It comes with "some" built-in protection circuit for preventing over charging or over discharging.
But what about short-circuit situation, which can easily happen, especially in my inexperienced hands. Do not I need some fuse to connect there?
Thanks a lot
STeN
There is no problem with including a fuse with your project. Just be sure the AMP value is only a bit above what your project will normally require.
Please understand that a fuse will never be able to protest your Arduino and associated electronics. The fuse only keeps the fire from burning the wiring insulation.
Paul
I power my projects with a lab power supply, I can set the voltage and the current. I purchased them a few years ago from a China supplier for under $50.00 for 30V 10A. Also there is virtually nothing that you can do if you connect some semiconductors wrong, they fry and may not even pull extra current. ESD would is my biggest worry and my lab is setup for ESD control. I would also suggest you learn how to use a CAD program for your projects, frizzing does not cut it. You can download one or several of the many that are available online, some are free, some donation, some cost and some are limited. I use KiCad and it allows me to take the project to finished PCB artwork.
Please understand that a fuse will never be able to protest your Arduino and associated electronics. The fuse only keeps the fire from burning the wiring insulation.
@Paul_KD7HB Thanks a lot for the comment - I really appreciate that. The fire/burning was exactly the reason why I look for a fuse. It is clear to me that the electronic is not protected.
Why would you want to power an Arduino UNO with a 3.7 V battery?
@Paul__B The nominal voltage of a single LiPo cell is 3.7V, that's why I used it, no other reason.
From wiring perspective: My understanding is that 3.7V should be fine if I do not connect via Arduino power regulator (VIN) and connect it directly to the 5V PIN.
From usability perspective: What I am not sure is how it will affect the way the the board works, when the battery will discharge considering board uses 16MHz crystal oscillator and (I think) that 3.7V is the absolutely minimum to run it in 16 Mhz. At least that was my understanding from Atmega328 datasheet (chapter "29.3 Speed Grades"): https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega48A-PA-88A-PA-168A-PA-328-P-DS-DS40002061B.pdf
Saying that - I am open to any suggestions about the ideal rechargeable battery to be used: E.g. I can use 2 LiPo batteries in series connected via VIN PIN.
I believe if you do the math on the speed grade chart, it will show 3.78V as the minimum for 16 MHz.
((4.5V - 2.7V)*.6) + 2.7V = 3.78V.
However, many folks have reported acceptable operation down as low as 3.3V, while some 328Ps begin having Serial problems with that combination.
Does your battery pack have built in overdischarge protection? I used some very similar looking 2700mAH batteries, 705060, that would cut off at 3V.
You could use a boost converter to get 5V from the battery until the discharge protection kicks in.
I was about to say, fuses don't go low enough to be just above what your circuit is using..... but then you aren't trying to save the electronics. General info: fuses are rated by I^2 * t meaning if the current doubles the clearing time is 4 times as fast.
You might consider a PTC resistor. There is one at the input of the older Raspberry Pi's. If overloaded they change to a high resistance. Then will revert to a low resistance when the short is removed.
I was just check it and will go to try it. Meanwhile I will be using the two Li-ion AA 18650 in series ( 18650 Batteries | Battery Junction) as it will work also with Arduino Mega, since Atmel2560 requires 4.5V.
@CrossRoads Finally I decided to use the convertor instead of 2 batteries in series. Thanks for the tip!! Based on that I have the converter related question here (5V step-up (boost) voltage regulator / converter) if you will have time to look.
A properly designed protection circuit will deal with shorts just fine (after all a short is really just a case of overcurrent).
Try it out! Take your battery to a safe place (preferably outdoors), bring a thick wire, and short it out. If your battery has decent protection circuitry it will kick in and nothing happens. If not and your battery does catch on fire, I'd call that good riddance. Remember to enjoy the fireworks.
A buck or boost converter indeed pretty much doubles as short circuit protection as there's only so much current it can supply (and, in turn, draw from the battery).
