a question for David Howey: during discharge Li ions flow from the anode to the cathode how do the overcome the 3.6v potential that should prevent this from happening???
Thanks to both of you. Most interesting. I have home battery storage and a BEV, so this information is very relevant. This is the first video I've seen on this channel, so it's time to 'go exploring', particularly for any information which you might have about electricity tariff zones, which are a new topic to me. Perhaps you could discuss them?
Ultimately since batteries degrade fairly slowly, it should be fairly easy to track the state of charge through the life-cycle by letting the battery run through its full capacity every so often. The information on degradation is great. I knew about temperature, but I am still a bit unsure about state-of-charge vs voltage. The reason is that when you charge a LiFePO4 cell you can charge it to above 3.45V/cell to get to 100%... most people charge to 3.55V/cell and chargers often go all the way to 3.65V/cell (BMS cutoff) which is a bit overkill. But once the charging stops, LiFepO4 (LFP) drops back down to a significantly lower voltage. With a very low load my 48V system drops from 56.8V all the way down to roughly 53.0V and is still at 98-99% SOC at 53.0V. That's only 3.3V/cell. LFP cells only have roughly a 10% voltage-range going from mostly-full (3.3V-3.35V) to mostly-empty (3.0V). The Float (holding 98-99% SOC) is at 3.35V/cell. * So the first question is... which has a greater impact on degradation? Being at near-100% SOC? Or the voltage? I've always been careful to get the voltage down into the 3.3V-3.35V range after fully charging the battery, but I haven't been as careful about maintaining a lower state of charge. In fact, I also have some very small 20Ah LiFePO4 batteries that I use in UPS applications where the battery is basically floated at 3.35V 24x7 365 days a year (i.e. all the time except of course during a power failure). * So my second question would be... is there a better way to float a battery in a UPS-style configuration? 8 months late but I'll post the questions anyway 🙂 -Matt
Did you ever get an answer to your questions. I'm also wondering on balancing configurations os batterries whether or not to discharge every now and then and the amount of time at 100% soc/v. I'm considering this for a home storage system where I can configure the inverter charge rate and soc ceiling, balancing to the usage trend over time/season etc.
@@ranzrumJojoJDDom373 Never did, no. But I think the #1 variable in terms of calendar life is temperature. State of charge is only a minor contributor if temperatures can remain controlled (i.e. batteries are inside a garage rather than outside in a shed).
I use off grid batteries for weather emergencies in the USA in Louisiana. So I`m studying this too. Thanks. My 12v 3.8 kwh LiFeP04 has powered a small air conditioner in my camper I live in through four heat emergency power outages this summer and my portable power stations ran my freezer and smaller stuff like WIFI and lights. My small makeshift solar setup has been such a blessing!
What size inverter do you use guessing 2000watt my 1000 watt refused to start my small air conditioning. It was supposed to be 600 watt input. Obviously not on start up.
Hello Battery Generation Podcast, I just finished watching your incredible video, and I'm genuinely impressed by the depth of information and the polished production. Your content is simply outstanding! I've got a unique idea to take it to the next level - creating bite-sized, engaging shorts from your podcast that can captivate a broader audience and supercharge your growth.
Fast charging offers undeniable benefits in terms of convenience and accessibility, it's important to consider and mitigate its negative impacts on battery health to ensure the long-term sustainability of electric vehicles. Balancing fast charging with slower, gentler charging methods can help maintain battery health while meeting the demands of EV users. I hope in the future we also develop something like battery limiters for EVs.
I think one of your questions wanted more specific detail, of which I would also love expert opinions. Regarding temperature of LFP cells; What is the sweet spot/range of temperature that is best for a cells longevity?. According to the diagram you showed, it seems a sweet spot is 30 - 40 degC. Would you agree? I'm in South Africa (considered warmer than Europe I think) and my cells indoors in summer only reach about 21-22 degC, nevermind winter where they get to about 12 - 18 degC. So I'm wondering if its worth insulating or controlling the temperature of the cells to get closer to 30 degC. I don't charge at high currents at least, but I am trying to get the most lifetime out of these cells.
Please explain, when the battery is charged, the cells in it are filled one after another (like communicating vessels), or when charging at 80-90%, some parts of the batteries and cells are not charged at all?
