new battery charging info needed

[Jriecke]

I am looking for advise on proper charging on a new battery,, I bought a new Recon Ranger, no manual came with it, called the company and they said to ride it to nearly zero charge then fully charge it , do this for about three times. This will give the battery the longest life. Other say to charge it after the ride no matter how much charge is left. And some say to let it go to 20% before charging to full or at least 80% charge.
Would like to know what the experts have to say about this.

 

[sammy]

Some chemistries are more resilient than others
An ebike battery can have individual 18650 batteries that have a high amp draw or a high miliamp hour capacity...rarely both....the charging process will damage your battery no matter what chemistry....but one will suffer more than the other....my advice is to charge your pack at the lowest amp that is convenient...1 or two amps charging...that will be less stressfull and make your battery charge more often before it loses to much capacity....

 

[m@Robertson]

Low amperage charging as noted above is an excellent first step. I use adjustable chargers that let me dial current waaay down. I set the charge current to match the downtime I expect the bike to have. So at work I may set it to as low as 0.20 amps, which is VERY low, but I don't need the bike for another 8 hours and then, since I know how much juice i need to get home, I don't want to go over an 80% charge. The low current level makes it that much safer in terms of potential max charge value should I calculate charge time/current wrong.

Speaking of that calculation, do this once or twice and you'll know how long to charge for: Before you plug in your charger, take a reading on the voltage level. Lets say the battery is 47.5v. Plug in and set a timer for one hour. Come back after that hour, and unplug the charger. What is your battery level now? If it is lets say 49v then you now know that one hour of charging gives you 1.5v of added current to your battery. A more involved but more precise way to do this is as follows:

1. Let the bike sit 30 minutes so the battery level is stable after your ride
2. Plug charger in and take voltage reading (the charger will be bumping up the reading but thats OK)
3. Come back in an hour and read battery voltage.
4. Come back after one more hour and get another reading
5. Do it a third time. Now average your three values. Use that as your expected hourly voltage gain

Next: go to Amazon and spend $10 on a mechanical countdown timer. Here's a link to the one I use. Now that you know how many volts you will gain in an hour (or a half hour if you do a little math), set the countdown timer to charge only for the time you need to get to your target voltage (80%, 90% etc.). When the timer runs out, power is physically cut and thats an added safety factor. It is also a way to do an 80% charge with a charger that has no adjustability.

Here are voltage charts so you can figure out what the percentages are for various voltages:

Li-Ion Ebike Battery Charge Charts

Whats an 80% charge on a 48v battery? These charts give answers to questions like this on common ebike battery voltages: 36v, 48v, 52v, 60v and 72v.

talesontwowheels.com

As for best practices while charging, which is what you really asked about in the first place, on your typical 18650/21700 Li-NMC cell, the 80/20 rule is pretty good. Fully draining the pack is generally a bad thing. Depth of discharge is every bit as bad for a pack as is fully charging it to 100% and letting the pack sit overnight like that. The thing is, most battery how-to blog posters know its tough enough to convince people to only use 80% of their battery capacity, so telling them draining the thing dry is also bad is a bridge too far for the layman to accept.

Here are some references for you.

BU-808: How to Prolong Lithium-based Batteries

BU meta description needed...

batteryuniversity.com

This is an easier read:

Are you killing your lithium batteries?

Lithium-ion batteries are expensive, and large battery packs such as those in everything from electric cars to electric motorcycles and...

electrek.co

This is a tough read. Maybe skip to the conclusions at the end, but it goes directly to what @sammy said above. Its an old article but still very relevant.

How to make a lithium battery last, or…kill it, if you like.

We have written in the past about tips that will help your expensive lithium battery pack last as long as possible. This article will cover some additional information about what happens inside the…

www.electricbike.com

And lastly, if you don't have an adjustable charger, or even a real time battery voltage indicator, here's an easy way to get one without breaking the bank buying a $300+ Cycle Satiator. I use these as onboard weatherproof chargers on some of my bikes. These units are fanless (no moving parts to fail), meant for commercial outdoor signs or municipal street lights and have incredible lifetime ratings in the 200,000-hour MTBF range.

