Charging efficiency LifePO4

[Sunking]

You are IGNORANT

All Floating a Battery means is a VOLTAGE at which the BATTERY is not charging or discharging.

Every emergency lighting system, telephone office, communication facility, your laptop, and cell phone work in this fashion. I will type slowly so you can understand.

You charge your battery up to a specified voltage, and hold that voltage. The battery is neither charging or discharging once SATURATED to the VOLTAGE, it is Floating. This allows the charge source )like solar panels or a Rectifier) to run the load equipment without using BATTERY POWER until NEEDED.

That is how any Solar battery system works. Anyone in the biz knows this from DAY 1 except YOU.

[QUOTE]Can't find any reference to your claims that a charger that is switched off, is float charging every single reference to float charging state categorically, you require charge input to float a battery and keep it at it's optimum capacity.[\QUOTE]

This is because you have no clue how electric current flows. In order for current to flow there must be a Difference in Potential (that means VOLTAGE) If the CHARGER and Battery are the same voltage, NO CURRENT FLOWS period. The charger is still on, just no current to or from the battery. Thus the power from the charge source is used by the loads instead of the battery It keeps the battery charged up until dark. Simple fundamentals and how every charge controller made is designed to operate. It is given the term FLOAT MODE. or FLOAT STAGE.

Even a 5th grader can understand that.

How to charge any battery. Apply a current until battery reaches a specified voltage. Hold that voltage until current stops and the battery is FLOATING. What does FLOATING mean? The battery is neither charging or discharging.

It is the exact same thing as putting 2 or more batteries in parallel The voltages equalize and current flow stops.

[dax]

To anyone with a working brain and not just a revolving door merry go round mentality, floating a battery is when you input a compensating charge which keeps the battery full. It is not by any recognised authority when you do not put in any charge, but use the stored energy.
"Float voltage is the voltage at which a battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery.^[1] The voltage could be held constant for the entire duration of the cell's operation (such as in an automotive battery) or could be held for a particular phase of charging by the charger.^[2] The appropriate float voltage varies significantly with the chemistry and construction of the battery, and ambient temperature.^[3]
With the appropriate voltage for the battery type and with proper temperature compensation, a float charger may be kept connected indefinitely without damaging the battery."

https://en.wikipedia.org/wiki/Float_voltage

"HOW DOES A FLOAT CHARGER WORK?
A float charger (also called a storage charger, maintenance charger, or smart charger) will charge a battery at a similar rate as a battery self-discharges, thus maintaining a full capacity battery. However, the main difference between a trickle charger and a float charger is that a float charger has circuitry to prevent battery overcharging."

http://www.batteryfloatchargers.com/how_float_charger_works

"Float chargers are typically constant-voltage chargers that operate at a low voltage. Operating the charger at a low voltage, usually less than about 2.4 V per cell, keeps the charging current low and thus minimizes the damaging effects of high-current overcharging."

http://www.engineersedge.com/battery/float_charging.htm

A good FLOAT charger charges the battery at a constant current until the 'FLOAT' voltage
(13.8V or 27.6V) is reached, then it progressively reduces the current to maintain that voltage.
This gets about 75% capacity back into the battery quickly but then takes a long time to
restore the other 25%.

http://www.operatingtech.com/lib/pdf/A%20Guide%20to%20battery%20Charging.pdf

Can't find any reference to your claims that a charger that is switched off, is float charging every single reference to float charging state categorically, you require charge input to float a battery and keep it at it's optimum capacity.

I'm sure you'll come up with come some pathetic excuse, or just babble out more abuse and deranged insults in your desperation to protect you clearly false claims. The truth is out there for all to see, how our approach is not floating anything, but bulk charging to a set voltage point, no more charge. When the pack drops to 13.6v from use, bulk charging restarts, not a small compensating float charge.

This is because we use a single stage charger, only a deranged fool would call a charger with one charge parameter a 2-3 or 4 stage float charger. Our chargers never supply a small charge to anything, just bulk 60ampor whatever is being produced.

Couldn't help but laugh at how quick you took the bait in your infantile desperation to find fault with my posts, so desperate you had to attack the semantics, hilariously funny. An electrical appliance sources its energy, so supplying energy to it, is supplying a source of energy consumption. Nothing wrong with my description, just your deluded reply.

