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Car battery (lead acid) discharges much, much faster than it charges?
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Let's assume a lead acid car battery (12V, 50Ah, 250A output).
According to BatteryUniversity article BU-403:
The charge time is 12–16 hours and up to 36–48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 8–10 hours; however, without full topping charge. Lead acid is sluggish and cannot be charged as quickly as other battery systems.
So the charging rate is no more than C/12. But car batteries (usually 6 cells) can discharge at often beyond 200A. 250A in my example. For a 50 Ah battery, this would mean discharging at a rate of 5C.
Does that mean, that a lead-acid battery can be discharged at least 60 times faster than it can be charged?
Or have I misunderstood something?
batteries battery-charging automotive lead-acid car-batteries
asked 4 hours ago
neverMind9
343216
add a comment |Â
up vote
1
down vote
favorite
Let's assume a lead acid car battery (12V, 50Ah, 250A output).
According to BatteryUniversity article BU-403:
The charge time is 12–16 hours and up to 36–48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 8–10 hours; however, without full topping charge. Lead acid is sluggish and cannot be charged as quickly as other battery systems.
So the charging rate is no more than C/12. But car batteries (usually 6 cells) can discharge at often beyond 200A. 250A in my example. For a 50 Ah battery, this would mean discharging at a rate of 5C.
Does that mean, that a lead-acid battery can be discharged at least 60 times faster than it can be charged?
Or have I misunderstood something?
batteries battery-charging automotive lead-acid car-batteries
asked 4 hours ago
neverMind9
343216
1
Some cars need 800A and trucks can require 1000A or more at 24v... However, newer designs have also helped lower the current requirements.
– Solar Mike
3 hours ago
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
Let's assume a lead acid car battery (12V, 50Ah, 250A output).
According to BatteryUniversity article BU-403:
The charge time is 12–16 hours and up to 36–48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 8–10 hours; however, without full topping charge. Lead acid is sluggish and cannot be charged as quickly as other battery systems.
So the charging rate is no more than C/12. But car batteries (usually 6 cells) can discharge at often beyond 200A. 250A in my example. For a 50 Ah battery, this would mean discharging at a rate of 5C.
Does that mean, that a lead-acid battery can be discharged at least 60 times faster than it can be charged?
Or have I misunderstood something?
batteries battery-charging automotive lead-acid car-batteries
asked 4 hours ago
neverMind9
343216
Let's assume a lead acid car battery (12V, 50Ah, 250A output).
According to BatteryUniversity article BU-403:
The charge time is 12–16 hours and up to 36–48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 8–10 hours; however, without full topping charge. Lead acid is sluggish and cannot be charged as quickly as other battery systems.
So the charging rate is no more than C/12. But car batteries (usually 6 cells) can discharge at often beyond 200A. 250A in my example. For a 50 Ah battery, this would mean discharging at a rate of 5C.
Does that mean, that a lead-acid battery can be discharged at least 60 times faster than it can be charged?
Or have I misunderstood something?
batteries battery-charging automotive lead-acid car-batteries
batteries battery-charging automotive lead-acid car-batteries
asked 4 hours ago
neverMind9
343216
asked 4 hours ago
neverMind9
343216
edited 4 hours ago
asked 4 hours ago
neverMind9
343216
asked 4 hours ago
neverMind9
343216
asked 4 hours ago
neverMind9
343216
343216
1
Some cars need 800A and trucks can require 1000A or more at 24v... However, newer designs have also helped lower the current requirements.
– Solar Mike
3 hours ago
add a comment |Â
1
Some cars need 800A and trucks can require 1000A or more at 24v... However, newer designs have also helped lower the current requirements.
– Solar Mike
3 hours ago
1
1
Some cars need 800A and trucks can require 1000A or more at 24v... However, newer designs have also helped lower the current requirements.
– Solar Mike
3 hours ago
Some cars need 800A and trucks can require 1000A or more at 24v... However, newer designs have also helped lower the current requirements.