An Ultra Reliable Ebike Battery Charger…

How about a charger – quickly adjustable for voltage and current – that is rated for hundreds of thousands of hours of use before it typically fails?

talesontwowheels.com

EDIT: Oh and there's this, which is largely anecdotal but comes from a long-time ebike vendor:
For a new battery, do not drain the sucker down. However, DO charge it to 100% for up to the first six charge cycles. When you do that, let it sit on the charger for a few hours after it reaches 100% charge. The reason for this is to let the BMS balance the cells in the pack. Once you have done this, go to an 80% charge regimen. Its not a bad idea to periodically do a 100% 'balance charge' on occasion in the future. For a daily-driven bike, once a month should be plenty.

 

[Jriecke]

Low amperage charging as noted above is an excellent first step. I use adjustable chargers that let me dial current waaay down. I set the charge current to match the downtime I expect the bike to have. So at work I may set it to as low as 0.20 amps, which is VERY low, but I don't need the bike for another 8 hours and then, since I know how much juice i need to get home, I don't want to go over an 80% charge. The low current level makes it that much safer in terms of potential max charge value should I calculate charge time/current wrong.

Speaking of that calculation, do this once or twice and you'll know how long to charge for: Before you plug in your charger, take a reading on the voltage level. Lets say the battery is 47.5v. Plug in and set a timer for one hour. Come back after that hour, and unplug the charger. What is your battery level now? If it is lets say 49v then you now know that one hour of charging gives you 1.5v of added current to your battery. A more involved but more precise way to do this is as follows:

1. Let the bike sit 30 minutes so the battery level is stable after your ride
2. Plug charger in and take voltage reading (the charger will be bumping up the reading but thats OK)
3. Come back in an hour and read battery voltage.
4. Come back after one more hour and get another reading
5. Do it a third time. Now average your three values. Use that as your expected hourly voltage gain

Next: go to Amazon and spend $10 on a mechanical countdown timer. Here's a link to the one I use. Now that you know how many volts you will gain in an hour (or a half hour if you do a little math), set the countdown timer to charge only for the time you need to get to your target voltage (80%, 90% etc.). When the timer runs out, power is physically cut and thats an added safety factor. It is also a way to do an 80% charge with a charger that has no adjustability.

Here are voltage charts so you can figure out what the percentages are for various voltages:

Li-Ion Ebike Battery Charge Charts

Whats an 80% charge on a 48v battery? These charts give answers to questions like this on common ebike battery voltages: 36v, 48v, 52v, 60v and 72v.

talesontwowheels.com

As for best practices while charging, which is what you really asked about in the first place, on your typical 18650/21700 Li-NMC cell, the 80/20 rule is pretty good. Fully draining the pack is generally a bad thing. Depth of discharge is every bit as bad for a pack as is fully charging it to 100% and letting the pack sit overnight like that. The thing is, most battery how-to blog posters know its tough enough to convince people to only use 80% of their battery capacity, so telling them draining the thing dry is also bad is a bridge too far for the layman to accept.

Here are some references for you.

BU-808: How to Prolong Lithium-based Batteries

BU meta description needed...

batteryuniversity.com

This is an easier read:

Are you killing your lithium batteries?

Lithium-ion batteries are expensive, and large battery packs such as those in everything from electric cars to electric motorcycles and...

electrek.co

This is a tough read. Maybe skip to the conclusions at the end, but it goes directly to what @sammy said above. Its an old article but still very relevant.

How to make a lithium battery last, or…kill it, if you like.

We have written in the past about tips that will help your expensive lithium battery pack last as long as possible. This article will cover some additional information about what happens inside the…

www.electricbike.com

And lastly, if you don't have an adjustable charger, or even a real time battery voltage indicator, here's an easy way to get one without breaking the bank buying a $300+ Cycle Satiator. I use these as onboard weatherproof chargers on some of my bikes. These units are fanless (no moving parts to fail), meant for commercial outdoor signs or municipal street lights and have incredible lifetime ratings in the 200,000-hour MTBF range.

