I was considering a project where I could attach a battery to the rak chip to track assets being shipped. I was curious how long the battery would keep the chip alive and broadcasting the gps location. Which battery would be best for this and how long would it last
Also would there be a better solution than a battery to wire one of these chips to lets say the trailer of an 18 wheeler?
Hi @a1projects ,
Battery life is highly dependent on the consumption. For a WisBlock application, you have to consider the overall average consumption including the active and sleep mode (if there is any). That is a factor of the device behavior and the overall algorithm like do you cut power on the gps, do you have other peripheral/sensors connected?
If you have the option to connect on the power source (battery) of the truck, that might be the best solution and then just have a Li-Po battery (even a small one) as backup. There are many 12V to 5V converter available for automotive.
My LPWAN Tracker Solution
build with RAK4631, RAK12500, RAK1904 and RAK1906 lasted 10 days from a 3200mAh battery.
Using AS923-3, payload size 30 bytes (can be reduced), sending every 2 minutes.
Ok, which converter do I need to hook it up to the battery of a car or 18 wheeler trailer? Were you referring to something like this? Seems a little bulky just to power that board
What I mean are car chargers like this.
USB source is what you need for wisblock 
What about something that is connected to like an 18 wheeler trailer or a boat?
Also, if I have a battery like that, will it recharge when it’s plugged in via usb? That way it can stay alive in while the car or whatever is off?
I am not sure if 18 wheeler trucks has 12V or 24V batteries. I also have no idea about boats. But surely, you can tap on those to have an available 5V supply. You can even use standard BUCK Converter modules.
I have a question about that. Is there a method to make it deep sleep unless it has moved like 5 feet for example? If it hasn’t moved 5 feet, maybe make it broadcast once a day? That way it preserves backup battery
It shouldn’t be impossible to do. But how would you know 5 feet movement? Via GPS? GPS tolerance is more than 5 feet so might not be a good parameter? Do you have other sensors? You just have to take note that you can’t be sleeping always because the module should be awak whie measuring the 5 feet distance requirement.
Doesn’t have to be 5 feet, I just meant some way to trigger based on movement so that it preserves battery if for some reason consistent power wasn’t always available. Was just trying to think of ways to save energy. Is there a better method you can think of?
Hmm. I really depends on your application. But keeping everything shutdown unless necessary be awake is a good idea. You just have to check once in a while if you need to transmit something.
It was aimed towards asset protection. So for security purposes. Now the one that would check for temperature and stuff is a different story because that needs more maintenance. I am just not sure which panel is generally a decent one to look at and battery
Solar panel at 6V should be able to charge the battery. This is a common one. Size depends on the energy rating.
Any Lithium Ion battery with nominal 3.7 volts should work. It is very common to see 18650 types also those in pouch.
I thought I heard it said something about how anything over 5v could damage the rak chip though. Is 6 ok regardless?
When you connect the 6V panel, it will still have to pass thru a diode internally so there will still be a voltage drop so it is still safe. Just make sure that 6V is the maximum you’ll have to be safe.
Also, the 6V will only go to the charging IC not on the wisblock core, etc.
You can also use 5V solar panels. There are some with USB output already so you can just hook it via USB.
Solar Panel
How is that for the solar panel and this for the battery? Battery These sizes should not be an issue
The solar panel is ok. I think I have those as well.
Battery is ok too. Just be cautious on the polarity. Not all JST connectors have the same orientation. If it is the opposite of the WisBlock Base connector, you will fry it.
How do I check to know, is there a kind or brand that is a safe bet with the polarity that will match of that size you can recommend?