Comparing EVE, SFK, REPT, & Common Battery Terminals for Lifepo4 prismatic cells Pros & Cons
Вставка
- Опубліковано 18 лип 2023
- Let see what is available and the pros & cons of each type of terminal! Sometimes the OEM is NOT the best.
Cells available form Sun Fun Kits: www.sunfunkits.com/category/2...
Great informative video. I just bought 12 304ah cells from sun fun kits. I made a quick 12v battery out of 4 of them and charged them up with 80 amps. I did match the highest capacity cells together (around 319ah). They reached 3.5 volts with a 50 mV deviation. That’s without doing any parallel charging! Amazing! After two hours of float at 14.3 volts with a muller active balancing bms. she was at 0.010 deviation. Awesome. Thank you.
They look ok, I will gladly accept them for testing and review on the channel,.
Best regards, ParagonDIY
New SFK terminals look great
Hi, thank you for the video. Can the laser welding at 3:45 be done with a hand held fiber laser welding machine? Or would a CNC type fiber laser be required?
Can the aluminium square top be directly laser welded to a flat post rather than using a steel pressed post underneath? If using 8mm aluminium here?
We only need to drill into the aluminium post on the top that we welded and not the actual terminal post of the battery, as the electricity will be flowing through the aluminium block into the terminal?
Sorry if I get my terms mixed up, I am trying to understand how that specific laser welded post works in 3:45. Hand held laser welding machines cost about $1k to 2k, if building multiple battery banks, might as well bite the bullet and do that because some sellers will not do anything for terminals for me, shipping to Pakistan.
For the old style round welded non-automotive grade batteries, would it be possible to add a washer around the top (small surface) contact area to include the larger circular area? Kinda thinking out loud here, but it *might* help.
Some people have used copper crush washers... but then you run into the issue of direct contact of copper and aluminum which can lead to corrosion with even the slightest bit of moisture.
Gut 👍 habe auch Lifepo4 zellen 👍
what type of welding is used to weld to the cells terminals
What about the new flexible busbars for the new two hole terminal? Ordered 16 new a grade eve from an european shop preorder. Two hole terminals come with flexible busbars. Should take out any issue with slightly angled flat surface not making the best contact. Also less stress on the terminals while swelling.
But nobody seems to have tested these yet.
Yes Flexible bus bars are an effective solution to most issues, but EVE has made a lot of improvements to there terminal we will release an updated video, they are now using JIG welding and the terminals are now very striaght. So much improved.
Previously, bassbars were with compensatory bend. Why are they flat now? Batteries no longer swell?
You can get them either way.
Question about using lock nuts, what is the temp rating on the plastic locking material?
Hate to have smoke inside a battery box when things get hot.
If the internal temperature gets hot enough to melt the nylon, then for all practical purposes you would have ruined the cell. The glass transition temperature of nylon is 70 degree C or about 160F. Your battery should never get this hot the BMS should shut it down at 55.