An Ultra Reliable Ebike Battery Charger…

How about a charger – quickly adjustable for voltage and current – that is rated for hundreds of thousands of hours of use before it typically fails?

talesontwowheels.com

EDIT: Oh and there's this, which is largely anecdotal but comes from a long-time ebike vendor:
For a new battery, do not drain the sucker down. However, DO charge it to 100% for up to the first six charge cycles. When you do that, let it sit on the charger for a few hours after it reaches 100% charge. The reason for this is to let the BMS balance the cells in the pack. Once you have done this, go to an 80% charge regimen. Its not a bad idea to periodically do a 100% 'balance charge' on occasion in the future. For a daily-driven bike, once a month should be plenty.

thanks for the great article!

 

[Rockbike]

Some chemistries are more resilient than others
An ebike battery can have individual 18650 batteries that have a high amp draw or a high miliamp hour capacity...rarely both....the charging process will damage your battery no matter what chemistry....but one will suffer more than the other....my advice is to charge your pack at the lowest amp that is convenient...1 or two amps charging...that will be less stressfull and make your battery charge more often before it loses to much capacity....

This is wrong. Fast charging a lithium ion battery (like the OP has) only accelerates the wear of the battery if the internal cell temperature climbs too high. As long as the temperature is kept below about 90 degrees F, the battery will be happy. Even a 4 amp charger on a 500 Wh pack (again, like the OP has) will not cause enough temperature rise to cause accelerated battery degradation in normal usage conditions.

Draining the battery to below 10% and charging above 90% will cause a small amount of accelerated degradation but the reason it doesn't cause a lot of degradation is because the manufacturer has already designed the battery management system to adjust the capacity of the battery such that it is never really charged to 100% of the cells capacities, nor is it ever drained to 0%. When the battery reports 10% State Of Charge (SOC), it's really at something more akin to 20% SOC. And when the battery reports 100% SOC, it's really more like 90% SOC.

The reason a diligent person can extend the life of their battery even further by not using the top and bottom 10% of the system capacity is because manufacturers don't want to leave too much capacity on the table. They want to report the largest battery capacity they can and give your bike the longest range possible without causing the battery to degrade too quickly (which would result in unhappy customers). Said another way, your bike is designed to be charged to 100% and discharged to 0% without causing too much trouble. By avoiding using the top and bottom of the battery, its life can be extended a little more.

The life of the battery will not be impacted by 4 amp charging speeds unless perhaps you live and ride in searing hot conditions and that extra amperage causes excessive heat build-up during charging. Normally that will not be the case. Batteries prefer 70-90 degrees while they are being charged or discharged and cool to cold temperatures for long-term storage, however, always above freezing. If you store your batter in a cool or cold area, always allow it several hours to warm up before (especially) charging or discharging it.

 

[canis2022]

Low amperage charging as noted above is an excellent first step. I use adjustable chargers that let me dial current waaay down. I set the charge current to match the downtime I expect the bike to have. So at work I may set it to as low as 0.20 amps, which is VERY low, but I don't need the bike for another 8 hours and then, since I know how much juice i need to get home, I don't want to go over an 80% charge. The low current level makes it that much safer in terms of potential max charge value should I calculate charge time/current wrong.

