Powering Dash - what are the options?


#1

There could be several ways to power the Dash Pro for my application.

  1. Using a Li-Ion battery. These supply voltage 3.6v +/- and I expect
    the Dash has a voltage regulator that accommodates such a battery;
    in fact, some cellular modules expect this kind of power source
    (high momentary current, 3.6v). I see that the Dash Pro has a
    recharging chip (possibly something like a MAX1555) — can the Dash
    Pro therefore be supplied with, e.g. a 5v source to recharge the
    battery even as it continues to operate?

  2. Using USB power. Can the Dash Pro run off a USB cable powered in
    conventional ways?

  3. Using power from a Duino, Beaglebone, etc – perhaps 5v or 3.3v sources that
    such devices often provide to shields.

Possibly there is already a FAQ on this topic of how to power a Dash/Pro. If so, do you have a pointer to that?


#2

These questions are answered in the Kickstarter FAQ: https://www.kickstarter.com/projects/konekt/konekt-dash-cellular-dev-kit-free-global-data-plan/description#project_faq_127925, but the link doesn’t seem to take you there.

Here is a copy of the FAQ:
The Dash / Dash Pro can work in the following modes:

  1. USB connected and a Battery Connected (Draws ~500 mA, charges battery)
  2. USB disconnected and a Battery Connected (All power is coming from the battery)
  3. USB 2A Cable is connected and a tiny jumper is installed (All power is coming from the USB)
  4. Power comes in externally as a LiIon/LiPoly battery via the VBATT pin between 3.3V and 5V(Accessible via all the shields)
  5. Power comes in externally via the VIN pin which is the same net as the USB In (5V@2A)

#3

Question. Will Note 5) using VIN Pin … with a battery Connected allow Dash Pro to keep running on power outage?
Does VIN charge battery same as Note 1) without USB connected?

Does the Battery need to be LiPo or can it be NiHm? What charging controller is used?
LiPo has stricter shipping issues.

Thanks


#4

Hello Powerful Majestic Jackson (Or perhaps Prudent Meticulous Jackson?)

Great question. Yes, absolutely the battery will provide uninterrupted power to the Dash in the event that USB power or VIN power are lost. USB Power == VIN, so they can be used interchangeably. The only difference is one is a USB connector and the other is a pin on our 0.1" header. Connecting 5V to VIN or USB and connecting a battery will charge the battery. If power is removed from VIN or VUSB, the system will draw power from the battery until it is drained.

The charging controller is currently an ST Micro L6924UTR which charges Li Ion or Li Polymer. It cannot be Ni-MH. LiPo definitely has stricter regulations, but if you are making a commercial product they are relatively easy and cost effective to implement and have a lot of performance benefits over NI-MH.

Two easy ways to comply with Li Ion shipping regulations:

  1. User installed batteries that are sealed and secured for shipment.
  2. Pre-connected batteries where the terminals are covered and cannot easily be shorted to anything (This is satisfied by connecting to our battery connector and then covering the pins on the Dash that are connected to the battery.

The rules have been changing about every six months for the last two years, so I would recommend working with a 3PL to make sure your product is in compliance for batteries.


#5

Thanks DD,

You must be a lot of fun to work with.

Thanks for the information. Very Helpful.

One more question? Is there a flag to tell the uC that main power is off? Or other battery info?

Thanks


#6

Thank you pmjackson. I’m actually a recovering pedant, so I try to be more fun these days :).

There is a battery monitor (Currently MAX17043G+U) with an API for reading the battery state of charge. If you’re not using a battery, then the system doesn’t have a way to monitor the input voltage. If the VIN goes away (Without a battery), the Dash will shut off and can’t monitor the VIN.


#7

Any example code for arduino that use the battery monitoring API? I would like to send the battery levels each time I send a message to the cloud.


#8

Hey @cdasher and @pmjackson,

I wanted to let you both (and the world) know that the battery monitoring API/library, along with the initial microcontroller sleep states API/library, will be available in the next Arduino IDE update (scheduled for next week).

These two updates will require only updating our Arduino IDE integration to gain access to their respective libraries, and will not require a firmware update. (There will also be a future firmware update that will expand the available sleep states.)

All the best,
PFW


#9

Have any power consumption measurements been done using the sleep modes? I only ask because I am thinking of using another MCU to wake up the Dash, but if the power draw isn’t too bad, I would prefer to just put the dash to sleep and move on from the other MCU thing.


#10

Hey @cdasher,

Great question. Tests have been made, but we’ll add some measurements to the tutorial on sleep states that we’re publishing this week (since, well, it makes sense for that info to be a part of that tutorial).

Really appreciate the feedback,
PFW


#11

One thing I mentioned to Pat and co. at CES was that the M0 controller should be very low power in standby (nano amps range). It would be cool if this could be used as a sort of watchdog to cut power to the main chip but, then again, maybe there are leaky components on the board that simply cannot be shut off. Technically, I’ve been reading that, on most platforms, the M4 is actually more power efficient than the M0. Still, it would be cool to see extreme power savings built into this guy one day.


#12

Hey @rubenk,

I don’t want to get too ahead of ourselves, but I will say that we believe we can power most components down to a pretty low power setting. We’ll be releasing various sleep modes in different stages, and, eventually, one of those will include a sleep state that switches off the radio while the system is asleep.

(Of course, if we find any components that are drawing an unnecessary amount of extra power, we’ll improve in future designs, but we’re pretty happy with what we’re finding in tests so far.)

Thanks for your feedback,
PFW


#13

@KonektPat thanks for this information! Anyway I can stay up-to-date as low-power modes evolve? Need any customer advisory support on that?

Low power management is critical to our applications and capability here will make the difference between using a product like Dash in large-scale production programs, or just for prototyping and switching to a custom-engineered solutions for production. This work is very actively underway, and while be on our critical path shortly.


#14

Over a week has gone by. Has the new sleep state arguing code been released and the tutorial created?


#15

Arduino not arguing :blush:


#16

Is it possible to utilize a non rechargeable battery with the current hardware? If not, is this something that will be available in the future? Thanks!


#17

I suspect this is a more difficult engineering challenge than originally surmised as Konekt began digging into it. @KonektPat Can you give us a heads up on if you’ve had bandwidth to look at this?
It looks like the Particle Electron’s deepest sleep mode (cellular turned off, of course) is 130-160 uA (micro-amps). Can we reach that low or lower?


#18

I typically operate my Dash with the battery + USB attached (both jumpers in the “closest to power connectors” position). So, to “cold boot,” I have to disconnect both the battery and the USB power. Understanding that the battery in this mode is the primary power source, I connect battery first on power up / disconnect battery last on power down. Usually. :slight_smile: I’ve noted that if I accidentally reverse the order, such that the Dash is powered only by the USB, despite the jumpers being in the battery power position, the Dash stays powered on (I’ve added an LED pulse to most of my sketches to show power on as a debug – thank you for the nifty Dash class!). So, my question: Am I causing great harm to the Dash by powering via the USB with the jumpers set to “battery?” I honestly have only done this a few times, and so far have seen no harm to the Dash, but thought it was time to check with the experts. Thanks in advance to all.