I have the two hole terminals and love them BUT there can be problems. The mat finish has bad contact. It is a abrasive blast finish which greatly increases the oxide layer. It MUST be buffed bright with 3M cloth (by hand!,no power tools!) and debris carefully blown away immediately before the buss bars are installed. Clean contact surfaces with acetone BEFORE buffing but not after, just air. Blow off contact surface and threaded holes with low pressure air or a can of dust-off being careful NOT to direct the air into the vent cover. A very light quick buff on the buss bar contact surface is ok but not too much because of coating is thin. The only anti oxidant that should be used is NO-OX-ID “A”Special. Not anti oxidants that contain any carbon or ANY metals(silver,copper,lithium or zinc)! I’ve ran tests with conductivity and corrosion. You want something that is Ph neutral, has no elements that inadvertently act as an electrolyte or noble substance yet can get out of the way while keeping air and moisture out. Throw the bolts that came with it away and use grub screws(6mmX20mm) that are long enough to use most of the thickness of the terminal and also extend through the buss, flat washer and flat bottom flange nut. Use hex key wrench to hold the grub screw to hight(not puncture case) as you run the nut down finger tight before you torque. The nuts and grub screws don’t have to be stainless. Zinc plated steel is fine. You can put a thin layer of the aforementioned anti oxidant if you have salt air. Things of note: If your buss are shiny and don’t have the Helicoils there’s no difference in performance or thread strength if the fasteners are deep enough. In both cases the terminals should be buffed bright just before assembly. If the block of the terminal is leaning down towards the battery case it’s probably been dropped on its top. Contact your seller! The battery post could be bent, fluid leaking from terminal,weld compromised are some of the potential issues. In some packaging there is foam across the top of the terminals and not on top battery case. Ideally the foam at the top would have three clearances, both terminals and vent window so the shipping Gorillas can’t hurt them. The risk of buss bar shorting is far greater with these so you should drop the buss over the four grub screws and get a nut down ONE buss at a time so it can’t accidentally get lifted across. Some of these terminals have sharp edges so route and secure the balance leads carefully so you don’t get a short and create glow worms. The flexible buss bars are the best. The traditional plated copper flat buss are ok but the thick blocky chunky ones I’ve seen don’t have flat sides and have poor contact and are nothing but trouble. In all cases, the contact surface must be flat, clean, free of oxidation and have a film of of anti oxidant prior to assembly. Failure of accomplishing this is the number one cause of poor balance, longevity and performance.
Thank you!
Great write up. The only thing I don't agree is using studs as this terminals are clearly made for screws and there is absolutely no issue to use screws here as you properly tie it down to torque spec which with stud and nut is not garunteed to work correctly as stud can move. I like this terminals a lot as it gives you enough surface area and the 2 bolts if done right press the busbars properly down. Yes always hold the busbar and put in all 4 screws by hand, then tie them down with a torque wrench, never an impact gun like done here.
@@chrisr819
The supplied screws are too short. Any time you have a soft material, you’re always better off using a stud and not a bolt. But yes you can use a longer bolt in the two hole terminal because the alloy is much stronger and it’s threaded all the way through. The earlier cells, stud less had a shallow tapped hole in very soft aluminum. They were very prone to being stripped out unless a grub screw was used to get every possible bit of thread in use and not start a pealing action of a bolt.
i need a tool to cut the surface of that second terminal type flat . for better connection surface area.
The UK supplier provides M6x16mm SS flange nuts, I suggested this in my review after first purchase. Second and third purchase, all came with flange nuts. I just add a spring washer and it’s spot on.
You picking on non issues here, happy selling, but US customers will bypass you to get this EVE cells. Many already did. You are shooting your own foot.
We sell all 3 types of terminals, the demand for our terminal is the highest of all, most people upset on this video are actually sellers who carry this terminal and now have to deal with customers asking hey have you seen SFK video? All one has to do is perform a google search for Eve Official Terminal to see the responses people have on online message boards. It is NOT good.
Unlike other companies who simply accept whatever a manufacturer is providing, we do our best to improve the product. The proof is EVE has ditched the round terminal for the EVE 230 cell.
The 304 cell is great, EVE diy approach is not. I do not think they care that much as this accounts for less than 1% of there sales.
SFK can provide any terminal the customer chooses.
Does someone know how to weld the thread diy?
I've had my 16 280ah EVE cells with this same terminal for 1yr with none of these issues that you have pointed out . No one is perfect I'm sure there's always some errors in manufacturing.
Why not use a traditional screw instead of grub screw?
I have the eve new terminals and have no problem with the terminals and i recieved bolts and not scews . Apply locktide with common sense , tide with common sense with nm meters 6nm up to 8nm max.
What i experienced is about the sunfunkits vs4 . i had to adapt the handle to fit on the new eve terminal diagonally . Terminal of the last cell pushing in got abit pushed down . i had to adapt the central plate with the actif balancer by cutting it and glued the rest of the central plate with the balancer on the back of the glass plate that holds the BMS. Sofar no problems with it but there is a consern that SFK should look at.
The major problem that i have with the recieved vs4 kit are the cables added with the kit. gauge 6AWG even double is nowhere near the size needed for 200 amps . ive kept open minded and tested with the recieved cable to confirm theoreticly and testing that the 2 cables of 6AWG are getting burning hot when pulling 199.95Amps for 30 min. I cant mesure the temps of the cables but i could not touch them anymore without burning and the BMS temp was almost 69c (celcius). I have pictures and screenshots if ya want them .
