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TheButcher

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TheButcher last won the day on June 28

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  1. You really should adjust the voltage your chargers are set at rather than using the BP to disconnect them even if it means calling in a friend / relative / etc. Using the BP to terminate charging is like using a hammer to put a screw in. It'll work but it's not really the right tool for the job.
  2. The Victron Battery Protect works well, but you have to keep within it's own specs. The BP is not intended to switch very high loads. People were hooking up inverters and the inrush current from the capacitors in the inverter charging up grossly exceeds the ratings of the transistors in the BP, and pretty much all FET (transistor) based protectors for that matter, and kills them. The FETs either go open, so no power, or short, so impossible to turn power off. Victron even advises that loads like inverters should not be connected to the BP, but it doesn't stop people doing it, and then blaming the BP when they kill it. Ideally the battery's own BMS should protect the cells rather than relying on something external turning the current off. Some solar chargers, such as Victron's blue / smart series, can be remotely turned off by pulling a pin on the VE.direct interface ... to +12v or 0v, can't remember which, but also with hex commands set via the serial lines on the VE.direct port. The problem with non-lifepo4/lto cells is that once thermal run away starts disconnecting the load makes no difference. It's all self sustaining. All it takes is one defective cell in a pack that draws current from its neighbouring cells, not necessarily enough to blow it's own fuse to the pack bus wire. The heat from that cell raises the temperature of its neighbours to the point where they run away, and all hell breaks loose. Watch this ... it started when just one cell failed. FYI, it's not just things like the BP that get destroyed with extreme current from inverter capacitors etc. BMSes that use FETs to switch the battery output can also be damaged. Even contactors degrade if subjected to another high current cycles. Precharging is mandatory IMO.
  3. Yikes. Glad you caught it before it got out of hand. Did you test the cells before building the pack - ie, full cycle capacity test, temperature rise during charging, resting voltage after charging, impedance test etc? Personally I'd never reuse any of the lithium chemistries that are prone to thermal run away unless I knew their full use history. Even experienced people can get caught out with cells randomly turning into glow plugs.
  4. TheButcher

    Hey Sid!

