So, lets spec out and set up a system of LiFePo4 batteries and inverter

[inMichigan]

I understand what you wrote, up to this point:

What you are doing is finding the right Voltage Set Point where the weakest cell (the one that got to 3.6 volts first and you noted) is roughly 3.4 volts rested slightly after being charged up. All others will be slightly lower voltage. In the end your voltage set point will be around 54 volts.

If at the end of the tweaking, it's 3.4 at rest, then it's > 3.4 during charge. I absolutely see your point in knowing cell is the one to watch. I had not done that. I'm not EV and not off-grid, so I'm willing to put a little more gap so that I do everything possible to increase the life over capacity. How sensitive do you think life is to time & exposure to 3.35 3.40 3.45 3.50 v/cell?
inMichigan

[Sunking]

Michagan go look at your specs for your Vampire boards and take note of two things.

Idle current = 4 ma

At 4 ma is is 4 to 100 times more current than most others. My Orion used 100 micro amps or 1/40th of what yours burns off as heat just setting there collecting dust. In practice 4 ma is just an average. No two use exactly 4 ma. The range is 2 to 6 ma, so each discharges the batteries at a different rate. If you follow the instructions and Top Balance with every charge the difference is no problem as the slight imbalance caused by the boards is re-balanced with every charge. The issue with that means you have to over-charge every battery with each cycle.

If you look further in the instructions it clearly tells you cannot re-balance an out of balance pack. That is not unusual, as none of the Balance Boards are capable of Balancing an out of balance pack. Well only a couple of them can, those that can bypass 3 to 5 amps can bring an out of balance pack back into balance. Your can only bypass .5 amps, and it could take days or weeks to rebalance an out of balance pack. In doing so would cook the cells that top out days before the lower cells balance.

All the BMS sold are not real Balance Chargers. They all use a form of Bleeders with a couple of notable exceptions. The EV guys who top balance use the same charger us Bottom Balance use. It is not a BMS at all. It is a real Balance charger capable of charging any battery type of today or tomorrow with any algorithm you want. We just use it differently. We use Hobby Chargers intended for RC models. It has one limitation. It can only charge up to 8S at 1400 watts, or 37 volts @ 40 amps.

I know what you are saying, I use 16S. So what, so do I. If I were to Top Balance I two options. What the Top Balance EVer's use is two chargers, us Bottom Balance guys just use one about once a year if needed. Top Balance guys use two, three or whatever number it takes as some DIY EV's run 32S. It lees expensive than the chargers and BMS and does a much betteer job without damageThey are installed permanently in the EV's. They run circles around any charger and most BMS. They have a real time log and can monitor cell voltages, capacity, internal resistance, how much charge was put in, how much charge is taken out. If a problem develops bells and whistles sound off. The hobby chargers are true integrated balance chargers. There is no Bleeding, each cell is given exactly what it needs. No more or no less. If you only want to charge to say 50, 60, 70, 80, 90, or if you are dumb enough 100% You pick whatever flavor you like. They are easily converted to use Solar as the power source. Having said that they are not for you.

Unfortunately there are no LFP chargers for DIY solar as LFP is not ready for solar. Economics do not work. With DIY solar you are forced to use Chi-Coms like Calb. None of the Chi-coms will last as long as Lead Acid. LFP cost roughly twice as much and last half as long, and in some cases only 1/5th as long as lead acid. Your CALBS came with a worthless 1 year warranty or 1000 cycles. Try making a warranty claim.

Have you seen this video? When you have a spare hour watch it. Jack is the nations leading custom EV builder. He walks you through Bottom Balance you can understand.

[karrak]

I don't know about you, but I see two major flaw here. Do you know what it is? The big obvious one is the boards do not control the charger. Only a very select few expensive Centralized BMS have that capability, and those are made for a EV only and customized AC LFP charger made to work with it. All of those chargers use CAN BUSS protocol developed for the EV industry.When that first cell reaches 100% or whatever level you choose must communicate with the charger to cut charge current back to whatever value the Bypass circuit can bypass. So if you have a typical .15 to .5 amps, charge current shall be cut back to that value so you do not overcharge any cell.