Before any reply . i know they are silicon cables . That doesnt mean they can handle more amps . It means that they can handle abit higher temps before melting the isolation. Its wrong thinking of the chinese and at this time SFK that these cable would be fine.
6AWG = 13.5mm2 x 2 = 27mm2 , 25mm2 =70A , 35mm2 =100A , 50mm2 =150A and 70mm2= 200A
So you need theoreticly 70mm2 or 2 x 35mm2 to keep it low temps.
I did test selfmade cables 2 x 35mm2 but couldend get fit aka cant get cover on the box . after testing many cables and pressed with hydrolic press of 6 ton , I finaly ended with 50mm2 single cable at B- , 50mm2 single cable on the positive and 35mm2 single cable on C-.
Cables used are Flexcable dubbel isolated category 6 (very flexible) spec is (celcius)70c nominal , 160c shorted .
On testing this cable setup for 30 min at 199.95 amps the 50mm2 i can hold on it , Its warm but ok the 35mm2 was getting hot , i could touch them with no burns and even hold it for few seconds and the BMS maxed at 58c (Celcius).
Btw the cells busbars where never hot as i used common sense
Not to be negative about SFK kit . Just to give info and hope that SFK addapt the cable sizes , maybe the size i used..
I understand that SFK try to find theyre own terminals so they dont have to addapt the kit for it but its a diy kit and as a good diyer its easy to addapt it yourself and even SFK could easely addapt by scewing the actif balancer undernead the glassplate under the bms and dont print the center plate with its support. less material used , faster printed.
Just my 2cents
Yes if only common sense was... "common"... Please contact us regarding the riser we have various version of the riser, the dual pole use the V4C which is smaller plate, i'm assuming you have V4B. 200 amp should only be used in burst situations and not sustained. This is why we rate our batteries at 125AMP continuous.
One of customer sent us a link to there build thread using the dual pole cells: diysolarforum.com/threads/my-build-thread-with-lf280k-from-18650batterystore-and-sun-fun-kits-sfk-v4-heated-kit.63360/ it just need the proper riser plate.
@@sfkenergy Im all good . i have fixed everything as a diyer should be so battery is completed.and finished and tested.
On youre website you sell the diy kit as 200amp also the BMS V2 is rated at 200amp continious discharge so rating and cables should be 200amp and not 125Amp
Anyway The cells are fine and the BMS is fine the kit is fine unless mount the actif balacer directly on the glassplate., its just the cables that you should change to better meet the specs of the 200amp BMS .If you sell these kits as 200Amp then the people believes it can handle 200amps.i made the change so it can handle 200Amp and my rv will not end in flames.
For the rest keep doing what you do , its perfect.
@@mrballbreeder3749 The Bms is rated for 200 Amp discharge and it can be with proper air flow over it. When inside a case, the limiting factor will be heat inside an enclosed environment. If you have proper airflow you can use it at 200 Amp continuous.
Inside a case our case which has no airflow you will hit thermal throttle / limit.
Also if you are in a cold environment then yes 200 AMP is possible as well as long as internal temperature does not exceed 140.
Most people are using 200 AMP for a short period, e.g. 2-3 minutes to run a coffee pot or something.
Again we explain it on are pre-built version the 300HP.
So I'm guessing EVE do Quality Testing with central screws rather than welding straight away? Otherwise, all the non-automotive grade EVE cells would look a lot different, I guess.
Anyway, I finally got round to testing each and every one of my QSO-supplied 304Ah EVE cells (manufactured late June 21) with 40 amps (about 0.13C) and they were all well above spec (and funnily enough, the best one was one where we had a misadventure with discharging cables so started again - it was over 315Ah after the second test, so they're good - lowest was just over 310Ah which was quite an outlier). I wouldn't try discharging above about 0.3C though (and have bought a load more since to ensure they're not too stressed). Guess I'll need one of those funky infrarouge phone dongles to test their best charge/discharge rates. Still, I'm pretty happy with them for storage grade.
