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I've never managed to even power on the simcom from my standard USB
2.0 port, so I've had it on a powered hub all the time.<br>
<br>
From the SIM5360 hardware design docs:<br>
<br>
<img src="cid:part1.D16682BA.7F1497B4@expeedo.de" alt=""><br>
<br>
<img src="cid:part2.162B4F43.566C55F8@expeedo.de" alt=""><br>
<br>
<blockquote type="cite">For the VBAT, the ripple due<br>
to GSM/GPRS emission burst (every 4.615ms)may cause voltage drop,
and the current consumption rises<br>
typically to peak of 2A. So the power supply must be able to
provide sufficient current up to more than 2A.</blockquote>
<br>
So HSPA data transmission + GPS may add up to 550 - 620 mA, and the
supply needs to cope with the bursts.<br>
<br>
The modem operates at 3.8 V (?), so the 5 V load will be lower, but
the ESP and peripherals add.<br>
<br>
USB 2.0 is spec'd at 500 mA, 3.0 at 900 mA.<br>
<br>
Can someone measure the actual current consumption? My multimeters
are far too slow.<br>
<br>
Regards,<br>
Michael<br>
<br>
<br>
<div class="moz-cite-prefix">Am 17.12.2017 um 04:26 schrieb Greg D.:<br>
</div>
<blockquote type="cite"
cite="mid:ca0dc7e3-a3d5-f650-13ef-9080a33c5d7b@gmail.com">
<pre wrap="">Random data points...
Powering the module from the high power USB port (the one with the
lightning bolt next to the USB symbol) is rock solid. GSM connection is
2 "bars", as displayed by Android app. Doesn't matter if WiFi is on or
off; nicely stable. I just have a ham radio HT antenna screwed into the
GSM port (well, it was handy, and I don't have a real GSM antenna).
If I power the module from my Raspberry Pi 2 (with USB high power
enabled), the module overall is stable (doesn't crash), but the modem
never makes it up - the power on message pair just repeat every few
seconds. WiFi works, however.
Greg
Mark Webb-Johnson wrote:
</pre>
<blockquote type="cite">
<pre wrap="">I too have started to see these under-voltage warnings. I’m wondering if it is something to do with the work we recently did to enable GPS. It doesn’t seem to be a problem with powered HUBs or high power boards, so is most likely an actual low voltage condition.
Regards, Mark.
</pre>
<blockquote type="cite">
<pre wrap="">On 16 Dec 2017, at 5:59 PM, Tom Parker <a class="moz-txt-link-rfc2396E" href="mailto:tom@carrott.org"><tom@carrott.org></a> wrote:
I've found the SIMCOM modem is very unstable when connected to my laptop via an unpowered USB hub. I see under-voltage warnings so I wonder if there isn't enough power? It seems stable when connected directly to my laptop. When it the modem reboots, the esp32 crashes too. I'm not sure if this is because it also ran out of power or because it is sad the network went away:
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<pre class="moz-signature" cols="160">--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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