Speaking of that calculation, do this once or twice and you'll know how long to charge for: Before you plug in your charger, take a reading on the voltage level. Lets say the battery is 47.5v. Plug in and set a timer for one hour. Come back after that hour, and unplug the charger. What is your battery level now? If it is lets say 49v then you now know that one hour of charging gives you 1.5v of added current to your battery. A more involved but more precise way to do this is as follows:

1. Let the bike sit 30 minutes so the battery level is stable after your ride
2. Plug charger in and take voltage reading (the charger will be bumping up the reading but thats OK)
3. Come back in an hour and read battery voltage.
4. Come back after one more hour and get another reading
5. Do it a third time. Now average your three values. Use that as your expected hourly voltage gain

Next: go to Amazon and spend $10 on a mechanical countdown timer. Here's a link to the one I use. Now that you know how many volts you will gain in an hour (or a half hour if you do a little math), set the countdown timer to charge only for the time you need to get to your target voltage (80%, 90% etc.). When the timer runs out, power is physically cut and thats an added safety factor. It is also a way to do an 80% charge with a charger that has no adjustability.

Here are voltage charts so you can figure out what the percentages are for various voltages:

Li-Ion Ebike Battery Charge Charts

Whats an 80% charge on a 48v battery? These charts give answers to questions like this on common ebike battery voltages: 36v, 48v, 52v, 60v and 72v.

talesontwowheels.com

As for best practices while charging, which is what you really asked about in the first place, on your typical 18650/21700 Li-NMC cell, the 80/20 rule is pretty good. Fully draining the pack is generally a bad thing. Depth of discharge is every bit as bad for a pack as is fully charging it to 100% and letting the pack sit overnight like that. The thing is, most battery how-to blog posters know its tough enough to convince people to only use 80% of their battery capacity, so telling them draining the thing dry is also bad is a bridge too far for the layman to accept.

Here are some references for you.

BU-808: How to Prolong Lithium-based Batteries

BU meta description needed...

batteryuniversity.com

This is an easier read:

Are you killing your lithium batteries?

Lithium-ion batteries are expensive, and large battery packs such as those in everything from electric cars to electric motorcycles and...

electrek.co

This is a tough read. Maybe skip to the conclusions at the end, but it goes directly to what @sammy said above. Its an old article but still very relevant.

How to make a lithium battery last, or…kill it, if you like.

We have written in the past about tips that will help your expensive lithium battery pack last as long as possible. This article will cover some additional information about what happens inside the…

www.electricbike.com

And lastly, if you don't have an adjustable charger, or even a real time battery voltage indicator, here's an easy way to get one without breaking the bank buying a $300+ Cycle Satiator. I use these as onboard weatherproof chargers on some of my bikes. These units are fanless (no moving parts to fail), meant for commercial outdoor signs or municipal street lights and have incredible lifetime ratings in the 200,000-hour MTBF range.

An Ultra Reliable Ebike Battery Charger…

How about a charger – quickly adjustable for voltage and current – that is rated for hundreds of thousands of hours of use before it typically fails?

talesontwowheels.com

EDIT: Oh and there's this, which is largely anecdotal but comes from a long-time ebike vendor:
For a new battery, do not drain the sucker down. However, DO charge it to 100% for up to the first six charge cycles. When you do that, let it sit on the charger for a few hours after it reaches 100% charge. The reason for this is to let the BMS balance the cells in the pack. Once you have done this, go to an 80% charge regimen. Its not a bad idea to periodically do a 100% 'balance charge' on occasion in the future. For a daily-driven bike, once a month should be plenty.

Thanks for doing this... it's the most complete guide to helping those of us who are new to maintaining ebikes and batteries are probably the most misunderstood of all the components.

 

[canis2022]

Low amperage charging as noted above is an excellent first step. I use adjustable chargers that let me dial current waaay down. I set the charge current to match the downtime I expect the bike to have. So at work I may set it to as low as 0.20 amps, which is VERY low, but I don't need the bike for another 8 hours and then, since I know how much juice i need to get home, I don't want to go over an 80% charge. The low current level makes it that much safer in terms of potential max charge value should I calculate charge time/current wrong.

