On Mon, Nov 18, 2019 at 01:58 PM, RFy wrote:
450mAh is... Not suitable for NanoVNA
2. Charge circuit pushes over 1A( over 2C rate )
My battery already swelled( PCB/LCD curved slightly )
Yes. This issue has been reported before (posts #3096, #4533, #6288 etc.)
Supplied nvna battery spec is here...
Maximum Charging Current specified as 450mA.
IP5303 Charging current specified as 1.2A typ and 1.4A max. There does not appear to be any way to reduce this without additional circuitry.
So worst case the 450mAh battery might be charged at 1.4/0.45 = 3.1C !
Qualifies as ultra fast charging...
Charge rate might depend on the source. If the nvna is being charged from a standard downstream USB2 port, such as those fitted to this computer, then the charge current could be limited to 500mA which is ~1.1C.
Might explain why my battery was fine until I subjected it to an iPad charger!
Looking longways on the nvna I can see that the pcb and rear panel are deflected by the battery swelling. Easily verified by removing one screw in the rear panel where a gap opens up between the panel and the brass spacer.
I have now removed the 450mAh battery and temporarily fitted a 1100mAh ex call phone battery stuck on the rear panel.
I will fit a "quality" protected 18650 cell when I assemble the repackaged nvna.
