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Cheap LiFePO4 BMS?


jetzi

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2 hours ago, ivan&alice said:

Do you mean for free as in the labour? The part will be the hard bit to find / expensive bit to buy. I wouldn't have thought RCR would help me with this, since it's not really an emergency as I can charge my starter on my domestic alternator?

 

 

 

Doesn't need to be an emergency. If it doesn't work the RCR will come out and replace the start battery alternator. We are on gold membership and for that they will pay for the bits as well as the labour.

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Bored sitting at home still in Queen Nicola’s lockdown so I’ve designed alternator controller v3. I’ve added a switch to select slow or fast charge (day’s cruising vs moored recharge) in addition to the state of charge switch (50%, 80% or 100%). I’ve added a galvanically isolated interface for VE.direct so it can know the SoC from a BMV battery monitor. when we get Lithiums the Smartgauge will be obsolete and I might get a BMV to supplement the Mastershunt.


I added an interface for those little OLED displays since they are cute, cheap and I might as well have the controller say what it’s doing. I ditched the relay to interrupt the field current in emergency. There are already several protections within the chip - the regulated voltage goes to 13.5v if no LIN data is received for 3 seconds (microprocessor crashed etc) and there is an independent built in over-voltage watchdog which stops the field current if the voltage gets too high. Plus of course emergency isolator (tyco relay etc) off-board.
 

Design duly uploaded to manufacturer in China, then I found a voucher on their website for free “Europacket” DHL shipping (5-8 business days) so total cost including shipping for 5 boards is £1.70. Ridiculous. I feel guilty, like I’m exploiting them, at that price.

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51 minutes ago, nicknorman said:

Ridiculous. I feel guilty, like I’m exploiting them, at that price

I often feel that way with silly little purchases from China but if their government wants to subsidise them... 

 

Keeps them too busy to hack RyanAir perhaps ;)

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1 hour ago, nicknorman said:

Bored sitting at home still in Queen Nicola’s lockdown so I’ve designed alternator controller v3. I’ve added a switch to select slow or fast charge (day’s cruising vs moored recharge) in addition to the state of charge switch (50%, 80% or 100%). I’ve added a galvanically isolated interface for VE.direct so it can know the SoC from a BMV battery monitor. when we get Lithiums the Smartgauge will be obsolete and I might get a BMV to supplement the Mastershunt.


I added an interface for those little OLED displays since they are cute, cheap and I might as well have the controller say what it’s doing. I ditched the relay to interrupt the field current in emergency. There are already several protections within the chip - the regulated voltage goes to 13.5v if no LIN data is received for 3 seconds (microprocessor crashed etc) and there is an independent built in over-voltage watchdog which stops the field current if the voltage gets too high. Plus of course emergency isolator (tyco relay etc) off-board.
 

Design duly uploaded to manufacturer in China, then I found a voucher on their website for free “Europacket” DHL shipping (5-8 business days) so total cost including shipping for 5 boards is £1.70. Ridiculous. I feel guilty, like I’m exploiting them, at that price.

Consider it payback for all the pain they have caused us by their dishonesty over the Covid virus!!!!!!

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If you keep sending large chunks of your IP to Chinese manufacturers  I would not be at all surprised to see a commercial version of the Nickulator appear from the east, once they have worked out what it does! 

 

N

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33 minutes ago, BEngo said:

If you keep sending large chunks of your IP to Chinese manufacturers  I would not be at all surprised to see a commercial version of the Nickulator appear from the east, once they have worked out what it does! 

 

N

Haha well it might be true except that most of the complexity of the project lies in the software. The hardware is standard stuff. They don’t get to see the software!

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44 minutes ago, nicknorman said:

Haha well it might be true except that most of the complexity of the project lies in the software. The hardware is standard stuff. They don’t get to see the software...

...which you design on a PC which is linked to the Internet via a Huawei router?

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1 hour ago, 1st ade said:

...which you design on a PC which is linked to the Internet via a Huawei router?

Could be. But the design software is american so it’s far more likely that the yanks are stealing my IP!

Edited by nicknorman
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If you really want to see if someone is watching, put a couple of spare connectors in  somewhere and, on the silk screen, label them " physics package enable".

 

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40 minutes ago, BEngo said:

If you really want to see if someone is watching, put a couple of spare connectors in  somewhere and, on the silk screen, label them " physics package enable".

 

?? is that code for detonator connections?

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"The physics package" is, usually, what the specialists call the  inner works  of man made sunshine.   All the physics inside that bit  is simple, involving a lot of high speed neutrons, plastic straws

and a timescale measured in shakes ( as in " two shakes of a lamb's tail") where a single shake is 10 milliseconds IIRC.  The prior  physics that are needed to make it go BNAG  are not simple and involve lots of seriously clever electronics, some very precise capacitors and a lot of precision machining of very unfriendly materials.

N

 

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9 hours ago, MoominPapa said:

10 nanoseconds, according to https://en.wikipedia.org/wiki/Shake_(unit) but what's a factor of one million between friends?

 

MP.

 

 I did think 10mS was a very long time for almost anything except human thought, thanks for clearing that up!

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25 minutes ago, BEngo said:

About 2 Megatons,  at a guess.

 

TY

N

 

Ha! When I worked on high performance scientific computing I used to run into the guys from Los Alamos and Livermore at conferences sometimes. There's a shared interest between the Human Genome Project and the bomb boys in making fast compute clusters of thousands of CPUs with fast simultaneous access to petabyte-sized file systems. We used ours to analyse DNA data; they used theirs to analyse nuclear explosions, but that's about as much as they'd ever say about it :)

 

MP.

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54 minutes ago, nicknorman said:

 I did think 10mS was a very long time for almost anything except human thought, thanks for clearing that up!

If you believe the wonderfully-named Carey Sublette, who seems to be the main purveyor of non-classifed information on such things, it's all over (for a fission weapon) in about 560nS, and most of the bang happens in the last 40-50nS of that. https://nuclearweaponarchive.org/Nwfaq/Nfaq2.html#nfaq2.1.3

 

MP.

 

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8 hours ago, WotEver said:

I always have to take a look at a reference once I start thinking about micro, pico and nano. “Now which one’s got 6 zeros?”

Picoseconds are commonplace for us, and we have to worry about femtoseconds sometimes...

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4 minutes ago, IanD said:

Picoseconds are commonplace for us, and we have to worry about femtoseconds sometimes...

Ahh, it’s Farads for me as opposed to seconds. 

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13 hours ago, WotEver said:

18 decimal places?

No, but when we're trying to get on-chip capacitors of a few femtofarads to match each other, we're looking for attofarads ?

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37 minutes ago, IanD said:

No, but when we're trying to get on-chip capacitors of a few femtofarads to match each other, we're looking for attofarads ?

What’s a few attofarads between friends... ;)

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