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New Contributor II
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What is the 12v tolerance of the dev board?

I would like to run the dev board on a drone, powered from a 3s LIPO battery. A fully charged 3s battery is around 12.6v (13.05v for the newer LiHV batteries). Is this a safe voltage for the dev board, powered through the DC barrel connector?

The trouble with running a BEC is that it will cut off as soon as it goes below 12v, which is almost immediately when the drone powers up.

I would run a SEPIC regulator but I can't find a 12v one that supplies enough ampage.

There's a good discussion here but it's inconclusive:

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Community Manager
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Hello fnoop,

 

 

Thank you for interest in the Intel® Joule™ Products.

 

 

I saw the link that you provided and it seems that to recommend a voltage greater than what is stated in the official documentation (12 V), or greater than the voltage tested by community member McCool (12.4 V), will be irresponsible from our side.

 

 

I understand that you want to use a 12.6 V battery, but anything different from what has officially been tested can't be recommended from our side. Even if a community member states that he has successfully tested higher voltage levels, it would be up to you to take the risk.

 

 

So, from our side, what I can tell you is: based on the official documentation, it is not safe to power the development board with a voltage higher than 12 V.

 

 

Regards,

 

Andres V.
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New Contributor II
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Hi Andre

Thanks for the response. So I've been looking at power supplies and regulators and they all seems to have varying tolerances, but 5% tolerance is not uncommon. For example here's a nice 12v regulator

http://www.hobbytronics.co.uk/s18v20f12-12v-regulator 12V Step-Up/Step-Down Voltage Regulator S18V20F12 | 2577 | Pololu

But it's a 4% tolerance, which means it could go up to 12.5v, and some wall PSUs have even worse tolerances, apparently. So it would be good to know what the actual range of the dev kit is, which tells us the quality of the power we have to give it. As the dev kit doesn't come with a power supply, this is not an unreasonable question that should be officially answered by Intel.

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Novice
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Hello,

I work at Intel, but I'm posting this as an enthusiast, not an employee. check out the expansion board schematics. On the dcin path, there is a B520-13-F diode and then a FPF3042UCX DC switch (to select between dcin and vbus). The FPF3042UCX is rated to 12.4V over-voltage cutoff, but is 14V typical; that is likely the limiter. The good news is the diode will create a 450mv drop(typical), so a 12.6v dcin minus 0.450mV diode drop shows ~12.2V at the switch.

Worst case, in an over-voltage situation the switch won't be damaged, but it will cut off the output voltage to the system. Bench testing the battery and expansion board and see if it cuts off.

Test it out and good luck!

schematics, switch and diode datasheets:

https://www.fairchildsemi.com/products/power-management/advanced-load-switches/slew-rate-controlled-...

https://www.diodes.com/assets/Datasheets/ds13012.pdf

http://www.intel.com/content/dam/support/us/en/documents/joule-products/intel-joule-expansion-board-...

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New Contributor II
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Thanks for such a great answer

So if my (very poor) understanding of the schematic is correct then it should also be fine when the battery drains down to 9.5-10v?

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Novice
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Hi Fnoop,

The expansion board design guide specs DCIN down to 7.0 volts, in section 5.1. Keep in mind that as the voltage drops, the current requirement increase, so ensure the design has some headroom over the 2.7A, just to be safe. 12V * 2.7A = 32.4VA, so 32VA/7V= ~4.6A. Good Luck!

http://www.intel.com/content/www/us/en/support/boards-and-kits/intel-joule-kits/000023394.html http://www.intel.com/content/www/us/en/support/boards-and-kits/intel-joule-kits/000023394.html

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New Contributor II
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@platform_skater Ah I hadn't come across that document, it's a fantastic explanation of the board. Fortunately LIPO batteries provide huge current - even the small 3s batteries on small/mini drones can usually provide 50A+. If they drop much below 10v then they get permanently damaged so looks like they are absolutely perfect for powering this dev kit. Thanks again for the responses

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