Electric bike battery care

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
So very true. Not matching manufacturer, age and internal resistance is a recipe for disaster

Pretty much what I was thinking when I said "really knows what they are doing". There's a bunch of stuff that needs to be considered. Didn't think going in to all the specifics here was worth it.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Pretty much what I was thinking when I said "really knows what they are doing". There's a bunch of stuff that needs to be considered. Didn't think going in to all the specifics here was worth it.

No worries... I got your back!
 

mogulskier

Active Member
Like others have posted, I follow the manufacturers care and maintenance practices, in the case of the Shred, don't leave it charging for more than 12 hours, don't fully drain the battery, store the battery between 50%-75% charge, etc.

I ride almost every day, so battery charge fluctuates between around 40% to 80%, I only fully charged it to 100% once when I bought it.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Like others have posted, I follow the manufacturers care and maintenance practices, in the case of the Shred, don't leave it charging for more than 12 hours, don't fully drain the battery, store the battery between 50%-75% charge, etc.

I ride almost every day, so battery charge fluctuates between around 40% to 80%, I only fully charged it to 100% once when I bought it.
To get top performance and best life from your battery, you owe it to yourself to fully charge, to 100%, more frequently. For details, look into "balance charging", what it takes, and the benefits of having all cells fully charged.
 

FlatSix911

Well-Known Member
Region
USA
City
Silicon Valley
To get top performance and best life from your battery, you owe it to yourself to fully charge, to 100%, more frequently. For details, look into "balance charging", what it takes, and the benefits of having all cells fully charged.
Most high-quality OEM battery packs from Bosch, Brose, Shimano, and Yamaha have an internal BMS to balance the cells. ;)
The best practice to maximize battery life is to charge to 80%... 3 times the number of useful cycles compared to 100% charging.
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AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
For starters, not all of us are riding high end bikes. Further, I don't see how even the best BMS can maintain balance on all cells indefinetly if it's shut off when the charge reaches 80%.

I'd have to see some pretty convincing documentation indicating ANY BMS is capable of bringing all cells up equally the entire time the charger is running. Even at that point, a blanket statement telling everyone that ALL BMS are capable of that, or that they should never balance charge is a huge stretch. Much easier to agree to disagree on your point.

I'll stand by my original point, that charging to 100% is a good plan on occasion, to assure the voltage in all of your pack's individual cells are charged equally. Maybe I'd add that an exception might be if you somehow know/believe you have some super BMS in play that's capable of balance charging when shut off at 80%. How's that? -Al
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Most high-quality OEM battery packs from Bosch, Brose, Shimano, and Yamaha have an internal BMS to balance the cells. ;)
The best practice to maximize battery life is to charge to 80%... 3 times the number of useful cycles compared to 100% charging.

For starters, not all of us are riding high end bikes. Further, I don't see how even the best BMS can maintain balance on all cells indefinetly if it's shut off when the charge reaches 80%.

I'd have to see some pretty convincing documentation indicating ANY BMS is capable of bringing all cells up equally the entire time the charger is running. Even at that point, a blanket statement telling everyone that ALL BMS are capable of that, or that they should never balance charge is a huge stretch. Much easier to agree to disagree on your point.

I'll stand by my original point, that charging to 100% is a good plan on occasion, to assure the voltage in all of your pack's individual cells are charged equally. Maybe I'd add that an exception might be if you somehow know/believe you have some super BMS in play that's capable of balance charging when shut off at 80%. How's that? -Al

I agree that it's best to bring the pack to 100% occasionally... but there are BMS 's that implement Active Balancing and balance as they charge. It's not magical or a super BMS... it's just a little more sophisticated and thus a little more expensive.

edit: Active cell balancing is a more complex balancing technique that redistributes charge between battery cells during the charge and discharge cycles, thereby increasing system run time by increasing the total useable charge in the battery stack, decreasing charge time compared with passive balancing, and decreasing heat ...
 
