This is my first design job outside of school and I have done some reading about this, but I am still unsure. I am working on a water level sensor which will be used to measure the water level in wells in some remote areas where cellular signal may be unreliable. As a result, we are putting an sd card reader into the device as a backup. The sd card reader has chunky current requirements of ~450mA, which is detrimental to battery life.
From the Boron datasheet:
Peak Current ILi+ pk 120 490 mA
Assuming worst case scenario current from the Boron, I am looking at close to 1000mA current requirements for my device. Based on this, I calculate ~85.6 days of battery life if the device turns on once a day for 120s and does its job and then goes back to sleep.
Also from the Boron datasheet:
This pin is internally connected to the positive terminal of the LiPo connector. You can connect a single cell LiPo/Lithium Ion or a DC supply source to this pin for powering the Boron. Remember that the input voltage range on this pin is 3.6 to 4.2 VDC.
I would like to connect two 3000mAh batteries in parallel to keep the 3.7V, but give me 6000mAh. I am unsure if I can do this because I am unsure if this would still qualify as a single cell battery. Can I do this, or will it break the Boron?
The batteries are internally regulated, as long as you’re still getting 3.7v then it may be ok. It’s not the best practice though. I would look for something like this first: https://www.amazon.com/dp/B01LYJ2K1M/ref=cm_sw_r_cp_apa_glt_fabc_MQAYHKE4JGAR6TK6PMTT
This was just a quick search, I don’t know if the polarity on this connector is the same, make sure you reference the docs for charge capacity, polarity, and other relevant information before tripling the battery capacity.
As long as bateries doesn’t have any regular, elecrtonisc etc and the best case they are from the bulk, lot no. Their internal resistance can be assumed as identical or almost identical you can easily go ahead. Just make sure that the parallel connections of your batteries are really solid (e.g. soldered)
The problem with that is if their internal resistance is just a little different
The one can be charged fully and the second not. Will be perfect if you can connect two resistors at least 2W 0.2ohm in series to your battery positive connectors
I have avoided any multi-cell battery for the Boron. I am using this particular battery - 10000mAh. I obtained it from eBay. Here is a description to lookup on the ebay.com site (the link was ridiculously long):
3.7V 10000 mAh Polymer Li Lipo Battery 1070105 For Tablet PC GPS power bank DVD
Be careful to check the polarity before attaching a JST connector to the battery wires. Otherwise, your Boron might not work very well.
I would definitely use a single 6000 or 10000 mAh battery instead of two batteries in parallel. The fuel gauge (MAX17043) will return inaccurate values for parallel batteries, among other issues mentioned above.
There’s more about batteries in the battery guide in the Particle documentation.
Thanks for the replies. The problem with using some of the bigger mAh batteries is that they are physically larger than the smaller mAh batteries, and we are rationing space in our design. We are using PVC pipe as the enclosure, and we have a diameter of ~5cm, and not a lot of batteries will really fit in here. The battery that Mjones linked looks like the width is acceptable, but the length is pushing it (and it looks like it has August 2 to 23 delivery estimate).
I think based on the replies to this thread we are going to order some 5000mAh batteries and use those by themselves.
Seems you received some really good advice so far. I can basically just concur with that the guys said (and in my humble opinion), try to steer clear of multi-cell rechargeable solutions. It might work off the batt, but you are bound to run into complications sooner rather than later, unless of course you followed all the advice given
I just came from a project where battery life was crucial. We ended up with non-rechargeable primary LiSOCL2 cell as apposed to normal LiPO. Of course here you will need to implement some clever Voltage regulation and implement a SPC or HLC to help pack the punch the GSM modem needs to start up. If you are 100% sure you only need 3G of LTE, the SAFT LSH20 is also a good option as no SPC is needed.
For us it worked out really well as we achieved much longer battery life than anticipated.
I agree with @no1089 , sorry for missing that part, I got fixated on the battery It seems strange to me that it is using any power really (other than that of ‘powering up’ the SD Card) let alone 450mA ??