My adventures

Ivo Staelens

Member
Joined
Aug 21, 2017
Messages
109
Hello all


This evening I finished my charging and discharching board for 18650 cells.

I can now charge 16 cells at once and discharge 4 cells at once. Tomorrow I'll post a picture of the setup I made.

I used tp4056 circuits and cell holders for the charging bit.

The discharger is a chinese opus knock off, but it's doing it's job.

As a power supply I'm using a recycled pc power supply I recycled from an old PC I had lying around and didn't throw away (you never know you can use it I always say to the misses) To convert it I used the good old youtube to learn it :)

As my first adventure I'm going to build a portable power pack to charge my drone lipo's on the field. All accessories for the build have been ordered in china and are starting to come in.

The final goal is to get my house off grid. It'll be a very very long road, but I'll try and keep you posted.

Regards,

Ivo
 
  • Like
Reactions: wim

jdeadman

Well-known member
Joined
Mar 28, 2017
Messages
926
Nice, it really doesn't matter what discharger you use just as long as it's consistent. have fun processing
 

Abarth595

New member
Joined
May 14, 2017
Messages
23
Are you from Belgium... the name sounds like you are...
I'm from Ghent.
 

DarkRaven

Active member
Joined
Sep 2, 2017
Messages
1,235
Always good to start with something rather simple on a long journey. A pack for your lipos will do the job!

Chinese knockoff off an Opus sounds dubious though given the "quality" of the original :)
 

Ivo Staelens

Member
Joined
Aug 21, 2017
Messages
109
As promised a picture of my cell processor.

It isn't a work of art, but it does the job.

image_gnmykv.jpg
 

jdeadman

Well-known member
Joined
Mar 28, 2017
Messages
926
looks great. Does not have to be fancy. Mine is just 12awg wire through holes in a piece of wood for cell holders
 

Korishan

Moderator
Staff member
Joined
Jan 7, 2017
Messages
6,325
Only 1 problem I see with that picture. There are no cells in those thar holders! :p

Looks pretty clean. At first I didn't notice the redone wires coming out of the psu. Then noticed there were only 2 colors. And then was like, NICE! But a little heavy for each TP, eh? ;) Afterall, each one will only pull 1A max. So you could of doubled or trippled the wire count by going with 18 awg and you'd have more chargers available to you. But, that's just my view point. I'm sure you had a reasoning for yours :)

Nice progress, though. I gotta get my capacity testers done so I can start getting some mAH ratings for mine.
 

DarkRaven

Active member
Joined
Sep 2, 2017
Messages
1,235
It think it's completely fine :)

Just a hint, not only for you but for everybody doing this:
You have to watch out when using ATX PSUs to power TP4056s. If it is a modern one it won't have much power on its 5V rail. If it is an older one it will, but probably won't like asynchronous loads. Some might even not work at all without some load on other rails. And if it is a shitty one it doesn't matter how old it is, watch out :)
 

Korishan

Moderator
Staff member
Joined
Jan 7, 2017
Messages
6,325
True. So far I haven't had an issue with 12V loads on modern psu's. The 5V rail I use on my other psu seems to be just fine as well, although, it is about 10yrs old. The former is about 1yr old and works fine. Though, I do use a psu tester to turn it on, so that might account for the load req'd to keep it running. Hrmm, I might wanna check that out as some point *ponders*
 

owitte

Active member
Joined
Oct 19, 2016
Messages
249
right, modern PSUs need a 12V load to supply stable 5 and 3.3V. I connected 4 of my OPUS chargers to 12V, when they're testing, there's no problem with 16 x TP4056s charging other cells:


image_pgnonk.jpg


Have sun!
Oliver
 

DarkRaven

Active member
Joined
Sep 2, 2017
Messages
1,235
Usually it is the other way round. Modern PSUs are basically 12V units and put out 5V and 3.3V via DC-DC conversion. Older ones often had issues with asynchronous loads.
 

Ivo Staelens

Member
Joined
Aug 21, 2017
Messages
109
Korishan said:
Only 1 problem I see with that picture. There are no cells in those thar holders! :p

Looks pretty clean. At first I didn't notice the redone wires coming out of the psu. Then noticed there were only 2 colors. And then was like, NICE! But a little heavy for each TP, eh? ;) Afterall, each one will only pull 1A max. So you could of doubled or trippled the wire count by going with 18 awg and you'd have more chargers available to you. But, that's just my view point. I'm sure you had a reasoning for yours :)

Nice progress, though. I gotta get my capacity testers done so I can start getting some mAH ratings for mine.

