Ordered a 280ah SFK v3 kit.

[LVLAaron]

Ordered my SFK kit a day ago. 280ah cells, with their BMS and new V3 lid/spacer system. Once I receive the kit and start building it I will update the thread.

 

[Grains]

I ordered one of SFK 300HP pre-built and should arrive in a week. Watch all video on it and so far it meets my criteria. Plan is to order 2 more if I like it.

Unfortuantely, my SOK 206 that I bought proved to be unpleasant and poor/no service from seller and SOK. Plan was to order 3, but all cancelled. The complaints of the SOK 206 on this forum reflects my issue with this battery. Not prime time for their battery at this time.

If I calculate correctly it is cheaper per watt hour and has a smart BMS, balancer, bluetooth, heating pad with switch, an open bms app, and it seems it will be able to communicate with Victron Cerbo GX with next app update or so. If it is more expensive, at least I get what I expected.

I have been dealing with SFK for awhile and always got replies and solutions to all my questions. I can see other brand sponsers attacking SFK as SFK can be a serious competitor and set a new standard, that is lacking with others.

I have to agree with some of the honest comments about SOK shortcomings from this forum as it became very clear, same issue here. I sense some of the comment against SFK and pro comments for SOK seem to be driven by people who are sponsered by the company. I ignore them as I view them as bias and protecting their income. At times, it can be hard to ID them.

I offer my experience and testing if anyone is interested with SFK 300HP.

IF successful, perhaps SFK will become the standard that all other lithium battery makers. We sure need it, too much junk products being sold and many not even meeting their claims. I believe many Will video open up the bateries prove it. Surprise that they are even allowed to be sold NA. Safety issues?

Products, even the best can fail at times. Warranty is only good if, they fix the problem. It is too easy for a company to say it not defective and deny warranty. With an open system, it is easier to prove the problem, if any.

A close/dumb system, well you are up the creek without a paddle. You are dependant on the generosity of the vendor. A modern version of slavery

 

[Quattrohead]

Is this for real? Maybe someone is trying some AI on us.

 

[Grains]

It for real, no on ai. Are you parnoid or is this the way you suggest the comment are not honest. This forum is proving to be odd

 

[houseofancients]

It for real, no on ai. Are you parnoid or is this the way you suggest the comment are not honest. This forum is proving to be odd

not paranoid, just familiar with the bad reputation skf has among members here

 

[Horsefly]

I have been dealing with SFK for awhile and always got replies and solutions to all my questions. I can see other brand sponsers attacking SFK as SFK can be a serious competitor and set a new standard, that is lacking with others.

You've only got 5 posts, and all seem to be praising SFK. That would be fine, but you've only said you have ordered a battery from them and not received it yet. What all have you purchased, received, and tested from them previously that has you so convinced they are so much better than everyone else?

 

[Sam Cho TX]

I also have a SFK v3 kit with the 280K cells from them. It was with there 150A bms. I DID NOT use the active balancer, but have since attached it and can not tell a difference in balancing so I don't think it is necessary or harmful. I have been very happy with the results. I can use both the xoaxing app or the SFK app to view the battery.

I did not get 280AH from there cells though, but 278, I would suppose the BMS used 2 AH possibly 3 AH. The sfk app has a testing feature which basically eliminates the need for capacity tester. These are my results: https://www.sunfunkits.com/app/ViewBenchmarkDetails?id=6bc89774f0f4 the cells are very closely matched so maybe this is why I don't think a active balancer is needed.

After seeing Brad Cagle's review I will be ordering some of the REPT 280 cells from and a v4 kit when it arrives.

On a side note I think SFK is bashing grade B too hard and making up claims that don't hold up to what they say, recently Andy from off grid garage did a review on the there cells and while it did pass capacity and it had in tact QR code, the Htihium grade B cell was just as good and cheaper in terms of capacity. So they could do themselves a favor and just stay out of the grade A vs grade B debate.

But I have read these forums for years and only registered this year, what these Chinese sellers send to these influencers and what everyone else gets that is not a YouTube is completely different. So for my piece of mind I will pay the premium for sales with the test report just to not have to deal with the stress.

