...
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