Speaking of that calculation, do this once or twice and you'll know how long to charge for: Before you plug in your charger, take a reading on the voltage level. Lets say the battery is 47.5v. Plug in and set a timer for one hour. Come back after that hour, and unplug the charger. What is your battery level now? If it is lets say 49v then you now know that one hour of charging gives you 1.5v of added current to your battery. A more involved but more precise way to do this is as follows:

1. Let the bike sit 30 minutes so the battery level is stable after your ride
2. Plug charger in and take voltage reading (the charger will be bumping up the reading but thats OK)
3. Come back in an hour and read battery voltage.
4. Come back after one more hour and get another reading
5. Do it a third time. Now average your three values. Use that as your expected hourly voltage gain

Next: go to Amazon and spend $10 on a mechanical countdown timer. Here's a link to the one I use. Now that you know how many volts you will gain in an hour (or a half hour if you do a little math), set the countdown timer to charge only for the time you need to get to your target voltage (80%, 90% etc.). When the timer runs out, power is physically cut and thats an added safety factor. It is also a way to do an 80% charge with a charger that has no adjustability.

Here are voltage charts so you can figure out what the percentages are for various voltages:

Li-Ion Ebike Battery Charge Charts

Whats an 80% charge on a 48v battery? These charts give answers to questions like this on common ebike battery voltages: 36v, 48v, 52v, 60v and 72v.

talesontwowheels.com

As for best practices while charging, which is what you really asked about in the first place, on your typical 18650/21700 Li-NMC cell, the 80/20 rule is pretty good. Fully draining the pack is generally a bad thing. Depth of discharge is every bit as bad for a pack as is fully charging it to 100% and letting the pack sit overnight like that. The thing is, most battery how-to blog posters know its tough enough to convince people to only use 80% of their battery capacity, so telling them draining the thing dry is also bad is a bridge too far for the layman to accept.

Here are some references for you.

BU-808: How to Prolong Lithium-based Batteries

BU meta description needed...

batteryuniversity.com

This is an easier read:

Are you killing your lithium batteries?

Lithium-ion batteries are expensive, and large battery packs such as those in everything from electric cars to electric motorcycles and...

electrek.co

This is a tough read. Maybe skip to the conclusions at the end, but it goes directly to what @sammy said above. Its an old article but still very relevant.

How to make a lithium battery last, or…kill it, if you like.

We have written in the past about tips that will help your expensive lithium battery pack last as long as possible. This article will cover some additional information about what happens inside the…

www.electricbike.com

And lastly, if you don't have an adjustable charger, or even a real time battery voltage indicator, here's an easy way to get one without breaking the bank buying a $300+ Cycle Satiator. I use these as onboard weatherproof chargers on some of my bikes. These units are fanless (no moving parts to fail), meant for commercial outdoor signs or municipal street lights and have incredible lifetime ratings in the 200,000-hour MTBF range.

An Ultra Reliable Ebike Battery Charger…

How about a charger – quickly adjustable for voltage and current – that is rated for hundreds of thousands of hours of use before it typically fails?

talesontwowheels.com

EDIT: Oh and there's this, which is largely anecdotal but comes from a long-time ebike vendor:
For a new battery, do not drain the sucker down. However, DO charge it to 100% for up to the first six charge cycles. When you do that, let it sit on the charger for a few hours after it reaches 100% charge. The reason for this is to let the BMS balance the cells in the pack. Once you have done this, go to an 80% charge regimen. Its not a bad idea to periodically do a 100% 'balance charge' on occasion in the future. For a daily-driven bike, once a month should be plenty.

Thanks for responding to this post. It's the most complete explanation I've seen on this subject and a lot of us who are new to owning an ebike have had a hard time understanding the most important element which is the battery.

 

[m@Robertson]

Draining the battery to below 10% and charging above 90% will cause a small amount of accelerated degradation but the reason it doesn't cause a lot of degradation is because the manufacturer has already designed the battery management system to adjust the capacity of the battery such that it is never really charged to 100% of the cells capacities, nor is it ever drained to 0%. When the battery reports 10% State Of Charge (SOC), it's really at something more akin to 20% SOC. And when the battery reports 100% SOC, it's really more like 90% SOC.

