Most reacted posts

I noticed the same thing here in the US. In May of 2021 I purchased EVE 280K cells from the Docan Houston warehouse for $149 each and they are now listed for $110.

It was my understanding that every one of the cells that we get from the commodity vendors are grade be at best.

@JanVJ I am planning to do the same thing but have not yet ordered the parts. I look forward to your experience and insight. I must say, Wow! I find it amazing that so many jumped on the OP with flames and arrows without any knowledge of the product in question (which per the documents he...

I can only comment from my direct experience YMMV. I have 920Ah of LFP installed in my Class A diesel pusher. The batteries are right behind the driver side steer tire. The engine is in the rear. The wires from the house battery are 2/0. They run from the battery compartment to the start...

Not everyone has the horsepower to create 70A at 3.65v. The nice part about letting the JK do it is that the time is free. You hook it up and put it to work. when you look a few days later you say to yourself, "I did a D&mm fine job of top balancing." No need to wait for it to get done...

I love that way this BMS does the 2A active balance as seen on Andy's vid. 30mA or 0.72 amps per day is a tiny price to pay for 2 amps of balance that only comes in above the knee and works with or without charging current.

The simple truth is that you cannot charge to any voltage that is higher than what you have when the highest cell goes into OVP. I recently received a 460Ah sealed battery pack and out of the box, it had a 300mv imbalance and would hit 3.65v on cell #3 and cell #1 was only 3.35v. This happened...

I know how hard it is on an alternator if it runs wide open because I only have about a 6' run of wires from the alternator to batteries on my boat and it would put out the full rated output for +6-hours if I let it and that is in a very hot engine room. In that case, I have external regulator...

The engineer in my needs to know the "why" so that I can control the 'what".

Being able to cut the sense wires on the JK is one of its very nice features. But it is not as nice as the ability to top balance a set of cells out of the box on the first charge. Just wire up the pack and put it on a charge with max voltage set at 13.6v and let it go until the voltage is...

It really sounds like you are just not charging any where close to full. 3.45v/cell should be the lowest stopping point for your charge voltage. I use 3.5v/cell on mine. If what you mean by "kill the current" is that the current begins to drop off, that will be normal when you get to the max...

And for FWIW, Andy on Off-grid Garage has repaired several stripped-out cells by screwing a standard 1/4" NC grub screw into a stripped socket. It is just slightly larger diameter and will go in without drilling and tapping.

I have both BMS's. I am a fan of the active balancing in my JK. Mine is a 12v but I did not need to do any top balancing or conditioning of the cells. I connected everything and set it to charging at 13.8v [3.45v/cell] and let it go. On the first charge, the imbalance got as high as 300mv...

Sorry but these questions cannot be answered in a simple way, so this is going to get a bit technical and have some math [shudder]. :geek: Q1 Yes, start battery bank is two Group 31 start batteries. Q2 You have the cause and effect backwards. The battery does not "pull current". It is a...

If it ends up that mine cannot be repaired or they replace it, I will mail my failed one to you.

If your alternator output on the dash is not getting to the same voltage when charging your house batteries as it does when they are full, then you are taking too much to the house and it will cause your alternator to to overheat. In that case, a DC2DC or a LiBIM225 is a good idea. I get 14.4v...

On my boat, I do not have solar. I have typically used about 140Ah per day when cruising in the summer. With a single 4D Lifeline this meant that I needed to run my generator a lot to keep up. In the two 10-day cruises since installing my 560Ah LFP bank, I have used just 100Ah per day in spite...

I do not see a problem with building two 8s packs each with its own BMS and then connecting them in parallel to double the total capacity and add redundancy. There was a big debate earlier this month about paralleling packs and Hankzor had a "NOT RECOMMENDED" warning on their site. That has...

I think it is 123456

Now we understand why Newsom has spent so much time in China.

Thanks, that worked. I switched off both the charge and discharge and then turned them back on and the warning went away. Hopefully that will solve the other problem that I encountered after my capacity test. When I charged them after the full discharge both batteries seemed to be taking...

If you do not have a very good resistance tester like Ray used in the video, at least check everything for hot spots. If you have a thermo-camera (flir) that is the best resistance tester. If not, just an infrared thermometer or even checking (carefully) with your hand will find connections...

Andy did not "set" it to 300 seconds. That was the default setting and JK rates it at instantaneous max of 350A and 200A for 300-seconds. Not saying this is prudent but his purpose was to test the limits not prudent settings. I am happy for him to blow up the first model if it gets me the info...

The current is not lost along the path, the voltage is. So, on a long wire round trip, the current is the same all locations along the wire but at the source the voltage is much higher than at the load. What the long length does is makes for a large voltage drop between the alternator and the...

I was one of those who had a failure on the 4s-8s JK. Mine was in the gen-1 units and was purchased about a week after they were released. My replacement JK was purchased last August and is working fine. I have been searching for failure of the newer units and have not found any reports since...