All are taken to the same level, don't think of it like a bar graph charge meter where some sections remain empty, at 80% for instance 100% of the battery is 80% charged
65% to 35% twice is better. All else being equal, avoid the extremes and sit in the middle. Occasionally, you should go to 100% for cell balancing and recalibration of the battery gauge. I only go to 100% just before a long trip out of town.
Question Lithium titanate chemistry is know for having up to 20.000 cycle life And verry expensive. Do you consider this type of battery being able to have good return on investment while used in off-grid for home appliances and power for the heatpump and also charging the EV Best Regards Roland
Modern EV cars designed for the fastest DC fast charging, preheat the battery considerably on the way to the charger to improve that fast charge speed to fill performance. But if you look carefully, the EV's performance while preheating the battery, the car's energy efficiency hit is noticeable, and in BMW's case, they've admitted it's a compromise they're making. Are we wasting more energy to placate consumers' perceived fast charging performance by A) wasting energy at the DC charger cooling the charging unit, cable, and battery and B) spoiling the efficiency of the car for 10 or 20 minutes before these extreme battery charging sessions. I believe I've also noticed a lower operating efficiency after a preheated DC fast charge. How much does hot battery affect its power delivery in terms of efficiency? I assume if the battery was performing better operating at that high temp, we'd operate it there, but maybe it's also a long term health consideration. In the interest of really addressing Climate Crisis, maybe these energy wasting compromises should be more carefully considered?
Agreed, but the effect is very small compared to the fossil energy chain where 2/3rds of all energy is wasted (often called rejected energy but it is just wasted). DW Planet has recently made an excellent video on that subject.
I bought a mower with two 4 ah 20 volt lithium ion batteries. It`s very useful for garden mulch and perfect for my 100x100 rural lot. But it`s so hot here. So I put a frozen gel pack wrapped in a thin towel on top of the batteries where the most heat is generated when in use and always recharge when the battery meter is showing two of five bars left and store them indoors. The mower was cheap but batteries cost twice the cost of the mower to replace. I hope to replace them (somehow) in the future with two 12v LiFeP04 batteries in series if I can figure out how.
I gave up on battery mower brought cheap 240v mower and long lead. Battery do not last long and con the price of 3 240v. Mowers also battery mowers less Powerful as well. Cannot beat a petrol mower.cost versus benefit just fails. To save 6 to 10 litres per year of gas. I have huge solar system to run home. So put the money to area of most benefit.
@@davidwright1752 I`m getting a standard plug-in mower next and I`ll power it with a battery/inverter setup. I`m not depending on gas. No transportation. On Social Security I can`t even afford to use a car if it was free.
@@baneverything5580 I mow the lawn with 240volt mower on long lead. .$130 worth. also light weight, I have a $650 EGO mower battery failed out of warranty.$350 replacement battery. So $1000 spent on heavy underpowered mower now sitting in the shed and $130 mower doing very well battery items like mower and cars are a rich man’s folly’s. I just paid a $1000 to find out if I need more power I will get a $300 gas powered mower.I do have a electrical background good luck with setting up a inverter your self and lugging around a battery as well. Save your money go 240 volt or gas mower. You are going to need a 2000 watt inverter and 200 amp battery 12 volt .Very heavy lead acid or go lithium still pretty heavy including inverter. Better to buy a EGO mower etc at least it has been engineered and still lighter than home made version.
@@baneverything5580 Our plug mower was cheap and does a great job compared to the heavy ego mower. That needed a new battery. Expensive.The only issue hope your block is not to big just use the power lead if you can.
There are the very long lasting, Radioactive degradation batteries, button type batteries used in Fire Alarms, lasting 10 to 30 years. Could they be scaled up to cars that have no charging.
Don't you need to remember the cumulative charge cycling at each state of charge, say 1000 parts, to know the degradation at the various depth of chemicals to estimate both the discharge curve and the percentage of parasitic losses as each state of charge is reached? EE here.
a question for David Howey: during discharge Li ions flow from the anode to the cathode how do the overcome the 3.6v potential that should prevent this from happening???
Thank you very much for this follow-up podcast, Prof. David Howey! 🙏🙏 Dear listeners, thank you so much for your questions!!! That was awesome!