 

[houseofancients]

I also have a SFK v3 kit with the 280K cells from them. It was with there 150A bms. I DID NOT use the active balancer, but have since attached it and can not tell a difference in balancing so I don't think it is necessary or harmful. I have been very happy with the results. I can use both the xoaxing app or the SFK app to view the battery.

I did not get 280AH from there cells though, but 278, I would suppose the BMS used 2 AH possibly 3 AH. The sfk app has a testing feature which basically eliminates the need for capacity tester. These are my results: https://www.sunfunkits.com/app/ViewBenchmarkDetails?id=6bc89774f0f4 the cells are very closely matched so maybe this is why I don't think a active balancer is needed.

After seeing Brad Cagle's review I will be ordering some of the REPT 280 cells from and a v4 kit when it arrives.

On a side note I think SFK is bashing grade B too hard and making up claims that don't hold up to what they say, recently Andy from off grid garage did a review on the there cells and while it did pass capacity and it had in tact QR code, the Htihium grade B cell was just as good and cheaper in terms of capacity. So they could do themselves a favor and just stay out of the grade A vs grade B debate.

But I have read these forums for years and only registered this year, what these Chinese sellers send to these influencers and what everyone else gets that is not a YouTube is completely different. So for my piece of mind I will pay the premium for sales with the test report just to not have to deal with the stress.

i suggest you take a look at youtube, channel "ray build cool stuff" ( a fellow member hete) and look at his video's , especially the one where skf threatens him, when they dont agree with his evaluation of their stuff.
what follows is a very sore attempt feom skf to prove them selves correct, which is horse manure.
this was not an isolated case, and they have been banned here for quite some time due to misconduct , and just plain nasty behavior

 

[Grains]

I did watch a video of one utuber, where he claimed test failed. About cells, however, he later admitted he made a mistake in his test. So, yes, if you do testing and you make a mistake, expect to be sued. I would do the same for incompetence. I watch it twice and including his admission of a serious error he made in testing. Did you see that video? Apparently not. You need to provide the whole story, not parts as evidence. Part truths are not full truths.......

I may be new in commenting, but I am aware of the garbage, lots of wrong conclusions. Yes, I haven't bought any until recently. However, I played with them with another user. So far, it met my expectation, at least with his unit.

Unfortunaely, I switch brands, because my sok 206 failed to meet my expectation and not impressed with sell or sok to resolve it. Even their attitude has turned me off..... Maybe it a language barrier, I don't know, but not going to take a chance monetarily.

 

[houseofancients]

i did see all his video's.
still doesnt excuse the way these idiots behave, and keep behaving when someone doesnt agree with their bogus claims, which they have proven on multiple occassions.

as to SOK, either is was before current connected go in their role as their us support, or something else is going on.

dexter seems to move mountains for his customers ( and even not his customers).

anyway, whatever makes you happy counts..

 

[Grains]

I also have a SFK v3 kit with the 280K cells from them. It was with there 150A bms. I DID NOT use the active balancer, but have since attached it and can not tell a difference in balancing so I don't think it is necessary or harmful. I have been very happy with the results. I can use both the xoaxing app or the SFK app to view the battery.

I did not get 280AH from there cells though, but 278, I would suppose the BMS used 2 AH possibly 3 AH. The sfk app has a testing feature which basically eliminates the need for capacity tester. These are my results: https://www.sunfunkits.com/app/ViewBenchmarkDetails?id=6bc89774f0f4 the cells are very closely matched so maybe this is why I don't think a active balancer is needed.

After seeing Brad Cagle's review I will be ordering some of the REPT 280 cells from and a v4 kit when it arrives.

On a side note I think SFK is bashing grade B too hard and making up claims that don't hold up to what they say, recently Andy from off grid garage did a review on the there cells and while it did pass capacity and it had in tact QR code, the Htihium grade B cell was just as good and cheaper in terms of capacity. So they could do themselves a favor and just stay out of the grade A vs grade B debate.

But I have read these forums for years and only registered this year, what these Chinese sellers send to these influencers and what everyone else gets that is not a YouTube is completely different. So for my piece of mind I will pay the premium for sales with the test report just to not have to deal with the stress.

Yes, I have watched Cagle and most of off grid garage. There are several things that even today, I don't agree with off grid garage (minor stuff).
But he is one that i follow alot and for years. I knew some of the probelm he probably face later and sure enough it happen. About time he switch completely over to a better brand and nice to see he found a smart BMS. I am hoping the SFK smart Bms will be great with my victron system.