My alternator was controled by a Heart Interface InCharge regulator. It did a decent job on my LFP batteries but did not have the smarts to limit the output or protect from overheating. I knew that if I allowed the alternator to run flat-out it would cook itself. As a first step to improving...

I just finished my first cruise with my new battery and it performed fantasticlly. Most days I motored for a couple of hours which brought the battery back up to full charge but on a couple of days, I had a bit of breeze so sailed with no recharge. Inspite of having 6 of us aboard and using...

If your small alternator is the stock alternator on your chassis, it will not have a field wire. Only an externally regulated alternator has a field wire. most stock alternators are internally regulated and do not have a field wire. They may have an excite wire but all that does it tell the...

The voltage drop is what limits the output but it is the current that creates the drop. When the battery is low, the current will be max and on my coach is self-limiting to about 60A. once the battery gets closer to full, it quits taking so many amps and the voltage drop is less. To put it a...

That is the way that mine were packaged as well. I reused the foam to haul the cells down to the boat so that I didn't do them any harm in the dock cart. :ROFLMAO:

In reading this tread and some others you have been in, it seems that you might not fully understand the "resting voltage" charts that you have posted and reffered to. If your battery is connected to anything, you most likely will never see a resting voltage. Resting voltage is the voltage in...

My pushbutton turns the JK on and off. You need to hold the button in for 5-seconds or so.

Have they changed the heating algorithm yet? The last I heard, it used the low temp cutoff for activating the heater. It would turn off the charge and turn on the heater. Then when the low temp recovery temp was reached, it turns off the heat and on the charge. I would much rather see a heat...

I do not know if they have changed it but when the heating first came out, the heat relay was the reverse of low temp cutoff. So when your BMS turns off charging, it turns on heat. Then it turns back on charging, it turns off heat. You can adjust the temp for turning on and off but that is...

I agree fully. My original point was that Andy was TESTING the first ever 4s JK sent to him for that very purpose and his objective was to push it until it tripped. He was marginally over the max discharge current and had the time set per the spec and default values for the purpose of seeing...

The cells showed up today and look great. Cell voltages of four were 3.32v and the other four were 3.31v. I modified six of my corner pieces to to also include a standoff to support an acrilic cover. It will be heat bent to an inverted "U" shape that will fit over the end caps and have...

Wow. From what you are saying, every single drop-in battery can only be used as a single battery and never connected to another in either series to increase voltage or parallel to increase amp capacity. Battle Born allows up to 4s (48v) and no limit on parallel. I know of boats using their...

If this is the case, I would suggest not charging LFP batteries directly from that alternator. Anything greater than about 14.2v will force the BMS to shut down charging due to OVP unless the pack is perfectly top balanced. My 460Ah drop-in packs could not be charged to anything greater than...

I agree with you that most people would prefer to have more than one circuit, but this switch answers the OP question. He specifically asked about a way to power just his fridge from solar. FWIW, you do not need to use an expensive transfer switch to safely and leagally power your whole house...

I came to many of the same conclusions as you with regard to the strength of the corners but ended up at a different solution. I have read all of the specifications on the 270A-304A cells and in none of them do I find the word "compression" What they actually say is "fixture". I am a...

There is no hard ABYC requirement for tinned wire but I have used it to replace a bunch of wire in my boat that was not tinned and had green conductor for 3-4 inches into the insulation.

Not interested in the JBD. I eventually got my card to work and the JK is on its way.

I agree. You certainly can use the same outlet but it MUST be done correctly. He will need to have a system that locks out the mains power before it will connect to the invertor so that there is no cross feed. For someone who doesn't understand this process or know how to do it, two outlets...

In my initial charge, all eight of the cell voltages were at 3.315v out of the box and I did no preconditioning before connecting them to the JK. They stayed within 5mV all the way up to 3.4v with 25A charge on my 2p4s setup which took 14 hours and about 336A. At that point #3 started spiking...

Is the copper tinned? In a marine environment, the bare copper conductors will corrode.

It came in several weeks ago and was better packaged and the box was in perfect condition. The difference was a smaller box made with better quality cardboard. The BMS was in two bubble wrap bags and fit snugly inside the box. This was then placed in a snug fitting mailer bag with the address...

I was asking if the cable was tinned copper fine strand wire.

Yep. All of this is in full agreement with my last comment in post #35. My analysis and system design is based on my coach and its charging and battery system and YMMV [your milage may vary] I suspect that you do not have a 90' round trip from alternator to battery. You also might not have...

This is one of the big advantages of the JK. Just let the BMS do its thing.

280K is an EVE spec and they are currently listed for $149 from Houston. I have seen the $110 price listed from China.