Thanks to both of you. Most interesting. I have home battery storage and a BEV, so this information is very relevant. This is the first video I've seen on this channel, so it's time to 'go exploring', particularly for any information which you might have about electricity tariff zones, which are a new topic to me. Perhaps you could discuss them?
Ultimately since batteries degrade fairly slowly, it should be fairly easy to track the state of charge through the life-cycle by letting the battery run through its full capacity every so often.
The information on degradation is great. I knew about temperature, but I am still a bit unsure about state-of-charge vs voltage. The reason is that when you charge a LiFePO4 cell you can charge it to above 3.45V/cell to get to 100%... most people charge to 3.55V/cell and chargers often go all the way to 3.65V/cell (BMS cutoff) which is a bit overkill.
But once the charging stops, LiFepO4 (LFP) drops back down to a significantly lower voltage. With a very low load my 48V system drops from 56.8V all the way down to roughly 53.0V and is still at 98-99% SOC at 53.0V. That's only 3.3V/cell. LFP cells only have roughly a 10% voltage-range going from mostly-full (3.3V-3.35V) to mostly-empty (3.0V). The Float (holding 98-99% SOC) is at 3.35V/cell.
* So the first question is... which has a greater impact on degradation? Being at near-100% SOC? Or the voltage?
I've always been careful to get the voltage down into the 3.3V-3.35V range after fully charging the battery, but I haven't been as careful about maintaining a lower state of charge. In fact, I also have some very small 20Ah LiFePO4 batteries that I use in UPS applications where the battery is basically floated at 3.35V 24x7 365 days a year (i.e. all the time except of course during a power failure).
* So my second question would be... is there a better way to float a battery in a UPS-style configuration?
8 months late but I'll post the questions anyway 🙂
-Matt
Did you ever get an answer to your questions. I'm also wondering on balancing configurations os batterries whether or not to discharge every now and then and the amount of time at 100% soc/v. I'm considering this for a home storage system where I can configure the inverter charge rate and soc ceiling, balancing to the usage trend over time/season etc.
@@ranzrumJojoJDDom373 Never did, no. But I think the #1 variable in terms of calendar life is temperature. State of charge is only a minor contributor if temperatures can remain controlled (i.e. batteries are inside a garage rather than outside in a shed).
Great stuff! 🔋 Thank you so much for asking questions from your German users…!
I use off grid batteries for weather emergencies in the USA in Louisiana. So I`m studying this too. Thanks. My 12v 3.8 kwh LiFeP04 has powered a small air conditioner in my camper I live in through four heat emergency power outages this summer and my portable power stations ran my freezer and smaller stuff like WIFI and lights. My small makeshift solar setup has been such a blessing!
What size inverter do you use guessing 2000watt my 1000 watt refused to start my small air conditioning. It was supposed to be 600 watt input. Obviously not on start up.
Hello Battery Generation Podcast, I just finished watching your incredible video, and I'm genuinely impressed by the depth of information and the polished production. Your content is simply outstanding! I've got a unique idea to take it to the next level - creating bite-sized, engaging shorts from your podcast that can captivate a broader audience and supercharge your growth.
Fast charging offers undeniable benefits in terms of convenience and accessibility, it's important to consider and mitigate its negative impacts on battery health to ensure the long-term sustainability of electric vehicles. Balancing fast charging with slower, gentler charging methods can help maintain battery health while meeting the demands of EV users. I hope in the future we also develop something like battery limiters for EVs.
I think one of your questions wanted more specific detail, of which I would also love expert opinions. Regarding temperature of LFP cells; What is the sweet spot/range of temperature that is best for a cells longevity?. According to the diagram you showed, it seems a sweet spot is 30 - 40 degC. Would you agree? I'm in South Africa (considered warmer than Europe I think) and my cells indoors in summer only reach about 21-22 degC, nevermind winter where they get to about 12 - 18 degC. So I'm wondering if its worth insulating or controlling the temperature of the cells to get closer to 30 degC. I don't charge at high currents at least, but I am trying to get the most lifetime out of these cells.
Tell us the bottom line first...then follow with facts please.
Please explain, when the battery is charged, the cells in it are filled one after another (like communicating vessels), or when charging at 80-90%, some parts of the batteries and cells are not charged at all?
