+Fr Robert Ballecer, SJ I have been working on the lipi and have run into a snag, the parts h...

[G+_Dan Baldwin]

+Fr. Robert Ballecer, SJ I have been working on the lipi and have run into a snag, the parts have all been printed and i have begun the process of installing all of the electronics. so far i have the dc plug installed wired the the ubec then on to the switch which powers the pi,done. the three lipo batteries and the tp4056 lipo charger have me confused. the pi requires 5vdc to operate and the 18650 output 3.8 ish volts not enough so i assume your running them in series and running them through the ubec also? then why not use just two batteries? also the charger is a 5 vdc input and outputs 4.2 V + / - 1%. and everything ive read says one charger per battery or you can cause an imbalance and ruin the batteries. so if you could please explain the logic? as far as the momentary push button for the shut down sequence there is plenty of documentation on the net to figure out. I have added a picture as a comment. thanks

[G+_Dan Baldwin]

[G+_Dan Baldwin]

Anybody?

[G+_John Sullivan]

I see your point(s), but I have a feeling we will have to wait until Padre broadcasts the next segment on this.

[G+_Daniel Stagner]

You are going to need one of these (below). And another UBEC set to 12.6 volts. I will need to take another look a the episode to see if the Father addressed balancing.

 

Can you remind me what episode it was.

 

ebay.com - Details about 1PC 3S 18650 Li-ion Lithium Battery 10A 12V BMS PCM Charger Protection Board

[G+_Dan Baldwin]

Daniel Stagner episode 360 towards the end

[G+_Dan Baldwin]

Daniel Stagner my son is into rc everything and told me the same thing about the charger board you referenced. What if we wired three of these 1A 5V Micro USB TP4056 Lithium Battery Power Charger Board Modules then we wouldn’t need the second ubec ?

[G+_Daniel Stagner]

Not sure about rigging anything up with the 18650's and leaving it unattended in any place other then my oven or fireplace. I like the purpose built stuff. It will also take up less room.

[G+_Jeff Johnson]

I'm having the same issue with the output of all the components being only about 4.1vdc. There is no way that the circuit can have more than that. Has anyone actually tested the circuit that Fr. Robert put together? Something has to have changed. If you follow the video exactly, all you get is a dead Raspi. :-(

[G+_Daniel Stagner]

Jeff dose your TP4056 look like the ones in this image below. The TP4056s below are the newer ones. The older ones lack the 5 volt output.

 

Also this is what I was thinking to allow for faster changing. It might just burn up the chips if the TP4056s are not ground isolated. Ground isolation can be done with B0505s like in the above post. It dose not matter if the batteries are in series or parallel. To match the Father's method you would put it in parallel like below for the 5 volt output.

 

 

[G+_Jeff Johnson]

Daniel Stagner These are the ones I ordered. I was not aware of older-newer versions.

amazon.com - Robot Check

 

Your design adds another diode drop to the output voltage, so you are going to go from 4.1vdc down to 3.5vdc-ish. That won't power a Raspi either.

[G+_Daniel Stagner]

You are correct. I also checked on my output and it is 3.9 volts. The same as the input from the battery.

[G+_Daniel Stagner]

Jeff Johnson Please talk a look at the attached. It may work. I used it to power up a raspi but did not charge the batteries at the same time due to only having one BEC.

[G+_Daniel Stagner]

Jeff Johnson Do you think I really need the B0505s for battery isolation. I am not mounting the batteries in series directly. But I do not know if the TP4056s have any type of isolation. Also the 11.1~12.6 volts from the series setup should be more efficient do to not having to step up the voltage.

[G+_Hyrum Smith]

Daniel Stagner

One major problem with the B0505S devices is that they are rated at 200 mA max @ 5V. The proposed circuit would likely cook the B0505S devices and cause an open. After doing a lot of research on these TP4056s, they work but have zero isolation. For every TP4056s you use, you will need a separate power supply! That's not really practical, for this project anyway.

 

My take on this project:

I don't like the idea of more than one cell on a single TP4056s but I am going to try two (in parallel) because three is just too risky for me. I picked up a step up board designed to provide 5V from 3.7 (posted the link in another LiPi thread on this group) and I have modified the case to place the board right next to the charge controller.

 

Currently prototyping (printing) the slightly modified case now and I will post it when I am happy with it, in case anyone else is using the same step up board. I have attached a photo of the most recent version (just one side of the bottom case). Comments?

 

Working with batteries that explode and catch fire really changes the DIY game compared to older battery technology. With the older stuff it might spark, get hot, or not charge but a certain amount of experimentation was acceptable. Li-ion technology has changed that - now a mistake or misapplication can result in a chemical fire. So caution, good circuit design, and proper applications for battery type are now absolute requirements. I need to step up my game....

[G+_Daniel Stagner]

Hyrum Smith Could I use diodes instead of the B0505s? I am pretty sure that the TP4056s will work just as long as I can get at least 4.2v DC to them. An other option for running in series is to use one BEC for every TP4056+Battery.

[G+_Hyrum Smith]

Daniel Stagner

According to the TP4056S datasheet the input voltage range is 4.5 - 6V DC. If your input UBEC is closer to 5.2V than 5V it might work but I have not seen any write-ups where diodes were used successfully, on the input or output of these things, for isolation.

[G+_Glenn Dalgliesh]

I Used adafruit.com - Adafruit Industries, Unique & fun DIY electronics and kits

Lithium Ion Battery Pack - 3.7V 6600mAh - PRODUCT ID: 353

PowerBoost 1000 Charger - Rechargeable 5V Lipo USB Boost @ 1A - 1000C - PRODUCT ID: 2465

Makes it a little more expensive but does the charge & boost, and battery pack is protected

[G+_Hyrum Smith]

Glenn Dalgliesh

That will work great depending on the current requirements of your actual load. If I we're doing a Arduino (or anything requiring up to 1A), then that would work great.

 

After taking a step back and looking at the complete project, I decided that for a RasPi 3B+, 1 Amp was just insufficient. I really need to provide 2 - 3 Amps @ 5V for everything. Back to the drawing board on this project for me.

 

Maybe one of the KITA's out there has already slayed this dragon and would like to share! One can always hope.