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Yes - the charge cut-off worked at around 8.5V and the discharge at around 5V - as per the specification of the DW01B protection chips on the board. I believe the charge levelling circuits should work OK as well, although I didn't try it.These protection boards are very good value from China and now I have studied the board's circuit with the powerful MOSFETs on board would be good for power switches of up to 40A. I might buy a few more to play with.
Hi Nick, Sorry about the formatting - I copied and pasted my conversation with the eBay supplier! Thanks for replying. I connected the output + pad to the 16.8, 12.6, and 8.4 pads and the top of the two cells. Without the intermediate connections the other pads were too sensitive to touch - they could turn off the mosfets. Both overcharge and low voltage working as per spec.Tony
Hi Nick,Great article, and since you have studied the subject a bit, I wonder if you can help. I bought a couple of 4S BMS boards from China and would like to use one with just 2 cells. The BMS has a lot of small transistors in addition to power devices and doesn't use a special chip. I have attached an image. Have you seen any circuits for these boards which might give a clue as to whether it is possible to bypass the unwanted stages?Tony
Ps that two capacitor paradox link is also something I have not been aware of - fascinating!
Hi idontlikeregsThis is a great bit of explanation that I will have to chew over for a while, and perhaps is now getting outside the normal level of comment seen on Instructables. It's great to stretch my 72 year old brain with concepts that I have never seriously thought about on components that I have used most of my life. I run a Wimshurst machine at my local Hackspace in Leicester, UK, and when I explain how it works to people, I often talk about pulling apart of capacitor plates where a fixed charge causes the voltage to increase - that was taught us in basic physics at school, but capacitors in series is quite a bit more complex, as you are pointing out. Tony
This explanation is good, up to a point. I already know about the combined value of caps in series, and this article tries to explain a bit more about about how the charging current has to come through the plates of the adjacent capacitor. However, it still doesn't quite explain the fundamental problem - if each cap charges up to 1/3 of the total supply, then each cap should be able to supply 1A for 50s, and the series result should be 5V at 1A for 50s. The answer is something subtle about the fact that the charge on each capacitor has to flow through the other two, so presumably one could get V/3 from each cap with a direct DC connection to the cap giving 1A for 50s, but only 1A for 16.6s when that current has to flow through 2 more caps.There's a lot more to understanding this than simp…
This explanation is good, up to a point. I already know about the combined value of caps in series, and this article tries to explain a bit more about about how the charging current has to come through the plates of the adjacent capacitor. However, it still doesn't quite explain the fundamental problem - if each cap charges up to 1/3 of the total supply, then each cap should be able to supply 1A for 50s, and the series result should be 5V at 1A for 50s. The answer is something subtle about the fact that the charge on each capacitor has to flow through the other two, so presumably one could get V/3 from each cap with a direct DC connection to the cap giving 1A for 50s, but only 1A for 16.6s when that current has to flow through 2 more caps.There's a lot more to understanding this than simply following the formula.
I've had a thought about capacitors in series as power sources - someone please explain. The value of the combination is 6.9V 16.33F, therefore it can supply up to 6.9V at 1A for 16.33s. However each cap is 50F which can supply 2.3V at 1A for 50s, so the series combination ought to supply 6.9V at 1A for 50s. Which answer is correct and why?
Hi mistrijeSorry you are still having so many problems.I have been using PulseView with the FX2LP Chinese clone board for many months now without problems. According to Zadig, the driver is libusbk(v188.8.131.52), and the USB ID is 04B4 8613. I scan for the board with the fx2lafw driver which finds the Cypress FX2 with 16 channels. PulseView is 0.5.0-git-844c461 and I am running under Win7 on a Samsung 64bit laptop with Intel i3 CPU.I have forgotten how I got it all to work, but it seems very stable nowadays. Tony
Hi AndbroIt's a long time ago now, and I have been using Pulseview with the Cypress clone regularly, so I can't quite remember what I did. I believe it was about trying different drivers with Zadig, till it started working. I still find that my old Samsung Windows 7 laptop sometimes doesn't recognise the board, but it usually works after reconnecting the board and running Pulseview again.
I performed the operations in the Instructable on Windows 7. All looks good and PulseView finds the device - Cypress FX2, but gives an error message "Failed to open device generic/unspecified error"I have tried rebooting the laptop. and tried another board from the same Chinese company, but same problem. Has anyone got solutions?
Hi ArduinoDeXXXThank you so much for a great article - I think you did a superb job with the written English, because, perhaps, your spoken English is not good enough for spoken commentary. The way you educated us through several iterations was superb, and very clever videos. I help run a Hackspace in Leicester, UK, and I feel this would make a great project for our members, demonstrating advanced motor driving and complex feedback in closed loop systems. I appreciate that you wish to hold on to your final code, but it is great that you have answered various posters' questions.Thank youTonywww.leicesterhackspace.org.uk
This may be an Instructable, but it doesn't give any information on how this works. Seems to me it's just a way to sell these 12V solenoid valves. Lets have some code examples rather than a preconfigured SD card. Goodness knows what spam you might be putting on it.
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