[Ovmsdev] Active GPS power consumption

Tue Feb 7 16:32:00 HKT 2023

I ran the numbers with some pretty accurate equipment, but (particularly in the radio tests) different modules gave wildly different values. Even on one module, consumption jumped up and down dramatically. A better test would be consumption over time, to get an average.

Anyway, here are the results I got for various tests:

State	SIM36xx	SIM76xx	GPS Antenna	WIFI AP	WIFI Client	DEEP SLEEP	CAN1	Volts	mA	mW	Diff	Notes
Everything off, USB powered	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	5.0844	60.6	308.1
+GPS antenna	FALSE	FALSE	TRUE	FALSE	FALSE	FALSE	FALSE	5.0832	66.7	339.0	30.9
+CAN1 started	FALSE	FALSE	TRUE	FALSE	FALSE	FALSE	TRUE	5.0822	71.8	364.9	25.9
+WIFI client	FALSE	FALSE	TRUE	FALSE	TRUE	FALSE	TRUE	5.0812	76.0	386.2	21.3
+WIFI AP instead of client	FALSE	FALSE	TRUE	TRUE	FALSE	FALSE	TRUE	5.0707	126.0	638.9	252.7
+WIFI AP and client	FALSE	FALSE	TRUE	TRUE	TRUE	FALSE	TRUE	5.0707	126.0	638.9	0.0
Everything off, 12V powered	TRUE	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	12.0000	17.2	206.4		5V USB supply shows 5.0961V, 9.6mA, 48.9W
+GPS antenna	FALSE	FALSE	TRUE	FALSE	FALSE	FALSE	FALSE	12.0000	66.7	800.4	594.0
Deep sleep	FALSE	FALSE	FALSE	FALSE	FALSE	TRUE	FALSE	12.0000	1.9	22.8	-777.6
SIM5360 modem connected but off	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	12.0000	22.9	274.8	252.0
SIM5360 modem connected but off	FALSE	FALSE	FALSE	FALSE	FALSE	TRUE	FALSE	12.0000	7.2	86.4	-188.4
SIM7600 modem connected but off	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	12.0000	27.0	324.0
SIM7600 modem connected but off	FALSE	FALSE	FALSE	FALSE	FALSE	TRUE	FALSE	12.0000	15.6	187.2	-136.8
Everything off, 12V powered	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	FALSE	12.0000	46.6	559.2		5V USB supply shows 5.0961V, 9.6mA, 48.9W
+GPS antenna	FALSE	FALSE	TRUE	FALSE	FALSE	FALSE	FALSE	12.0000	52.0	624.0	64.8
+WIFI client no AP	FALSE	FALSE	TRUE	FALSE	TRUE	FALSE	FALSE	12.0000	63.0	756.0	132.0
+WIFI AP no client	FALSE	FALSE	TRUE	TRUE	FALSE	FALSE	FALSE	12.0000	79.0	948.0	192.0
+No WIFI but cellular	FALSE	TRUE	TRUE	FALSE	FALSE	FALSE	FALSE	12.0000	110.0	1320.0	372.0
+The lot	FALSE	TRUE	TRUE	TRUE	TRUE	FALSE	FALSE	12.0000	160.0	1920.0	600.0
+Deep sleep (GPS connected)	FALSE	TRUE	TRUE	TRUE	TRUE	TRUE	FALSE	12.0000	40.3	483.6	-1436.4
+Deep sleep (GPS disconnected)	FALSE	TRUE	FALSE	TRUE	TRUE	TRUE	FALSE	12.0000	35.2	422.4	-61.2

Note that the USB async serial chip is powered by USB and draws about 49.9mW. When powered by 12V vehicle power, that goes to zero.

I too see about 60mW for the GPS antenna.

But the biggest surprise was the difference between SIM36xx and SIM76xx modems on power down. SIM7600 almost 100mA greater usage power down. I can’t explain that. Something in the SIM76xx is pulling a lot of power even when powered down. Also, bizarrely, toggling the DTR (EGPIO#2) line (implemented in 3.3 to help with sleep) off increases 1.3mA @12V!

Anyway I will work with the manufacturer to try to find out what is using the power in the SIM7600 power down mode.

Regards, Mark

> On 3 Feb 2023, at 10:47 PM, Michael Balzer <dexter at expeedo.de> wrote:
> 
> Signed PGP part
> Mark,
> 
> in the thread with Patrick Stein I measured the GPS antenna at ~ 5 mA / 55 mW, and added that info to https://docs.openvehicles.com/en/latest/userguide/warnings.html#average-power-usage
> 
>> GPS consumption includes the active GPS antenna, which accounts for ~ 5 mA / 55 mW. Antenna power cannot be switched by the module.
>> 
>> ESP32 deep sleep mode (e.g. triggered by the power management module) reduces the consumption to ~ 15 mA / 165 mW with the active GPS antenna attached, or ~ 10 mA / 110 mW with the GPS antenna detached. The hardware isn’t capable to go any lower than this.
>> 
> 
> But maybe you can do a more precise measurement, I only have some basic electronics tools here.
> 
> Regards,
> Michael
> 
> 
> Am 31.01.23 um 01:53 schrieb Mark Webb-Johnson:
>> 
>> Re: https://www.openvehicles.com/node/3545
>> 
>> I think it worthwhile having this discussion here. Synopsis seems to be:
>> 
>> Our modem design uses the SIMCOM reference design to power the active GPS antenna from VBAT. This increases power consumption (powering the active antenna), even if the GPS is turned off in software.
>> 
>> There is an alternative approach using pin 44 and the AT+CVAUXV / AT+CVAUXS commands to enable/disable and/or adjust voltage.
>> 
>> Would be interesting to see the exact power readings and impact this change would make. I will try to get these this weekend.
>> 
>> Regards, Mark
>> 
>> 
>> 
>> 
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>> OvmsDev at lists.openvehicles.com <mailto:OvmsDev at lists.openvehicles.com>
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> 
> --
> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
> 
> 

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