Will Prowse says charging 0%-100% daily is a non-issue for lifepo4 battery longevity. Thoughts?

[JRH]

Btw … I charge my 12.8 batts to 100 % everyday the sun allows … ..at 28.8 ( 24 v) they sit for an hour or two or more and then go to float which I vary depending on conditions and time of year…

then in a normal draw and operation they go back down to about 30-40% over night that fulfills my needs …
Then start new in the morn… and go back to 28.8….. and start over.

I run them to zero % SOC about once every 3 months to test them out..and log the numbers..

then back up to 100%….. the numbers look fine …

2.5 years now of continuous run .. no problems…

Although I would buy newer tech nowdays , I like my dumb batteries ..
They don’t get together at night and start thinking and talking….
They don’t give me attitude ..or problems ..

J.

 

[Sonne]

Commercialization of Lifepo4 did not start until around 2015 and costs did not come down until much later meaning that for most of us there is no long term data to really base an opinion on other than our own experience which I suspect for most is less than 10 years.

Where did you get 2015 from? I was buying and using LiFePO4 cells (A123 26650) in 2007 and 2008. They were very much commercially available.

 

[OfflineAlberta]

Check timestamp 3:35

I've just placed an order for 2x 280Ah packs with PACE bms, and opted for 2 DALY external active balancer units.
Manufacturer told me charge 20%-100%. I thought they mistakingly said 100% and meant 80%.
General consensus has been to keep 20%-80% for longevity.

Will here says this is a misconception and charging/discharging 0%-100% all the time is fine.

Thoughts?

I recently watched this video as well and realized I might be actually mistreating my batteries. My theory was that I would design my system so that I could live in the top 20% of my batteries day to day. The way I see it if my warranty says 2000 cycles at 80% soc then if I always stayed at the top 20% instead of using 80% of the battery I would be able to make my batteries last longer (regardless of warranty). Now it is said that if I don't use the whole battery I will kill it anyway.

By the way lots of inverters have too much variance in their voltage detection which NEVER allows for 100% usage - I have no idea on how to achieve that other than putting a 12v load onto the batteries to force it to use 100% of the battery. There are too many safety systems that stop us from actually allowing us using the full spectrum of our batteries.

 

[sunshine_eggo]

I recently watched this video as well and realized I might be actually mistreating my batteries. My theory was that I would design my system so that I could live in the top 20% of my batteries day to day. The way I see it if my warranty says 2000 cycles at 80% soc then if I always stayed at the top 20% instead of using 80% of the battery I would be able to make my batteries last longer (regardless of warranty). Now it is said that if I don't use the whole battery I will kill it anyway.

Not sure what your concern is. It's been long said that calendar aging is likely to take cells out before cycle life is reached.

By the way lots of inverters have too much variance in their voltage detection which NEVER allows for 100% usage - I have no idea on how to achieve that other than putting a 12v load onto the batteries to force it to use 100% of the battery. There are too many safety systems that stop us from actually allowing us using the full spectrum of our batteries.

Please elaborate on this. My system can take full advantage of my battery, and most systems can be configured to run the BMS to HVD and LVD thus using the entire capacity.

 

[toms]

Every time you take your LiFePO4 to full capacity you cause lithium plating and loss of capacity. What most manufacturers call 100% SOC isn’t fully charged.

If you get your new cells (lets say they are 280ah), and float them at 3.5V until zero amps, then run them to 2.8V and get 280ah out of them them you have 100% capacity. The cells were never fully charged or discharged though. You will not harm your cells by doing this every day as long as you don’t exceed the maximum C rate the cells allow.

The manufacturers recommend to discard your battery when you cycle it between these voltages and get less than 80% of your original capacity.

 

[Daddy Tanuki]

Not sure what your concern is. It's been long said that calendar aging is likely to take cells out before cycle life is reached.



Please elaborate on this. My system can take full advantage of my battery, and most systems can be configured to run the BMS to HVD and LVD thus using the entire capacity.

If I were to shut off my SCC's from charging then I could drain my batteries to zero. For my CALB cells (SE 180 ) 0% is anything below 2.5 per cell. So for a 16s battery that would be 40 volts. for my winstons they list the bottom as 2.8 volts so that would be 44.8 volts. my magnum will run down to 36 volts so I am quite sure I could... IF only the sun would stop shining for about a week....