[Sunking]

Look at at this way, the pack reaches 14v or a cell reaches 3.5v, charge is disconnected, panel energy is directed to other sources.

Hogwash. What other sources?

Do you even know the difference betwen source and load? I did not think so. You are really showing you know nothing about electrical. Give you a hint. a SOURCE is a Solar Panel a SOURCE provides power to loads like batteries.

[Sunking]

No it's a single stage charger, bulk charge to 14v then switches off, there is no more input into the pack until the pack drops to 13.6v.

What a ******. That is 2-Stage******. You are FLOATING your battery at 13.6 volts.

[Sunking]

Can't do this unless you have top balanced the battery and/or have individual cell monitoring.

That is why I qualified it with 100% SOC.


When I first installed my LFP battery I had drunk the Kool-Aid and decided to only charge my battery to 90% and not float charge to maximise the battery life. This meant charging it with a cell voltage of 3.375Volts/cell (13.5 Volts). The problem with this approach is that the battery started going into Absorb at an SOC of around 75% and would take forever to get up to 90+% and there is only so much sunlight in each day.[/QUOTE]Simon I don't have a problem with that. I have been telling Createthis the whole time he has to find the right voltage for him.

It is DAx who thinks he is doing something different and magical, when in fact he is just using a simple Two Stage Charger. and is FLOATING his battery. He does not have the capacity to understand.

[karrak]

A good 2-stage Lithium charger is one used for Solar, any of them that allows you to set the Bulk/Absorb, and Float, EQ disabled. Set Bulk/Absorb to 14.4 volts, and Float to 13.6 volts. Battery charges up to 14.4 volts 100%SOC, and reduce voltage to 13.6 volts so the battery stops charging and floats at 13.6 volts waiting for the sun to set. In the meantime while the Sun is out, the panels provide the power so you can save the batteries for after the Sun Sets. Kind of the whole point.

Can't do this unless you have top balanced the battery and/or have individual cell monitoring.

As for me I am a simple KISS engineer. and only use one stage for Lithium Charge to 13.4 to 13.7 volts, Hold and Float the battery the cells will saturate to about 90% SOC (why I give a range 13.4 to 13.7). Does the same thing a bit slower, less expensive/complicated and less voltage stress on the cells.

This works great for all chargers except chargers using solar as the power source. I use exactly this charging method to charge my electric bicycle batteries.

When I first installed my LFP battery I had drunk the Kool-Aid and decided to only charge my battery to 90% and not float charge to maximise the battery life. This meant charging it with a cell voltage of 3.375Volts/cell (13.5 Volts). The problem with this approach is that the battery started going into Absorb at an SOC of around 75% and would take forever to get up to 90+% and there is only so much sunlight in each day.

After doing more research and getting information from others who are using LFP batteries on other forums I have come to the conclusion that charging to 3.45 V/cell (13.8V) will not make much difference to the battery life compared to charging to 3.375 V/cell(13.5V) and will mean I have a battery >99% full at the end of the day.

Simon

[jflorey2]

It is not two-stages. . . .

What I am saying here Jeff is all battery chargers are CC/CV.

Constant current - bulk - first stage
Constant voltage - absorb - second stage

That's why a three stage charger really only has two voltage settings - absorb and float. The third stage is the current limit that occurs during bulk charging.

[dax]

I assume your charger actually has two stages - a constant current phase (often called bulk) and a constant voltage phase (often called absorb.) These often do not seem like two-stage chargers because you don't have to do anything to get them to switch over; it happens automatically as the charger comes out of current limit.

You can charge a battery with a single stage charger, but you will then either have to choose a slow charge rate with the battery getting close to full, or a fast charge rate with the battery being only partially charged when the charge is terminated. That's why most people use two-stage.

No it's a single stage charger, bulk charge to 14v then switches off, there is no more input into the pack until the pack drops to 13.6v. It seems none here have got past the lead acid syndrome, lifepo4 will take bulk charge until they reach capacity, there is no need for slow charge rates unlike li-ion or lead acid. Lifepo4 don't heat up, or offer big resistances to input when taking big charges.