All are taken to the same level, don't think of it like a bar graph charge meter where some sections remain empty, at 80% for instance 100% of the battery is 80% charged
Is it better to discharge a battery from SOC 80% to 20% once or from 65% to 35% twice?
Thanks.
65% to 35% twice is better. All else being equal, avoid the extremes and sit in the middle. Occasionally, you should go to 100% for cell balancing and recalibration of the battery gauge. I only go to 100% just before a long trip out of town.
Question
Lithium titanate chemistry is know for having up to 20.000 cycle life
And verry expensive. Do you consider this type of battery being able to have good return on investment while used in off-grid for home appliances and power for the heatpump and also charging the EV Best Regards Roland
Modern EV cars designed for the fastest DC fast charging, preheat the battery considerably on the way to the charger to improve that fast charge speed to fill performance. But if you look carefully, the EV's performance while preheating the battery, the car's energy efficiency hit is noticeable, and in BMW's case, they've admitted it's a compromise they're making. Are we wasting more energy to placate consumers' perceived fast charging performance by A) wasting energy at the DC charger cooling the charging unit, cable, and battery and B) spoiling the efficiency of the car for 10 or 20 minutes before these extreme battery charging sessions. I believe I've also noticed a lower operating efficiency after a preheated DC fast charge. How much does hot battery affect its power delivery in terms of efficiency? I assume if the battery was performing better operating at that high temp, we'd operate it there, but maybe it's also a long term health consideration.
In the interest of really addressing Climate Crisis, maybe these energy wasting compromises should be more carefully considered?
Agreed, but the effect is very small compared to the fossil energy chain where 2/3rds of all energy is wasted (often called rejected energy but it is just wasted). DW Planet has recently made an excellent video on that subject.
Very good but, please, it's equilibrated, not 'equilibriated'.
Beside BMS
lithium ion can only take what it takes
you can’t push cv or cc in each cell
I bought a mower with two 4 ah 20 volt lithium ion batteries. It`s very useful for garden mulch and perfect for my 100x100 rural lot. But it`s so hot here. So I put a frozen gel pack wrapped in a thin towel on top of the batteries where the most heat is generated when in use and always recharge when the battery meter is showing two of five bars left and store them indoors. The mower was cheap but batteries cost twice the cost of the mower to replace. I hope to replace them (somehow) in the future with two 12v LiFeP04 batteries in series if I can figure out how.
I gave up on battery mower brought cheap 240v mower and long lead. Battery do not last long and con the price of 3 240v. Mowers also battery mowers less
Powerful as well. Cannot beat a petrol mower.cost versus benefit just fails. To save 6 to 10 litres per year of gas. I have huge solar system to run home. So put the money to area of most benefit.
@@davidwright1752 I`m getting a standard plug-in mower next and I`ll power it with a battery/inverter setup. I`m not depending on gas. No transportation. On Social Security I can`t even afford to use a car if it was free.
@@baneverything5580 I mow the lawn with 240volt mower on long lead. .$130 worth. also light weight, I have a $650 EGO mower battery failed out of warranty.$350 replacement battery. So $1000 spent on heavy underpowered mower now sitting in the shed and $130 mower doing very well battery items like mower and cars are a rich man’s folly’s. I just paid a $1000 to find out if I need more power I will get a $300 gas powered mower.I do have a electrical background good luck with setting up a inverter your self and lugging around a battery as well. Save your money go 240 volt or gas mower. You are going to need a 2000 watt inverter and 200 amp battery 12 volt .Very heavy lead acid or go lithium still pretty heavy including inverter. Better to buy a EGO mower etc at least it has been engineered and still lighter than home made version.
@@baneverything5580 Our plug mower was cheap and does a great job compared to the heavy ego mower. That needed a new battery. Expensive.The only issue hope your block is not to big just use the power lead if you can.
There are the very long lasting, Radioactive degradation batteries, button type batteries used in Fire Alarms, lasting 10 to 30 years.
Could they be scaled up to cars that have no charging.
Don't you need to remember the cumulative charge cycling at each state of charge, say 1000 parts, to know the degradation at the various depth of chemicals to estimate both the discharge curve and the percentage of parasitic losses as each state of charge is reached? EE here.