 

[OffGridInTheCity]

I'm 18650 3.0v -> 4.2v chemistry instead of LifePo4 but there are similarities. I operate between 80%-20% SoC with a lifetime average of 35% DoD to date - e.g. in summer it's 45%-80% SoC range and winter 20%-55% SoC range on average. I designed my powerwall around Battery University's "How to Prolong Lithium-based Batteries" page - https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries This page hasn't changed in the last 7 years I've been referencing it.... and I wonder if it's just 'misinformation' or what.

I do wonder where Battery University and LifePo4 6,000 or 8,000 (or whatever) cycle counts come from specifically. Are they from actual tests in the factory or lab somewhere? Are they done for each major brand? I've only see actual data that's 10+ years in terms of earlier EV battery life showing scatter diagrams of years vs capacity but short on details that can be directly related to solar systems. EV charge/discharge patterns are likely different enough from Solar to matter. Temperature and C for example I'm guessing would be lower stress for home solar than EV applications.

Bottom line - without actual data, or defined test procedures, or even agreed 'common scenarios' (EV vs Solar for example), I think there's much fuzziness around this topic and arguing 90% vs 100% SoC is just too fuzzy to draw any firm conclusions over a small number of years.

Thus, I'm tracking my data (voltage range, current levels, and DoD numbers) and maybe it will be useful to others and maybe not. Currently, 40% of my powerwall is over 2,000 cycles with no issues and I'm guessing very little capacity degradation. My oldest battery is at 2,138 cycles as of today and is already a major bright spot of DIY solar.

 

[Daddy Tanuki]

I'm 18650 3.0v -> 4.2v chemistry and I operate between 80%-20% SoC but with a lifetime average of 35% to date - e.g. in summer it's 45%-80% and winter 20%-55% SoC on average. I designed my powerwall around Battery University's "How to Prolong Lithium-based Batteries" page - https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries

However, I do wonder where LifePo4 6,000 or 8,000 (or whatever) cycle counts come from specifically. Are they from actual tests in the factor or lab somewhere?

I've only see actual data in terms of earlier EV battery life showing scatter diagrams of years vs capacity but short on details that can be directly related to solar systems.

Bottom line - without actual data, or even an agreed 'common scenarios' I think there's much fuzziness around this topic. Thus, I'm tracking my data (voltage range, current levels, and DoD numbers) and maybe it will be useful in another 10 years. Currently, 40% of my powerwall is over 2,000 cycles with oldest battery at 2,138 cycles as of today and seems near the same capacity as the 1st 100 cycles.... but I think more time/data is needed for actual answers

got to admit I admire your dedication to the craft... but not living at the cabin full time (and refusing to go with an internet connected system) means that I can't watch mine 24-7 like some of our more involved members can, I just built for overkill and walk away know that it will last at least 10 years (probably in all honesty 20-30 years) and don't worry about it.

 

[sunshine_eggo]

got to admit I admire your dedication to the craft... but not living at the cabin full time (and refusing to go with an internet connected system) means that I can't watch mine 24-7 like some of our more involved members can, I just built for overkill and walk away know that it will last at least 10 years (probably in all honesty 20-30 years) and don't worry about it.

By comparison, I've built a glass house that will shatter if I look away...

 

[Daddy Tanuki]

By comparison, I've built a glass house that will shatter if I look away...

i doubt that highly.

 

[wpns]

Honestly, I haven't completely ruled it out. It's highly automated, and I can log the data. It's a matter of how much it will interfere with other operations that actually make-a dee monies... AND...

I've been working on this...

View attachment 255056

Want a way to remotely monitor my 420# propane tank on the RV now that I'm using it to keep temps above freezing. This is a test run on a 20# bottle I have at the house. Will be up there again in two weeks to get it installed and implemented.

Mopeka Pro Check sensor and a RPi running Venus OS that I had laying around to play with the dbus-serialbattery driver for interfacing JBD, JK, etc. BMS with Victron.

@Adam De Lay - damn you man... you have a video for everything...

I'm feeling the joy on your face in that damn video, you smiley bastid...

I'm using a separate RPi because there's no BT signal that will get through a shipping container.

