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diy solar

diy solar

Our NEW GO-TO LiFePO4 vendor...09.20.21

The benefits of reliability and a better torqued connection with the welded stud, outweighs the larger surface area of the drilled and tapped hole.
 
I half assed my cells together yesterday. 7 out of 8 where at 3.31v, the last one was at 3.32v. I run my other packs 24-26.7v (rarely below 26v), so I added them on for now. I will redo the wiring later (might retire the BYDs).IMG_1235a.jpg
 
On a slightly hilarious note (after the fact), when I hooked them up, my LV2424 started beeping. Just a little at first, and then a lot. I checked everything and couldn't figure out what it was. I finally realized that it was actually my volt meter telling me that I had left it on (idle) for too long and it was auto shutting off... At some point I probably should have remembered that the audio feature is turned off on my inverter. :p
 
Thank you @ghostwriter66 for sharing this supplier.
Ordered 16 EVE 160's 10/21 There was no stock in Houston so had to be shipped from China. Fedex shipper printed 10/26. Tracking went live 12/24 when Fedex picked up from customs. 10 scans later, they were delivered today 1/2.
Boxes in good condition, completely wrapped in cellophane tape. Cells fully entombed in foam. No marks or smudges on terminals or blue wrap. No detectable deformation of the underlying aluminum case.
All cells 3.293/4. First 4 are on the charger with a Daly going to 3.4 volts. I'll charge the others the same and then parallel to top balance.
These will join 16s Lishen 150's from the group buy.

Communication from @Amy Zheng at Docan was perfect. I'll be back...
Thank you.
 

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My 4 LF230’s arrived today. Beautiful, good packing no damage, read the QR codes they were all made within a few days of each other in june last year, all measure 3.290V.

Only problem is one terminal is missing its threads. :(

Someone posted a link for post adapters to M10 and those will work nicely.

Waiting to hear if I should try tapping threads or return the one.





 
I wonder if high conductivity glue would be a solution? I’d probably want a refund on that cell before I attempted.
 
Tap it. It's really not all that hard. If you have never done it before watch a video on the subject.
 
Yeah, I'd tap that.
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Lol. Yeah, tapped it, grub screw locktited in, it’s solid.
Why are these terminal screws so tiny? M6? They should be at least M8.
 
The terminal is stepped, with a shoulder, so the mating surface for the lug is also very small. I’m going to have to source lugs with a 1/4” hole.

I only need 60-80A thru-put so I’m not too worried about it. If I had a 2000W inverter I surely would be, although it’s probably ok anyway.
 
Broke out the new power supply last night, installed all of the grub-screw terminals, hooked the cells up parallel, and put the charge on them, initially to 3.4V. They've been on for over 18 hours and have only gained about 2 tenths of a volt. LOL They started out drawing about 9A, now down to 5.

I'm doing the step method - to 3.4V and rest, then 3.5 and rest, then 3.6, call them balanced. I'm guessing the second and third steps will go quicker.

So far so good...

 
Broke out the new power supply last night, installed all of the grub-screw terminals, hooked the cells up parallel, and put the charge on them, initially to 3.4V. They've been on for over 18 hours and have only gained about 2 tenths of a volt. LOL They started out drawing about 9A, now down to 5.

I'm doing the step method - to 3.4V and rest, then 3.5 and rest, then 3.6, call them balanced. I'm guessing the second and third steps will go quicker.

So far so good...

It takes the LF280N between 70-76 hours to parallel top balance with a 10amp power supply.
 
Why are these terminal screws so tiny? M6? They should be at least M8.
My guess is that these cells are designed are to be implemented in battery packs with fully welded connections/bus bars. I can’t imagine an industrial use of these cells would have any sort of threaded connection with such weak method.

These studs or serviceable connections are an afterthought to unload cells on the DIY market

Again just my thought.
 
My guess is that these cells are designed are to be implemented in battery packs with fully welded connections/bus bars. I can’t imagine an industrial use of these cells would have any sort of threaded connection with such weak method.

These studs or serviceable connections are an afterthought to unload cells on the DIY market

Again just my thought.

And why the sockets are laser-welded on after they're manufactured.
From what I can tell it will all work out fine. I sourced lugs with 1/4 holes and they fit nicely and have plenty of mating surface to the terminal.
 
What is the largest cells Jenny or Docan can supply. i can't seem to find out. on Alibaba there site hints to 500, 450 ect but no direct info.

PS. ghostwriter66, "RF Engineer goddess extraordinaire" I whole heartedly agree and Jenny Wu also. both smart and hot. (sorry for being truthful.)
and thank you both for all the info presented.
 
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What is the largest cells Jenny or Docan can supply. i can't seem to find out. on Alibaba there site hints to 500, 450 ect but no direct info.

280 is the largest listed on the new website :


Edit: as you can see in the post below they have 304. Guess I didn’t look close enough. ?
 
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What is the largest cells Jenny or Docan can supply. i can't seem to find out. on Alibaba there site hints to 500, 450 ect but no direct info.
Why not ask Docan directly?

AFAIK, the largest aluminum cased prismatic cells anyone can supply (to retail customers) is 304Ah (EVE) or 302Ah (CATL), I believe Docan carries both, and I believe any seller saying they can supply cells above that should be treated with extreme skepticism, until you see a real manufacturer datasheet and model number. Cells advertised above 304Ah at this current moment in time are probably being misrepresented (whether that is the common mild misrepresentation of "rounding up" 302-304 to 310-320, or outright fraudulently advertising 400+ Ah cells that just are not available yet).

You can get cells above 400AH, if you go with the older, larger, and more physically robust but less energy dense nylon cased prismatic cells from companies like CALB/Winston/GBS/Sinopoly. Winston makes cells up to 1000Ah, but they cost an arm and a leg through legitimate channels.

From my research, the most energy dense cells at the moment are the EVE and CATL ~300Ah cells, and the CALB, EVE, and ETC ~230Ah cells. And the current ceiling for aluminum prismatics is around ~300Ah from what I've seen. But the market/manufacturing process is continually evolving, a year or two back ~280 was the maximum we saw for aluminum prismatics, today its ~300, tomorrow who knows.
 
400ah? 500ah cells?
 
The posted link from Alibaba has Docan advertising some hefty 500ah cells, but havent heard of anyone purchasing them.
 

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