I had seen that $26 tester and it is partly what prompted my question. I posted a question on Amazon about the minimum milliOhm reading and someone said 1.0 milliohm on the 3.2v LFP setting. That is fine for small cylindrical cells but as the capacity goes up, the IR goes down so on our 289A...

@Evan Bate In Andy's video, he used his 24s JK to run a 4s configuration. The JK allows you to tell it how many cells are in the battery but it still has a minimum operating voltage. For the 24s that minimum voltage is around 44v minimum so the boost converter needs to be a 12v/48v. For the...

Given the tiny amount of resistance we are talking about, I would assume that the pressure method you outlined above would produce huge swings that would not be within the ability to adjust to. You could try making a jumper lead with one of the cut off pieces with ring terminals on both ends...

I am a coastal cruiser so loss of the LFP house bank would be inconvenient but not critical. I also have the LFP house and AGM start banks totally isolated but by turning the 3 battery selector switches in a certain combination, I can have the start bank run the house loads and disconnect the...

You did not misunderstand my comment, I just did not include all of the info. My alternator is an external regulated alternator and has a rated maximum safe operating temperature of 100ºC. I am building a regulator that will have a PWM controller on the field strength that allows me to derate...

The probe wires are only about 12" long from the plug. In my first build, I had the BMS mounted to the end of the pack and the probe would not even reach to the middle of the pack. The only way that I can mount a prob near each end of the string is to mount the BMS on top of the string.

Have you been into the advanced setting on your JK? I have asked for screen shots of the advanced settings a couple of times, and you have not posted any which makes me wonder if you have been onto that page yet. On mine, the default settings were way out of whack starting with the fact that...

Update on my Basen Green 460Ah @ 12v packs. The tracking was dark until the package was received by FedEx, but I was able to get the name of the boat they were shipped on. Thanks for the tip @sunshine_eggo. They arrived on the day that Basen predicted when I first ordered them which was very...

All of the issues that I have heard of are in a 12v application which was not possible before because the system needed 24v to function. those BMS's could be used for 12v by connecting the last + wire on the plug to a 24v boost converter. I had always assumed that they model that can be used...

The last two wires both go to 8+

I have never seen those terminals listed on Docan cells? I would have preferred those but could not find them. That said, sorry for your situation, mine came in earlier this month and have checked out perfectly.

Just to clarify. Everything DC powered that I own is 12-volt, so this is only about 12-volt systems. The BMS that I will use is the JK 4s 200A unit with 2A active balance. It is rated for 200A charge/discharge with 350A surge for 5 minutes. It uses seperate strings of (20) 100A FET's for...

@ Nami If this is correct it will take the JK BMS from my #1 choice to not being in consideration. I find it hard to believe that this is correct. Anyway, my order that I was going to make tomorrow is now on hold. This would be a truly sever limitations that even Daly and JBD can handle with...

I am partial to the JK and it is 200A in and out. Mine has kept my cells within 5mv balance since the first charge. You can now get one in a week from the Docan US warehouse.

Looks very nice and organized. In the first photo, your main positive lead out from the battery looks a little light to my eye. What is that 18-guage? ;) :devilish:

One of the very nice features of the JK is that it samples the resistance of the sense wires and adjusts itself accordingly. Nami had said last year that they can be extended up to 32" long and I assume that would be based on using the same gauge wire. If I needed to go a bit beyond that, I...

Good writeup. Time limits prevented me from a very through read so I will go back to it later. One question that I have is relating to the heat function. It sounds like the heating pad turns on at the same temperature as the charging turns off. Is there any way to set the heating function to...

I am also one of those Many People. Another of his common mis-speaks is to call an individual cell a "battery". I cringe every time I hear it. My sensitivity to it must come from that fact that I write the checks for the "Errors and Omissions Professional Liability Insurance" for my...

This is just a WAG of a possible way to to avoid the in-rush current to the inverter when the BMS turns one. Could you wire the inverter to a high-amp normally open contactor and have it in parallel with a pre-charge resistor? The control for the contactor would run through a delay relay so...

I would double check the sence wires. Do you have the last wire on the plug and the 4th red wire both connected to the most positive cell?

Can you provide the serial number where this change was made so that we will know if our BMS is affected?

With 14.2v charge and the parameters that you describe I can concede that you still have redundant protection as long as your imbalance is not too great. With my pack,I could not charge to 13.9v without tripping my OVP at 3.65v. Like I said, I started with 300-mv imbalance. At that level, I...

Yep. He really showed how to crush your opponent! :ROFLMAO: :ROFLMAO: :ROFLMAO:

Could it be that your balancing threshold is greater than the imbalance in your pack?

Your settings are all wrong for the JK. You are showing that is it actively balancing the cells at the bottom of the charge, and it should only be active at the top over 3.45v. Watch this video for good, suggested settings for the JK.