What is this propane tank sensor and how does it work?

 

[wpns]

I realize most of you probably have DIY packs, or at least the ability to monitor individual cell voltages. Hoping I don't end up kicking myself in the future, but I started out with 12.8V Battleborn and 12V inverter, added more and more 12.8V LFP batteries in parallel, and now have a big collection of "dumb" sealed 12.8V LFP batteries in 4S (4S4S?) with Sunny Islands at 51.2V.

I'm interested in longevity, but it looks like (with a dumb sealed 12.8V LFP) not regularly charging to 100% is probably a greater threat, as the cells will drift out of balance over time, and make it more likely to encounter over and under-voltage protection events, as @Hedges alluded to. (agree or disagree, feel free to respond to this poll I set up a while back)

As my neighbor discovered recently with a golf cart, dumb LFP packs in parallel can go off-line either temporarily because of protection, or permanently because of failure, and unless you get in there with a DC clamp ammeter you might never know until the problems become severe.

 

[wpns]

My EG4 batteries start balancing once they’ve hit 100% charge, and they do that almost every day, so I figure I’m good. Since they are enclosed loop with the inverter, I don’t even obsess about what exact voltages are happening.

 

[sunshine_eggo]

i doubt that highly.

Well... okay... it's probably pretty reliable, but without the monitoring and control of VRM, my mental glass house would shatter, and I'd be unable to function in civil society.

What is this propane tank sensor and how does it work?

Mopeka Pro Check

Magnetic mount to bottom of tank. Manually level using the app to maximize accuracy. Uses sonar to determine height of propane level. You specify the type of tank and it reports % full based on height. Can also enter custom sizes. Reports data via bluetooth.

Normal use is with the Mopeka phone app.

Venus OS has drivers for it, so you can connect to the bluetooth device in the GX device, and it will report it on VRM. I've setup a separate RPi to connect to it since the tank is outside the shipping container. The RPi will be located in Badgerton (Keystone Montana 5er) and connected to the mesh wifi, so I'll be able to monitor it on a dedicated VRM instance.

@Adam De Lay has a great video for it. He's using a higher end version. Mine is just the consumer version. I don't anticipate any issues with the BT signal 15' between the outside tank and wherever I want to put the RPi in Badgerton. He's giggly and excited like a fat kid in a candy store, or @Crowz / @Daddy Tanuki in one of their many hooker-rooms.

 

[Crowz]

Well... okay... it's probably pretty reliable, but without the monitoring and control of VRM, my mental glass house would shatter, and I'd be unable to function in civil society.



Mopeka Pro Check

Magnetic mount to bottom of tank. Manually level using the app to maximize accuracy. Uses sonar to determine height of propane level. You specify the type of tank and it reports % full based on height. Can also enter custom sizes. Reports data via bluetooth.

Normal use is with the Mopeka phone app.

Venus OS has drivers for it, so you can connect to the bluetooth device in the GX device, and it will report it on VRM. I've setup a separate RPi to connect to it since the tank is outside the shipping container. The RPi will be located in Badgerton (Keystone Montana 5er) and connected to the mesh wifi, so I'll be able to monitor it on a dedicated VRM instance.

@Adam De Lay has a great video for it. He's using a higher end version. Mine is just the consumer version. I don't anticipate any issues with the BT signal 15' between the outside tank and wherever I want to put the RPi in Badgerton. He's giggly and excited like a fat kid in a candy store, or @Crowz / @Daddy Tanuki in one of their many hooker-rooms.

I use these :

SLZB-06M

Amazon.com

to connect handle my zigbee network of home automation stuff. They also have a bluetooth repeater function which should allow you to reach any bluetooth device that is to far away. At least thats how I interpreted what it says. I haven't used them as bluetooth repeaters personally.

 

[sunshine_eggo]

Wut?

Are you suggesting I could use that to get a BT signal through a shipping container?

If so, I don't see anything on that product page about use as BT repeater.

 

[Crowz]

Wut?

Are you suggesting I could use that to get a BT signal through a shipping container?

If so, I don't see anything on that product page about use as BT repeater.

Again I am not saying this will work for sure. I'm just mentioning it has the option and mentions it in the documentation.

Bluetooth proxy mode in the center of the screenshot.

