That's good info. I still think due to the softness of the cell terminals threads we should try 4nm and under. I don't have a way of testing that because I am using low C rates. But we are getting closer to a safe torque with a good electrical connection. Perhaps 4.5nm max would be good enough. Maybe even 5nm is safe. Anyway thanks. That info is reassuring.
Xuba Electronics: DEAL - 280AH LiFePo4 cells. Purchase & Review
- Thread starter Steve_S
- Start date
ArthurEld
Solar Wizard
I doubt anyone cares but above I use a deep socket so I don't short anything and so my knuckles don't drag on the studs and busbars.
Derek S
New Member
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- May 18, 2020
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Hi everyone. I was thinking of doubling my EVE 16s set up to 2p16s. Lishen cells look like they're a good price. Can I just paralel them into my current set up?? So it would be 1 Eve cell paralleled with 1 Lishen cell and then 16s the paired cells.
Also on the conversation of torquing the screws I think 6-8Nm is way to much. I set mine to 2.5Nm and I feel it's enough. I originally tried to do this with a torque wrench and had very limited precision/success. I purchase an electricians Wera adjustable torque screwdriver and it's been great not just for the batteries but all the electrical work in my home.
Also on the conversation of torquing the screws I think 6-8Nm is way to much. I set mine to 2.5Nm and I feel it's enough. I originally tried to do this with a torque wrench and had very limited precision/success. I purchase an electricians Wera adjustable torque screwdriver and it's been great not just for the batteries but all the electrical work in my home.
Darkstar
Rain Wrangler
- Joined
- Dec 31, 2019
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- 339
Good suggestion but that wont work for those of us with studs as opposed to screws.
Ouch, I mean ouch.
Torque for screws and small nuts - finger tight till there is no wobble, you can feel the connection not want to move if you try to wiggle it. If you want test it, you could measure the Ohms across it??
I use this wheel fat torque screwdriver
www.midwayusa.com
Torque for screws and small nuts - finger tight till there is no wobble, you can feel the connection not want to move if you try to wiggle it. If you want test it, you could measure the Ohms across it??
I use this wheel fat torque screwdriver
Wheeler F.A.T. (Firearm Accurizing Torque) Torque Wrench Screwdriver
The Wheeler Engineering F.A.T. Torque Wrench is a hand driven, click/clutch style torque wrench that is very useful for applying the necessary torque to...
www.midwayusa.com
hankcurt
Solar Enthusiast
1 Nm ≈ 8.85 in. lbs
One newton-meter is equal to 8.8507457676 inch pounds.
One newton-meter is equal to 8.8507457676 inch pounds.
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hankcurt
Solar Enthusiast
Newton is a unit of force but it is a little more difficult to conceptualize than the pound.
Because we think of a pound in terms of how hard gravity pulls on something that weighs one pound. It is something that we experience every day. The newton is defined in terms of inertia, how much force it takes to cause something to change speed.
So the actual definition of a newton is:
1 Newton is equal to the amount of force required to accelerate a mass of 1 kilogram at a rate of 1 meter per second, every second.
But since we know the Earth's gravity accelerates objects at a rate of 9.8 meters per second per second, you can visualize newtons in kind of the same way as a pound. So the feeling of a 1 kilogram weight being pulled towards earth is 9.8 newtons of force.
Because we think of a pound in terms of how hard gravity pulls on something that weighs one pound. It is something that we experience every day. The newton is defined in terms of inertia, how much force it takes to cause something to change speed.
So the actual definition of a newton is:
1 Newton is equal to the amount of force required to accelerate a mass of 1 kilogram at a rate of 1 meter per second, every second.
But since we know the Earth's gravity accelerates objects at a rate of 9.8 meters per second per second, you can visualize newtons in kind of the same way as a pound. So the feeling of a 1 kilogram weight being pulled towards earth is 9.8 newtons of force.
