1s3p Pack Portable Light Tube

Questions
1

I am working on a project where I will have (6-10) light tubes that are 6’ (2m) long. I am using ws2812 currently. I may do some sk6812 as well. 60 LED per meter.

I have already made some 4’ prototypes but I decided to go with a longer tube.

Each tube has its own esp32. Each one will be powered by (3) 21700 molicel p42A cells. 45a discharge, 30a continuous per cell. (Left over from an electric skateboard battery build)

I am currently building the battery packs. I have ordered all the material already, but I wanted to check here to see if there were any better options.

I want the 1s3p pack to

  • be easily chargeable
  • have over charge protection
  • have under voltage protection
  • provide as many amps as 2m @60/M will need

I will be spot welding the pack together with kweld and nickel strips.

I ordered the liporider plus below which should get me 2.4A I think that can likely get me full brightness single color, but ideally I’d like to be able to go full brightness white. Or full white with sk6812.

I can’t find anywhere where the liporider states that it has over discharge protection. So I should probably get BMS to protect from that as well.

Is there a cheap efficient way to step the 3.7v up to 5v and maintain high amps to run this at full brightness? The battery pack can certainly handle it, it just seems like most of the boost converters are for small amps.

3s1p is also an option, I think I’m my research, I decided stepping up voltage was better in this case?

Also I was trying to build this one a budget to some degree, that’s partially why I picked the liporider. I just have to imagine there is a cheap safe option that I am overlooking.

2

Just a quick update, after a bunch more research…

2A is pretty common, I managed to find a 3.1A module, but anything over that doesn’t seem like it exist.

I did find a video of someone who is trying to make them on pbcway that are 10A capable.

Link to the. 3.1a one that I bought below. Also video link with description.

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3

I’m really interested in your portable tube project. Is there any chance you could list the various parts you put togethor (including the battery packs) to make the tubes? Also how long do they last on a charge?
Thanks, in advance.

4

Sure no problem, I kinda put it on the back burner but have a working prototype, I still need to clean things up.

(1) ws2112 strip
(1) esp32
(1) battery bank
(1) 3d printed case for battery
(1) diffuser tube

I’ll list the diffuser tube that I used, battery charge circuit which are the two tough things to track down.

The tubes that I used are 2 meters in length. The majority of the ones out there are 1 meter. 1 seemed.a little short for the effect that I wanted. 2 meters is a little bit of a pain to carry around but not terrible. I have considered cutting these down to 5’.

The diffusers come in at about $15 each and I had to order (10). I ended up keeping 6 for myself and selling 4 to my buddy.

The cheap alternative are at Home Depot. They are fluorescent tube protectors and can be found in that aisle. I think they are like $2-4 per 4’ and you can buy single tubes. They are clear, so you’d want to buy a cheap white spray paint and coat them.

The adhesive doesn’t love these tubes so when I experimented with them, I hot glued the strip at the top and the bottom. I found just sticking the tape alone would let go over time.

The diffusers I list below are great because you stick the light strips to the aluminum channel, then slide the diffuser over. If you ever need to tweak something you can just pop the differ cover off pretty easily.

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Charge circuit
-Over charge protection
-Under voltage protection
-3.1A output
-5v output

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I used this charge circuit, a long with (4) molicel p42a that I had on hand. P42a are over kill high discharge for the measily 3.1 A that the charge circuit can put out.

You’d get more runtime using a lower discharge but higher capacity cell like 5000 MaH.

I haven’t done full runtime test. It’ll vary significantly on light brightness and effect.

I happened to have (24) cells left over which is why I made (6) packs of (4) cells. (3) cell 5000 MaH packs would probably give you a pretty de wnt runtime.

If I tried to quantify it at all… I’m pretty sure I had red on 50% power and left it on all night by accident and it was still on the next morning.

You could probably look up the cell specs, and figure 88% efficiency one the charge circuit conversion. Then figure 3.1 amps at 5volt and get a theoretically max run time.

If you have any other questions let me know. I’m still trying to design a sleek printed case for the battery, but have been working on other projects.

5

Very interesting.
I still have 20 old Samsung INR21700-50E batteries. They can now only handle 4000maH of the original 5000, but that is still too good to throw away the batteries.
Do you see a problem, apart from the long charging time, in building an 80000maH power bank with this PCB?
Another thing I’m interested in: Have you seen any PCBs that allow for faster charging?

6

Short answer is no, I haven’t

If your goal is to make a 1S20P pack, then your charging current will be limited by the cell itself to some degree. The standard charge rate is 2450 mah for that cell and max of 4900 mah which isnt recommended for the life cycle.

In theory, you could build a 2S10P and double the max charge rate. or a 5S4P for that matter and quadruple your charge rate.

the problem then becomes A.) finding a pcb that will charge at 5A or 10A, and B.) you now need the board to step voltage down to 5v from 8.4 or 16.8.

I built a 15S5P 21700 pack that I charge at 10A. but that utilizes a $30 BMS and then a $40 DC/DC converter that will supply 5V 6A.

So it is possible, but now we aren’t really talking small $1 PCB’s. If you dont need a smart BMS and don’t need 6A output, you could probably get them for like $40 total. But keep in mind, you will then need a charger of the correct voltage.

if you want to make good use of the cells i’d look at the board from this video…or just suffer through the super long charge

7

Thanks Jack, Those diffuser tubes are a really good find. Any chance we could see a video of your project in action.

8

Not sure the best way to share that… Does this drive link work?

https://drive.google.com/drive/folders/1o8yyvnH6KwsuBDCOgUhCs_gmxjRs7DJV

9

Thanks for your advice.

Very cool. Are all the controllers independent or is there an uber network controller controlling them all?

10

I booked a digital mic up to 1 of them and it is one of the sounds reactive effects to music.

All 6 of them are on my home network. 1 is working as the master and the other 5 are syncing. ( I had to download user a usermod14 for this…maybe it’s included in the latest update of Wled now)

It seems like there are some sync delays so everything doesn’t line up perfectly… But pretty good. It seems when there are only 2 the sync is better… Maybe that’s just the luck of the draw.

I have also started to mess around with ledfx which can controll them as well. I think sync delays could be worked out per device and get them all lined up perfectly.

11

Common experience around here is that sync delays are more often a function of the WiFi network and other devices rather than WLED.

You might try a simple dedicated WiFi router on a different SSID or just use the builtin AP mode if the range is good enough.

12

Maybe the ESP-NOW sync feature coming in 0.15 will improve the speed - ESP-NOW: Add feature of sync! · Issue #2680 · Aircoookie/WLED · GitHub