Custom battery pack (200 cells approx.)

[tight sage]

I want to build a battery pack which will be 44.4v (12s) and 40,000mAh. I want the pack split into 4 separate equal packs that will go into the 4 slots of my hexacopter frame. I would like someone experienced to guide me and also help me with the balance charging of my battery pack. As for the C rating, I am still trying to figure that out as well 🙂

I want 4 of these

but made out of li-ion cells

It will be much cheaper that way

[potent shuttle]

Ok, so, my advice ; don't
Go learn all that you need to learn about batteries, go practice soldering and all that stuff, because you can't do that kind of thing with just the guidance of an experienced person, if you want to do that, you most definitely need to already be able to do it yourself without second guessing yourself, because soldering batteries is not for fun, it is actually dangerous, and I hope you have a chunky ass cinelifter to lift 40 Ah 12s lipo/Li-Ion battery

[tight sage]

We already have a spot welder, no soldering required

[tight sage]

it will be 10Kg relax :)))

[potent shuttle]

Can I see the quad you entend to use it with, by curiousity?

[tight sage]

sure thing

(its a hex btw)

[cosmic ruin]

I'm 110% for you building a battery pack, but just not immediately right now. Definitely keep in mind that you have plenty of research to do about the basics before you can start working on a large DIY pack

[frigid igloo]

Best just to watch a lot of youtube and read articles, building a battery which a presume is li-ion on a "large" scale requires additional steps compared to a lil guy

[potent shuttle]

Sure, so first of all, I am not going to help you, cause you are going to burn your house down if I do, since not knowing anything about batteries and wanting to do that is suicidal thoughts at best, and second of all, you entend to buy a 7929$ drone, and budget is a problem ?

[snow kettle]

why exactly do they have to be liion

[tight sage]

Yes of course I won't start immediately playing with lithium batteries without knowing much about them first. I will do my proper research before buying them. I only want your help because I want to know if it is possible and if I can balance-charge the appr. 200 cells all together.

[tight sage]

If you are a millionare maybe you can help me with my budget

[potent shuttle]

Also, you can buy some 6s 40Ah batteries, and plug them in series, and 12s 40Ah batteries are a thing

[snow kettle]

man i was boutta say that

[snow kettle]

i can tell you buying 200 liion cells will not be cheaper than this

[tight sage]

Maybe I will do that, but I also want to have this alternative with the li-ion pack

[potent shuttle]

Well, you already have the funds to buy a drone that cost 8000$, why not buy a 3000$ cinelifter and a 12s 40ah battery and voila

[potent shuttle]

It will probably be more expensive since a third will go bad since if you aren't an expert already, you will have some magic smoke

[snow kettle]

what are you gonna use this drone for

[cosmic ruin]

Yeah as long as it's built and wired as "normal," I don't see any issues other than cooling/heating problems, but I don't think you'll build a battery big enough for internal cooling to be a problem while still having it light enough to fit an unmanned drone lol

[potent shuttle]

I was gonna ask that next, see, I steal your message, you still mine, we are equal now

[tight sage]

The thing is, I am trying to figure out the wiring for the balance charging. It will be 12 in series but also 7 or 8 in parallel. How will I balance charge that?

[potent shuttle]

How about you don't ? You just buy a 12s 40Ah battery or two 6s 40Ah in series and don't burn your house down ? That would be much more economical

[frigid igloo]

Tho i understand you wanting to do this, tattu 40,000mah 6s lipo $900 yikes

[tight sage]

Thank you.

[frigid igloo]

Depending where you get it 600

[potent shuttle]

Maybe, but a house is like, hundreds of thousands of dollards

[tight sage]

Suppose that I'm homeless.

[potent shuttle]

You're not, you won't buy an 8000$ drone if you were homeless

[frigid igloo]

If you really set on doing it, do alot of research, a 12s battery is no joke. Wire something wrong or short circuit it and you got yourself a portable campfire.

[potent shuttle]

Not so portable once you house becomes the campfire

[frigid igloo]

A dry chemical fire extinguisher would be recommended

[snow kettle]

or two..

[tight sage]

You're making it sound like li batteries are like some kind of monsters that will explode if you upset them. I am a university student and I have professors and personel as supervisors for this. Please don't worry about my house 🙂 We will take all safety measures

[potent shuttle]

Buy three, just in case

[frigid igloo]

Why didn't you say so?