Balancing boards can be used without any expensive or complicated chargers on a solar charged system without any problems by making sure that the battery is balanced before it is commissioned and only expect the balancing boards to fix any minor imbalance that might develop over time. If used in this way the charge controller will have gone into Constant Voltage mode and will be limiting the current before the balancing boards have to start working. Regardless of whether you have balancing boards or not, as a safeguard I would recommend some sort of individual cell monitoring and alarm system so that if you get the case where a cell gets so far out of balance that it goes out of its safe operating voltage range that you get an alarm which can alert you to shut down the charger or will do so automatically.

The CAN Bus protocol was not developed for the EV industry but for the automotive industry in 1983 https://en.wikipedia.org/wiki/CAN_bus. Not much of an EV industry in 1983.

Simon

[karrak]

Because the solar charge controllers are 'dumb', another potential source of damage is that I don't have the ability to limit the charge 'into' the batteries. I have a coulumb counting shunt that is monitored by a FlexNET DC (FN-DC) but it's not really designed for lithium and doesn't have the control functions needed. Let's say it's a beautiful sunny day, the net output of the panels could be 240 ADC at 58 VDC. Normally, the 16kw of AC inverter can slurp up that power, and the batteries sit at a constant voltage of 58V. But if the grid goes down at night, the system drops into battery mode and the voltage drops, in the morning the sun comes out, and the batteries are charged at a reasonable rate as the sun rises slowly out of the morning murk until they reach 58V; all is well. But, if the grid goes down at night, we drain the batteries, and it's heavily raining in the morning until around noon, and all of the sudden the sky clears; wack, my batteries are going to be exposed to 240 A of charging.... 2.4C. This is my other risk of an undersized bank, but few catch on that.

If you are only charging at 3.4 volts/cell I would think the internal resistance of the cells would limit the current to some extent. Have you found this to be the case. Maybe it will limit the current to the recommended maximum of 1C. If not the best way I see with your setup would be to disconnect some of the panels from the solar controllers if you detect too much current going into the battery to drop the current charging the battery.

I'll say the one thing I did learn in the last few days is that even though I knew to avoid the shunting effect of the BMS boards, it didn't sink in (and I've been lurking on this board since 2012) that the presence of the board creates enough of a parasite loss that might explain what I've measured. I interpreted the parasite and vampire (mentioned many times in many posts) as one and the same, as the shunting current. Really, they refer to two DIFFERENT losses. Assuming my 'divergence' clears up and the measurements of the Mini-BMS's find one totally out to lunch board, I'd like to think these postings with data & excellent discussion of the last few days will give confidence to other users to do you you've strongly advocated since early this Spring, let your batteries be naked.

I might be wrong, but I am sceptical of Sunking's assertion that the current consumption of your boards varies between 2mA to 6mA when they are in the normal cell operating range. I think it is more likely that the cell voltage variation is caused by the the balance in the battery varying. If we go to this point in one of Sunking's favourite video's https://youtu.be/pxP0Cu00sZs?t=1567 we see that the coulomb/current efficiency of LFP batteries changes as the cells age from new, if it didn't the curve would be flat. I showed in this post http://www.solarpaneltalk.com/showth...l=1#post155624 that if the coulomb/current efficiency of the cells is different that the battery will go out of balance at the bottom end. If the cell capacities vary relative to each other the top balance will change. I think it is these two factors that is more likely to cause a change in balance of the battery. Changes in battery balance are more likely to occur when the battery is new and probably when the battery gets old.

Simon

[karrak]

Unfortunately there are no LFP chargers for DIY solar as LFP is not ready for solar. Economics do not work. With DIY solar you are forced to use Chi-Coms like Calb. None of the Chi-coms will last as long as Lead Acid. LFP cost roughly twice as much and last half as long, and in some cases only 1/5th as long as lead acid. Your CALBS came with a worthless 1 year warranty or 1000 cycles. Try making a warranty claim.