Cell # Manufacture Line/Order Capacity Ah Energy Wh IR after 3.34 Note
1 21/06/21 71/23 312.0 1010.65 0.2mR Torque?
2 26/06/21 71/28 312.5 1011.79 0.2mR Discharge average V 3.24 for all
3 22/06/21 71/23 310.9 1006.63 0.2mR
4 26/06/21 71/28 313.1 1013.26 0.3mR Waited a while before IR
5 26/06/21 71/28 314.3 1017.77 0.3mR Waited a while. Dodgy -ve thread
6 22/06/21 71/23 312.6 1011.77 0.2mR
7 26/06/21 71/28 314.9 1020.28 0.2mR Forgot to scan QR code, so is last of 16
8 26/06/21 71/28 313.2 1014.41 0.2mR
9 22/06/21 71/23 312.6 1011.56 0.2mR
10 22/06/21 71/24 312.9 1012.92 0.2mR
11 21/06/21 71/23 313.7 1015.54 0.1mR Dodgy -ve thread
12 22/06/21 71/24 312.4 1011.8 0.2mR
13 21/06/21 71/23 313.8 1016.86 0.2mR
14 26/06/21 71/28 315.6 1021.18 0.2mR Had to restart after cable issue during discharge. Interestingly, this is the highest capacity cell.
15 22/06/21 71/24 313.3 1013.68 0.2mR
16 27/03/21 71/28 314.1 1016.99 0.2mR
313.24375 16227.09
ave capacity total energy
1014.193125
ave energy
Sorry for formatting!
And I was going to ask why you don't do centrally screwed threads, but I guess all automotive grade EVE cells have their welding already in place (after watching some more). Quite a dilemma.
Same...My 304's from QSO all tested above 310Ah...My EVE 280's from 18650 battery all tested between 280-287 Ah and never had a problem with the double hole Eve's....My 280's from Gobel all tested above 280 Ah's..
I prefer eve terminal with flexible bus bar. And using simple screw.
So REPT has some 320ah 10,000 cycle batteries now. You guys carry those as well?
On order!
@@sfkenergy Right on. What will the price be per battery (roughly if you are not sure yet)?
We don't know we placed the deposit for 1152 cells and are waiting for them to ramp up production, But I would assume around $120-125.00/cell shipped when buying as part of a 48 cell pallet.@@b3owu1f
@@sfkenergy oh damn..that's a fantastic price. 28 cell pallet is odd to me.. why not 16 or 32? Is it due to weight? I'd likely look to buy 16 or 32 of these depending on when they are available and final price with shipping.
Sorry we meant 48! 48 cell pallet 😆
Nylon melting point also high
I would rather have eve's terminal and use bolts.... but that's just my preference.
EVE supply short bolts with their bussbars now. I really like it, makes it easy to build a pack fast. Did brush the terminals and torqued to 5nm. No issues and suprisingly cool when under constant 200A load. To run my second bank of 8 i needed to make a custom bussbar. But also when only one hole is screwed with a normal bussbars still enough contact area for continuous load of 200A. I sell the packs limited in BMS to .5C charge and discharge (154A) 304ah cells. But test with 200A discharge as part of our quality controll. Testing envision 305ah cells now and they do not meet our quality requirements, they are cheap though. And will be sold with 125A hardlimit in the BMS, in our value line ESS storage cabinets.
So, I can tell my wife that there is someone more boring than me 🙂
Never thought it could have so many flaws, thanks, I thought these two screws was a perfect solution, I will be more careful!
Loctite can be applied with pin inside but not on the screw.
Need a Canadian Seller
I am right there 18:15
Laser weld give 6000 life cycle, bolt model give 3500 life cycle ,, said by HIGH STAR battery china😊😊😊
I do not understand why there is no standersation on the LiFePO4 terminals as is on many other batteries.
Did EVE explain why they have changed these terminals (again)?
I have seen how Chinese manufacturers align the terminals, their jerryrigging often consists of some laser-pointer type of set-up (if any) and by hand place the terminal. Inaccuracies are bound to happen. But so bad as your video depicts I've never seen before.