Worth noting: the approx 10% fudge factors at top and bottom of the SOC as noted above are only likely to be there if you are using a manufactured name-brand pack that is more or less at the top of the pricing food chain... a Specialized, Bosch or Shimano battery part of a branded system for example, found as oem equipment on a dealer-network bike.

Unless you can find mention of it in your owner's manual, or get a manufacturer's help line to acknowledge its existence, its best to assume that sort of foresight does not exist on whatever it is you bought. Especially not on any direct-to-consumer brand bike or battery, where that battery is very likely to be generic in construction. I know for example on the various Sondors packs going back to that brand's origin its not there. You can bet it won't be on any Rad Power Bike or similar bike in that price category. That is not by the way a dig at either company (although there is plenty of ammo to do that for other things).

The best way to KNOW one way or the other is have an actual real-time voltage indicator. Look at voltage for yourself. Don't rely on a battery graphic, ever or you'll be forever guessing. The displays I use all have this. Being in volunteer tech support for one DTC brand for several years I can say when that company moved away from displays that showed voltage levels, life was complicated enormously for end users; particularly when problems with charging occur and it was time to try and diagnose an issue.

All of this is way more thought than your typical consumer is going to give to battery charging.

One last thing: Its not so much a problem to charge even a typical, simple pack to 100%. Its a problem to charge to 100% and then let the battery sit for a length of time. If you charge to 100% right before a ride, and then jump on and ride it, the degradation is so small you won't create a noticeable difference vs. using careful babysitting practices over time.

---

The biggest lesson of all is don't let anal-retentive battery geeks like me stop you from enjoying your ebike. the best thing for most people is to charge the crap out of it and ride it into the ground. Let the conservation stuff creep in as a secondary thing.

 

[hsdrggr]

I am looking for advise on proper charging on a new battery,, I bought a new Recon Ranger, no manual came with it, called the company and they said to ride it to nearly zero charge then fully charge it , do this for about three times. This will give the battery the longest life. Other say to charge it after the ride no matter how much charge is left. And some say to let it go to 20% before charging to full or at least 80% charge.
Would like to know what the experts have to say about this.

Lithium Ion batteries degrade more when fully charged. Storage recommendations are to store at 50-60% state of charge. So the best way to extend their life with a standard charger that charges to 4.2v per cell is to charge it before you use it. So don’t charge it after each ride. Also you don’t need to charge it until it gets fairly depleted. Batteries generate heat every time they are charged and heat degrades li-Ion batteries. If you only ride a few miles each time you ride you may want to wait until after several rides before charging.
You can easily triple the life of your batteries by only charging them to 80% state of charge instead of 100%. You don’t loose very much usable capacity when doing this. I charge my batteries that way. Only charging them to 4.05v/cell. Mine are 48v batteries which have 13 sets of 4.2v cells in series.
4.05x13=52.65v. So I have my charger set to disconnect at 52.6 volts. Also the slower you charge the battery the less heat is generated which also reduces deterioration of the cells. So I charge at a 2amp rate. Standard battery chargers that come stock with e-bikes charge at a 4amp current and to 100% capacity (54.6v on a 48v ebike battery).
I use the “Cycle Satiator” adjustable charger made by Grin Technologies in Canada. It’s kind of expensive, but I have 5 e-bikes also, with varying voltage Batteries. So it makes sense for me. However, I bought it 3 years ago when I was building my first ebike.
If you monitor your battery voltage as it’s charging you can always disconnect your standard charger when the voltage hits 80% state of charge and increase its life that way without having to buy an adjustable charger.

Also don’t ever, ever, ever leave your charger connected to your battery continuously. Disconnect it when your done charging.

This web page is an excellent source for info on charging Li-Ion batteries.

Are you killing your lithium batteries?

