Uses for weak EBike batteries

akakpaws

Member
While discussing my battery problems with my 2015 epic SE, a friend of mine mentioned that there was a way to use the old battery as a power supply for less demanding applications. while the battery may no longer have enough power to run the bike it can certainly charge phones and tablets perform and other less demanding applications. Anyone heard of anything like this? I was told there is a way of connecting a USB charging port like they have on the 2016 and newer EJoe models. would love to hear comments on this from the forum. Thanks.
 
You can, but do you really want to? The size and energy density ratio isn't that good.
Also, from my experience, weak batteries take just as much electricity to charge it to full, but drains a lot quicker. (somebody correct me if I'm wrong)
The cost benefit factor isn't that good.

Would you take 15 year old Toyota Prius battery so that you can recharge your ebike battery?
Great points! I was just looking for some way to re-purpose this very expensive battery rather than just toss it. Recycling is fine but repurposing is better am I right?
 
You could keep it around for power outages to run a light bulb, play a radio or charge a phone... But that is going to depend on how big of a problem that is in your area. Keep in mind that to store your used battery for emergency use it would be best to do so at 50-65% so when an unexpected outrage occurs it will already be half drained, not to mention that it is weak already. Then you'll have to periodically check /charge it to maintain the storage voltage.
It could be used for this and it can always be recycled later on down the road...but it's usefulness is something that you will need to decide.
 
You could keep it around for power outages to run a light bulb, play a radio or charge a phone... But that is going to depend on how big of a problem that is in your area. Keep in mind that to store your used battery for emergency use it would be best to do so at 50-65% so when an unexpected outrage occurs it will already be half drained, not to mention that it is weak already. Then you'll have to periodically check /charge it to maintain the storage voltage.
It could be used for this and it can always be recycled later on down the road...but it's usefulness is something that you will need to decide.
thanks again GR
 
The problem is that you have to spend some money to be able to use the 36v or 48v DC current. You'll need a transformer to either get 120v or (10v ?) to charge a phone. Seems like throwing good money after bad.
 
While discussing my battery problems with my 2015 epic SE, a friend of mine mentioned that there was a way to use the old battery as a power supply for less demanding applications. while the battery may no longer have enough power to run the bike it can certainly charge phones and tablets perform and other less demanding applications. Anyone heard of anything like this? I was told there is a way of connecting a USB charging port like they have on the 2016 and newer EJoe models. would love to hear comments on this from the forum. Thanks.
As Li-ion batteries age they lose storage capacity. Some ebike manufacturers actually base their battery warranty on remaining capacity after a certain number of charge cycles such as "75% minimum capacity after no less than 300 charge cycles". Under these terms a 500Wh battery would be termed OK if it still held 500Whx0.75=375Wh of energy after 300 charge cycles.

This graph from Battery University illustrates typical Li-ion cell capacity loss vs charge cycles.
lithium2.jpg

Higher charge voltages boost capacity but lowers cycle life and compromises safety.

I
like this article that discusses Li-ion Battery Repurposing. It argues that an old EV battery pack still has valuable applications as it would typically still have 70% capacity avaialble. An example is home battery backups for solar systems. I read a recent article that reviewed a business having good success with this but can't find it in a quick search tonight.

There's no technological reason this couldn't be done with ebike batteries as well. For now it will be volume limited, probably not enough ebike batteries to bother with. On a personal level I can see keeping an older ebike battery around as a range extender or as a power source for charging any number of devices much like Power Banks are used today. A voltage converter would be needed to get the desired output voltage. This $12 solid state converter will provide 5VDC @ 3A (think USB charger ports) from an input voltage ranging from 8-58VDC (12, 24, and 48 volt ebike batteries would work). This could be handy during power outages, some camping and boating setups, etc.
 
6z I checked out that thread but I am not sure what you wanted me to see there. So what am I missing?
My point was that a weak battery has value in that it can be refitted with new cells rather than be used for a purpose it wasn't intended. Just another option.
 
My point was that a weak battery has value in that it can be refitted with new cells rather than be used for a purpose it wasn't intended. Just another option.
Not sure proprietary Specialized or Giant batteries could be refitted as you say. (Anybody knows for sure?)
 
Not sure proprietary Specialized or Giant batteries could be refitted as you say. (Anybody knows for sure?)
I don't know about Giant or Specialized. Generally speaking, if the case can be disassembled (screws or seams that can be cut) there is a good possibility it can be rebuilt. Some batteries have molded cases which can be very difficult to take apart.

A few places to check are:

Among others, this place lists Giant rebuilds:

This site says they will rebuild ANY e-bike battery:


There are various you tube videos on how to do it yourself but it requires a good deal of skill. There is also a certain amount of risk involved should you make a mistake.
 
The possible issue is the proprietary batteries store a lot of diagnostic information, and I see a devil there.
 
The possible issue is the proprietary batteries store a lot of diagnostic information, and I see a devil there.
Yes, I agree. The BMS in many batteries have a memory and need to communicate with the charger. Some also use Bluetooth to transmit information to a smartphone app. All of this could be affected by a rebuild.
 
Yes, I agree. The BMS in many batteries have a memory and need to communicate with the charger. Some also use Bluetooth to transmit information to a smartphone app. All of this could be affected by a rebuild.
Wow, really encouraging to see so many EBike enthusiasts take an interest in this issue. As the E bike thing takes off there will be zillions of these things out there and this is a good time to think about what to do with them so they don't end up someplace where they can do more harm than good. Thanks to all for your comments and insight to date and keep them coming!
 
I don't know about Giant or Specialized. Generally speaking, if the case can be disassembled (screws or seams that can be cut) there is a good possibility it can be rebuilt. Some batteries have molded cases which can be very difficult to take apart.

A few places to check are:

Among others, this place lists Giant rebuilds:

This site says they will rebuild ANY e-bike battery:


There are various you tube videos on how to do it yourself but it requires a good deal of skill. There is also a certain amount of risk involved should you make a mistake.
I don't know about Giant or Specialized. Generally speaking, if the case can be disassembled (screws or seams that can be cut) there is a good possibility it can be rebuilt. Some batteries have molded cases which can be very difficult to take apart.

A few places to check are:

Among others, this place lists Giant rebuilds:

This site says they will rebuild ANY e-bike battery:


There are various you tube videos on how to do it yourself but it requires a good deal of skill. There is also a certain amount of risk involved should you make a mistake.
If anyone has had experience with this company Ebike marketplace getting their battery rebuilt hopefully they will share it here?
 
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