I believe it is a poor choice in design as the terminal (and its positioning) should never become a question of bend over due to mechanical stress or poor workmanship when laser-welding those terminals. Any design should be pretty fool-proof in manufacturing and in usage.
Using loctite in an electrical situation is a big no-no, it is indeed non-conductive. (LocTite does have conductive liquid product but that is an epoxy adhesive, not for thread-locking) Indeed use locknuts (or two nuts back-to-back to counter-lock) and if so applicable, knurled ring.
BTW, I also dislike this change as it often means you will also need different busbars again...
The diy segment is very small for eve 99% of there sales are to oem and electric buss makers for them they will build the entire battery pack with an enclosure. I supposed they did not like the little studs that are common as they aren’t rated for 280a amps. This is true but on the same token hardly anyone is pulling 280a from these cells. In fact the average draw is about 40.
@@sfkenergy Fair enough but you outlined some very clear shortcomings, I would hope they listen to your feedback.
I'm an OEM myself but still we build our own (12v) packs and source the enclosures as we want to tightly control the quality.
(we have learned that hard way that outsourcing those steps can create "challenges" at times and occasional hiccups in the supply-line).
I agree, even we hardly come close to the rated 1C loads, at best it is a very short peak.
Still, I'm puzzled by EVE's recent move as they could have done so much more better avoiding the mistakes you have clearly outlined.
Thanks for the heads-up, much appreciated!
@@InspectorGadget2014 the eve terminal is sufficient for stationary storage I think will keep it as is. It’s only where you are in a mobile or vibration probe situation where the dual poles have issues. I believe majority of these cells are used in stationary back up power so for those users it’s fine and probably doesn’t require threadlocker and other stuff to secure cells.
@@sfkenergy Our application is mobile/ambulant and we did have a few recent failures which are still under investigation (x-ray & such).
Granted, one was a drop (of about 20 inches, cracked the casing but not the cells AFAIK) and why we contacted you via email about a business enquiry for your kits as we have some specific needs. Generally speaking, to date we never had any failures on the post-connections but we stuff, similar as with your kits, plenty materials to secure the cells. So I agree, it should be okay but I foresee some challenges next to what you already outlined. It is good you offer your customer the choices.
The price is what you guys need to work on, no one wants to pay more than $400-$550 for 4 cells..$700-$800 for 4 cells is a rip off...
Where are you getting these prices from? Our cells are the cheapest for certified cells online.
@@sfkenergy I just bought 16 cells 5 days ago with the double terminal you showed in the video, that is most certainly certified and delivered 600 miles, cheaper than just the cost of 16 cells from you guys, without delivery, which is $2,500 dollars..And the ones I just bought last week, are the most expensive cells I ever bought..The others might not have been "certified" but the 304's tested around 315 Ah and perform flawlessly, as do the other 280 AH cells I bought from China, if I wasn't in a hurry, I would have bought this batch from China too, even though it is a pain in the arse, and sketchy..But, for solar, my cells don't need to be able to pass the strict regulations of being EV compliant..I tested some grade B 304 Ah envision cells I've had running for 6 months straight, and they are still testing around 300Ah's and they were $80 each..Now, your prices are lower than last time I looked, which is a good thing. And I wish you guys nothing but good luck...It is safe buying cells from you, and we need American companies selling these cells, but price is always going to persuade many people, it's a tricky business...
@@sfkenergy And maybe some day I'll wish I would have bought my cells from you, that's possible, time will tell...But, I do have limited funds, I don't play with credit cards ever, I save my money and pay with cash and live within my means..I'll not be a debt slave...Or a utility slave, or even work for anybody but myself...
@@realeyesrealizereallies6828 your comments are unreasonable. Cell prices are based on market prices, if you compare us to any vendor with test reports you will find we are cheaper or about the same with our coupons. We have no desire to price match grade b sellers from the Ali sites or the slew of sellers on a-m-a-zon.
@@sfkenergy And I was nice enough not to mention where I bought those 16 certified cells in Georgia on your thread, but your so unreasonable, it's like you want me to say it, not smart, but I guess you can't help yourself..