Lithium-ion batteries are expensive, and large battery packs such as those in everything from electric cars to electric motorcycles and...

electrek.co

 

[HillAversion]

CHARGING AND CARING FOR YOUR LITHIUM-ION EBIKE BATTERY

Your ebike battery is expensive. Knowing how to charge it properly and care for it can make it last 2 or 3 times longer. There are also a few things to avoid that can dramatically shorten your battery's life. This article will tell you: What to do when your battery is new Basic ebike battery...

www.electrifybike.com

 

[Smaug]

I am looking for advise on proper charging on a new battery,, I bought a new Recon Ranger, no manual came with it, called the company and they said to ride it to nearly zero charge then fully charge it , do this for about three times. This will give the battery the longest life. Other say to charge it after the ride no matter how much charge is left. And some say to let it go to 20% before charging to full or at least 80% charge.
Would like to know what the experts have to say about this.

I work in the cordless power tool industry.

Lithium batteries don’t “like” being fully charged nor discharged. They will live the longest lifespan if they’re kept between 20-80%.

Practically speaking, you can charge fully every time if you don’t leave it at that level for days at a time.

If you store it for the winter, leave it at around 30%.

Don’t worry too much about discharging it all the way. The controller should be set to keep it at a safe minimum voltage. It prevents over-discharging; that’s why It’s a sharp cutoff. I just charge when I notice it’s not as peppy.

 

[hsdrggr]

I just wanted to add some info about a charger that I found that is very inexpensive and allows variable termination voltages to be set for e-bike batteries. Sometimes It’s a pretty hard pill to swallow for some when they see the price of a Grin Satiator Charger at $365. While it is probably one of the best fully adjustable chargers out there, it’s a difficult decision to pull the trigger on one when regular 2amp e-bike chargers are around $25.
Shenzhen Hengji Power Electronics Co. has an adjustable output e-bike battery charger, model HGJI-1608, for approximately $30. Even though I have 2 Grin Satiator chargers I ordered one of these chargers to see if it would work to charge e-bike batteries to 80-85% SOC. And does fairly closely. While the voltages are not actually adjustable on this charger there are enough voltages that are selectable that will get you very close to the 80-85% SOC for 48v(13s) and 52v(14s) e-bike battery packs. According to my Grin Satiator 85% SOC for Li-Ion cells calculates out to 4.046volts per cell. So for a 48v 13s battery pack that is 52.6v and for a 52v 14s battery pack it is 56.65v.
So I charge my 48v e-bike batteries to 52.2v on the LiHv battery type setting, and my 52v batteries to 56.55v on the LiHv battery setting. These voltages are in the range of 80-85% SOC for these batteries. Keeping batteries charged only to 80-85% SOC reduces battery cell degradation significantly and will pretty much triple the life of Li-Ion e-bike packs.
Then if you really want to charge to 100% SOC to get the max out of your battery, charge it from the 85% to 100% just before you ride. That way cell degradation is minimal due to only being at it’s 100% SOC for a short time. Here’s a link to the charger on Aliexpress: it’s kind of like China’s eBay but it is worldwide. I’ve been using this charger for about 6 months and it has worked perfectly.

Adjustable Power Adapter Charger 3V-60V 150W With Display Screen Charger 2.8V 14V 28V 36V 48V 56V 60V Li-ion battery Charger

https://a.aliexpress.com/_mqN2BUy

Facebook link: https://fb.watch/kxsQJHXhYi/?mibextid=v7YzmG

 

[Smaug]

Thanks for the info. Would you mind sharing an image of the safety certification marks? (if any)

I see vents in the sides of it; I presume it's fan-cooled then?

I really like this idea. It's more sophisticated than the timer method and making calculations based on assumptions.

It seems to just have the one charging plug. I think that would fit my Lectric XP Lite and Aventon Level.2, but certainly not the multi-pin one on my Electra.

 

[Smaug]

As a high labor hack for this with the stock chargers, you could just use the OEM charger and unplug it when it starts to cool down. (if you're around and you think of it)

Lithium-ion batteries charge with a constant current scheme, then switch to constant voltage, once the maximum voltage has been reached. In the constant current phase, the charger puts out its maximum current, since the pack voltage is below the max allowed. When the pack reaches its maximum voltage under constant current, it just keeps it at that max. voltage and scales down the charge current until it reaches a minimal level. As it scales down, one will notice the charger getting cooler.