[tight sage]

Sorry

[frigid igloo]

I feel better now

[potent shuttle]

Ok, so you come in, saying us you know nothing about batteries at all and are doing this basically blind, and now you are saying "yeah no actually, I am supervised by proffessionnal any way"

[tight sage]

Yes, but I am doing research! Asking for your valuable help won't ignite my house

[frigid igloo]

Thats fine then, uni should have the correct extinguishers if needed

[potent shuttle]

But still buy the extinguisher

Being alive is more valuable than an extinguisher

[tight sage]

We have boatfulls dont worry :))

[frigid igloo]

Man if the uni will let him use it use theres, fire extinguisher arnt cheap

[tight sage]

Don't worry, it's on me

[potent shuttle]

Also, if you have proffessionnal supervising you, Wich you given us has battery experts, why are you seeking help on a hobby discord to randoms who might very well be giving you completely wrong info and actually want you to burn your house down

[frigid igloo]

Tho if you do it, buy good (usually green) cells, dont buy cheap Chinese (usually purple) cells

[potent shuttle]

Also, yes, lithium batteries are monsters that will explode if you give them an excuse to do so, such excuse has a short or charging too fast

[tight sage]

I never said that they are battery experts 🙂 I need to do my own research and present it

[snow kettle]

cant go wrong with samsung ones

[potent shuttle]

Ok, and I sure hope you aren't only doing research on discord, because that is the worst way to do research, because you might very well fall on idiots who tell you to do stupid things

[frigid igloo]

SHORT THE POWER PINS

[potent shuttle]

(not the worst way I guess just asking on Facebook to randoms is worse, but check what people say with more trust worthy sources, cause you might fell on experts, or you might fell on idiots)

[tight sage]

Of course not, I am doing an extensive research. I only want to know from you how can I balance charge this pack because I have trouble finding stuff on the internet

[frigid igloo]

✨ Youtube ✨

[tight sage]

Look who's trying to make me homeless

[frigid igloo]

Get some marshmallows, make a bad situation better

Nuh uh

[tight sage]

https://tenor.com/view/burn-hell-fire-chicken-nuggets-gif-25058613

this you?

[potent shuttle]

Well, you can always just make sure the voltage is actually 12s, buy a 12s ready charger, solder a xt60 or xt90 (tho I don't really know if xt60 is 12s ready) at the end, and plug it in your charger, and wait, a long, long time that it charges

[tight sage]

ok, but will the cells that are connected in parallel charge equally?

[frigid igloo]

Yes

[potent shuttle]

If you are fricking paranoiac about the voltage of every single cell and make sure they are all the same voltage in every group of cell that are in parrallel, then yes, but really be fricking paranoiac about it, because 200cells is a lot of cells, now, what I recommend doing, is making a custom pcb where you can plug the connectors of each battery in (make sure, like, really really really sure that you design of the pcb and the chips and all is ready for the higher voltage, or else the pack will go kaboom) and the connector will link them in parrallel, so you do each packs that are in parrallel separately, like they are all only one battery (don't forget the balance cable, it's the most important) so you charge them all separately, then you put them in parrallel using the pcb, Wich will basically be X number of xt60-90 plugs that go in parrallel and give one xt60-90 plug at the other end

Also just in case,if you die it isn't my fault, blame it on your soldering skills instead

[snow kettle]

luckily for you, he cant blame anyone once hes dead..

[tight sage]

I would never blame you

[potent shuttle]

Well, then he will say it to his family, I don't want to get sued

[potent shuttle]

Good, blame Mr slowfood instead

Or any others that helped you

[frigid igloo]

(The drone community and its members take no responsibility or for any broken/damaged property or harm done to another being, caused by miss use or general fuckin around and finding out.)

[tight sage]

You advised me not to do it, why would you be blamed?

[potent shuttle]

Idk, but just in case, I prefer to cover my butt if you die and your family search your phone and finds me giving you advice

[snow kettle]

oh yeah maybe upgrade your insurance

[potent shuttle]

Double your life insurance for the next month

Your family will thank you later

[snow kettle]

but seriously: be fuckin careful

200 liion cells are nothing to mess with

[potent shuttle]

Also, were are joking around here, but really, be fucking careful and paranoid, death is no fun

[snow kettle]

dying is deadly

[frigid igloo]

Tru dat

[tight sage]

I, Aerospace Enjoyer, 
hereby state that I will take full responsibility for my actions and will therefore not hold any other members of this server accountable for anything. I am taking all the safety measures required, and will continue my research on lithium batteries before I attempt building one.

[potent shuttle]

And I am pretty sure you will say that you know, but we all know until we fuck up and pay the price

[frigid igloo]

Record it tho, i wanna see death

If it happens of course not saying it will

[tight sage]

Yall mean Im about to leave

😂

[snow kettle]

otherwise post it on youtube as a fun school project

[potent shuttle]

Yeah, ask your teacher to post it on social media afterword, they will get millions

[snow kettle]

just dont take any responsibility for harm done to people trying to make their own

[static parcel]

let him cook (possibly himself)

[tight sage]

Can you please explain?

