Getting more life out of a lithium ion bike battery

[Veggyhed]

I agree with this 80% rule. It's also really good to use on your cell phones or any other lithium based energy storage solution.
I really need to buy one of these charges. Thank you for posting these.

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[radrover4fun]

I have been watching this thread and it struck a chord with me.  I have a Tesla and it is only supposed to be charged to 80% unless I am going on a trip and need more range.  So today I received my Lectric xp, I already have 3 Rads and finally got my oldest daughter interested in riding so I figured lets check out the Lectric.

It says basically what has been said on this thread, charge to 75% and top off either the night before or morning of rides.  Keep it close to 75% for storage.

I am not sure why Rad has us topping off after every ride, but between my Tesla and now the Lectric XP saying not to keep fully charged I am going to stop charging them up after each ride.

Gary

[Altema]

I am not sure why Rad has us topping off after every ride, but between my Tesla and now the Lectric XP saying not to keep fully charged I am going to stop charging them up after each ride.

I think Rad's idea is that it will keep your bike ready to go all the time, and having a full charge gives a more favorable impression. Basically, Rad is putting perception above battery longevity.

[vudude]

I think there is good reason to use this 80% charge method. The Luna 48v advanced charger just arrived. After setting for 80%, 2A the charger charged to about 87% according to the volts, then went into this oscillation turn off 3-4 sec., turn on 3-4 sec., turn off 3-4 sec., turn on 3-4 sec., ..., can anyone confirm this is normal?
Seemed kind of weird to me!  Thanks

[Altema]

I think there is good reason to use this 80% charge method. The Luna 48v advanced charger just arrived. After setting for 80%, 2A the charger charged to about 87% according to the volts, then went into this oscillation turn off 3-4 sec., turn on 3-4 sec., turn off 3-4 sec., turn on 3-4 sec., ..., can anyone confirm this is normal?
Seemed kind of weird to me!  Thanks

yes, the off / on cycle at the end of the charge is doing the final balancing of the cells in the pack. quite normal...

That particular on/off cycle, with the Luna charger on the Rad battery, is because the BCM (battery control module) of the Rad battery does not give back an accurate voltage reading unless current is flowing into it. It's a protective design, and Luna Cycle tech support informed me that the Rad battery key switch needs to be in the "On" position. So that's what I do now, and the charger just stops charging when it's done and stays that way without cycling.

[wkindred]

I think there is good reason to use this 80% charge method. The Luna 48v advanced charger just arrived. After setting for 80%, 2A the charger charged to about 87% according to the volts, then went into this oscillation turn off 3-4 sec., turn on 3-4 sec., turn off 3-4 sec., turn on 3-4 sec., ..., can anyone confirm this is normal?
Seemed kind of weird to me!  Thanks

yes, the off / on cycle at the end of the charge is doing the final balancing of the cells in the pack. quite normal...

That particular on/off cycle, with the Luna charger on the Rad battery, is because the BCM (battery control module) of the Rad battery does not give back an accurate voltage reading unless current is flowing into it. It's a protective design, and Luna Cycle tech support informed me that the Rad battery key switch needs to be in the "On" position. So that's what I do now, and the charger just stops charging when it's done and stays that way without cycling.

wish the luna cycle tech would have told me the same when i inquired several months ago...     

[vudude]

Thanks guys, good tip Altema. I'll turn the key to on next time.

[Altema]

wish the luna cycle tech would have told me the same when i inquired several months ago...     

That would have been nice 
Perhaps they weren't aware of it back then, or at least that tech wasn't.

[galvitron]

I think there is good reason to use this 80% charge method. The Luna 48v advanced charger just arrived. After setting for 80%, 2A the charger charged to about 87% according to the volts, then went into this oscillation turn off 3-4 sec., turn on 3-4 sec., turn off 3-4 sec., turn on 3-4 sec., ..., can anyone confirm this is normal?
Seemed kind of weird to me!  Thanks

yes, the off / on cycle at the end of the charge is doing the final balancing of the cells in the pack. quite normal...

That particular on/off cycle, with the Luna charger on the Rad battery, is because the BCM (battery control module) of the Rad battery does not give back an accurate voltage reading unless current is flowing into it. It's a protective design, and Luna Cycle tech support informed me that the Rad battery key switch needs to be in the "On" position. So that's what I do now, and the charger just stops charging when it's done and stays that way without cycling.

I'm having this issue with the charger cycling on/off after reaching 80% even with the battery key switch in the "On" position. I have a RadCity Step-Thru 3 purchased in Sept. 2020. The original controller went out and the support person said the corresponding control wasn't available and sent a different one that's compatible (referred to as 'Controller 2020 - City HS' in the order). The controller works fine for the bike, but I wonder if it's the reason the charger is cycling.

[Altema]

I think there is good reason to use this 80% charge method. The Luna 48v advanced charger just arrived. After setting for 80%, 2A the charger charged to about 87% according to the volts, then went into this oscillation turn off 3-4 sec., turn on 3-4 sec., turn off 3-4 sec., turn on 3-4 sec., ..., can anyone confirm this is normal?
Seemed kind of weird to me!  Thanks

yes, the off / on cycle at the end of the charge is doing the final balancing of the cells in the pack. quite normal...