1. I am looking at the 2p4s for simplicity and reducing the "can-o-worms" congestion of wires from two seperate batteries, each with its own BMS. 2. If you connect the cells into a pair of 4s batteries, each requires a bms.

The PWM control to the field is controlling the magnetic field which is not an instantaneous change. More of growth and decay so if you look at the voltage on an oscilloscope it will have a reasonably smooth voltage. Are your batteries sealed case with or without Bluetooth or DIY? It sounds...

Great resource. Thanks for posting it.

Typically, when you say 2p8s this means that you parallelize eight pairs of cells and then hook those eight pairs into an 8-cell parallel string. That I similar to what I did with my 2p4s 12-volt pack.

I got the design for a simple DIY alternator charge system for lifepo4 batteries (12v system) on boats from one of my Facebook forums and it will cost $18 in electronics components and probably twice that amount for the plastic box and bits of wire to connect it. Still $35 isn't bad for a...

Especially true given that my other battery has a JK BMS and the active balancer in that BMS top balanced all 4 pairs of cells with 560Ah total capacity to perfect 3.65v in one charge. Huge difference between +2A active and .15A max (and usually much less) passive balancing.

Has anyone seen video put out by "Ray builds cool stuff" this week where he was saying that the owner of SFK is treatening to dox him because he gave them a less than stellar review?

You have said several times said something to the effect of "brought it down to 13.6". I do not believe that there is any charger that applies a load to a battery for the purpose of bringing the charge voltage down to resting voltage. If you are disconnecting one battery from the charging buss...

The spelling of Hooke has nothing to do with olde or new English. It is based on how Rober Hooke spelled his name. From Wikipedia ..."The law is named after 17th-century British physicist Robert Hooke.".

I have the same situation although my motorhome has 2/0 wires from the start battery to the house battery. The round trip distance from the alternator to the house LFP is about 90'. My alternator is an internally regulated 160Ah alternator but the most I can get to my LFP's even when they are...

I have some statements and questions before I can offer any opinion. The statement is again, batteries do not pull current the generator pushes power in watts and the battery accepts that power. If you always think in those terms it will start to get easier to understand how to design your own...

I received notice this morning that Docan Powers's new stock of 280K cells is in and has been shipped this morning. I should receive them this Friday. Their website is showing them in stock at the US warehouse.

Given the length of the wire this is almost a given. On my build, it must be mounted on the wall of the battery encloser. I can have is to that I reach it from inside the box or outside the box. Neither of these locations can be reached without getting into a locker and cannot be seen by...

Did they indicate why the heat function would make it more fragile? One possibility might be that pumping up to the 10A limit might cause internal thermal stress. I was planning to use the heat function for my boat land motorhome given that I am based on Washington state and have been known to...

I have not seen anywhere that you identified what type of batteries that you have. I assume that they are drop-ins of some kind. Do you have Bluetooth connectivity? That would greatly help to figure out what is going on inside. I have two 460Ah packs in sealed cases and one of them arrived...

Where did you get the torque spec? I have EVE 280k cells with the M6 welded studs with the smallish ≈10mm conctact area.

This is one of the reasons that I would not get a battery without a Bluetooth BMS or a serviceable case. It sounds like your battery it badly out of balance but without knowing with the actual cell voltages are we are just guessing. As a worst-case scenario, if it were my battery and it got to...

It sounds to me like you did the same thing that worked for me based on the info I got from post #2. I get that message any time I turn off the FETs for charge or discharge and they stay there until I manually switch it back on. I have needed to do that a lot, so it is second nature now. One...

It looks like cool tech but at nearly 4-times the cost of the JK, I wonder if it is worth it.

It appears that you have your charging set to 14.6v which means that your pack needs to be perfectly top balanced to 3.65v and even then, will still shut down due to OVP. In normal charging conditions it is best to not charge that high. down around 14.2 - 14.4 is fine.

In my opinion, some of your ideas are correct and some not so much. As far as how I top balance, you have it right except that after you get the pack balanced at 13.6v it will not take days, it will take minutes to get to each new high point. By the time you get all cells to 3.45v, you are at...

On one of my packs, I had a 300mv delta with cell #3 was at 3.65v. Even with that huge delta, the cells were all within 5mv when the battery was between 12.8v and 13.3v. After that, the delta would just go off the chart.

Mine is not in Chinise but on the last line it says 4s-8s whereas yours says 8s. ? Hopefully Docan will make it right. I almost bough one from them but with the shipping it was about 50% more expensive than other souses. You can make that one work by using a boost converter to get 24v on the...

I did that when I my cells arrived and found that they had all be built on the same production line within a few days of each other with an average date of production of 52-days before they arrived. Nice to know

The 2A8S20P will run on the native 24v nominal voltage on an 8s pack. It can also be used for a 4s pack but that would require a boost converter to get from 12v up to 24v. I am hearing that they will come out with a 4s BMS in March.