[snow kettle]

batteries wired in parallel act like one high capacity battery

[potent shuttle]

Also, keep us informed about if you die or not, or at least put in your testimony that you want to keep us inform about if you are dead or not, and if you don't fry, well you will get a pat on the back I guess

[snow kettle]

its not like charging 2 batteries at once and more like charging one big one

[tight sage]

I will write you all my electronics in my will

[potent shuttle]

But you can't really measure the voltage of every single cells with a balance cable like with normal batteries, it's like parrallel charging, that's why you need to be paranoids about the voltage of every cell

[snow kettle]

true dat

actually

[tight sage]

So the current is evenly distributed once you connect them together?

[snow kettle]

i think they balance themselves out

[snow kettle]

pretty sure yeah

kinda like having 2 glasses of water that are connected at the bottom

[potent shuttle]

Yes, and normal batteries with their balance cable get balanced by the charger, but in parrallel charging, they can't

[snow kettle]

if you fill one up the other one will too

[potent shuttle]

I don't think so

I am not sure, but I don't see how it would do that

So, don't rely on that, and do the parrallel board I talked about earlier, so you can have a balance cable for each cell group that makes the charger balance the cells for you

[tight sage]

I read it somewhere online and I asked here just to confirm its true. But I think it makes sense because the battery which is charged more, will charge the less-charged battery

[potent shuttle]

Ok, but still, if there is more than like 0.15v I believe it is, it won't work, or at least it won't work well, so don't rely on that

[tight sage]

Yes, they will stop when they are both equal v

[snow kettle]

well itll balance out even while charging so it will never get that much of a difference

aslong as they are all at the same voltage while you build the thing

otherwise they will still equalize either way

[tight sage]

yes

[potent shuttle]

Maybe, but having a more reliable plan B, is still a better solution than relying on that, more security is better than less

[snow kettle]

plan A is physics

if they dont equalize then you have way bigger problems

[tight sage]

I will keep looking online for other solutions like you said to monitor the cells better

[snow kettle]

"When connecting batteries in parallel, energy will move from the higher-voltage battery to the lower-voltage battery and they will naturally balance."

[potent shuttle]

Always monitor the cells to actively equilize them while it is charging, there is a reason why batteries have a balance cable

[snow kettle]

balance cable is only needed for cells wired in series

[potent shuttle]

Well, yes, and he has a lot of cells in series

[snow kettle]

12

so yeah

[tight sage]

but I may create 4 battery packs (6s each) to fit in the slots of the hexacopter

[potent shuttle]

Doing multiple smaller batteries that you can charge independently without having them in parrallel is way better, there is a reason why almost all lipo fire occur to people using balance boards

So even if physics can work, having redundant security when it comes to something that actively want to burn you to a crisp is way better

[potent shuttle]

Can you give me what cells exactly you want to use ?

[tight sage]

I couldn't agree more my friend

[potent shuttle]

And do you entend on just like, ductaping them together, or do you have a 3d printer to hold them in place ?

[tight sage]

I am still looking for the appropriate cells. If you want, you can help. I want the end product to be like the tattu 6s 20000mah (4 of them).

[potent shuttle]

Well, an easy way of doing it would be to just buy 4 tattu 6s 20Ah, it will be a lot safer

[tight sage]

I will spot-weld them together using small metal rails (nickel special for connecting lithium ion batteries together) and then heat-shrink wrap

[potent shuttle]

Ok, and you will be using some 18650 then

[snow kettle]

itll weigh around 10kg if he uses 18650s

[tight sage]

Yes, we will probably get them but incase the budget is too tight and we don't feel like spending 2k in batteries, we might have to consider this custom pack

[tight sage]

or any other size

[potent shuttle]

Also, if you have access to a 3d printer, I would recommend you printing spacers for each batteries, then then using a heat shrink

[potent shuttle]

Custom pack is The tatuu ?

[tight sage]

We do have 3d printers. I will let them know 🙂

[tight sage]

no

[snow kettle]

what is the use of the drone? you didnt answer that last time

[tight sage]

Surveillance

[frigid igloo]

https://tenor.com/view/sus-among-us-suspi-gif-25732650

[potent shuttle]

Then definitely do that, with some heat resistant filament (make sure your printer can print with them tho, because if you use say pla or petg it will just melt when you shrink the heat shrink), spot welding them will be much more easy and consistent, and the overhaul structure will be much better, so definitely spend some time to make a good spacer design

[potent shuttle]

Of what ?

[tight sage]

Large areas I guess

The goal is 3h+ flight

[snow kettle]

good luck with that

[tight sage]

thank you very much

[snow kettle]

youre not gonna get 3h of flight time on one charge

[potent shuttle]

Did you already test the drone with a battery and recorded the flight time and weight of the battery ?