Yep, it would take some supervising. Or maybe a time calculation and then just come and unplug it. (if one is home and conscious)

By the way, in that Electrek article that M@ linked to above, Micah said:

Unfortunately I don’t know of any cell phones or laptop manufacturers that make 80-90% charging easy, ...

Apple has it as a charging option for their iPhones now. If you allow it, when you plug in at night, it will wait until you're within about an hour or two of when you normally get up to fully charge it.
With phones, it's a little easier, since chargers are everywhere. I've been just not plugging in at night and instead charging here and there. At my desk, in the half hour car drives, etc.

My wife has not allowed that charging scheme and tops her phone off all the time. We'll see how battery life compares between our two phones, which we got at about the same time.

More here: https://support.apple.com/en-us/HT210512

It will be awhile before eBike manufacturers catch up to this tech.

 

[Smaug]

There were some earlier comments on using within the 20-80% SoC range.

You guys are using pack voltage measurement, rather than displayed capacity. I'm not sure we can accurately correlate open circuit pack voltage to state of charge.

We also can't really trust the level of displayed capacity, since we don't know how the manufacturer's BMS works. (or do we?)

For example, My Aventon Level.2 has a nice display that shows SoC with a percentage. Is that the true percentage, or does that take into account a tolerance? For example, it is not going to let it discharge to 0. When it says 10% SoC is it really 20%? Someone else alluded to this above.

One thing is for sure, though. For the purposes of battery life, it is better to have more capacity than we need, so that we can sacrifice some of it in the interest of pack longevity. My wife's eBike, an Electra Townie GO! 7D, has a 36 V, 7 Ah pack. There's not a lot of extra capacity to play with here. It's also built into the frame, so probably not easy to change.

 

[Smaug]

I just did a quick video on the charger hsdrggr suggested in Post #12:

 

[hsdrggr]

Thanks for the info. Would you mind sharing an image of the safety certification marks? (if any)

I see vents in the sides of it; I presume it's fan-cooled then?

I really like this idea. It's more sophisticated than the timer method and making calculations based on assumptions.

It seems to just have the one charging plug. I think that would fit my Lectric XP Lite and Aventon Level.2, but certainly not the multi-pin one on my Electra.

I haven’t tried it on 3-wire charging e-bikes that use a sense wire. There are mfgs that make a few adapter cables that have the 5.5mm female for this. I have one for the 3-pin GX16 charging port that I used on 2 batteries I built. I know the Satiator works with the Aventon Aventure in Force Mode without issues. I’ll have to try the HGJ1 to see if it will charge an Aventon battery also. I’ll let you know when I get a minute to make a cable and try it.

 

[hsdrggr]

Just FYI, the %SOC on the Aventon display is pretty close to correct. If you disconnect the factory charger as soon as the battery indicator starts flashing blue, the bikes display shows around 85% and the voltage is approximately 52v.

 

[Smaug]

I made a mistake yesterday and overcharged my Lectric XP Lite battery. I set it for 53.2 V NOMINAL, instead of the 52.2 V charging voltage. On the back of the charger, that 2nd column from the table in hsdrggr is only in Chinese, so I was late in figuring it out.

Luckily, nothing happened, except that the pack voltage was at 61 V and it was still putting 0.3 A into it when I got home. After checking that the smoke hadn't been let out, I rode it around for about 10 minutes at full throttle to make sure it was back to the safe range.

Re. multi-conductor cables, the one Electra uses is a lot more than 3-conductor, probably to communicate with the optional external battery pack.

Re. charging the Aventon battery, it did fine on my Level.2's.

 

[hsdrggr]

Yeah, got to be careful. I’m Glad your battery is ok. But it’s nice that the charger keeps the previous setting when it’s turned on. At least if you’re only charging one type pack it makes it less likely that you will make a mistake.