Look at at this way, the pack reaches 14v or a cell reaches 3.5v, charge is disconnected, panel energy is directed to other sources. When the pack drops to 13.6v, charging is redirected to the pack until it reaches 14v then the sequence starts again. That's it, nothing else as we are using lifepo4, not li-ion or lead acid and lifepo4 perform and take charge very differently to other lithium chemistries and nothing like a lead acid.

These chargers have been working excellently for years now and anyone watching them in operation, can see and test there is no slow down in charge input up to 14v just bulk, then no charge enters the pack. The voltage of the pack controls the charge regime, not current. This is the 21st century, not the 19th, we are in a different energy storing era, it's not lead acid and every argument put forward here against this revolves around lead acid mentality and not 21st century lifepo4.

Got nothing more to say on this, no good talking to brick walls.

[Sunking]

I assume your charger actually has two stages - a constant current phase (often called bulk) and a constant voltage phase (often called absorb.)

It is not two-stages, just a simple 1-stage CC/CV Charger aka Float, Equalize, Bulk/Absorb, Maintainer or plain ole Battery Charger

2-Stage is two Voltage Set Point like Float and EQ, or Bulk/Absorb and Float.
3-Stage is 3 Voltage Set Points like Bulk/Absorb, Float, and EQ


Some LiFePo4 chargers have what they call 5 stages like this one from Battery Tender. Step 1 is Recovery Stage if the battery voltage is below 2.5 vpc. Applies a low current level to recover cell to 3 volts for up to 4 hours. Step 2, 3, and 4 as you can see on the graph are really one stage of Bulk/Absorb/Float as it holds 3.6 volts on the cells until current tapers to .1 amps. Then stage 5 is Float at 3.45 volts to hold the charge and run equipment.

What I am saying here Jeff is all battery chargers are CC/CV. Stages are voltage Set Points. Take any DC power Supply with a Current Limit, and you have a CC/CV battery charger. 1-Stage is required to charge any lithium battery. a 10 amp 12 volt battery charger will charge any battery type assuming you set the voltage correctly. For a 4S LiFeP04 is 14.4 volts. Apply 14.4 volts until current tapers and you are charged up. Exactly the same you would do for any Pb battery, same charger, same voltage.

A good 2-stage Lithium charger is one used for Solar, any of them that allows you to set the Bulk/Absorb, and Float, EQ disabled. Set Bulk/Absorb to 14.4 volts, and Float to 13.6 volts. Battery charges up to 14.4 volts 100%SOC, and reduce voltage to 13.6 volts so the battery stops charging and floats at 13.6 volts waiting for the sun to set. In the meantime while the Sun is out, the panels provide the power so you can save the batteries for after the Sun Sets. Kind of the whole point.

As for me I am a simple KISS engineer. and only use one stage for Lithium Charge to 13.4 to 13.7 volts, Hold and Float the battery the cells will saturate to about 90% SOC (why I give a range 13.4 to 13.7). Does the same thing a bit slower, less expensive/complicated and less voltage stress on the cells.

Now if you want to see the Caddilac of Battery Chargers Elcon HF PFC chargers are it. I use the PFC 1500 which means 1500 watts which can charge any battery type from 24 to 240 volts with as many and any algorithms you want. Just make your list of Profiles and order it. I have 4 Profiles in mine. Lithium is easy

[Sunking]

Hilarious, can't read, blind to fact and determined to be right not matter the cost to your credibility and rationale, when everything categorically states you are wrong, wrong, wrong. Once again you have changed you stance because you made such a ridiculous statement that float is when you disconnect the battery at full charge.

You really are ignorant. Not only can you not do simple 5th grade math, you know nothing about electricity

You do not even grab or understand the most basic fundamentals of electrical laws and physics ity. One such fundamental, th every first one you must learn by heart is Ohm's Law. If you knew what it was you would know if there is no current there is no power. Simple Ohm's Law a 5th grader understands is Power = Voltage x Current. It means one of two things. You are either a 70 year old Ignorant SOB or a Fraud.Which is it?

You came here looking for trouble and you found it.

[Sunking]

I assume your charger actually has two stages - a constant current phase (often called bulk) and a constant voltage phase (often called absorb.) These often do not seem like two-stage chargers because you don't have to do anything to get them to switch over; it happens automatically as the charger comes out of current limit.