[tight sage]

no

[potent shuttle]

Gosh... Do you already have the drone ?

[tight sage]

the frame

only

[snow kettle]

do you know what components youre gonna use

[potent shuttle]

Well, if you can, build the drone first

[snow kettle]

since last time you were looking for ONLY european parts

[tight sage]

yes we know

[snow kettle]

which isnt possible

[tight sage]

yes exactly\

[frigid igloo]

If you worried about the price of the battery wait till you see the price of a 12s esc

x4

[tight sage]

If possible

[snow kettle]

isnt

[tight sage]

*6

[frigid igloo]

Oh boi

[snow kettle]

do you know what components youre gonna use or not

[tight sage]

We found out and it upsets us

[tight sage]

yes we know

[snow kettle]

so i assume youve also calculated the price of everything

[potent shuttle]

So, important if you know you will do you study or whatever on that drone, build it, before doing the battery, then do a test flight with a battery, that will have the same output amp and voltage has the final battery (not necessarily capacity) record the real capacity of the battery and the flight time, then weight the battery, and then add the weight of the final battery minus the weight of that one, and record the flight time, it will give you a real idea of what kind of battery you will need to build

[snow kettle]

either way im pretty damn sure it wont fly 3h

[tight sage]

noted

[snow kettle]

45 minutes would probably be a stretch already

[potent shuttle]

Once you do that, then we can talk, because right now, it is only speculation

And speculation can only get us so far

[tight sage]

Agreed

[potent shuttle]

So once you did that, you can ping me, and then we will be able to talk about what you really need to do

[snow kettle]

ping me too

[tight sage]

Yeah I will update you here

[potent shuttle]

Well ping us both

[potent shuttle]

Also, you might want to send like, a coma or something every few days here, or else it will be shut down, I believe there is an option that makes it so after like a day to a week of non activity the channel closes

[snow kettle]

or you make a new one once youre ready

[tight sage]

yep

[potent shuttle]

In both case, ping us, we will be happy to help you once you will have all the data we need to actually be of any help, also, train yourself on welding batteries, it isn't easy to get it right without toasting them, and if you toast one, you basically toasted all the other ones that it was welded to, so train on real batteries too (with a sand bucket and a dry extinguisher and all that, cause a lithium fire is 2000-3000c, and litteraly un extinguishable, since it is self sufficient), has much has you need to, and on the safety needed to do this

[tight sage]

I will do that! Thank you very much for your help and I wish you a Merry Christmas (or Happy Holidays) and a Happy New Year. Until then!

[potent shuttle]

Thanks, and I hope you won't take 3 month to build the drone or that you are trolling, anyway, hope to see you again

[tight sage]

I am definitely not trolling. As for the time, I'm not promising anything...

[potent shuttle]

Ok, well regardless of the time frame, see you next time

[tight sage]

See you and all the best!

[cosmic ruin]

I see... I'm seeing lots of potentially useful sources by googling "lipo wiring," maybe that'll help?

the parallel+series thing is definitely beyond my knowledge... actually I think Tom Stanton recently wired a pack in series+parallel in his recent video ah that was a capacitor pack. Theoretically it's the same but he charged it using straight DC, so no charging board stuff. might not be helpful

Someone here sent an amazingly clear diagram for wiring this kinda stuff. I think it was @ chiggy if you're interested in asking

[potent shuttle]

hello again, since you talked about it, I am looking to buy some 18650's for an rc car, looking to buy samsung cells, and they have a 3450mah purple cell, should I buy it ? or should I stick with green cells ? since it is samsung cells, I don't really know if this rules apply
https://bestpiles.fr/piles-rechargeables-18650/1019-pile-rechargeable-18650-inr18650-32e-samsung-li-ion-37v-3200mah-64a-7417940525839.html
https://bestpiles.fr/piles-rechargeables-18650/992-pile-rechargeable-18650-inr18650-25r-samsung-li-ion-37v-2500mah-20a-8438493100709.html
https://bestpiles.fr/piles-rechargeables-18650/993-pile-rechargeable-18650-inr18650-35e-samsung-li-ion-37v-3450mah-8a-9009316342928.html

[frigid igloo]

Also long as their samsung, Panasonic or lg cells there good.

I said usually purple cuz when i take cells out of a cheap laptop or toy they are purple

[potent shuttle]

ok

[potent shuttle]

also, do you know an 18650 charger that can charge at 3 amp, so it charges at 1c ? cause I don't really want to make a janky station with my charger, and most chargers are at like 500mah so it would take 6h charging them

(that can charge like 6 at a time)

[quasi forge]

i use my regular lipo charger lol, i wired a battery holder to have a balance lead

and just put it on 3A balance charge