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Gauranga108
New Member
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Wanted to purchase 16 cells, but they only have the lishen, are these comparable to the eve brand
Gauranga108
New Member
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Also its hard to determine who is telling the truth as you shop on alibaba many will say grade a when you ask but other suppliers for example from Winston or calb or others say thr lishen are grade b. Any thoughts or experiences on grade and brand
If you are looking for Calbs there has been some problems mentioned here that Dongguan Huanhuan Energy Technology Co., Ltd is selling used Calbs. They offer really low prices on Calbs and that is the reason. I agree with you it is really hard to filter through these boards to get vendor information. From what I hear most of the 270 and 280, in fact most none brand name cells, are probably grade B, because although they are run through some basic checks they are not matched cells directly from the factory and the factory probably sells the Grade A to large commercial customers. So if you buy the cheaper ones you assume they may get out of balance and you can compensate for that by having a good BMS and setting the charge and discharge parameters conservatively so a cell does not run too high or low. People on the board have had good luck with Amy who has now just opened her own business. She posted about it yesterday. The hope is she will be able to provide us more reassurance on grading because right now it remains a dice roll. https://diysolarforum.com/threads/introducing-the-new-improved-shenzhen-luyuan-technology-co.15880/
Gauranga108
New Member
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Thanks appreciate it
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Leaping to Conclusions based on Assumptions and "personal feelings or opinions" usually results in someone looking like an ASS.
A sign that was posted in our Science Lab at Uni. True then & True now.
EVE, Lishen and these companies are Big Multi-million dollar ++ Corporations.
Vendors (Representatives) only get the Datasheets and told what they are selling, few have the tech knowledge folks assume they have.
"Matched" is misused and sadly misrepresented due to a lack of clarity on this point.
These cells may indeed be Grade A and fit the General Manufacturer Specification for Grade-A Storage Cells (ESS) which is much less rigid than EV Grade Cells. They can still be properly Matched, Batched & Binned but generally at the cost of 50%+ of cell cost, on top. So your $80US cell becomes $120 US or more + Shipping etc.
CALB also makes "Blue-ies" with aluminium shells as opposed to the ABS shells. They are still Good Quality CALB cells but their grade rating is for ESS and their performance reflects that as well.
I would suggest looking at the link in my signature regarding ESS cells.
A sign that was posted in our Science Lab at Uni. True then & True now.
EVE, Lishen and these companies are Big Multi-million dollar ++ Corporations.
Vendors (Representatives) only get the Datasheets and told what they are selling, few have the tech knowledge folks assume they have.
"Matched" is misused and sadly misrepresented due to a lack of clarity on this point.
These cells may indeed be Grade A and fit the General Manufacturer Specification for Grade-A Storage Cells (ESS) which is much less rigid than EV Grade Cells. They can still be properly Matched, Batched & Binned but generally at the cost of 50%+ of cell cost, on top. So your $80US cell becomes $120 US or more + Shipping etc.
CALB also makes "Blue-ies" with aluminium shells as opposed to the ABS shells. They are still Good Quality CALB cells but their grade rating is for ESS and their performance reflects that as well.
I would suggest looking at the link in my signature regarding ESS cells.
Is this true for the 200, 120 and 105 "Blue-ies" as well? I was considering making my 48v off-grid battery with the smaller cells since so many people seem to be having balancing issues with the 280s and I want as much of a "Set it and forget it" system as I can get.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Applies to ALL commodity bulk cells.
Fully Matched & Batched cells (which is the only type of cell installed in EV's which have "to be right", regardless of chemistry) are the only ones you can setup, & forget more or less.
But this applies if you want to use 100% of the capacity. If going for long life & max cycles, most folks reserve off the top above 3.50 and below 2.90. Given that LFP's primary voltage curve is 3.5 to 3.0 with the Nominal Power at 3.200 there is actually little to gain by pushing the cells to their edges.
ArthurEld
Solar Wizard
Steve you are so rigid. Nobody is an ass for sharing the conclusions they come up with. Even when the conclusions come with little knowledge or experience.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
That and many similar signs were posted in one of my Uni Science Labs.
Please just hit IGNORE for my posts. You really do not need to see anything I post.
Please just hit IGNORE for my posts. You really do not need to see anything I post.
ArthurEld
Solar Wizard
Same for you Steve. This is a forum. Most of us are here to learn. Dumb shit is often spoken.
At least I'm not lonely
At least I'm not lonely
ArthurEld
Solar Wizard
Amy should offer cells with helicoils pre installed
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