For the DMW1001-Dev units with enclosures, RCR123a/16340 batteries are specified. These are the rechargeable counterparts to the CR123 batteries you can get any store.
- Beyond 3.7V spec, are there any other specifications for these batteries? (650mAh, 700, etc.)
- Any particular manufacturer preference? I don’t recognize any of the names.
- CR123 are a 3.0V, non-rechargeable battery. Are these sufficient for the DW1001-Dev in environments where power consumption is low (tags move infrequently)?
I’m also thinking of a scenario where several thousands items are tagged, say in a 1 week period. Then a year later they all need a recharge in the same week (given identical usage). If the CR123 is viable, it is a nice option to know.
It is all in how you use it. The DW1000 is a power hungry SOB. Whatever mode you run it in make sure your battery can source the needed current. CR123 can source 1500 mA.
i use 3.7v 18650 battery and it work like a charm…so far…i guess i ll need to redesign new enclosure for that.
I do not have experience with the DMW1001, but I have used various batteries with the Trek1000 board. From that experience, it is important for the battery to be able to sustain sudden surges in current draw. These sudden surges occur on Rx and Tx, for example. Therefore, 3 AA batteries will sometimes fail to keep the board running.
I used a small LiPo battery (4A17, 3.7V, 240mAh) and it was able to power the board for about an hour with one charge (duration of course depends on the number of times the Tx Rx is active).
I have also used USB powerbanks such as: PowerCore+ Mini 3350 with Capacity :3350 mAh / 12.06 Wh, Output :5V / 1A. This lasts for hours.
Batteries can also be purchased form here and here
Thanks for the replies.
I bought some Eastshine RCR123a rechargeable batteries plus smart charger from Amazon. The batteries last about 24 hours in DMW1001-DEV board with the tags sitting motionless. Less if constantly moving. The same boards as Anchors lasted about 18 hours. Recharge on the batteries was about 3 hours. Charger was great as it has a display showing the level of charge and the elapsed time.
I noticed weak signal strength on the Anchors on battery mode. Greatly improved once I moved on to USB chargers. This is a definite for the Anchors.
The DMW1001-Dev are development boards, so they are very power hungry even when stationary. Have a stack of batteries ready when one goes dark. Great for functional testing, but you are going to have to design your own board for any final product. But that is exactly what these Dev boards are for.
One week in and very happy with the results.
You really need to characterise the batteries that you’re going to use as the capacity on the label isn’t always correct.
I’ve measured RCR123A/16340 batteries from several manufacturers and found that the capacities vary widely.
I made a circuit to measure the discharge time of the batteries by setting a load current and keeping that current constant as the voltage decays. The circuit is based on On Semi CAT4101-D. I can give you the schematic).
Lomon (labelled 800 mAh) were less than half the labelled capacity. Nitecore (labelled 650 mAh) had the labelled capacity. Fenix (labelled 700 mAh) actually exceeded the labelled capacity.
So I can recommend the Fenix brand as the best that I have measured. https://www.fenix-store.com/fenix-arb-l16-700-16340-battery/
In testing with DWM1001-Dev as a tag, it lasted three days (LEDs off, responder mode disabled, ranging constantly to a single anchor at 1 Hz), from just under 4.2 V down to 2.8 V.
On the DWM1001, you have the Segger IC which has a constant current draw. Also, in most applications, you won’t need to range every second. In applications requiring long battery life, it’s very common to use a motion sensor, so that you only range when you really need to. This is why the sensor is included on the DWM1001 module.
Hope this helps.
Correction: ‘On the DWM1001-Dev, you have the Segger IC which has a constant current draw’.
I’d like to build off of what you said and mention that if anyone else is looking to determine the capacity of the battery they chose or compare against multiple, this $6 part is quite handy:
It isn’t incredibly accurate but it gets the job done. Just make a quick rig to hold your cell or cells and wire it up. If you don’t have a 16340 battery holder, you could cut the traces on a spare DWM1001-DEV and use that, or perhaps purchase something like this and get rid of the recharge circuit:
It would be beneficial to have a spreadsheet of what 16340 batteries people have tried and what their actual capacity is, considering many people will be in the same shoes looking for what batteries to order. Thoughts?
Do you know whether the Segger IC consumes much? Is it possible to disable it and/or its LED when not in use to save energy?