– Solar Mike
3 hours ago
add a comment |Â
3 Answers
3
active
oldest
votes
up vote
3
down vote
You are entirely correct. The issue comes down to the fact that it's pretty easy to overcharge a lead-acid, but normally you try not to "over-discharge". So you have to be careful about the last stages of charging. This is not (exactly) true for discharging, but that is only true because you don't want to completely discharge lead-acid anyways. Unless you have a deep-cycle battery, you don't want to pull more than about 50% of the available charge out when discharging. If you do, you'll severely reduce the battery life.
answered 3 hours ago
WhatRoughBeast
47.4k22771
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
add a comment |Â
up vote
2
down vote
You said '..a lead-acid battery can be discharged at least 60 times faster than it can be charged?"
In general that may be true of a particular charging system, but it varies depending on the charging system and the charge profiles used.
Your premise is far too simplistic to cover all situations. Battery University presents quite reasonable information, but it does not usually provide highly accurate technical details that cover all situations. The main premise of the statement in BU-403 you referred is to "Learn how to optimize charging conditions to extend service life". But the charging profile presented is only one of many possible options.
For example the design of many car alternator charging system is typically a simple current limited (not CC) and CV profile. You discharge the battery at perhaps 200-800A when starting the vehicle but charge the battery at perhaps 70-100A once it's running. The current profile drops when the battery terminal voltage rises but the profile is simple. Here the discharge/charge ratio may only be 10:1, at least for a short time.
If you read relevant information on smart charging profiles you may get a better picture of the situation. Start with something like this from TI.
If you want in depth detail for extending battery life you may find this paper on VRLA EV use of use. This uses a ZDV profile to ensure the minimum of overcharging, but maintaining fully charged terminal voltage.
answered 3 hours ago
Jack Creasey
12.2k2622
add a comment |Â
up vote
1
down vote
For use in boats and RVs, I've seen C/5 recommended as a maximum charge rate, but lower rates are probably kinder to the battery. For marine and RV use, you want to charge the battery as fast as practical (without damage), but for stationary use (UPS and similar applications), you usually have lots of time between discharges, so a slower charge rate is practical.
Engine starting batteries are made to deliver very large currents for a short time. Look at the Cold Cranking Amps (CCA) rating of a starting battery for examples. The diesel engine on my boat requires a starting battery with a 900 A or greater CCA rating, if I recall correctly.
answered 3 hours ago
Peter Bennett
34.7k12661
add a comment |Â
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
You are entirely correct. The issue comes down to the fact that it's pretty easy to overcharge a lead-acid, but normally you try not to "over-discharge". So you have to be careful about the last stages of charging. This is not (exactly) true for discharging, but that is only true because you don't want to completely discharge lead-acid anyways. Unless you have a deep-cycle battery, you don't want to pull more than about 50% of the available charge out when discharging. If you do, you'll severely reduce the battery life.
answered 3 hours ago
WhatRoughBeast
47.4k22771
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
add a comment |Â
up vote
3
down vote
You are entirely correct. The issue comes down to the fact that it's pretty easy to overcharge a lead-acid, but normally you try not to "over-discharge". So you have to be careful about the last stages of charging. This is not (exactly) true for discharging, but that is only true because you don't want to completely discharge lead-acid anyways. Unless you have a deep-cycle battery, you don't want to pull more than about 50% of the available charge out when discharging. If you do, you'll severely reduce the battery life.
answered 3 hours ago
WhatRoughBeast
47.4k22771
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
add a comment |Â
up vote
3
down vote
up vote
3
down vote
You are entirely correct. The issue comes down to the fact that it's pretty easy to overcharge a lead-acid, but normally you try not to "over-discharge". So you have to be careful about the last stages of charging. This is not (exactly) true for discharging, but that is only true because you don't want to completely discharge lead-acid anyways. Unless you have a deep-cycle battery, you don't want to pull more than about 50% of the available charge out when discharging. If you do, you'll severely reduce the battery life.
answered 3 hours ago
WhatRoughBeast
47.4k22771
You are entirely correct. The issue comes down to the fact that it's pretty easy to overcharge a lead-acid, but normally you try not to "over-discharge". So you have to be careful about the last stages of charging. This is not (exactly) true for discharging, but that is only true because you don't want to completely discharge lead-acid anyways. Unless you have a deep-cycle battery, you don't want to pull more than about 50% of the available charge out when discharging. If you do, you'll severely reduce the battery life.
answered 3 hours ago
WhatRoughBeast
47.4k22771
answered 3 hours ago
WhatRoughBeast
47.4k22771
answered 3 hours ago
WhatRoughBeast
47.4k22771
answered 3 hours ago
WhatRoughBeast
47.4k22771
47.4k22771
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
add a comment |Â
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
But this answer electronics.stackexchange.com/a/398854/174733 claims 70 to 100 A of charging ampèrage for a short time, which would mean around 2C of charging rate. Have I confused something? Or is it true that the charging rate can peak at 100A but needs to be no more than 2.5A (C/16) once the high terminal voltage is reached?