Until I do all the testing, sfk300hp pre-built unit, run it through it paces, etc. if all goes well (up to 4 x 300) I make my final conclusions. One of my son, has cells and he has been successful without a active balancer, while on another setup, balancing was poor. Quality, well match cells usually result in better balancing, but not always for various tech reasons.

Keep in mind, this is a smart bms with an active balancer, not a dumb bms with an active balancer always running, yes, that is the issue. I think off grid came to realize that recently. Also I watch another video where he came to realize he had the wrong active balancer, always on unit. Not sure, but I believe it wasn't a smart bms either. So to say there are no good or do damage, that depends on the setup.

SFK is a smart bms and acitve balancer kick in around 3vdc, if i remember right. more or less

I got one of SFK active balancer, with the plan to install in my sok206 and was planning to replace the bms with overkill. But decided against it, not work fixing the patient. It be one of my kick around batteries. So the balancer will go into my tool chest, if needed to. test or prove something.

Most video i see about batteries, very little if at all is mention about balancing quality. However all the SFK video I watch so far, third party, all showed the great balancing. Impressive if this happen for me...... Look like SFK smart bms and controled active balancer may be a perfect marriage.

It a good thing, I never bother to login. I be spiting mad with too many, the stupidity, the attacks, the interest groups, china buying loyalty, the uninformed statements. If this keep going this way, I be gone....

 

[Sam Cho TX]

Well for me I found no difference with or without the active balancer, but again my cells were very well balanced. I did not even need to top balance the kit.

But I have now found out that the 280K cells are not very high capacity wise so one should only expect around 280AH usable. Which my cells do.

As for the Ray video, all I can say is that when I first watched I was very upset with SFK but now, I do not agree with Ray. At all actually. He makes a lot of comments that do not add up. I ran a taco truck for 10 years and cops were my regulars, we had kids doing very stupid things shooting windows out with potato cannons, pumpkin rolling, even worse cow tipping... never would they have gotten permemnant criminal records as minors.

I do not want to get into it as this but I have never heard of a minor getting a permeant record for something as petty as a cassette tape, these things are expunged when they turn 21.

I have also seen many people with docan280K getting tests in 260AH range, so its very curious on how he gets all passing grade B cells, maybe there was rounding up?

I think if there was a systematic issue the other reviewers that have tested there products would be saying the same, many reviews came out after I had already made my purchase the only one I had seen was from Lithium Solar, he was very happy and got 286 AH from there cells.

There is another site that seems to be popular as well 18650batterystore.com, I would not hesitate to buy from them, they have the test report like sfk as well on the 280K and 105 cells.

 

[Grains]

One reason, I suspect it so common faking the cells (unless you have the know how and access to manufacturing SS) the average person wouldn't know. Try sueing a foreign non-demo country. So, they can sell and switch id easily. It was one reason why I avoid buying solar system from those countries as much as possible. Maybe I paid a little more with Victron, but i have reasonable recourse in the netherlands.

Too early to say this is final, but I think I may found the batteries that meets everything that I wanted in a battery.

 

[Horsefly]

SFK is a smart bms and acitve balancer kick in around 3vdc, if i remember right. more or less

I certainly hope it doesn't kick in at 3V. That is not a good balancer strategy. If it is really a smart BMS, I would hope you would be able to set the balance limit voltage, which should be at around 3.4V.

I got one of SFK active balancer, with the plan to install in my sok206

Unless they've changed their product line, the only active balancers I remember seeing from SFK were the always-on dumb capacitor-based ones from Heltec. Probably not a good idea, as you probably already have seen if you've watched off-grid garage.

Too early to say this is final, but I think I may found the batteries that meets everything that I wanted in a battery.

I still don't get how you can say this if all you have done is order it. As of yet you don't have it, but you think you found the battery you've always wanted?

 

[Alkaline]

These little heltec style active balancers are not bad, I had 3 of them on my 3x 8s battery banks. I just left them connected. All cells would balance back up as long as you would do a full charge every now and then.

this is a nice video, they basically work based on how different the voltage is, if the voltage difference is low then they hard do anything at all. Its not like the JK where it makes you are getting 2amps.

