Resistor value 12V output

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paulcrawford
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Resistor value 12V output

Unread post by paulcrawford » Thu Mar 07, 2019 3:49 am

According to the wiki for SmartPower2, it is possible to increase the output voltage to 12V. https://wiki.odroid.com/accessory/power ... er2_12vout

The new resistor value for R30 is noted as 91K but the smd number is given as 1005(0603). I am not sure what the "1005" means but "0603" seems to mean 60K.

Which is correct?

Thanks,

Paul

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Re: Resistor value 12V output

Unread post by odroid » Thu Mar 07, 2019 10:19 am

R30 resistor value is 91Kohm.
1005 is the SMD type resistor size code in Metric. Imperial code must be 0402 not 0603. We will update the wiki page soon.

Image

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Re: Resistor value 12V output

Unread post by paulcrawford » Thu Mar 07, 2019 12:02 pm

Thanks @odroid

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mad_ady
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Re: Resistor value 12V output

Unread post by mad_ady » Thu Mar 07, 2019 2:15 pm

I had no idea SMDs had both metric and imperial codes. Seems obvious now, since discrete resistors could have color codes or normal codes - why have only one standard when you can have many? :D

https://xkcd.com/927/

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Re: Resistor value 12V output

Unread post by odroid » Thu Mar 07, 2019 2:30 pm

World wide standard must be Metric system. But US people always have enough power to make many fragmented standards probably. ;)
https://en.wikipedia.org/wiki/Metricati ... ted_States

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Re: Resistor value 12V output

Unread post by back2future » Fri Mar 08, 2019 4:58 am

mad_ady wrote:
Thu Mar 07, 2019 2:15 pm
I had no idea SMDs had both metric and imperial codes. Seems obvious now, since discrete resistors could have color codes or normal codes - why have only one standard when you can have many? :D

https://xkcd.com/927/
[ Then it's time to speculate how this numbers for resistor values arose?
https://xkcd.com/688/
... difficult for 0402, 0603 and (0)1005 ]

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Re: Resistor value 12V output

Unread post by paulcrawford » Tue Oct 08, 2019 11:26 am

odroid wrote:
Thu Mar 07, 2019 10:19 am
R30 resistor value is 91Kohm.
1005 is the SMD type resistor size code in Metric. Imperial code must be 0402 not 0603. We will update the wiki page soon.

Image
I think the above statement is incorrect. According to the jpg image attached 402 is the metric and 1005 is the Imperial.

I did order some 91Kohm 402 SMD resistors and managed to get it soldered in today. The Smart Power 2 works fine after I updated to v1.5 of the firmware. I can connect to the Bluetooth using SmartPower2_8017f8 as the SSID, but when I try to open the webpage at 192.168.4.1 the only thing I get is “FileNotFound”.

Before I installed v1.5 I was able to get the correct web page with the values and voltage slider but of course with the older version I could not set a voltage above 5.3V.

@odroid, can you please verify that this error exists on your Smart Power 2 with v1.5? The photos in the wiki entry for 12V power show that the firmware version is 1.3 so something must have changed.

Thanks.

EDIT: Bluetooth above should read WiFi :oops:

EDIT2: Telnet does work fine by WiFi

EDIT3: Despite having been running for a few hours at at least 2.7W the Wh totalizer still reads 0.000

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Re: Resistor value 12V output

Unread post by lsc1117 » Fri Oct 11, 2019 11:03 am

@paulcrawford

I have fixed the error. Please refer to this log.
https://github.com/hardkernel/smartpowe ... bc25d1R663

You can also get the latest awesome project about the smartpower2.
It consists of based on PlatformIO. So it is easy to build and upload.
https://github.com/ytrikoz/smartpower2

I recommend you to use the ytrikoz's firmware. You can follow this thread.
viewtopic.php?f=86&t=35445
These users thanked the author lsc1117 for the post:
paulcrawford (Fri Oct 11, 2019 11:14 am)

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Re: Resistor value 12V output

Unread post by paulcrawford » Thu Oct 17, 2019 2:18 am

lsc1117 wrote:
Fri Oct 11, 2019 11:03 am
@paulcrawford

I recommend you to use the ytrikoz's firmware. You can follow this thread.
viewtopic.php?f=86&t=35445
I have switched to @ytrikoz's firmware which is very good but he is having trouble with controlling the output voltage as I changed the R30 resistor to 91K to deal with 12V output for an N2. Also the SP2 USB output voltage is 7.55, much too high for USB. He suspects that this is a hardware issue. Can you confirm that this can be fixed in software?

Thanks

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Re: Resistor value 12V output

Unread post by odroid » Thu Oct 17, 2019 1:18 pm

Both two output ports share the same source.
So they must show the same voltage.

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Re: Resistor value 12V output

Unread post by paulcrawford » Thu Oct 17, 2019 9:52 pm

I realized that I was using a CHARGER Doctor to measure the USB output voltage. It has a maximum voltage reading of ~7V so the 7.55 reading is not surprising. Confirming with a DMM shows that the USB output is the same as the main DC output as you say.

I think I will remove the USB output jack to ensure that no USB device sees 12V.

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