[Answer]- Charging a 9V battery via the Asset Tracker

Hello,

The Asset Tracker shield has a connection for a 9V battery.
If I connect a rechargeable 9V battery and also the USB cable to the Electron - will it charge the 9V battery ?
If not - will it cause any damage to the battery ?

It won’t charge or damage the battery since a diode prevents from feeding back to the connector.
https://github.com/spark/shields/blob/master/electron-shields/asset-tracker/pdfs/asset-tracker-sch.pdf

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This is an old topic, but I have similar questions.

I just fried my tracker trying to use a 9v battery. I had started hooking the 9v to the blue screw terminals on the GPS shield, but that didn’t seem to powerup the Electron. So I tried using VIN/GND and it still didn’t seem to power everything up right.

So… stupid me, I tried VBAT/GND pop (and that unmistakable smell)

Needless to say, that split second completely ruined my day.

SO… What is the recommended connection? If there is a 9v adaptor out there somewhere with the same connector end as the LiPo battery that would be great, but I don’t know what kind of plug to search for?

Does anyone know what type of plug is on the Electron LiPo battery?

If there is a 9v adaptor out there somewhere with the same connector end as the LiPo battery that would be great, but I don’t know what kind of plug to search for?

Thanks
Don

The battery connector is a JST-PH, however under no circumstances attach a 9V battery to it.

The maximum input voltage is 3.7V, and applying 9V will likely permanently damage the PMIC, fuel gauge, and possibly the whole Electron.

Also, connecting a non-rechargeable battery to the battery port without disabling charging is not recommended.

However there’s a more fundamental problem with 9V batteries. Most are in the range of 800 mAh to 1200 mAh, or about half the capacity of the LiPo battery. Running constantly without sleeping, less than 9 hours of runtime, not including the AssetTracker.

Thanks rickkas7,

I’m confused the Electron says it can run on 3-12v?

If the 9v option is out of the question we can plan on stocking the standard Electron LiPo, I just need confirmation.

Here’s the background on what I’m working on and why the 9v is desirable…

  • The 9v battery is a 10 year LiPo https://www.amazon.com/gp/product/B01684J7P0/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

  • The reason is; the device I’m building is a remote deployment there is no way to recharge it in the field

  • The device needs to be watertight

  • When serviced it shouldn’t need to be disassembled beyond the battery compartment.

  • While in the field it will be in low power mode 99% of the time only waking up (weekly?) to report battery status or send a hazard alert (rare or never)

  • If the hazard alert actually occurs hand’s-on maintenance is required to reset it and the battery will be replaced

The Electron can run on 3.9V to 12V on VIN. You should have been able to power it from 9V between VIN and GND.

If you need a non-rechargeable battery, search the forum for LiSOCl2. That’s your best option, generally speaking.

Aside from a huge capacity, a 3.6V LiSOCl2 battery can be connected to the battery connector (if you disable charging). This is important because you can only get the 130 uA deep sleep current when supplying 3.6-ish volts on the battery connector. If you supply a higher voltage by VIN the regulator needs to be turned on, and you’ll have much higher sleep current due to loss in the regulator.

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Thanks rickkas7, this is a huge help I’ll check out the LiSoCl2, sounds like it may be a good option.

I just found the datasheet for the Energizer Li 9v and it’s rated at 1000 mA continuous

Looks like the D-cells are the answer!

Or these…

Looks like the correct plug too JST-PH-2P

If battery charge longevity is important, make sure you account for the self-discharge characteristics of your chosen battery. Some LiPos can self-discharge in a matter of months. There have been several discussions on this forum about that subject.

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I looked again at the tracker specs, there is a blue screw terminal power connection on the tracker shield that can accept 5-12v to support a car electric system (that’s where I saw it, it’s just hard to find in the documentation)
https://docs.particle.io/datasheets/discontinued/particle-shields/#electron-asset-tracker-v2

The question is does that provide power to the Electron as well? I sounds like it in the “Power” section, but doesn’t actually say so, nor does it say that the 12v supply will charge the LiPo.

The screw terminal supplies the Vin pin and the Vin pin is connected to the Electron’s LiPo charging circuitry.
https://github.com/particle-iot/shields/blob/master/electron-shields/asset-tracker/pdfs/asset-tracker-sch.pdf

ScruffR!

I am not an electronics guy so confirmation helps more than you know.

Thanks for confirming
Don

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