I think the most I ever even measured was like 1.2 amps right as the cells began to top off.

 

[Alkaline]

Also mine never shut off the yellow light always stayed on regardless, but I measured the current in the wires when all cells reached around 3.5v it was doing like .01 Amp now and then.

the ones I ordered said it had a range for 2.9 - 4.2 volts.

 

[Grains]

I certainly hope it doesn't kick in at 3V. That is not a good balancer strategy. If it is really a smart BMS, I would hope you would be able to set the balance limit voltage, which should be at around 3.4V.

Unless they've changed their product line, the only active balancers I remember seeing from SFK were the always-on dumb capacitor-based ones from Heltec. Probably not a good idea, as you probably already have seen if you've watched off-grid garage.

I still don't get how you can say this if all you have done is order it. As of yet you don't have it, but you think you found the battery you've always wanted?

yes, true, but i have played with it with an friend who has them. Which is why I switch. I notice lot of video on this battery, they show the balance and dead on, even after discharge and charge. I made a point of looking at balancing, even if it wasn't their theme, but they display the screen.

I have seen some make claims of the best start cell voltage to activate balance. He concluded it damage balancing. Later on in another video, his cell were still not balance before and after. So to make a claim, like that, is questionable. Many making claims balancing is not needed, or active balancing is no good, etc. Those video lack scientific analyses. There are several factors that can result in wrong conclusions.

Most were not the system or type I am looking at. As a percaution, I always order one at a time, just in case something was missed. Did that with SOK 206, found it didn't meet my criteria and all the video I saw on it, never mention balancing issue and that the app was lock out from the user. I didn't have an opporutinity to play with it before buying, unlike sfk. So the sok will be repurposed and not be included in any of my projects.

Better to lose a little than a lot..... It also easy to unplug the balancer if so desired. Balancing not neeed, hummm is that why my sok is not balancing.

 

[Horsefly]

These little heltec style active balancers are not bad, I had 3 of them on my 3x 8s battery banks. I just left them connected. All cells would balance back up as long as you would do a full charge every now and then.

this is a nice video, they basically work based on how different the voltage is, if the voltage difference is low then they hard do anything at all. Its not like the JK where it makes you are getting 2amps.

I think the most I ever even measured was like 1.2 amps right as the cells began to top off.

Ok, I'll admit I have a bit of a bias. I have several of these, and had decided they were a good thing to add to my Overkill 8S BMS, and to have spares.. I was testing the system over a few weeks, including in cold temps. Then one day I opened the battery box to find that the cells were WAY out of balance. That is to say, one (or maybe two?) cells were dropping dangerously low, below 2.8V with the rest above 3.2V. Then I found that about half of the caps on the Hultec 8S capacitor balancer were rapidly approaching 100°C, too hot to touch. Yikes! I pulled the whole thing. That board had clearly failed and was taking my battery (and maybe my house) with it. Suffice it to say, I would *NEVER* trust these cheap little boards to be plugged into my battery without me checking multiple times per day.

So I am NOT a fan of these $2.99 active balancers (cost of parts, not what we pay) because it almost wrecked my battery. Besides that, there were two other things I realized, back when I thought they might be good:

1. Balancing all the time is just a bad idea. If you have top-balanced cells, the balancer will work like hell to bottom balance them when the cells are low, and then work like hell to top-balance them the next time you charge. Meaning, it will be meaninglessly moving energy all day long as you cycle. Since those moves are clearly less than 100% efficient, you are losing energy from your battery. Moreover, it will defeat your careful top-balance the first time you get the cells towards the bottom end of the discharge curve. This was the crux of what Off-Grid Garage showed, if anyone wants to go watch his videos.
2. They will virtually never balance at a meaningful current. The "2A" rating is assuming that there is a *HUGE* misbalance between cells. I measured less than1A when I intentionally created a 0.8V imbalance between two adjacent cells (2.5V and 3.3V). For smaller differences, the amount of current is proportionally smaller. This means that the passive balancing in something like the JBD/Overkill BMS is probably more effective.

So, I'm not judging them harshly for no reason. To each his own.

