Lithium Battery Pack - Build or Buy?

[etriker]

I disagree. I have worked on over 1000 pairs and I only saw that condition 2 or 3 times.

It is not rare in the packs in that video. I saw one right after the other.

I test each cell every time and label it before making a pack with them.

I know some people don't but for picky ebike battery pack builders that is what we have to do.

Test each and every cell.

 

[SamTexas]

Test each and every cell.

I'm not discouraging nor stopping you from doing that. It's just silly and wasteful. Here's why:
Let's say I have two 2.4Ah recycled cells in parallel. So total of 4.8Ah when the cells were new. Now I test both of them in parallel and I get 4.0Ah (83%). Why would I want to break them apart and test them individually? What am I going to gain?

On the other hand, if the capacity is only 3.0Ah (63%) , then there is a remote possibility that one cell is very low and one cell is still high enough. Now it makes sense to break them apart and test them individually. That was what I did when I first began this journey. Now I just throw them both away.

 

[etriker]

I like to test each cell and write numbers on them then when I have enough that match I build a pack.

Matching up the cells is another picky thing I do.

I think it is fun !

 

[SamTexas]

You still don't get it, do you? I write numbers on them too and I match them too. Except that I'm doing it in pair or in triplet, which makes mine twice or three times as fast. I'm not cutting corner.

 

[etriker]

You still don't get it, do you? I write numbers on them too and I match them too. Except that I'm doing it in pair or in triplet, which makes mine twice or three times as fast. I'm not cutting corner.

Tried it once and it just did not seem right. Each cell has to have it's own numbers.

I am not doing it for a business but for fun and learning and riding out.

There is no hurry.

And some of us don't have enough cells to be able to throw good ones away because it is too much trouble to cut them apart and test them.

I know there is a lot of newer stuff out there but I still like those pink Samsung cells a lot.

How did you see it 2 or 3 times ? You had to cut them apart to know if one was open ? Right ?

I know it is not that uncommon because I took the time to cut them apart to see.

And took the time to tell ya'll about it so you won't be throwing away good cells ?

 

[SamTexas]

OK, end of discussion for me.

 

[999zip999]

Mad professor I would buy a Ping 36v 15ah battery for your dad. It has led's on the bms as to easily check balance and he has great support. They last a good long time if not treated right and Ping will help if any problems. Your dad would love a plug and play.