DumFume 300Ah 200A Battery Teardown

[crezno]

I recently tore down 10 DumFume 300Ah 200A Batteries. Made 2 48v packs with matching cells.



Results below

1x - EVE LF280K 280Ah (299AH)
1x - Envision AESC 305Ah
11x - Trina Storage 314Ah (338AH)
1x - Cornex 314Ah (229AH)

QR codes: (If someone can figure out what the 314Ah Cells are that would be great information to have)

EVE LF280K 280Ah
Capacity Test: 299Ah


AESC 305Ah
Capacity Test: Pending


Trina Storage 314Ah
Capacity Test: 338Ah


Cornex 314Ah
Capacity Test: 329Ah



The LF280K 280Ah and AESC 305Ah Both had the following BMS. (Has a finned heatsink. A rather large one.) Temp sensor could be a switch?


All of the 314Ah Packs had the following BMS (Same exact size as the above, but the heatsink is flat with no fins.) Looks like it has a normal non switched temp sensor?

 

[crezno]

Capacity Test for the 314Ah:
4335.1Wh 338.7Ah

 

[Sights]

Hey Crezno, as a newbie to lithium, what is the advantage of this break down and making your own packs, and what does it involve?

 

[crezno]

I bought the yixiang diy 48v box, so instead of these 4x 4s bms wire in series to make a 48v pack, I have 1 BMS controlling the whole set, and its in a metal box now with a fire extinguisher in it. Also ensures that I have matching cells. As you can see they arent all the same.

As far as whats involved, I would only recommend doing this if you are getting batteries very cheap. With coupons and the credits game on Temu, I landed 11 of these batteries for roughly $1600. Which is less than $47 a cell average. Its a gamble if they arent all the same though. Without a coupon or credits, these 300Ah Dumfumes are $269 right now free shipping.

Opening the original battery boxes is extremely difficult if you want to be able to easily glue it back together. I just dremeled the lids off. Takes 1bout 1 minute to get it open. Then unbolt it all and remove the bms.

The Yixiang US stock DIY boxes are $569 each. So i built 2 using the 314 Cells from these Dumfumes and complete Batteries cost me a little under $2300 for 2x 17Kwh. (34Kwh) Not UL listed, but alot of storage for the money.

 

[Sights]

As a first time customer with AliExpress, I can get 16 Eve 280AH cells for $1742.21. That’s $188 ea, which is roughly a 50% discount in Oz. Then, if I purchase 4 Dumfumes, which I can get for a similar price, I have another 16 x Eve 280AH Batteries. If I do 8 in series x 4 and connect those 4 banks in parallel, I would have a 24V 1120AH bank.
My question is, could I use one or more of the Dumfume BMS or would I need to get a bigger one to manage the lot?

I’m reasonably experienced with the lead acid/AGM technology, but as stated, just getting into lithium.

 

[crezno]

There is no guarantee that the dumfume will have the lf280k cells in them. The 9 of 11 i have opened only 1 has had the eve cells in them. Almost all the new ones I opened have had 314 cells. Granted they tested st 338ah meaning they could still be a quality cell, there is no indicator of brand. I prefer the 314s anyway.

As far as bms, the bms that come with the dumfumes are configured for 4s. You would need to buy 8s bms for each pair.

 

[Sights]

Good to know about the 314s. Maybe I need to get all Dumfumes in the hope of consistently, but as you’ve indicated, there’s no guarantee - bummer! I don’t want a lower AH battery, dragging down a higher one – would seem like a waste of good battery power.
Nice that Dumfume getting their act together and creating a “genuine“ 300AH battery, but I guess they’re going to sell old stock and we take a chance. As a pensioner, my budget doesn’t have a choice.
Thanks for all your help. Crezno, it’s been an informative chat. Much to think about.

 

[monkeyz47]

I am doing the same thing with a bunch of dumfume batteries too (and some yeagulch - they seem to be identical based on my teardowns.) I received 6 batteries with the AESC 305 cells (2 yeagulch in this set), and 6 batteries with the unknown 315ah cells.

Given the price of these batteries (on Temu) I do not care if I end up not having all the same cells. My last dumfume 12v300ah battery was $100!! That comes out to about 3 cents per watt-hour lol.

Do you have a picture of the finished 48v pack? I'm wiring up my bms balance leads in the next couple days; I went with a 200a Daly bms.

*editing to add I just saw your post on the diy yixiang battery box with these - that's a good idea. I think I'll go that route for my next one, since I already have the BMS for my current build.

 

[crezno]

I am doing the same thing with a bunch of dumfume batteries too (and some yeagulch - they seem to be identical based on my teardowns.) I received 6 batteries with the AESC 305 cells (2 yeagulch in this set), and 6 batteries with the unknown 315ah cells.