Hi, thanks for the positive feedback :)

I'm limited in cell holders by the 20A max on the 5V power rails (shows on the PSU itself). So by taking 16 cells I thought I'd have some safety there.

The reason using one pair of wires per TP is both cosmetic and practical. I thought It'd be looking nice if I have a bundle of wires coming together in a box and then going from that box to the PSU. And the practical reason is that (for me) it's easier to solder bundles of wire together in a connection box, than working with a bus bar system, soldering a wire from a bus bar to a TP. I know it's overkill, but the wires I scored for free at work, they were gonna throw away five packs of 100m brown and blue wire!!!!! I asked nicely and they were mine :)
 

Korishan

Moderator
Staff member
Joined
Jan 7, 2017
Messages
6,325
It's sad when a company just "throws" that kind of stuff away. Well, sad in the sense that that is the kind of things that makes stuff so expensive to the end consumer (not sure what your company does, but just imagine how much good stuff is thrown away from an Auto' Parts store, or Electrical, etc).
But, at least you scored some decent wires. Can't go wrong with free!

The other good thing about individual wires is that you don't get voltage drop after each TP connection. Some have used 16awg and by the time they got to the 5th or so TP, the voltage was below 5V and it started having troubles charging. You won't have those issues :)
 

Ivo Staelens

Member
Joined
Aug 21, 2017
Messages
109
Good evening all.

While I'm harvesting cells, I'm also thinking ahead on the wiring of everything.

I've been drawing up a schematic with some free software I downloaded. I attach the pdf in attachment.

At the moment not all components have been defined in detail, I'm first thinking on the main picture.

What I'm doubting on at the moment is where I'll input the generator electricity.

At the moment I intend to have a choice switch, switching between electricity from battery bank and electricity from generator when battery bank is empty. But this means that generator has to be active all the time while the battery bank is not charged by solar. And I think in winter this can take a couple of days.

Another alternative would be to have the electricity from generator injected on the "grid" side of the PIP.

First priority is to use electricity from battery bank. If battery bank is too low, generator needs to be started and depending from load needed, part of the electricity generated can be used to charge battery bank if solar isn't enough to charge the battery bank.

I think in the end the second alternative would be better, this'll surely be better in diesel usage I think.

What's your advice guys?

Regards,

Ivo Staelens
 

Attachments

  • Off grid setup.pdf
    219.3 KB · Views: 217

Ivo Staelens

Member
Joined
Aug 21, 2017
Messages
109
The story continues. All materials for my first project (ie the portable powerbox to charge drone lipo's) are in, so construction can start.

I chose my cells with my cell database and the configuration will be 4s10p.

For the four cells I have following capacities:


image_oaagnv.jpg


I also have a question. The fourth cell I have following cell choice:


image_iebpnh.jpg


Is it a problem that there's a 600mAh difference between top cell and lowest capacity cell?

In my opinion at a certain time the higher capacity cells will be pumping energy in the lower capacity cells, generating a cell with total capacity more a less sum of capacities of individual cells. Is this correct?
 

DarkRaven

Active member
Joined
Sep 2, 2017
Messages
1,235
It is correct in a mathmatical way. In reality it may also be that the cell with the higher capacity just puts out more current. But you will have uneven current flow across the cells anyway. The effect gets worse with higher total current draw obviously and because you have only 10P it will not even out as it would with 100P for instance. You just don't have the statistical benefit.

If you can then you should avoid it. But you have to work with what you got, it will certainly work. Maybe you can get a better result by sacrificing some capacity and settling for 22 instead of 25Ah or by adding more cells like 4S15P.
 

Ivo Staelens

Member
Joined
Aug 21, 2017
Messages
109
I redesigned the cell distribution for my mobile powerpack.

Per 10p pack the max difference between highest capacity and lowest capacity cell is now more a less 200mA.

I have following pack capacities now:

Pack 1: 21252 mAh
Pack 2: 21228 mAh
Pack 3: 21178 mAh
Pack 4: 21230 mAh

I would call that reasonably balanced. Future will tell how it'll work :)

I keep you informed!
 

jdeadman

Well-known member
Joined
Mar 28, 2017
Messages
926
It's good way to start.
 
Top