I am experiencing voltage drops with the following setup and I hope someone with mad electronics skills can explain my mistake to me:
- Raspberry Pi 3 Model B
- TFP401 Display Driver
- 7.0 Inch TFT Display
- Adafruit Micro LiPo Charger
- PowerBoost 1000 Basic
- 4000mAh 3,7V Lithium Ion Polymer Battery
When I boot this system up, the RasPi gets stuck in a boot loop. Which means the screen turns on for a couple of seconds and then the lights of the TFP401, as well as the screen, turn off and restart again. This setup draws around 0.7A, which should be no problem for the PowerBoost as well as the battery. If I only connect the RasPi without Display the system boots up, drawing around 0.2A.
I have researched this topic already and found the following post to describe almost the same problem. Unfortunately I don’t have an Oscillometer to see what is happening. The PowerBoost however features a LED light, that will light up if voltage drops below 3.2V.
In my first setup (all components) the light is almost constantly on, which indicates massive voltage drops. The second setup (only RasPi) does not show the LED most of the time. However, even there the LED will flicker for very short amounts of time.
Doing research on the battery I bought, I saw that it is rated for 0,3C continuous and 0,5C peak (which should still suffice for the test setup). My end goal is to have a continuous draw of around 1,4-1,6A, so I will probably have to get a battery with higher rating.
Again, can someone with electronics knowledge explain to me what is happening and how I can prevent this from happening?
I append two pictures. First, is the safety circuit of the battery. Second, is the wiring of my setup.
EDIT: So what I have found out so far is that you should not try to boot a RasPi 3 with less than 2A. I believed the battery to have a 0,5C rating (as it was described in an eBay description), which turned out to be false. Furthermore, I did not consider any loss due to stepping up the voltage. So the power draw coming from the PowerBoost I describe in my post, is roughly 1.5 times higher for the battery.