Just put the VPU through JLCPCB, and after taking into account the connectors that need to be ordered from LCSC, the BOM cost comes to $25AUD per board, for 5 boards. This is too expensive. I will need to do some BOM optimisation, focusing on not using too many of JLC’s extended parts, which make up $40 of the total cost, just in the extra labour required for the extended parts. I’m thinking about making smaller boards featuring a single voltage, and you can just add the board for the voltages you need (doubt most people would need 3.3v). This will lower cost, size, and allow me to make some space concessions to get costs down.
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Currently one 12V 1A JST 2-pin connector would do what I want. Have you asked what people would be willing to pay though?
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I’d be happy to have it just be a single 1A output, as long as the general concensus is in agreeance. It will save me some space.
I am thinking that VESC Power Unit should actually be a series of very small modules designed for very specific but fairly simple tasks, such as powering a 12v fan from a 84v battery or controlling brake LEDs from PPM. I’d love to keep boards under $15AUD each, so that buying a few boards won’t break the bank. What would you be willing to pay for a board that does just 12v 1A and that’s it?
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Have a couple of 12v devices that need 1A? Just buy 2 boards, cheap enough to not be an issue.
Ouch $4 each.
LCSC has them for $2.80AUD a unit, they basically halve in price again when buying 100+. If there’s significant interest I would buy a heap in bulk
I need 8 volts. We can change the feedback resistor or put a 25 turn pot. Put me down for 50 units.
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I’m slidin in those DMs fam
@linsus @Gamer43 so @kevingraehl wants to add a thermistor that only allows an output when a certain temp threshold has been reached. Could I use an NTC thermistor in combination with some resistors on the ENABLE pin of the LM5164? Or is there another approach that won’t add too much complexity?
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Yes, but controlling the temperature cutoff is non trivial and requires a bit of math.
It really shouldn’t overheat. The LM5164 has built in overtemperature protection anyway.
Thermistor would be external, placed on an ESC and allowing the output to turn a fan on/off. Definitely of the built in thermal protection
Forced air wont do much inside of an enclosure, unfortunately. But certainly an idea.
This isn’t for me to judge. Would this be trivial to implement?
Yes, just choose values such that the 85°C resistance value on the NTC causes the voltage divider to be above the enable voltage.
And below at 25°C
It’s not inside an enclosure that’s is sealed. It’s actively cooling. Open to the environment
What I’m pursuing is the ventilation system being open to the environment, but not the rest. Basically only the fan would be exposed, the intake and outlet would go through a hollow heatsink that’s sealed to the enclosure.
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Here is the 8v 1A VPU designed for @kevingraehl
Here you can see a third JST conector, this is for a thermistor which has been setup to turn on the unit after the thermistor has reached 50c. With my rudimentary knowledge of electronics this should work but happy to be shown otherwise. The outputs now have a 1A fuse, in case you want to run a single output at 1A, instead of at 500mA. The output of the unit has not changed. The traces are now all wide enough to carry 1A. There are thermal relief vias under the LM5164 which can have solder flowed through, although that isn’t necessary.
The size of this board is 33 x 33mm which is great. Without the thermistor circuitry, and with smaller connectors, the size could be taken down even further. This will allow for ease of mounting the unit inside an enclosure. If there is significant interest in the thermistor version I could offer that at a later stage, after testing and stuff. If that is something people want, I would want to spend some time figuring out smaller connectors and stuff to save space.
An order will be placed for some units soon. Once some testing has been done, I can place orders on the different voltage versions and test each of them. Once each iteration has been tested a working I will make public the design files with instructions on how to order from JLCPCB and LCSC. I will also be offering boards prebuilt with all connectors and stuff
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I say ‘and stuff’ a lot.
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You just did it again.
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Simple words coming out of simple minds
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