Electron Project Discussion [Hardware]


#1

I have some non-rechargeable 3.6V 12Ah (handling up to about 2A peaks) batteries incoming in a few days. They come with the JST-plug added to them.

I’m just wondering what the best course of action here is. Is it safe to connect these directly to the JST port on the Electron, considering this was designed for the 3.7V LiPo? Or should they rather be connected to the VIN or Li+ pins?

The voltage drop is minimal so I’m not expecting the voltage to dip too far below 3.6V.


#2

The JST plug and the LI+ pin go to the same pins on the PMIC so just use the JST connector to keep things simple.

If the batteries are 3.7v LiPo batteries then there is nothing else you need to do.


#3

They’re 3.6V LiSOCl2-batteries. I indeed got them with JST made on them because of the much simpler design (and easy to replace once on runs empty). I just wanted to be sure I won’t accidently kill some of my Electrons with this stuff :scream: Good to know connecting to JST and Li+ will result in the same behaviour.


#4

Provide a link to the batteries you bought. That’s a different battery type than LiPo, I’ll look at the specs.


#5

Had these ones made with the JST-PH2 plug that the LiPo ones use.Claims it has a 13A capacity and support for 2A continuous currents.


#6

Cool, just know that these batteries are NOT rechargeable so don’t try to supply power to the Electron via the VIN or USB port or else you could explode the battery which I’m sure is not what you are wanting. Fire :fire: :fireworks: :fire_engine:


#7

I will have to pass on the arson-starting for now :smiling_imp: :fire:

But yeah I realize they’re not rechargeable. As much as I like the LiPo batteries however (perfect size and great performance for plenty of my little projects so far) I need something that’s gonna last me for a very long time (preferably 2 years or more). With the 2A LiPo I managed to get to about 4 months, but due to the high self-discharge rate getting much higher than this would require an impractical setup of LiPos.


#8

Lipo’s self-discharge at a rate of 5% per month, the battery your looking self-discharge at 2% per month.

Based on the battery capacity graphs I think you get less than the 13Ah stated battery capacity since that’s at the 10mA discharge rate, it will probably be more like 7-8Ah of overall capacity minus the 2% self-discharging per month.

Sounds like you just need an energy harvester for solar or thermal to keep the LiPo trickle charged anytime there is light or heat available. Is any of that available in your use case location?


#9

I think the reported self-discharge rate is supposed to be 2%/year though?

Also, my device will be in Deep Sleep for 23h 59m a day, so the typical discharge rate should only be around 200uA or so. For my project there’s absolutely no access to any light/heat power source, everything must be coming from a battery.


#10

Doubt it’s only 2% per year. It’s a chemical compound that loses energy over time so I would expect 2% per month.

Also, you have to expect that a lot of the time the Electron will and can take a few mins to successfully connect to the Cellular network when waking from Deep Sleep. That’s pretty normal for my testing when not using Sleep Network Standby to speed up the cellular reconnect times which is not what you would want to do since it consumes more power while sleeping.


#11

The numbers I’ve seen for LiSOCl2-batteries are around 0.08%/month, so less than 1% per year. All batteries undergo various chemical reactions, but the rate of those reactions is very dependent on the particular chemistry involved.


#12

Interesting, I have 10 devices right now outside that all seem to connect within 15 seconds of trying…then again I’m in a pretty big urban area with good coverage, so that makes a difference. It’s something I need to check later on if the connection times indeed go up for other areas here in the city.

Also like Ric said, LiSOCl2 in general should have only about 1% self-discharge per year…This is a number often reported by a lot of different suppliers, so unless this one is considerably different (I assume they state 2% just to be on the safe side) it should also be close to this rate? I specifically went with this composition for this reason. The downside is that they’re really hard to get here in Canada (I saw some retailers selling single D batteries for $30 to $40) so it all has to be imported in bulk.


#13

Cool, it’s all new to me so I learned something new today.

I wonder how this self-discharge rate varies with temperature? With most batteries, the self-discharge rate is dependant on the actual ambient temp of the battery. Hotter temps self-discharge quicker and colder temps cause slower self-discharge rates.

I would assume that its the same for these batteries?


#14

Yes, sometimes I also get the quick connection times but a lot of times it takes much longer. I’m in a major city with good cellular coverage also.

It will be interesting to see how the batteries work out for you.

Can you share what your application is?


#15

They’re to be used in the monitoring of waste containers (measuring how full they are, if they’re picked up time, at a later stage maybe take pictures with a camera to detect type of trash thrown out). As they’re inside the actual container, there’s no way to power them through an outlet, use thermal energy or use a solar panel (this probably would end up getting ripped off or stolen).


#16

That’s a good application use for these.

I’m certain you could integrate a small solar panel for continuous use. Would just need to create a rugged metal surround for the panel. But the battery should work for your initial testing.

Do you have 10 units running now doing this?

What are the benefits for the garbage company?


#17

Sometimes waste containers are also located indoor (e.g. parking lots, enclosures) so I really do need a solution that can power it either way without the use of any external energy sources. There’s some technology out there like this already, and I know they all use batteries.

Our company doesn’t own its own trucks, but contracts them, so getting rid of inefficient waste hauling (i.e. when there is a container collected always three-quarter empty) reduces costs significantly as you can make less runs.

I have 10 devices atm doing all of this (minus the camera at this point) working perfectly fine. The only bottleneck left is the battery as the 2Ah battery powers it for roughly 4 months only. I’ll see how the LiSOCl2 performs - from what Ive heard so far theres a very good chance it will work great for this


#18

It all makes perfect sense. This is the way it will be done in the future.

I saw some companies doing this so it’s working all over the world to reduce cost.

When you talk about cameras are you talking about something like this:

Solar would do the job, the design could be a clip mount so one part of the device hangs over the outside to see sunlight and the other side could see inside the can.

The battery you got should last you at least 4 to 5 times longer than the 2Ah LiPo.

Are you measuring the larger metal containers? Has one sensor been enough to get an accurate gauge of the trash levels?


#19

I think that’s something out of my reach to do, as an internship student with very limited software and electronics experience. My idea is to add an OV-7670 camera to it, and output the images to a server a few times a day. Then these images could be accessed to monitor if illegal waste is being dumped in containers. There’s often incidents where people dispose of bulky items that trucks aren’t really designed to pick up (e.g. blocks of concrete, entire couches, toilet bowls, used christmas trees). People think just because it fits in, it’s ok to put it in.

I’m interested in monitoring both the large containers, and also smaller tote bins.


#20

Looking at the specs on these long life cells it looks as if they can’t handle the up to 2 amp current burst that the Electron would need when transmitting. Their charts show the battery voltage dropping quickly under these few amp loads if they are longer than a second or so and that’s with a capacitor attached to the battery.

This place has a good selection of the type of batteries like you purchased.

http://www.tadiranbat.com/index.html

Found a good article on IOT and Primary battery and other power options here.

http://www.powerelectronictips.com/batteries-industrial-internet-things/

Interesting stuff.

So what type of sensor are you using to detect trash levels? Ultra Sonic? I have tested the VL53L0x TOF distance sensor and it would probably also work.

Sending pictures back makes alot of sense. Not sure if I remember anybody sending images from a camera to the web using an Electron.