1st battery pack

1st off I'd like to say hello to all from Springfield Va.

I am building my first pack of 18650 cells. I have charged and tested all 80 cells and have put them into holders. I have tested and charged all of them and they work out to 182280 mah. I am wondering if that is too much for 1 pack and how to configure it. I plan on running lights and small things for emergency power. I am not sure if I should run a 48 volt or not.

Any help would be very much appreciated.I have watched so many videos for you guys. truly inspirational.

Welcome!

I'm not sure what you mean by too much for 1 pack and how to configure. It all depends on what you want to do with it, your resources, and any number of other factors. I am building 20 cell packs to start. Once I am up and running I can add parallel packs to my system to increase capacity. Most builders here are doing larger packs than I am.

As far as Voltage of your system again that's up to you based on use and needs and so forth. I was going to build a 24 volt system to start. The more I read the more I'm convinced I will ultimately want to upgrade to a 48 volt system. So all the equipment like inverters and so forth would have to be replaced. So I decided to be patient and just build a 48 volt system from the beginning. It will take longer but in the end it will be less expensive and better in all ways. Less expensive when you factor replacing 24 volt equipment is what I am saying.

At any rate I suggest you dig in and read read read as much as possible. There is a huge library of knowledge on this forum, and MANY knowledge friendly builders with lots of experience. There are a couple electrical engineers here as well who can lend some brain power.

Welcome again! Post up pics of your project. We love to see new ideas.

Alec

You need to decide on voltage to run. 48V is preferred for higher current applications like house and for future proof the setup.

When you decided on that you should start working on your packs. Dont assemble any packs untill you have all batteries you need for a full string!
Why? Because then you can make them either by random picking or by mathematically sort them together. If you build packs as you get the cell you may end up with a pack with crap cells compare to the other. Its better to spread it all out and then you also leave the cells to sit so you can test for self discharge.

Thats how I do it and it have worked out fine.

Thanks to both of you for the fast response. I think I am going the 48 volt route. So far I only have about 150cells. I'm adding to them every day. Getting ready to add another OPUS to speed up the process some. That only makes 2 charger/testers but it's a start.

My first pack was 12 volt 3s and I think thats a good place to start for first build although now I think 4s is better.
There are lots of loads readily available for 12 volt.

daromer said:

You need to decide on voltage to run. 48V is preferred for higher current applications like house and for future proof the setup.

When you decided on that you should start working on your packs. Dont assemble any packs untill you have all batteries you need for a full string!
Why? Because then you can make them either by random picking or by mathematically sort them together. If you build packs as you get the cell you may end up with a pack with crap cells compare to the other. Its better to spread it all out and then you also leave the cells to sit so you can test for self discharge.

Thats how I do it and it have worked out fine.

Click to expand...

I have just finished testing about 300-400 cells. Looking for good advice on what sort of or how big of packs I should create, also how should I combine them. Meaning mAh group and what is the cut off points in using them. 1100mAh,2200mAh. Also what are the best bms system for the packs

iofosho: If you look around a bit on the forum all those questions have been answered before
How you should do i cannot tell since its like how long is a string. I personally do is another thing.
I dont use less than 2Ah since i got enough above. I group on 80p and have 14s system. I spread all my cells random in terms of 100mAh groups. I use Batrium BMS for this setup. I also design my packs as n+1. Where i always can remove 1 string of cells without the system will go down. I also always have 1 pack to spare in case.

With that said if you do like I do you need 2320Cells above 2Ah It all depends on what the goal is. The best tips I can give is to NOT build the packs untill you have all the cells so you can sort them evenly!

daromer said:

When you decided on that you should start working on your packs. Dont assemble any packs untill you have all batteries you need for a full string!

Click to expand...

Hey Daromer can you clarify 'a full string". Do you mean enough cells for all the parallel packs in a series? For example: 14s 100p = 1400 cells, so don't build any packs until I have all 1400 cells? I understand your logic of not ending up with one back pack, just want to be sure I understand 'string'.

Thanks.

daromer said:

iofosho: If you look around a bit on the forum all those questions have been answered before
How you should do i cannot tell since its like how long is a string. I personally do is another thing.
I dont use less than 2Ah since i got enough above. I group on 80p and have 14s system. I spread all my cells random in terms of 100mAh groups. I use Batrium BMS for this setup. I also design my packs as n+1. Where i always can remove 1 string of cells without the system will go down. I also always have 1 pack to spare in case.

With that said if you do like I do you need 2320Cells above 2Ah It all depends on what the goal is. The best tips I can give is to NOT build the packs untill you have all the cells so you can sort them evenly!

Click to expand...

Sorry if you have to keep explaining yourself, I will stop being lazy and go through the forums. Really appreciate the advice you made it easier for me to wrap my head around it. Mahalo

Eric Koshinsky: Exactly. in my case 14s80p i need to have 1120 cells before i build ANY of the packs. And the reason is that i want to make sure i have same set of cells in terms of grouped capacity in all

iofosho: No worries m8! The word is free and you are allowed to ask

Having all cells before build. No matter if its 20 cells or 2000 cells thats a preferens that I like a lot and it have worked out great for me. If you build before you might end up with a pack in the end that have left-over cells and that can/will cause issues