Need to replace 2 cells in my DIY packs and looking for a US supplier

[sparrowhawk]

I have 2 cells in two of my DIY 24 volt Basen battery banks that are dragging down my system. They're only two years old but have never performed as well as the others and seem to be going down hill fast. One of them I believe is venting. I suspect this because when I did a top balance in an effort to bring some of my capacity back and when I charged one particular cell I started smelling an unusual odor It also happens to be one of the ones that has terrible performance. I see no physical evidence of any leakage but the odor has me concerned. I would characterize it as a slightly sweet odor.
Anyway there's no way am I going to try and order directly from China again so I'm looking for the good, the bad and the ugly from others who have ordered from local US suppliers.

 

[MisterSandals]

when I did a top balance in an effort to bring some of my capacity back and when I charged one particular cell

How did you perform this "top balance"? Does not sound like a parallel top balance.

By writing "terrible performance", you are referring to them reaching high charge state before the rest and conversely discharging to low Soc before the rest?

Have you tried capacity testing? I recently went thru the process and the results were enlightening.

 

[sparrowhawk]

No this time I did not do a parallel top balance but with my lab power supply they were all individually brought up to the point were the power supply stopped putting power into the batteries. I had it set at 3.58 volts. My concern was not to fill the batteries to the absolute top but to bring them very close to hopefully get back some of the lost capacity do to the pack being out of balance.
I did give a parallel top balance when I first assembled them 2 years ago and again 1 year ago and found 2 that I had to lower the discharge rate a lot lower than the rest to get the same amps as I did the rest of them. Those same 2 run when being charged and fall way below the others when being discharged.
If it wasn't for the odor I would just use as is but I keep them in my house and it would be catastrophic if one decided to have a melt down and do a major venting.

 

[MisterSandals]

If it wasn't for the odor I would just use as is but I keep them in my house and it would be catastrophic if one decided to have a melt down and do a major venting.

Yeah, you are doing the right thing. You are in an area where there are not a lot posts or info. From my recollection, when someone smells the odor, the cells are well deformed.

Good luck in your quest to find matching cells!

 

[sparrowhawk]

Finding cells matching in capacity is not going to happen. Finding cells that are neither runners or slackers is the goal. At the very least cells that I fell comfortable using.

 

[42OhmsPA]

I've had good luck with Docans Texas warehouse, others are also happy with 18650 battery store.

 

[chrisski]

What are the size of the cells?

I can dig up where I Ordered some 25 ah cells from the US. They did not have bigger.

If you try a search using phrases like “in stock US warehouse“ may find that thread.

 

[sparrowhawk]

What are the size of the cells?

I can dig up where I Ordered some 25 ah cells from the US. They did not have bigger.

If you try a search using phrases like “in stock US warehouse“ may find that thread.

They are 272ah. So I figure the current 280ah batteries would be close enough since they started out above that anyway

 

[chrisski]

@42OhmsPA made reference to the Doucan Warehouse and that was the post I was thinking of. The place I ordered from was small cells, probably specialized in remote control cars and such.

 

[sparrowhawk]

I've had good luck with Docans Texas warehouse, others are also happy with 18650 battery store.

At Docans I would have to buy a minimum of four batteries and at 18650 I can buy one if that's all I needed so that leaves out Docans.

 

[MisterSandals]

At Docans I would have to buy a minimum of four batteries

Roughly where are you located?

You may find others in a similar situation to split a 4 cell purchase.

 

[sparrowhawk]

Roughly where are you located?

You may find others in a similar situation to split a 4 cell purchase.

I live in the sticks in South Carolina.

 

[RV10flyer]

18650 Battery, south of Atlanta is where I go now.