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Depends what you mean by fixed from ends. If it has moment(torque) support both ends but floats axially? If both ends are fixed for both moment and axial movement it works mostly like cable and deflection is something else. Lazy to work out the numbers as both cases get bit more complex and are...

If you have several panels from same manufacturer it is easier to establish some sort of "baseline" and compare the output to that. If one panel is 20% lower than others it looks quite suspect. Other than that you would need solar irradiance meter like...

Sourcing proper BS or DIN standard barrel butt splices is easy enough and they are not expensive. You just need to shop electrical suppliers, not amazon or ebay. Tooling is another matter if you are on the market for cheap. You probably just need to try your luck with cheapo tooling and...

Digikey has bit over 6000 possible matches with input voltage range between 88v and 750v and over 500 different models in stock...

Some interesting forums and posts from my bookmarks: https://www.diyelectriccar.com/threads/dalas-evnx.204062/ https://secondlifestorage.com/index.php?threads/dalas-battery-emulator.12471/ https://forums.aeva.asn.au/ https://www.evcreate.com/shop/charging/bmw-i3-lim-ccs-fast-charging-module/

It all depends.. If you are fluent with CAN buses, protocols and hacking and foolishly brave to not to be afraid of high voltage EV batteries it's doable. But generally speaking this is one of those projects that if you need to ask how to do it is not for you.

The 2 first calculators I used are for "simply supported beam" with support on both ends so PL^3/48EI. Thus cantilever beam has 2x deflection compared to simply supported beam with 2x span. I throw the 2 first calculators just to trying to wake you up that you or ghatGPT made gross error...

Did you bother to read? Cases with support on both ends were for 12m beam making it similar-ish to 6 meter beam fixed from one end. Also the last link was for beam supported from one end. Mechanical engineer…

https://www.omnicalculator.com/construction/bending-stress?c=EUR&v=section:6,b:300!mm,t:30!mm,tw:15!mm,M:1920000!nm,d:540!mm

beam supported from both ends but you get the idea: https://sunsetpatios.com.au/beam-deflection-calculator.php 12m span 610UB125 beam supported from both ends and 36 000kg load on middle: The total maximum stress in the beam: 342 MPa...

No need to switch to parallel. You could hypotetically drain the highest reading cells with your electronic load or 12V 55W car light bulb for couple of Ah. Or alternatively charge the lowest reading cells with adjustable power supply. Or combine both. 3.38 to 3.69 cell to cell variation is...

Should be ok assuming the cables are not buried inside insulation or anything crazy like that. Note that even two cables(minus and plus) bundled together already lower the allowable max current.

There is no easy way to fix the imbalance. Per youtube teardown video the BMS is jbd-hp28sa with passive balancing. I couldn't find the balancing current anywhere but assume that it is not more than 100mA even at best. Fixing 10Ah imbalance with 100mA balancing current would take 100 hours or...

Small bridge is not same as tall bridge :whistle: Different sort of engineer (EE-ish) here but can calculate enough to tell that HEB600 is not going to bend by couple solar panels. I did my crude calculation from HEB600 flange dimensions, flange distance and calculated tensile stress in the...

well.. https://www.amazon.com/ECO-WORTHY-Balancer-Equalizer-Supports-Nickel-Metal/dp/B0CKTQF6J9 https://www.aliexpress.com/item/1005003046936197.html https://www.amazon.com/iSunergy-Battery-Voltage-Balancer-48V/dp/B0CKN5DTQH/ref=sr_1_15?sr=8-15

Victron has suprisingly good reputation considering what components they use. Hard to imagine that SMA for example would use Ruichips and Sancon.

Gazillion standards and countries to cover. NEC for single conductors Table 310.15(B)(17) allows 190A for 2AWG https://www.sabcable.com/pdfs/datasheets/tech-nec_ampacity_chart.pdf KIV seem to be 60Cel rated cable so 60mm2 single wire in free air would be abouts 210A with NEC rating. Your 217A...

600 kg load is a lot but you were talking about frikking HEB 600. You would use something that size to build small bridges for 60 ton semis! 6 m tower built from HEB600 can handle around 320kN wind load at the 6 meter lever arm. 600 kg is only 6 kN 6 meter section of HEB600 alone would weight...

You could have 7 cells at 3.65 and one cell at 3.35v. 3.35v cell voltage during charge can be anything above 10%soc

Problem with these sealed "mystery boxes" is that it is very difficult to know if the cells have reached balance. "mystery boxes" can also have varying quality of cells that have slightly different self-discharge rate and after sitting 1 year in warehouse one of the cells could be at 20% lower SOC.

"it depends" I have no idea of required code in Japan. here in Finland 70mm2 cable in free air is rated for 208A in free air installation. Scaled down to 60mm2 it would make 178A 'Murican NEC standard calls for 3/0 cable for 200A fuse if the insulation has the highest 90Cel temperature rating...

Do not use those tables for anything! That website is written by someone who doesn't have clue. Or written by AI-bot. 6 AWG cable for 300A .. for fuck's sake you can as well pour gasoline on your living room as well if you want to burn your house down. 200A breaker for 60mm2 cable is bit too...

2 MW systems are "slightly" outside of the scope of DIY-solarforum. Also sounds totally nuts that someone would order this scale of investment as a school project :whistle: You probably get better idea what is typically done by googling other MW-range solar farms how they are built. ABB...

I'm no mechanical engineer but HEB 600 for panel mount sounds like something gone wrong.

I'd be vary of Liitokala products also. They are well known for selling counterfeit or repurposed Panasonic 18650 Cells for example. I'd rate Liitokala batteries B-grade at best, sketchy but usually "close enough" to rated capacity. btw the correct spelling is "Liitokala" that means literally...

4x12v battery equalizer would solve the balancing issue for few bucks

Would be interesting to know 4 year results from stand-by use, ie minimal cycles but hold at 90…100% charge

I'm not sure about terminology and this goes to maybe irrelevant nit-picking for this thread. But I would still call it feedforward as output current is not really the end goal (output voltage control is the "end goal") It is still open-loop "best guess" of the needed compensation unlike...

LFP going for <100usd/kwh this deal sounds crazy but maybe there is devil in the rebate details. Or they forgot to work out the details.. :ROFLMAO: We don't have anything as wild as the US marketing or rebate campaings in here. Like the pepsi-co Harrier fighter jet..

-- You could at least in theory also do the feedforward to reference voltage from the AC output current. Analog domain only, no need to get the AD-converters in the mess. But I also envision it as more unstable or prone to oscillations, especially if you over-compensate with the feedforward.

Isn't the DC bus voltage already one part of feedforward? DC bus current is just additional feedforward to compensate for I*R losses in transformers/wiring? As far as I can see both options have their positives and negatives: DC bus load current compensation: slower to react, compensates...

Why do think that it would be a problem? Wiring can handle it, the whole idea of gG fuse rating is that it can handle similar overload as the cable. Your BMS is already dead and your inverter is also dead, faster fuse won't bring them back. With really wishfull thinking your inverter could be...

400 kWh for december so pretty much in line with my numbers.

Suprisingly neat/clean construction. Balance wires going trough holes in the metal brackets would be a bit worrying if used in vibrating environment.

Cheapest battery on aliexpress is not a great start. There is no lower limit on what kind of crap they sell on aliexpress. Plenty of professional con-artists there that are good in convincing ali customer support that YOU are at fault. The seller and aliexpress itself is just going to spin you...