 

[Bud Martin]

Ok, I'll admit I have a bit of a bias. I have several of these, and had decided they were a good thing to add to my Overkill 8S BMS, and to have spares.. I was testing the system over a few weeks, including in cold temps. Then one day I opened the battery box to find that the cells were WAY out of balance. That is to say, one (or maybe two?) cells were dropping dangerously low, below 2.8V with the rest above 3.2V. Then I found that about half of the caps on the Hultec 8S capacitor balancer were rapidly approaching 100°C, too hot to touch. Yikes! I pulled the whole thing. That board had clearly failed and was taking my battery (and maybe my house) with it. Suffice it to say, I would *NEVER* trust these cheap little boards to be plugged into my battery without me checking multiple times per day.

So I am NOT a fan of these $2.99 active balancers (cost of parts, not what we pay) because it almost wrecked my battery. Besides that, there were two other things I realized, back when I thought they might be good:

1. Balancing all the time is just a bad idea. If you have top-balanced cells, the balancer will work like hell to bottom balance them when the cells are low, and then work like hell to top-balance them the next time you charge. Meaning, it will be meaninglessly moving energy all day long as you cycle. Since those moves are clearly less than 100% efficient, you are losing energy from your battery. Moreover, it will defeat your careful top-balance the first time you get the cells towards the bottom end of the discharge curve. This was the crux of what Off-Grid Garage showed, if anyone wants to go watch his videos.
2. They will virtually never balance at a meaningful current. The "2A" rating is assuming that there is a *HUGE* misbalance between cells. I measured less than1A when I intentionally created a 0.8V imbalance between two adjacent cells (2.5V and 3.3V). For smaller differences, the amount of current is proportionally smaller. This means that the passive balancing in something like the JBD/Overkill BMS is probably more effective.

So, I'm not judging them harshly for no reason. To each his own.

I am curious as to what the DC Voltage rating of the caps are, for them to get hot it either due to over Voltage or reverse Voltage being applied to the caps, most of those caps are rated at 85c or 105c. I wish I can find the schematic of these Active Balancer board to see how they work.

 

[Grains]

Not all create equal. Some brands have option to set the balance difference to a greater amount. Off grid is a hobbyist, he is using specific products and I am sure lots of it is foreign junk and wouldn't meet regulation in our country. His experience is with his setup and equipment. You can not scientifically say balancing is no good base on his hobby experience. I even question his approach to charging, 3.4 or 3.45. Perhaps this is good for his battery chemistry and quality. I seen his graphs, look good, but doesn't cover all variables.

This is one reason why BMS parameter need to be open to match your equipment, quality of parts. Also to ensure, prove that you have at least saturated the cells. I avoid closed system or secrecy in equipment. It can be dangerous.

I think, it time to leave the forum.....

You are using hobbyist experience of their setup, this isn't always proof or evidence that this or that is not good. You need to consider their experience, see if it work for you or not. But don't push this is as good or not good or bad or junk if you do or don't follow the hobbyist views.

One thing I like about off grid, he admits when he made a mistake and has change his views. He is moving away from junk brands and to more proven products. His seplos was interesting, and now I wouldn't consider it, thanks to his videos. If he had to start again, seplos would not be his first choice, is the sense I get from his talking. Maybe the conclusion is wrong, but doesn't matter.

Not all are humble, especially those who consider themselves to be advance, will attack before admitting their errors. Remember they are hobbyist and started that way. Equipment is always evolving, so what was good yesterday, may now be garbage today. Outdated information or using outdated equipment to judge what is good or bad is not scientific but bad science.

Hardware is important, but if software is poor then none of it is good or safe. It seems hardware is usually ok, it the software that weak, buggy or too basic programming. I unfortunately experience system where the product and the software is real bad and they shouldn't even been allowed to sell to NA markets.

There has been a few times, where I bought something, base on other people reviews, only to discover how poor the review were and misleading. Once I see it, i refuse to invest, instead will dump and switch to another widget that seems promising.

A product fails, I bet it usualy from a dictator country where they can sell you anything, laced with dangerous elements. They know, they will never be sued or even found. Blame them for your product failures, not the concept, just poor execution of their product.

Why I buy from NA market when possible, or from nato countries. At least I can have legal recourse and they are motivated to build the best and safist product. If you see a product that interest you, will you buy from the west or from the east first. Unfortunately not all are avaialble in both places.