    OK, so you can be pretty much guaranteed that the flash content is encrypted so let the loader do it's thing and then ... you're kidding right? They've provided a method to interrupt the load/boot sequence? Oh my. I can see people are going to be trying that out to see if they can wander around the filesystems / memory map to get a username / salted password from the standard *nix files and presto-change-o login thankyou ma'am. Of course, firmware updates will be pushed to correct 'issues' and you won't have a choice about it, much the same as per Tesla cars. Should a username / password become available that door will be shut pretty quickly, I imagine.
  5. Same path here, one day I might cut mains but until then ... (yes, my column is the blank one!)
  6. I have no doubt that as more people move to solar the private, and government, electricity supplier / authorities will be figuring out ways to keep the money flowing in. I can appreciate that the poles and wires have to be paid for some how, but if it's a privately operated electricity network with poles and wires owned and operated by private enterprise, well, frankly, if they tried to impose a pole and wire charge on me even though I had no account with them I'd be raising hell. On the other hand in many places the network itself is government owned and operated as a common good, and in that case I wouldn't mind contributing to pole and wire maintenance, providing it was a reasonable fee.
  7. Nicer than mine too. My setup started small and simple and fitted nicely into an open frame cabinet (about 1.2m x 0.9m) but as with this sort of stuff it grew a bit. One day I'll have to take it apart and rebuild it two cabinets high. Just as a suggestion, check the voltage drop across the outputs of the chargers to the bus bars when they are pushing full current. It's more of a nicety than a requirement but with lithium's fairly flat charge/discharge curve (except at the ends) you can find that even though you have ample solar and might think that your load is being fully supported by it, you may find that you are shallow cycling your battery more than you would otherwise imagine. It's very easy to get 60mV of drop across the wire+switch+fuse (and that's just one side of the wiring, the - side has drop too) and 60mV of shift in voltage for a lithium battery represents a fair amount of capacity. Your chargers will attempt to keep their terminals at the configured voltage and will only supply enough current to do that. Until the battery discharges down far enough to exceed the total voltage drop from your wiring etc your chargers will never go 'all in'. Chargers with remote sensing don't have this problem since they see the far end voltage and attempt to hold it at their set voltage compensating for the drop through the wiring etc. I'm not a micro-cycle nutter that thinks the world will implode if you do it, but you may find that you are pushing your batteries through 15% DOD cycles so it's food for thought.
  8. You could take a miniport driver from NT3.5 and install it on NT4 and Windows 2000 too. The layers above, and below the driver would recognise that the driver didn't import / export certain hooks / functions and not try to use them. Cutler really did his homework when the basic framework of NT was penned.
  9. It has the potential to fry the charger if the charger is poorly designed or uses substandard components but even the MakeSkyBlue chargers are good enough to survive, and trust me, I've deliberately tried to kill a MSB by winding it up to full current and disconnecting the battery. The bigger risk here is to your load electronics. If your loads stay connected to the charger, and there is high current from the charger and the battery spontaneously disconnects, there can be a huge spike in the output voltage and that will damage or outright kill voltage sensitive electronics. Most of the chargers I've come across, I'm not sure about the MSBs, have transient protection on their output to clamp the voltage to some safer level. There is a weakness here in that for chargers that support multiple battery voltages, say ranging from 12V to 48V, and have simple single diode clamp the protection has to be greater than the maximum battery voltage so for a 48V battery that will mean over 56V (full charge voltage). A 12V electronic device hit with a 56V spike isn't going to have a good day. I haven't tested a MSB V119 charger, but V117 chargers tend to go a bit loopy when the battery disconnected with their output turning very noisy and voltage flitting around all over the place. I wouldn't like to subject any of my loads to that.
  10. React is a nice idea but I think I'll be dead from old age before they get to a release version and TBH WINE on *nix will meet most people's needs to run a Windows program without Windows. IMO Microsoft releasing the source code for anything close to a current version of Windows would only happen just before they drop Windows. perhaps moving to a compatibility layer in linux etc. 'Next' versions of Windows aren't built in a vacuum. It's an evolutionary process rather than revolutionary, to the point where a vulnerability found in a current version of Windows has a pretty high chance of existing in a discontinued version if that vulnerability isn't in some truly new thing that didn't exist in any form in the old version. Releasing, say, Windows NT3.1 source code would still give away far too many secrets, methods and concepts that exist today in Windows 10.
  11. From what I've seen even the elcheapo chinese HF inverters have internal fuses. Sure there's still scope for a wiring fault inside the inverter between the DC terminals and the fuse on the PCB but I think you are pretty safe there. Personally I wouldn't run without protection between the busbar and inverter, and at the busbar end of the wire too. Accidentally shorting the leads with a wrench while fitting to the inverter may require a change of underware and a new set of eyes.
  12. How many cells in parallel are you talking about? I'm assuming this is a build using cylindrical cells.
  13. The original RISC concept was a rigid simple ISA specifically intended for high instruction throughput and easy parallelism resulting from the much simpler design of the execution unit. Instructions generally execute in a single clock cycle once all the data is available. Memory accesses are all aligned with the native bit width of the CPU, 32, 16, 64 bits etc. All the massive amount of silicon that current goes into parallelising and optimising (out of order execution and that ails it, hellllo spectre etc) the x86 ISA is not needed. Even the current ARM ISA is bloated by genuine RISC standards. The heavy lifting of code optimisation and parallelisation was moved to the compiler where it could evolve and develop without changes to the silicon. Anything CISC can do RISC can do too, and vice-versa. The difference in performance comes down to the hardware and software engineers.
  14. Everyone knows Windows is better. Is there a version of linux with gardening support? Nope. Windows NT has support for gardening built right in with its Dynamic Hose Configuration Protocol.
  15. Always interesting to see how things were done in another country. Long haul passenger trains in my state, QLD Australia, weren't air-conditioned at all until 1953 when a new set of diesel hauled trains replaced the old steam hauled wooden carriage trains that only had fans. The new train had a dedicated generator car that provided 240/415 50Hz AC. That set ran until 2014 when they were replaced by a tilt train (diesel and electric versions depending on where in the state it runs) that is permitted to run up to 160km/h on QLD's narrow gauge track.
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