– neverMind9
9 mins ago
add a comment |Â
up vote
2
down vote
You said '..a lead-acid battery can be discharged at least 60 times faster than it can be charged?"
In general that may be true of a particular charging system, but it varies depending on the charging system and the charge profiles used.
Your premise is far too simplistic to cover all situations. Battery University presents quite reasonable information, but it does not usually provide highly accurate technical details that cover all situations. The main premise of the statement in BU-403 you referred is to "Learn how to optimize charging conditions to extend service life". But the charging profile presented is only one of many possible options.
For example the design of many car alternator charging system is typically a simple current limited (not CC) and CV profile. You discharge the battery at perhaps 200-800A when starting the vehicle but charge the battery at perhaps 70-100A once it's running. The current profile drops when the battery terminal voltage rises but the profile is simple. Here the discharge/charge ratio may only be 10:1, at least for a short time.
If you read relevant information on smart charging profiles you may get a better picture of the situation. Start with something like this from TI.
If you want in depth detail for extending battery life you may find this paper on VRLA EV use of use. This uses a ZDV profile to ensure the minimum of overcharging, but maintaining fully charged terminal voltage.
answered 3 hours ago
Jack Creasey
12.2k2622
add a comment |Â
up vote
2
down vote
You said '..a lead-acid battery can be discharged at least 60 times faster than it can be charged?"
In general that may be true of a particular charging system, but it varies depending on the charging system and the charge profiles used.
Your premise is far too simplistic to cover all situations. Battery University presents quite reasonable information, but it does not usually provide highly accurate technical details that cover all situations. The main premise of the statement in BU-403 you referred is to "Learn how to optimize charging conditions to extend service life". But the charging profile presented is only one of many possible options.
For example the design of many car alternator charging system is typically a simple current limited (not CC) and CV profile. You discharge the battery at perhaps 200-800A when starting the vehicle but charge the battery at perhaps 70-100A once it's running. The current profile drops when the battery terminal voltage rises but the profile is simple. Here the discharge/charge ratio may only be 10:1, at least for a short time.
If you read relevant information on smart charging profiles you may get a better picture of the situation. Start with something like this from TI.
If you want in depth detail for extending battery life you may find this paper on VRLA EV use of use. This uses a ZDV profile to ensure the minimum of overcharging, but maintaining fully charged terminal voltage.
answered 3 hours ago
Jack Creasey
12.2k2622
add a comment |Â
up vote
2
down vote
up vote
2
down vote
You said '..a lead-acid battery can be discharged at least 60 times faster than it can be charged?"
In general that may be true of a particular charging system, but it varies depending on the charging system and the charge profiles used.
Your premise is far too simplistic to cover all situations. Battery University presents quite reasonable information, but it does not usually provide highly accurate technical details that cover all situations. The main premise of the statement in BU-403 you referred is to "Learn how to optimize charging conditions to extend service life". But the charging profile presented is only one of many possible options.
For example the design of many car alternator charging system is typically a simple current limited (not CC) and CV profile. You discharge the battery at perhaps 200-800A when starting the vehicle but charge the battery at perhaps 70-100A once it's running. The current profile drops when the battery terminal voltage rises but the profile is simple. Here the discharge/charge ratio may only be 10:1, at least for a short time.
If you read relevant information on smart charging profiles you may get a better picture of the situation. Start with something like this from TI.
If you want in depth detail for extending battery life you may find this paper on VRLA EV use of use. This uses a ZDV profile to ensure the minimum of overcharging, but maintaining fully charged terminal voltage.
answered 3 hours ago
Jack Creasey
12.2k2622
You said '..a lead-acid battery can be discharged at least 60 times faster than it can be charged?"