 

[sunshine_eggo]

Gotcha. Thanks. I don't think I have the spare CPU cycles to figure this out. I've got the RPi and the sensor paired up nicely. I can live with it being separate from my primary VRM.

 

[Recovering EE]

There are lots of things out there that are obsolete that keep on doing their thing because they don't know any better....

An old boss of mine was an early adopter of the home computer.
he had a modern PC in his office when I worked for him but he also had this TRS-80 that had all this old software he wrote in basic that did all kinds of tables and calculation for you.
He fired that old machine up now and then to do things that you could not find modern software for or were not willing to calculate by hand...

I've got a 20 year-old (?) 60" Panasonic 3D plasma TV. It still works great, and as an added bonus (in winter), it heats our viewing room. Over the years, I just couldn't give it up, because LCD just wasn't able to match its deep blacks. Truth be told...the savings in power consumption alone probably would have paid for a new LCD set several times over.

I've been waiting for five years for a tech that gives a better picture, and nothing's been close...until QD OLED came out. Now I'm just waiting for good quality/feature set one to come in under $2k.

In the mean time...break out the s'mores makin's, and I'll put a video of a fireplace on the plasma.

 

[wildbillpdx]

I'm going to ask here as I've already got another post running. I have an EG4 Lifepower4 48v battery with one cell out of balance (one battery out of six). They are about one year old. They've been cycling up and down (30% to 100%) which I thought should keep them happy (leaving a little reserve for power outages). So, why did the BMS let the one get out of whack? Some of the responses I received indicate I should be deep cycling the batteries regularly to below 20% SoC. I'm now facing the issue of re-balancing one cell and don't want to have to do it again. Does this seem like it should have caused a problem? Should I deep cycle them regularly?

 

[sunshine_eggo]

I'm going to ask here as I've already got another post running. I have an EG4 Lifepower4 48v battery with one cell out of balance (one battery out of six). They are about one year old. They've been cycling up and down (30% to 100%) which I thought should keep them happy (leaving a little reserve for power outages). So, why did the BMS let the one get out of whack? Some of the responses I received indicate I should be deep cycling the batteries regularly to below 20% SoC. I'm now facing the issue of re-balancing one cell and don't want to have to do it again. Does this seem like it should have caused a problem? Should I deep cycle them regularly?

It's not about SoC, it's about voltage.

What per cell voltage are you achieving?

Where does your BMS start balancing?

How many hours per month are you keeping them in the balance range?

 

[wildbillpdx]

It's not about SoC, it's about voltage.

What per cell voltage are you achieving?

Where does your BMS start balancing?

How many hours per month are you keeping them in the balance range?

This what shows on the problem battery. I haven't had a problem until this week when it dropped to very low charge. I've been letting them cycle based on solar charging and Grid when there isn't any sun. The 6000ex uses SoC for settings when in closed loop with the EG4 batteries, not voltage. Not sure about the BMS settings, whatever is the default for EG4.

 

[sunshine_eggo]

This what shows on the problem battery. I haven't had a problem until this week when it dropped to very low charge. I've been letting them cycle based on solar charging and Grid when there isn't any sun. The 6000ex uses SoC for settings when in closed loop with the EG4 batteries, not voltage. Not sure about the BMS settings, whatever is the default for EG4.

View attachment 255244

Ah. Well, it's been often referenced that some closed loop systems do not maintain battery balance well. It's part of the reason some choose to go open loop even when closed is available, so that they can dictate suitable absorption and float charge parameters. Many of the server rack pylontech-type batteries simply charge to a voltage and hold it with no effort to go to float. This is not regarded as best practices and can cause capacity loss due to low current over-charge and lithium plating. I believe some of the recent EG4 battery firmware updates have been directed at issues with balance and charge/float voltages.

@EG4TechSolutionsTeam - please correct me where I'm wrong.

 

[ricardocello]

I believe some of the recent EG4 battery firmware updates have been directed at issues with balance and charge/float voltages.

I have not updated to the multipack firmware yet. Are you telling me there is hope?

 

[wildbillpdx]

I believe some of the recent EG4 battery firmware updates have been directed at issues with balance and charge/float voltages.

The version on the batteries, 3.37, was supposed to fix some of that. There is a later version, but I haven't installed it yet.