You can charge a battery with a single stage charger, but you will then either have to choose a slow charge rate with the battery getting close to full, or a fast charge rate with the battery being only partially charged when the charge is terminated. That's why most people use two-stage.

Jeff he is to ignorant and has no clue what he is talking about. He has proved it over and over again he has no idea how a battery charges or how battery chargers work. He has no idea he uses a Float Charger and charges exactly like you would any battery.

He is so ignorant he has no clue he charges exactly how I am telling Ceatethis to do it. Float the battery.

[jflorey2]

We use our own designed and manufactured single stage lifepo4 chargers. I repeat single stage, bulk single stage. Note, bulk single stage chargers.

I assume your charger actually has two stages - a constant current phase (often called bulk) and a constant voltage phase (often called absorb.) These often do not seem like two-stage chargers because you don't have to do anything to get them to switch over; it happens automatically as the charger comes out of current limit.

You can charge a battery with a single stage charger, but you will then either have to choose a slow charge rate with the battery getting close to full, or a fast charge rate with the battery being only partially charged when the charge is terminated. That's why most people use two-stage.

[SunEagle]

Just a couple of points, I'm 70 so not so young and have been a master builder since 20. Always had the philosophy if something new comes along and it looks good, will make an improvement if life, check it out with an open mind, that's how we got into lifepo4. It's the same with everything I do, have virtually no fuel bills as every vehicle, piece of machinery and modes of transport we have, runs on either electricity, or used veggie oil, which we collect for free. This reduces our costs, which we pass on to customers.

You are right, we do have a high costing grid power, the last time I looked, the average grid bill in rural area's of Aus comes in at $400-$800 a quarter. So you could say a user will pay from $1600 up per year for power, if we balance it, that's over $2000 a year and we know of many who part out much more than that. Commercial interests, have bills over $1000 a quarter and in areas without power and just diesel generators, thousands a month.

For an average home that is thrifty in energy use, you can have a 24v x 3kw panel system with 1000ah, 12v pack 240v output lifepo4 system installed and running for $7000, depending on location. Basing it on $400 a quarter, you get you money back within 5 years and still have 5 years of a warranted system left to enjoy. A remote system of over 10000ah lifepo4, taking over from diesel generation, gets you your money back within 2 years and sometimes sooner.

I don't see our system as a break through, just common sense according to the facts. We use simple peltiers for controlling enclosure environments, controlled by cheap raspberry Pi's and will change that as soon as we have a better approach.

By using linux we've constructed our own custom OS, in fact we have 3 for different things and all are totally compatible and play with the servers very nicely. No proprietary, support or upgrade costs and all our work software is what we have developed and this has saved us thousands a year. It's how you approach things which make the difference and how willing you are to experiment. There are many times when lots of knowledge can make you blind to the evolving reality of a technology, lifepo4 seems one most electrical engineers can't seem to broach.

As we've been installing off grid since 1981, know the economic difference when comparing off grid lead acid systems to lifepo4 systems and lifepo4 wins hands down by many years. No one can offer a 10 year guarantee for a lead acid system, but we bit the bullet and did it with lifepo4, because we know they will make it well beyond that. Our first lifepo4 installations have 3 years warranty to go and none have ever complained or had a problem of any significance, that speaks for itself.

Sounds like you have had many opportunities to experiment with new ideas. I unfortunately did not have that based on living in a highly populated area were making my own fuel would have been frowned on. Still I was able to try out some new things and found ways to reduce my electric bills through conservation and more efficient type of loads.

As always I look forward to seeing new technology that makes it to market and becomes a cost effective product for people like me that is not in the top 1% that can throw money at every little thing.

When it comes time for a battery system I will be happy to look at what your company can provide and make a decision if it is something I would financially benefit from it's purchase.

[dax]

Could not agree with you more. Does the same thing for lithium. Your is charged to 14.0 volts. When charged you lower voltage to 13.6 and Float your battery. That is what ever 2-Stage battery charger does. Every solar charge controller makes them that way.