That particular on/off cycle, with the Luna charger on the Rad battery, is because the BCM (battery control module) of the Rad battery does not give back an accurate voltage reading unless current is flowing into it. It's a protective design, and Luna Cycle tech support informed me that the Rad battery key switch needs to be in the "On" position. So that's what I do now, and the charger just stops charging when it's done and stays that way without cycling.

I'm having this issue with the charger cycling on/off after reaching 80% even with the battery key switch in the "On" position. I have a RadCity Step-Thru 3 purchased in Sept. 2020. The original controller went out and the support person said the corresponding control wasn't available and sent a different one that's compatible (referred to as 'Controller 2020 - City HS' in the order). The controller works fine for the bike, but I wonder if it's the reason the charger is cycling.

I assume the original Rad battery charger works fine, and the only issue is with the Luna Cycle charger. You can eliminate the controller affecting the Luna charger by removing the battery from the bike, turning the battery on, and trying the charger. If the charger operates normally, then the controller may indeed be the cause. If the Luna charger is still acting up, I would contact Luna Cycle and make it clear it does it with the battery turned on.

[galvitron]

I think there is good reason to use this 80% charge method. The Luna 48v advanced charger just arrived. After setting for 80%, 2A the charger charged to about 87% according to the volts, then went into this oscillation turn off 3-4 sec., turn on 3-4 sec., turn off 3-4 sec., turn on 3-4 sec., ..., can anyone confirm this is normal?
Seemed kind of weird to me!  Thanks

yes, the off / on cycle at the end of the charge is doing the final balancing of the cells in the pack. quite normal...

That particular on/off cycle, with the Luna charger on the Rad battery, is because the BCM (battery control module) of the Rad battery does not give back an accurate voltage reading unless current is flowing into it. It's a protective design, and Luna Cycle tech support informed me that the Rad battery key switch needs to be in the "On" position. So that's what I do now, and the charger just stops charging when it's done and stays that way without cycling.

I'm having this issue with the charger cycling on/off after reaching 80% even with the battery key switch in the "On" position. I have a RadCity Step-Thru 3 purchased in Sept. 2020. The original controller went out and the support person said the corresponding control wasn't available and sent a different one that's compatible (referred to as 'Controller 2020 - City HS' in the order). The controller works fine for the bike, but I wonder if it's the reason the charger is cycling.

I assume the original Rad battery charger works fine, and the only issue is with the Luna Cycle charger. You can eliminate the controller affecting the Luna charger by removing the battery from the bike, turning the battery on, and trying the charger. If the charger operates normally, then the controller may indeed be the cause. If the Luna charger is still acting up, I would contact Luna Cycle and make it clear it does it with the battery turned on.

Yes, the original Rad charger works fine. I tried charging to 80% with the battery removed and the Luna charger still cycles on and off with the voltage on the Luna display going from 52.8 V to 36.5 V. So the controller is off the hook. Measuring the battery directly with a voltmeter reads 41.7 V. The 52.8 V value must be correct because the bike display shows full bars, but why would the battery read the lower voltage even with the key in the 'on' position? Maybe it's a feature of the BMS? I'm hesitant to reach out to Luna because it seems like the Luna charger is working correctly, but keeps getting turned back on because of the lower (incorrect) voltage reading.

[Altema]

Ok, controller ruled out 😊
Where were you measuring the battery voltage from with the meter, from the charge port or the two outer pins from the connector on the battery? A 48 volt battery at 100% is 54.6 volts, but the Rad charger usually gets the battery up to 54.4 - ish.
Charge the battery up with the Rad charger until the green light comes on, disconnect the charger, then measure the battery voltage at the terminals after 15 minutes. If it measures low, below 50 volts, then your battery may be bad. If the Battery voltage measures full, between 53.8 and 54.6 volts, then contact Luna about a possible problem with the charger. They will probably walk you through a few tests.

[Veggyhed]

What an interesting topic.
So if you turn the key on and the charger works that means that there is no BMS when the battery is turned on and the BMS for the most part is regulated by the controller of the bike.

Have you been able to take a voltage reading from the charge port and not from the lower terminals of the battery? Is there a difference?

I'm not so sure it would be safe to charge the battery with the key in the on position if it really is bypassing the BMS. I realize the charger is fairly smart but it's better to have two safety checks hence the BMS and the charger and the BMS in the battery.

How many other people who own the Luna charger are having this kind of problem?

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[Altema]

What an interesting topic.
So if you turn the key on and the charger works that means that there is no BMS when the battery is turned on and the BMS for the most part is regulated by the controller of the bike.

Have you been able to take a voltage reading from the charge port and not from the lower terminals of the battery? Is there a difference?

I'm not so sure it would be safe to charge the battery with the key in the on position if it really is bypassing the BMS. I realize the charger is fairly smart but it's better to have two safety checks hence the BMS and the charger and the BMS in the battery.

How many other people who own the Luna charger are having this kind of problem?

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I would have to take a Rad battery apart to confirm, but I believe the BMS does not get bypassed with the key on. The battery voltage measures differently at the charge port than it does at the output terminals when the key is off, and they measure the same when the key is on. Maybe some sort of extra protection circuit before the BMS? I'm just guessing about the BMS at the point, but the tests should be valid.

[Veggyhed]

Well that's interesting. I wonder if it has to do with the circuitry that allows for battery charge level on the battery itself. The small LED display at the top of the battery because the key has to be in a set position for the LEDs to display the charge on the battery.

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