Rubbish, any solar controller that allows you to set the charging voltages or has an LFP setting can be used with LFP batteries.

Economics for solar and LFP does work if the grid connection costs are too high.

How long do LFP batteries last? it the past you have said 5-7 years in EV's, then you changed to 2.5 years and now because you made a mistake and used the wrong battery chemistry in your golf cart you say it is even less. Meanwhile in the real world there are many off-grid systems, some that are over four years old that are still working just fine.

Things might have changed since you last looked at their warranty, it is now three years or 2,000 cycles http://www.calbusainc.com/additional-information/. Not sure about the fine print.

Simon

[Willy T]

One thing you can count on from Sunking is lots of bloviating, he was for it before he was against it. Take the Balancing Boards in his golf cart, he had them and he sold them to a sucker. When he first had LiFep04 batteries they were great, then it was only CALB that were good and everything else was a POS as others got them. It was easy to see something changed a couple months ago, it became a mantra that all Chi-Com batteries were a POS. What Changed ??

Back in July there was a thread about using salvaged Nissan Leaf LI cells. The poster was excoriated by Sunking and his minions. He tried to get the thread deleted and called the poster all the usual names he uses to diminish other posters and Labeled him as Dangerous.

http://www.solarpaneltalk.com/showthread.php?18995-lithium-maganese-cells/page2

Low and Behold, Fast forward 4 months, he now has the temerity to make posts about his golf cart now having Nissan Cells made in Japan in the last couple weeks and selling his LiFep04. Watch him , he may evolve right before you eyes. Bottom line he doesn't have a PV system with Charge Controllers and Inverters with loads, he has a golf cart charging on the grid, if he doesn't like what he sees, he pulls the plug.

[SunEagle]

......

Back in July there was a thread about using salvaged Nissan Leaf LI cells. The poster was excoriated by Sunking and his minions. He tried to get the thread deleted and called the poster all the usual names he uses to diminish other posters and Labeled him as Dangerous.

http://www.solarpaneltalk.com/showthread.php?18995-lithium-maganese-cells/page2

......

Willy

If you check that thread you will see that I indicated the use of "used" leaf batteries as a home energy storage system was unsafe and that I would make sure others did not go down that path.

LI batteries are fine if properly charged and used. But most people do not understand the dangers and shouldn't even experiment with them.

Why is that so hard for you and others pushing for Li or LFP to understand? That technology is not ready yet for the masses.

I would suggest you stop using this forum to complain about certain individuals and instead provide support and answer questions as professional as you can.

[Willy T]

Willy

If you check that thread you will see that I indicated the use of "used" leaf batteries as a home energy storage system was unsafe and that I would make sure others did not go down that path.

LI batteries are fine if properly charged and used. But most people do not understand the dangers and shouldn't even experiment with them.

Why is that so hard for you and others pushing for Li or LFP to understand? That technology is not ready yet for the masses.

I would suggest you stop using this forum to complain about certain individuals and instead provide support and answer questions as professional as you can.

What Nissan batteries do you think they have besides used Leaf batteries ?? They don't sell batteries to the Public. I am sure it's different with a Pack of batteries sitting in a EV in someones garage, is it just as dangerous as in a out building powering a home. Don't you think that posting about them at all increases the chance that someone will try to use them in a unsafe way. It seems that poster's do drift here from the DIY EV forum following their favorite poster.

[Sunking]

Rubbish, any solar controller that allows you to set the charging voltages or has an LFP setting can be used with LFP batteries.

No rubbis Simon. You cannot find a controller for LFP except Genasun so shut your trap.

Both PNJunction and I have both repeatable told you many times the same thing backed up with many references, but yet you keep you head stuck in the sand along with the great pretender/liar Willy.

LFP cells do not drift and become imbalanced on their own, you need to learn that real quick because you are only fooling yourself and no one else.