Given the price of these batteries (on Temu) I do not care if I end up not having all the same cells. My last dumfume 12v300ah battery was $100!! That comes out to about 3 cents per watt-hour lol.

Do you have a picture of the finished 48v pack? I'm wiring up my bms balance leads in the next couple days; I went with a 200a Daly bms.

*editing to add I just saw your post on the diy yixiang battery box with these - that's a good idea. I think I'll go that route for my next one, since I already have the BMS for my current build.

Yea, I had started another thread on that. And I agree the Temu price is hard to beat. I will probably make a Frankenstein battery and make a 3rd. Ill just need to order another battery. I am going to tear down my 10th battery tonight and hope for a 314 so I can finish my 2nd bank off. The Yixiangs are a decent value. Unless you buy the BMS from Jikong, you are looking at $200+ for the BMS and screen anyway. So $350ish for the box. Dont really need the insulator pads if you tear these batteries down, unless you just want a squishable insulated vs there hollowed out cardboard insulators. You can shave off about 6-7 lbs by cutting the bands and removing the metal end plates, not that it makes an overall huge difference. You can use the bus bars that come with the yixiang, you just have to use a step bit to round the hole out very slightly to get the post in. Otherwise everything works perfectly swapping these cells in.

 

[MikeCal]

need help. I purchased a dumfume 12v 100ah battery. it only shows 7.8 volts. it will not take a charge. I tried to wake it up but no good. what should i do? can they send another?

 

[zcskywire2]

QR codes: (If someone can figure out what the 314Ah Cells are that would be great information to have)

You have caught my attention and I'm trying, I do not know which manufacturer has 0Q2 and I know more than most sights.

I know it's hard but is there any chance you can give me an idea of how the terminals are shaped on the mystery 314ah cells. It helps for matching them up.

Edit: for anyone who is wants to identify and unknown cell, feel free to tag me on it. I enjoy the challenge and it helps the community

 

[zcskywire2]

QR codes: (If someone can figure out what the 314Ah Cells are that would be great information to have)

To me after some looking, Trina Energy Storage 314Ah cells. The actual cell picture is grade b rejects with the QR done over and a new lid applied. But it matches the terminal and vent shape. The cell datasheet matches the shapes and shows the polarity markings your cells show. Full datasheet in resources

 

[crezno]

To me after some looking, Trina Energy Storage 314Ah cells. The actual cell picture is grade b rejects with the QR done over and a new lid applied. But it matches the terminal and vent shape. The cell datasheet matches the shapes and shows the polarity markings your cells show. Full datasheet in resources

View attachment 332877

View attachment 332875

I will look into this for you late tonight. I actually have that battery still tore down, so I can try to see if they are square or round. Will be hard but ill give it a shot.

 

[crezno]

I remember that some of the laser welded tabs were a little bent down and i bent them back up, and I put some pads under the overhang just in case. But some of the tabs were pretty flush with the edge of the terminals, and I feel like they were square as they are in these pictures.

 

[retro]

I just got three Dumfume 300ah delivered from Temu purchases, dirt cheap. All three have Trina 314ah cells in them. They arrived at about 45% SOC and two of the packs are balanced with matching cell voltages. The unbalanced pack is close and should top balance right away. I am gonna put the cells in better boxes with the newest v19 hardware 300A JK BMS. The cells may be factory rejects, but they appear to be better than I expected.

 

[crezno]

All 8 of the 314ah Trina cells packs have tested between 336 and 338 ah. They seem pretty solid.

 

[patato battery]

All 8 of the 314ah Trina cells packs have tested between 336 and 338 ah. They seem pretty solid.

Has anyone heard anything about the serial numbers on the batteries, for instance the ones with the serial number beginning in qz-yw having the 280 ah cells and the ones with the serial number beginning in qz-yj having the 314 ah cells I am curious because I got 8 of the 300ah s awhile back and also plan on using for two 48 v batteries thanks for any responses

 

[doing it different]

So far all mine are qz-yw... testing 130+AH at 150watt draw

 

[retro]

All of my Dumfume 300s have Trina 314ah cells in them. The numbers on each of them begin with QZ-YJ. I do not have a QZ-YW numbered battery so I can't confirm whether the cells in those are different or not.

 

[crezno]

Ill update my post, but i recently got a non trina storage 314ah cell. Its a 314Ah cell made by cornex.

 

[crezno]

Updated post with a picture of the Cornex QR code. Also I did capacity test it at 329Ah. However, it could be a little low as I was capacity testing it in the garage and it hit the high 30s low 40s, so it may have cut out a little early.

 

[doing it different]

No picture

 

[crezno]

No picture

no picture of what

 

[doing it different]

Updated post with a picture of the Cornex QR code.

no picture of what

No picture in the last post. Thought you might have missed it...

 

[hardtop]

All batteries over achieved.