Guru
Joined: 17/05/2016
Location: United StatesPosts: 3778
| Posted: 08:25pm 09 Mar 2025 |
I'm trying to monitor the capacitor of various 18560 batteries--nominal capacities of 3400, 5000, and 9900!! mWh. The batteries are in an 18650 holder/charger with 5V USB output. My display shows voltage, current, and total mWh.
My load is a little Harborfreight 3-AAA LED with 3 on positions--red LEDs, white LED, and red LEDs blinking every second with about 50% duty cycle. I removed the AAAs and directly wired 5V and 0V from the USB output.
The white LEDs draw too much and the battery shuts off (even though it nominally has a 5V 3A rating). The red LEDs on solid draw between 360 and 390mW. This is nominally close to C/10 for the "3400mAh" battery. The battery shuts down at about 1080mAh.
I'd like to be able to get closer to C/20, which I think is a typical test current draw for the ratings for these batteries. WIth the blinking red LED, the reading fluctuates every second between about 120mA and 300mA. I tried putting a 220uF capacitor across 5V and 0V, but that made no significant difference.
My question is, what size capacitor am I likely to need to get the display to approximately half of the 360mW reading--to around 180mW?
PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on FOTS