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AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
edit: Active cell balancing is a more complex balancing technique that redistributes charge between battery cells during the charge and discharge cycles, thereby increasing system run time by increasing the total useable charge in the battery stack, decreasing charge time compared with passive balancing, and decreasing heat ...
So unless you're pretty sure you have a BMS with "active cell balancing" (which I find not very likely for the majority of us), charging to 100% on occasion is a good plan. If you would like to find out if your rig has "active cell balancing" I wish you the best of luck.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
So unless you're pretty sure you have a BMS with "active cell balancing" (which I find not very likely for the majority of us), charging to 100% on occasion is a good plan. If you would like to find out if your rig has "active cell balancing" I wish you the best of luck.
I'd assume that if your battery has Active Balancing that it would be advertised as having it. It wouldn't make sense for a manufacturer to implement this technology and not utilize it as a selling point. That said.. I believe most of us have Passive Balancing BMS's
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
"Passive" being the key word. Not "Active". Meaning you need to balance charge on your own. it's NOT being done automatically....
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
"Passive" being the key word. Not "Active". Meaning you need to balance charge on your own. it's NOT being done automatically....
No... Passive meaning that the BMS doesn't implement a process during the charge but instead burns off the excess voltage in cells as it reaches full charge. The BMS is still doing the balancing. Maybe understand the process before you get your panties in a bunch.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
No... Passive meaning that the BMS doesn't implement a process during the charge but instead burns off the excess voltage in cells as it reaches full charge. The BMS is still doing the balancing. Maybe understand the process before you get your panties in a bunch.
Sorry, you're above my pay grade. Show me something that can be covered in a blanket statement regarding the need to balance charge, or not. Something relelevant to the majority of riders with e-bikes today.

Could care less about the details.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Sorry, you're above my pay grade. Show me something that can be covered in a blanket statement regarding the need to balance charge, or not. Something relelevant to the majority of riders with e-bikes today.

Could care less about the details.
Jeeezz dude... I agreed with you that most of us need to fully charge. 10 minutes ago you didn't even know active balancing was a thing., so I tried to inform you. I could care less what you know or understand. You're creating a disagreement out of nothing.
 

mogulskier

Active Member
Thanks guys for the info on this. Point taken. Will start on the path of charging to 100% occasionally to extend the life and performance of the battery.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Jeeezz dude... I agreed with you that most of us need to fully charge. 10 minutes ago you didn't even know active balancing was a thing., so I tried to inform you. I could care less what you know or understand. You're creating a disagreement out of nothing.
Many apologies. Maybe I was. What I was after was a simple statement that applied to most everyone reading this. KISS! No technical understanding required or implied nor exceptions noted. Kinda like the statement I started with up in note #44
 

FlatSix911

Well-Known Member
Region
USA
City
Silicon Valley
Unfortunately, there is a lot of misinformation in this thread... here is a more accurate summary from our resident battery expert, Ravi Kempaiah (electricbikereview.com) ;)
(9) Balance Charging? 100% Charging? | Page 2 | Electric Bike Forums - Q&A, Help, Reviews and Maintenance (electricbikereview.com)
Thanks for tagging me in. I spoke with a friend of mine who has many years of experience designing BMS for battery packs before replying here.
You are right about the parallel groups but you need to balance the cells in series as well. There are many ways to do that and it is not as easy as it may seem. The summary is:
  1. Passive balancing is more common in BMS boards where cost is a major design constraint and it makes use of bypass resistors. This kind of balancing works when you are charging the battery pack and not when you are discharging. Packs that can be be purchased for ~$250, it may most likely use one of these bypass resistor based balancing circuits.
  2. Active balancing on the other hand is more complex and needs more components in the BMS board. What you are referring in your question comes under the gamut of active cell balancing where one cell transfers the excess charge to the next cell. To transfer this charge, the circuit needs to know when to initiate this process, when to stop this process, how much to transfer etc. This necessitates a few more components, larger footprint and I frankly don't think run-of-the mill E-bike batteries can afford that. To explain the complexity of your question, I am attaching this document by Analog Devices ( which is a well respected company just like Texas Instruments). They explain it much better than I could do now.
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AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
What is your point? You contradicted my point saying we should balance charge frequently. That an 80% charge isn't accomplishing a good balance charge. Are you saying all of us have the potential to charge as indicated in Ravi's post with our OEM batteries and chargers?
 

FlatSix911

Well-Known Member
Region
USA
City
Silicon Valley
What is your point? You contradicted my point saying we should balance charge frequently. That an 80% charge isn't accomplishing a good balance charge.
Are you saying all of us have the potential to charge as indicated in Ravi's post with our OEM batteries and chargers?
Please re-read my post and Ravi's as a follow-up.
TLDR... It's not a good idea to charge to 100% frequently for your battery life. YMMV. ;)
 
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