In general that may be true of a particular charging system, but it varies depending on the charging system and the charge profiles used.
Your premise is far too simplistic to cover all situations. Battery University presents quite reasonable information, but it does not usually provide highly accurate technical details that cover all situations. The main premise of the statement in BU-403 you referred is to "Learn how to optimize charging conditions to extend service life". But the charging profile presented is only one of many possible options.
For example the design of many car alternator charging system is typically a simple current limited (not CC) and CV profile. You discharge the battery at perhaps 200-800A when starting the vehicle but charge the battery at perhaps 70-100A once it's running. The current profile drops when the battery terminal voltage rises but the profile is simple. Here the discharge/charge ratio may only be 10:1, at least for a short time.
If you read relevant information on smart charging profiles you may get a better picture of the situation. Start with something like this from TI.
If you want in depth detail for extending battery life you may find this paper on VRLA EV use of use. This uses a ZDV profile to ensure the minimum of overcharging, but maintaining fully charged terminal voltage.
answered 3 hours ago
Jack Creasey
12.2k2622
edited 1 hour ago
answered 3 hours ago
Jack Creasey
12.2k2622
answered 3 hours ago
Jack Creasey
12.2k2622
answered 3 hours ago
Jack Creasey
12.2k2622
12.2k2622
add a comment |Â
add a comment |Â
up vote
1
down vote
For use in boats and RVs, I've seen C/5 recommended as a maximum charge rate, but lower rates are probably kinder to the battery. For marine and RV use, you want to charge the battery as fast as practical (without damage), but for stationary use (UPS and similar applications), you usually have lots of time between discharges, so a slower charge rate is practical.
Engine starting batteries are made to deliver very large currents for a short time. Look at the Cold Cranking Amps (CCA) rating of a starting battery for examples. The diesel engine on my boat requires a starting battery with a 900 A or greater CCA rating, if I recall correctly.
answered 3 hours ago
Peter Bennett
34.7k12661
add a comment |Â
up vote
1
down vote
For use in boats and RVs, I've seen C/5 recommended as a maximum charge rate, but lower rates are probably kinder to the battery. For marine and RV use, you want to charge the battery as fast as practical (without damage), but for stationary use (UPS and similar applications), you usually have lots of time between discharges, so a slower charge rate is practical.
Engine starting batteries are made to deliver very large currents for a short time. Look at the Cold Cranking Amps (CCA) rating of a starting battery for examples. The diesel engine on my boat requires a starting battery with a 900 A or greater CCA rating, if I recall correctly.
answered 3 hours ago
Peter Bennett
34.7k12661
add a comment |Â
up vote
1
down vote
up vote
1
down vote
For use in boats and RVs, I've seen C/5 recommended as a maximum charge rate, but lower rates are probably kinder to the battery. For marine and RV use, you want to charge the battery as fast as practical (without damage), but for stationary use (UPS and similar applications), you usually have lots of time between discharges, so a slower charge rate is practical.
Engine starting batteries are made to deliver very large currents for a short time. Look at the Cold Cranking Amps (CCA) rating of a starting battery for examples. The diesel engine on my boat requires a starting battery with a 900 A or greater CCA rating, if I recall correctly.
answered 3 hours ago
Peter Bennett
34.7k12661
For use in boats and RVs, I've seen C/5 recommended as a maximum charge rate, but lower rates are probably kinder to the battery. For marine and RV use, you want to charge the battery as fast as practical (without damage), but for stationary use (UPS and similar applications), you usually have lots of time between discharges, so a slower charge rate is practical.
Engine starting batteries are made to deliver very large currents for a short time. Look at the Cold Cranking Amps (CCA) rating of a starting battery for examples. The diesel engine on my boat requires a starting battery with a 900 A or greater CCA rating, if I recall correctly.
answered 3 hours ago
Peter Bennett
34.7k12661
answered 3 hours ago
Peter Bennett
34.7k12661
answered 3 hours ago
Peter Bennett
34.7k12661
answered 3 hours ago
Peter Bennett
34.7k12661
34.7k12661
add a comment |Â
add a comment |Â
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1
Some cars need 800A and trucks can require 1000A or more at 24v... However, newer designs have also helped lower the current requirements.
– Solar Mike
3 hours ago