[inMichigan]

If you are only charging at 3.4 volts/cell I would think the internal resistance of the cells would limit the current to some extent. Have you found this to be the case. Maybe it will limit the current to the recommended maximum of 1C. If not the best way I see with your setup would be to disconnect some of the panels from the solar controllers if you detect too much current going into the battery to drop the current charging the battery.
Simon

If I had that very rare situation (quoted in post #64) that risked hitting the batteries with such a high charge, I would just shut down 3 of my 4 CC's until the batteries aren't so hungary.

inMichigan

[SunEagle]

What Nissan batteries do you think they have besides used Leaf batteries ?? They don't sell batteries to the Public. I am sure it's different with a Pack of batteries sitting in a EV in someones garage, is it just as dangerous as in a out building powering a home. Don't you think that posting about them at all increases the chance that someone will try to use them in a unsafe way. It seems that poster's do drift here from the DIY EV forum following their favorite poster.

According to the OP who started that thread, anyone could purchase a used Nissan Leaf battery and use it anyway they wanted. I have no problem if the people that do purchase one belong to a scientific lab or company for testing. They should at least perform any tests in a safe and controlled area.

I do not condone or suggest "joe diy" get one of these used battery packs and think they can safely convert it to a home energy storage system.

And yes I do feel that some people that post details about battery experiments on this forum can increase the chance of someone else using it in a unsafe way if they are uneducated with that type of technology they are playing with.

It is bad enough that people chose to post Youtube videos that make all types of claims that are totally false or worse dangerous to the people that believe in what they just saw.

If people want to post their experiment results then at least add warnings that what was done could be dangerous and deadly. No different then telling someone to go measure an electrical circuit without warning them about how easy it is to get shocked when you use the wrong tools or perform the task in an unsafe way.

[inMichigan]

Have you seen this video? When you have a spare hour watch it. Jack is the nations leading custom EV builder. He walks you through Bottom Balance you can understand.

Thanks for the link. I had stumbled into that site before to admire some of his cell charge/discharge curves.

I was very pleased to see his description for the CALB CA180FI 180AH LiFePo4 CELL he's selling from (http://store.evtv.me/products.php?cat=10)


A new cell from China Aviation Lithium Battery Company with improved power output (10C - 30 seconds), improved thermal performance, improved cold weather capacity, and longer cycle life. 180 ampere-hour capacity. 3.2v nominal voltage. 576 Watt-hours.

The best battery we've found for electric vehicle applications and far superior to GM or Nissan cells in every way.


Bold is my emphasis. Having lived and worked in in manufacturing in China for 8 years, I've seen both ends of quality, a country of very rapid change.

Anyway, I have no doubt that my +200 mV flier (near death) cell was my own fault for it not having a BMS board like the others. As for the variation of the others, in the coming months, I'll have the data for the same cells, being used in the same manner, charged in the same way, without the boards. I'll post what I find. Unfortunate most forums are filled with opinion without the underlying data, for me, raw data is supreme.

inMichigan

[inMichigan]

No rubbis Simon. You cannot find a controller for LFP except Genasun so shut your trap.

Both PNJunction and I have both repeatable told you many times the same thing backed up with many references, but yet you keep you head stuck in the sand along with the great pretender/liar Willy.

LFP cells do not drift and become imbalanced on their own, you need to learn that real quick because you are only fooling yourself and no one else.

The charger in my Outback Radian 8048A has plenty of flexibility for lithium, from the manual:
Lithium-ion, sodium-sulfur, and similar advanced battery technologies may require charger settings that are very different from the inverter’s defaults or the three-stage cycle in general. The Charging Steps section describes the individual selections and behavior. All charger settings are adjustable. The selection range for each step allows very different priorities from the defaults. For example, the Float voltage could be set higher than the Absorption voltage, or a step could be completely skipped.


It would be nice if all the special stages needed for lead acid would 'go away' from the screens. Of course there are models out there still programmed with dip switches that I didn't consider using for my system.

inMichigan

[inMichigan]

No rubbis Simon. You cannot find a controller for LFP except Genasun so shut your trap.