Hilarious, can't read, blind to fact and determined to be right not matter the cost to your credibility and rationale, when everything categorically states you are wrong, wrong, wrong. Once again you have changed you stance because you made such a ridiculous statement that float is when you disconnect the battery at full charge.

Not going to post your comments, anyone can see what you post and the number of times you make insane claims, then have to change them in an effort to cover your tracks. That's what blind ideological people do, claim one thing, then when reality looks them in the face, they change tack, deny and lie, to try to save face and support their unsupportable fantasies.

We use our own designed and manufactured single stage lifepo4 chargers. I repeat single stage, bulk single stage. Note, bulk single stage chargers.

They are called single stage bulk solar chargers, which supply just one stage, called bulk and nothing else. in case you didn't get it, they shut down completely when the bank or pack reaches 14v. They restart charging when the pack voltage drops to 13.6 volts and shuts down completely when it again reaches 14v, load comes from the pack, not the panels. Would you like me to repeat that again, single stage bulk charge controllers, not 2-3-4 or 5 stage, single one stage and nothing more.

[dax]

I would add that getting out of the FLA thinking also requires someone to compare the costs. Based on all existing data a Lifepo4 chemistry battery costs a lot more up front then quality FLA batteries. While your charger may allow the Li battery to get a longer life the final cost / kWh being generated by that battery is the final determination to go that way or another.

Since both you and karrak are technically neighbors you both share the high cost and low reliability of grid power. So it is an easy sell for your area and the other areas you mention. But when it comes to most of the US and Canada going with any lithium battery would not be cost effective for a home owner. The POCO's might be able to afford those systems by not the average guy down the street.

As for my thinking being old and "trapped" in the last century, that is something stated by people that have no understanding or patience of their parents generation. Making that type of statement does not win you any friends. I should know since I did the same when I was in my 20's but grew up and got to know my father's generation ideas so I could find ways to make technology better. I believe I have made a difference with my 40 plus years of electrical engineering experience but I choose not to brag about it.

So I look forward to actually seeing your charging system hardware and how it works with lifepo4 batteries. I hope it is a breakthrough but again it still comes down to cost.

Just a couple of points, I'm 70 so not so young and have been a master builder since 20. Always had the philosophy if something new comes along and it looks good, will make an improvement if life, check it out with an open mind, that's how we got into lifepo4. It's the same with everything I do, have virtually no fuel bills as every vehicle, piece of machinery and modes of transport we have, runs on either electricity, or used veggie oil, which we collect for free. This reduces our costs, which we pass on to customers.

You are right, we do have a high costing grid power, the last time I looked, the average grid bill in rural area's of Aus comes in at $400-$800 a quarter. So you could say a user will pay from $1600 up per year for power, if we balance it, that's over $2000 a year and we know of many who part out much more than that. Commercial interests, have bills over $1000 a quarter and in areas without power and just diesel generators, thousands a month.

For an average home that is thrifty in energy use, you can have a 24v x 3kw panel system with 1000ah, 12v pack 240v output lifepo4 system installed and running for $7000, depending on location. Basing it on $400 a quarter, you get you money back within 5 years and still have 5 years of a warranted system left to enjoy. A remote system of over 10000ah lifepo4, taking over from diesel generation, gets you your money back within 2 years and sometimes sooner.

I don't see our system as a break through, just common sense according to the facts. We use simple peltiers for controlling enclosure environments, controlled by cheap raspberry Pi's and will change that as soon as we have a better approach.

By using linux we've constructed our own custom OS, in fact we have 3 for different things and all are totally compatible and play with the servers very nicely. No proprietary, support or upgrade costs and all our work software is what we have developed and this has saved us thousands a year. It's how you approach things which make the difference and how willing you are to experiment. There are many times when lots of knowledge can make you blind to the evolving reality of a technology, lifepo4 seems one most electrical engineers can't seem to broach.

As we've been installing off grid since 1981, know the economic difference when comparing off grid lead acid systems to lifepo4 systems and lifepo4 wins hands down by many years. No one can offer a 10 year guarantee for a lead acid system, but we bit the bullet and did it with lifepo4, because we know they will make it well beyond that. Our first lifepo4 installations have 3 years warranty to go and none have ever complained or had a problem of any significance, that speaks for itself.