Break in for 18650B Panasonic

For all you people who built packs using 18650B Panasonic's or just 18650's in general....have you had to break in them in by charging and discharging a few times?

Only to weed out possible duds... lithium cells seems to either be good.. not not good.. conditioning not required imo..

Damn so even though they began to perform as expected after a few cycles they should be considered duds?

Well, assuming you got a pile of these cells to build a pack, that were acquired as a batch, all sitting for equal amounts of time, the good one's that will get along well together should stand out.. and really bad one's that self discharge horribly will be obvious as well.

The process i used ( when tearing power tool packs up ) was to fully charge them to 4.20v and let them sit overnight... anything that drops below 4.14v was considered " not good " .. anything that holds 4.18v or more is excellent..

These cells were brand new from illumn.com

Brand new cells should be just fine. I check the voltage on mine and as long as they're close I use them.

I also prefer to build packs at shipping voltage (around 3.6v) instead of fully charged. Less energy if I do short something.

You shouldn't need to break-in new 18650 cells, but monitoring the pack and cell balance is a must for any DIY project. I had issues with damaged cell from soldering and welds coming off in another case. If I hadn't manually monitored the cell balance using a volt-meter, i probably wouldn't have found out before a catastrophic failure of some sort.

Good luck.

For the bunch of 18650 packs I have built, I only checked voltage of each cell before assembly.
I have never built a pack immidiately from cells I got delivered. They have always been sitting in cool storage for a while before the packs has been constructed.
My thoughtprocess is that if the cells are still equal voltage when I get to building the pack, they have held the charge equally well over time, and are likely all good.
The same thing could be applied to cells that you know the manufacturing date or month. If they all sit at for example 3,68V after 5months, they are very likely good.
Furthermore, I like to build larger packs and then individual cell capacities gets mixed up in the parallell strings.

No need to break in. But doing capacity test and discharge voltage drop off test will tell you about your cell quality and allow you to group them properly.

Yea i think they have been sitting for a while. This shop sells flashlights and batteries. I cycled the pack a few times with my TP1430C and it seemed to help. Its weird the Sanyo ncr-16850GA's that I also bought dont seem to need to be cycled.

At the moment I am conditioning a batch of no-name 18650's that I got from eBay as a cheap computer battery pack purchase. I have pulled them apart to make a series of 9v packs that I am going to use for my battery powered amp and stomp box for this summers street performances I plan to do.

After a first time full charge and first time full discharge I notate the results. I have found that a second full charge and second full discharge the capacity is around 20% more, on average then the first full charge and full discharge. (4.2v charge to 3v discharge at about.5C. In my case, 1 amp discharge). All my testing is done on 1 iMax B6. One battery at a time testing takes time, but equate to accurate results relative to all the cells being tested on the same device. Once my testing is complete I the then group the cells so the the most accurate total capacity is about equal for all groups of cells. In my case we are talking about a .003% difference in capacity of the three cell groups for my 9v+ packs. These packs should balance out just fine.

And yes, the duds will show themselves through this process.

My conclusion: With the cheap no-name 18650 cells that will suit my need for these battery packs, the cells need to be charged and discharge several times to garner their best performance. So yes, IMO, condition them to the tune of at least three full charges and three deep discharges for best results.

Yes, if you're using junk cells, you need to test them.

If you're using factory-new name brand cells, they should be fine.

Syonyk said:

Yes, if you're using junk cells, you need to test them.

If you're using factory-new name brand cells, they should be fine.

Click to expand...

So are there never bad cells with a large brand name? No such thing as a lemon? Do brand name items always perform perfectly?

I would prefer to test and know for sure.

Up to you.

If you want to cycle brand new batteries a few times to validate them, go for it. I assure you, no major pack manufacturer is doing this, as the factory QC is quite solid.

Syonyk said:

Up to you.

If you want to cycle brand new batteries a few times to validate them, go for it. I assure you, no major pack manufacturer is doing this, as the factory QC is quite solid.

Click to expand...

Assuming, of course that nothing happened to them in transit, or they haven't sat on a shelf somewhere for a long time or they are not counterfeit or good cells are mixed with "B" quality cells by an unscrupulous seller.....all stories heard around 18650 batteries buyers/users.

So yes, if it is up to me I say two or three full charges and discharges, keeping careful notes on each cell capicity, then match them by capacity to give you optimal parallel groups to serialize.

e-beach said:

Syonyk said:

Up to you.

If you want to cycle brand new batteries a few times to validate them, go for it. I assure you, no major pack manufacturer is doing this, as the factory QC is quite solid.

Click to expand...

Assuming, of course that nothing happened to them in transit, or they haven't sat on a shelf somewhere for a long time or they are not counterfeit or good cells are mixed with "B" quality cells by an unscrupulous seller.....all stories heard around 18650 batteries buyers/users.

So yes, if it is up to me I say two or three full charges and discharges, keeping careful notes on each cell capicity, then match them by capacity to give you optimal parallel groups to serialize.

Click to expand...

Lol Id like to see someone do that with 200+ cell packs.

By brand name from good resellers and dont worry about it.

Grizzl-E said:

.......By brand name from good resellers and dont worry about it.

Click to expand...

LOL...yup...cuz nothing ever goes wrong with battery packs! :lol:

joeyan310 said:

Yea i think they have been sitting for a while. This shop sells flashlights and batteries. I cycled the pack a few times with my TP1430C and it seemed to help. Its weird the Sanyo ncr-16850GA's that I also bought dont seem to need to be cycled.

Click to expand...

The difference is:

NCR18650B's are garbage cells for anything but a laptop or dim flashlight.

NCR18650GA's are good cells for many applications.

e-beach said:

LOL...yup...cuz nothing ever goes wrong with battery packs! :lol:

Click to expand...

Empirically, packs built from new, OEM-direct cells, seem to be pretty reliable.