Both PNJunction and I have both repeatable told you many times the same thing backed up with many references, but yet you keep you head stuck in the sand along with the great pretender/liar Willy.

LFP cells do not drift and become imbalanced on their own, you need to learn that real quick because you are only fooling yourself and no one else.

The charger in my Outback Radian 8048A has plenty of flexibility for lithium, from the manual:
Lithium-ion, sodium-sulfur, and similar advanced battery technologies may require charger settings that are very different from the inverter’s defaults or the three-stage cycle in general. The Charging Steps section describes the individual selections and behavior. All charger settings are adjustable. The selection range for each step allows very different priorities from the defaults. For example, the Float voltage could be set higher than the Absorption voltage, or a step could be completely skipped.


It would be nice if all the special stages needed for lead acid would 'go away' from the screens. Of course there are models out there still programmed with dip switches that I didn't consider using for my system no matter the battery technology. Midnite and Schneider also had what I would have wanted for lithium. These are for home RE systems, I don't claim anything for the EV or hobby charger world, that being a different application.

inMichigan

[Sunking]

One thing you can count on from Sunking is lots of bloviating, he was for it before he was against it. Take the Balancing Boards in his golf cart, he had them and he sold them to a sucker. When he first had LiFep04 batteries they were great, then it was only CALB that were good and everything else was a POS as others got them. It was easy to see something changed a couple months ago, it became a mantra that all Chi-Com batteries were a POS. What Changed ??.

Willy you have not been here long enough to even form a decent conclusion. I am not like you. I am educated and continue to learn and evolve. I am also a skeptiic and do not believe or buy into hype or stick my head into the sand like you and Karrak. I have worked with every major battery manufacture for over 35 years, and set on IEEE Battery committe who makes the standards and practices. I have forgotten more than you will ever know.

If you had been around here as long as I have, 7 years the first Chi-Com battery that came out was Thundersky. They were a POS and do not exist anymore. Yep back them I hated back then because they were a POS battery. I warned many along with many others on many other forums. They were junk. When they went bankrupt in , their technology was bought up and split among 3 more Chi-Coms of Sinopoly, Winston, and CALB. Sinopoly and Winston are virtually the same cell as failed Thundsky. Both Sinopoly and Winston are going belly up because hey are the same POS Thundersky with a different label. CALB is China Aviation Battery is owned by the Chinese government and took Thiundersky original design, tweaked the design process and starte using them in Chinese Balistic missles. So when the Chinese atck us, th eAtomic warheads will have CALB batteries raining down upon you.

In the meantime in 2011 CALB release large Format prismatic cells to the USA. Someon ehas to ppay for our destruction, we are stupid enough to do just that. Anyway since the initial release, CALB has gone through 4 product revisions, count them Willy I know counting up to 4 is difficult for you with a Tennessee 1st grade education. So much for that yacht on the ocean lie you tell, Its a John boat on a pond. Anyway one must ask why a company would have to revise a product 4 times in 4 years.
Enough said about that.

As for me and my racing golf cart is a product of evolving. I did not wake up one day and say I am going to build a racing golf cart. Firs tone in around 2008 was just a plain ole cart using DC motors and FLA batteries with. FLA batteries were too expensive with a horrible track record. Everyone for the EV community knew about Thundersky Turds. Being an engineer and studying at first it appeared Thundersky batteries problem was lack of battery management. I was one of the Forum Engineers typing away one MUST USE BMS or ELSE. Bu tunlike you and Karrak I did not stick my head into the sand. I actually kept an open mind and researched.

I heard of Jack on EVTV going aginst the grain when he discovered it was the Shunt Boards that were causing a great deal of the failures and fires. I dismissed it at first as BS because I was an engineer and knoew you MUST USE BMS. Well as it evolves BMS is meaningless. BMS has no definition. In the early days a BMS was the Shunt Boards aka Vampire Boards.

