Products > Other Equipment & Products
Dyson v7 Trigger cordless vacuum - TEARDOWN of battery pack
Steve1M:
Just joined this forum.
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Such a relief to find this thread and your priceless youtube material, very much appreciated.
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I have V8 with SV10 battery.
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I sourced some Molicel 20700A cells, and have successfully changed out individual cells twice in the past, soldering, with no issue.
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Poor performance yet again, tired of repeated strip down of pack, so decided to replace all 6.
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Bought ten brand new Molicels, (expensive here, in UK) and and spent a long time performing discharge tests on quality RC iCharger, 2A down to 3V/cell, and managed to select 6 with only 40mAh between best/worst. Really lucky.
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Charged all to exactly 3.85V each.
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Spot welded them all in yesterday, which I was really pleased with, after having experimented for an eternity first.
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End result - 4 x red LED flash if press trigger, or plug into charger.
If hold trigger, 4 x red, then 1 x blue.
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Lots of web searching, to discover this Dyson PCB "kill feature", and additionally, was absolutely shocked to discover lack of BMS balancing function (an absolutely essential function of any BMS...unbelievable).....absolutely furious, after so much cell research/welding prep etc.
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Anyhow, I only wish to be able to unlock the BMS, changing the 2 x values in the eeprom positions, and have a couple of questions:-
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a) Can someone please tell me the correct pcb mapping (N7,N3,N4,N8,N9) to Vpp/Vdd/Vss/Data/Clock.
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b) Also, if my pack is all assembled, do I need to check the Vdd box, or is the chip powered within the pcb?
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Many thanks, Steve
tinfever:
--- Quote from: Steve1M on January 20, 2023, 05:35:31 pm ---Anyhow, I only wish to be able to unlock the BMS, changing the 2 x values in the eeprom positions, and have a couple of questions:-
-
a) Can someone please tell me the correct pcb mapping (N7,N3,N4,N8,N9) to Vpp/Vdd/Vss/Data/Clock.
-
b) Also, if my pack is all assembled, do I need to check the Vdd box, or is the chip powered within the pcb?
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Many thanks, Steve
--- End quote ---
On the GitHub repo (https://github.com/tinfever/FU-Dyson-BMS), part way down under "How to install it" there is an image showing the correct programming pinout. Edit: I'm 99% sure the pinout for the V8 is the exact same order, just with the ground pin in the same group. Reasons:
Just realized I never really thought about the V8/SV10 pinout. Given others have reported success with the V8's, not mentioning any pinout differences, another person (Aleksey1406) traced out some of the circuitry for the V8 and that also looks the same (https://github.com/tinfever/FU-Dyson-BMS/issues/20), and also someone else (dr-mark-roberts) reverse engineered part of the schematic long before I did any of this and their info matches (https://github.com/dr-mark-roberts/open-dyson-battery/tree/master/hw/docs), I think it is the same.
I recommend letting the microcontroller be powered by the PCB (Leaving the box unchecked, I believe.) You'll need to do something to wake up the BMS like push the button and apply a magnet (if applicable), then run the programming software while it is awake. I believe this is the safest method, although supplying VDD from the PicKit will work too, I'm just slightly more suspicious about doing it that way given how many times I've broken the VDD regulator portion of the ISL94208 IC for unknown reasons.
Hope that helps! Good luck!
Steve1M:
Yep, it's in the same order.....thanks.
Pic - bit concerned about how long it retains power if use magnet, press switch...will it corrupt if I mess up and it powers down mid-write?
Thanks for your intetest/time.
tinfever:
--- Quote from: Steve1M on January 20, 2023, 10:19:46 pm --- Yep, it's in the same order.....thanks.
Pic - bit concerned about how long it retains power if use magnet, press switch...will it corrupt if I mess up and it powers down mid-write?
Thanks for your intetest/time.
--- End quote ---
Once it is in programming mode, the PIC isn't running normally and so it won't shut down on it's own. You'll notice that if you place the magnet and press the button to wake it up, then take away the button press and magnet, it stays awake for a bit. This is because the software inside decides when it is time to turn off again. I think just having the programmer connected and clicking Tools > Check Connectivity while it is awake is enough to get it into programming mode and then it will wait indefinitely for you to do whatever until you remove the programmer.
I wouldn't worry about it powering down mid-write. Since you are only editing the EEPROM hex to unlock your BMS, take very special care to configure the programming software correctly to only program the EEPROM. I believe the correct checkboxes and buttons are listed previously in the thread.
Steve1M:
Excellent!!!
Many thanks for your concise, detailed explanation.
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