Designing a Solar and Li-ion Battery Powered Charger / Power Source Part 1

[@user-kg1jn4ql9w]

Great presentation! Something valuable I learned: Do NOT let a lithium-ion battery get too low.

[@ForceTronics]

Thank you 😊

[@mmh1922]

Excellent presentation! Thank you

[@ForceTronics]

Glad you liked it!

[@thenextproblem8001]

Thanks for sink and source tips for typeC!

[@ForceTronics]

No problem glad you found it useful

[@TheChalansillo]

Could you explain why do you need R14? (Parallel with the zener)

[@ForceTronics]

The purpose of r14 is to pull down the USB power bus once power is removed from it. There are some caps there that can store some energy after power is removed. R14 just helps bleed them off quickly. Put it there to be safe, may not be needed

[@lhoussain7852]

Hello, will I find all the previouse exclusive content you've made in patreon ?

[@ForceTronics]

Yes

[@lhoussain7852]

​​@@ForceTronics Thank you!

[@jaredharvey1511]

Any suggestions on how to have 1 USB, 1 load, with 3x 18650 battery at 3.3v? Mostly how to safely charge in parallel.

[@ForceTronics]

Even when working with Lithium Ion batteries that are the "same" they still vary with capacity as well as charge and discharge rates. As they age the differences typically become more pronounced. With that in mind, to get the most out of them you need to charge them individually and monitor their discharge rates individually to prevent one from over discharging when the other batteries still have capacity (or over charging). That is why electric vehicles designs have complex "battery management systems." Other battery technologies, like nickel metal hydride, you can get away with charging and discharging at the same rate since they are more rugged to over charging or over discharging, but of course their capacity is not as good as Lithium. So the challenge is coming up with a design that can charge them individually, control their rate of discharge individually, but still use them as parallel power sources.

[@jaredharvey1511]

@@ForceTronics agreed, BMS is good. I'm planning on a TP4056 with under voltage and short circuit protectors for each cell. However I'm not sure how to distribute the load evenly. I'm tempted to use a diode to prevent one battery from back charging another cell.

[@ForceTronics]

It might be better if you try to find a way where you don't have to operate cells in parallel. For instance can you just find a high capacity single cell that equals the three cells you're using or why not just operate the cells one of the time and switch them out once one is drained. With these two approaches you totally avoid the load balancing aspect of it