OK back to golf cart. A few years ago I wanted something much faster and could climb hills without loosing speed. DC motors do not do that very well. But 3-phase Induction Motors and Controllers became available. At the time I was in the process of shutting down shop, retiring, and moving to Panama. I did not want to take a golf cart or any vehicles to Panama because of the expense of shipping. But what I did was buy the parts in stages and collecting the parts needed. At that time I was still one of those Engineers with my head stuck in the sand who demanded everyone must use a engineered solution and MUST USE a BMS. I was ignorant. So th efirst two things I bought weere a set of batteries and Vampire Boards to take to Panama because that crap i snot available down there and has to be imported with high Duty Tax. Or I could bring it with me TAX FREE. I left the USA to get away from Taxes. I worked hard for my money and not about to give it away to you.

So I played with the Vampire boards and chargers. Guess what happened Willy. I got up one morning and found a dead cell out of the clear blue sky. A vampire board failed shorted and destroyed the cell. Guess what? I remembered seeing Jack's video a couple of years earlier. Called him and got more up to date information. Hit up the EV community and found there were hundreds of people with the same problem. Not only did I learn it was the Shunt Regulators causing the destruction, it was also the source of DRIFT Karrak and you are clueless about.

So wanting to learn more, I did a lot more research, talked to battery manufacture I knew personally for 35 years and worked with, Custom EV builders. I evolved from the darkness and learned I was part of the problem being an Engineer that you MUST USE Automation and the public is not smart emough. I was right. You are not smart enough to operate lithium without a lot of technology.

Bottom Line is a commercial product using LFP does take some automation in consumer products. But most of what you and Karrak believe is completely False. There is no EV manufacture that allows you to fully charge a LFP. or Fully Discharge. The manufactures DO NOT USE POS CHI-COM Batteries. They use quality CoBalt, Manganese, and one use quality nano-particle A123 cells. The public does not have access to any of those batteries, just Chi-Coms. The tolerance of those cells is such they are matched up. They can balance at any point they want as it makes no difference. If you could access those cells would not make any difference where you balance. The consumer has no interaction when Balancing takes place. All of it is done by the vehicle computer. Only way to Balance in a commercial product economically is Top Balance for those rare times they need balanced. Why do they gout out of Balance? Because of the monitoring equipment used on each cell do not draw the same amount of power. It is called Parasitic Loads. Get rid of the Parasitic loads and cells do not go out of Balance or drift. They just loose capacity at roughly the same rate. It is like stuffing ball bearings into a pipe. You always get the same amount out as you put in. But Balance is a misleading word. With batteries it is not capacity that is equal. The only time the cells have the exact same amount of capacity and voltage is when empty at 2.5 volts. When fully charged voltage eis equal, but you have no clue what the capacity is. The capacity is dictated by the lowest capacity cell. Makes no difference if you have 16 cells. If 15 are 200 AH and one is 100 AH you have a 100 AH pack end of story. No fantasy you and Karrak believe change the science. Bottom Balance the cells at ZERO Capacity pump 100 AH in dictated by the lowest capacity and you still have a 100 AH pack. They are charge and discharge at the exact same rate. When you get to the Bottom, all arrive at the bottom at the same time making it impossible to over discharge them with no automation required. As Jack discovered 6 years ago if you Top Balance, those 15 stronger ceells will turn and eat the weak ones, just as it is in nature. The Strong Survive and the weak are food for the strong.

So Willy and Karrak I agree with you 100%. You MUST USE BALANCE BOARDS because you are that part of the 99.999% of the population who are ignorant and not capable of managing you rown batteries. You are followers and consumers. So please keep buying our engineered products. It makes us rich and keeps you in the dark. Perhaps someday soon the general public can get access to large format LFP or even better Lithium Titanate cells that you do not even know about yet. Those cells have 99.998 coulometric efficiency an don paper can last several thousands of cycles without capacity loss. But Coulometric Efficiency has nothing to do with Drift. It is charge efficiency and the heat generated which breaks down the electrolyte and contaminates the SEI barrier. That is the Flaw with Chi-Com cells as their CE is on th eorder or 96 to 975 that causes th elow cycle life and rapid capacity losses.