Battery Test
- Thread starter akakpaws
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Gionnirocket
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- Y. O.
Easiest test for a battery is a real life load test. Charge it up and go for a ride and put it under some load by going up some hills. Don't be abusive but ride it a little hard and take note of voltage before, during and after.
There are ways of opening it up and checking cells but I wouldn't recommend doing that, especially since it's a 5 year old battery and there's not much you can do to repair it other than making sure the pack is as balanced as possible.
What are your concerns for testing it?
There are ways of opening it up and checking cells but I wouldn't recommend doing that, especially since it's a 5 year old battery and there's not much you can do to repair it other than making sure the pack is as balanced as possible.
What are your concerns for testing it?
thanks for your response and help. On a recent ride the power suddenly died even though the battery showed full charge. The power comes back after a little while but then when I try to ride it again the same thing happens. It happens when I am going up hills and peddling mostly. I can pedal or use the trigger on the flats with no problem. So the problem only happens under load apparently.
Gionnirocket
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- USA
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- Y. O.
Does your display have a voltage reading? If so do you see a large voltage drop when you ride?
Or do you have a voltage meter that you can take a measurements with in the garage? Full charge voltage? Voltage after a ride?
Or do you have a voltage meter that you can take a measurements with in the garage? Full charge voltage? Voltage after a ride?
my bike does not have a display at all to give a voltage reading. I have a voltmeter. but I'm not sure how to connect it to get the reading you are suggesting. if there is a large voltage drop when I ride what does that indicate? thanks for your help.
Gionnirocket
Well-Known Member
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- USA
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- Y. O.
A large voltage drop would indicate that you have some weak cells. The battery and/or controller have a low voltage cut off to protect the battery. On a 5 year old battery it's probably not worth repairing as it does involve some cost, skill and knowledge and not something that I recommend doing yourself.
It could also be a problem with the controller or BMS as well but the more likely problem is the battery.
To take a voltage reading, you might be able to use your charging port if you have one or you can unplug the battery from the motor and test there.
It would be helpful to test under load so you could fabricate a tap on the main power plug for your meter leads. Set the bike up on a stand and run the motor. To simulate load you could gradually apply the brakes. If your brakes have motor cut off built in you could actuate them at the caliper. You can also apply load by applying friction to the back tire with something like a stiff broom.
Keep in mind that doing this is somewhat unsafe, would require 2 people and a mechanics working knowledge. I wouldn't do it repeatedly or for long periods.
If this is something you are not familiar with or are not comfortable doing it would be best to seek out some local professional help.
edit: a helpful tool could be to install something like THIS between the battery and the motor and it provides a little more info all at once unlike a multimeters
It could also be a problem with the controller or BMS as well but the more likely problem is the battery.
To take a voltage reading, you might be able to use your charging port if you have one or you can unplug the battery from the motor and test there.
It would be helpful to test under load so you could fabricate a tap on the main power plug for your meter leads. Set the bike up on a stand and run the motor. To simulate load you could gradually apply the brakes. If your brakes have motor cut off built in you could actuate them at the caliper. You can also apply load by applying friction to the back tire with something like a stiff broom.
Keep in mind that doing this is somewhat unsafe, would require 2 people and a mechanics working knowledge. I wouldn't do it repeatedly or for long periods.
If this is something you are not familiar with or are not comfortable doing it would be best to seek out some local professional help.
edit: a helpful tool could be to install something like THIS between the battery and the motor and it provides a little more info all at once unlike a multimeters
Last edited:
harryS
Well-Known Member
Hi akakpaws. You've got a familiar story. When an old battery shows full charge but cuts out under load, it's just an old battery that has lost capacity. You could measure it and analyze it, but the end result is you will be buying a replacement.
I just had a battery go bad on me. Used to get 10 miles before it dropped a bar. Now it goes 5 miles, and when it's down to 2 bars at 10 miles, it quits when I reach a hill or use throttle. I've got a voltmeter in my display. I've got the wattmeter discussed earlier. I could bore everyone with the voltages and the amp-hours. It won't change what I have, a tired out battery.
If you have a meter, you can test the pack after it comes off the charger, taking it out of the Ejoe and applying the test probes to the battery pins. A new 48V pack will read 54.6V and a 36V pack will read 42.0V. You can also re-test after the bike starts shutting off, but it will just re-confirm what you already know. Battery is tired.
It could also be unbalanced. and some batteries have balance circuits to correct that, but I'll let you look it up or someone else may discuss it. Even if it rebalances, it's still five years old.
Sad thing about lithium. Unless you stored it properly, it could be this way after five years even if you barely used it.
Thanks HS. So far everything I've heard researched and referenced indicates exactly that, a tired battery. I guess that's the downside of an electric bike, the batteries are very expensive, touchy about upkeep, and useless once they go bad. There should be a refurbishment service for these things rather than have to buy the whole expensive thing every few years. thanks again for your input.
GRocket thanks for your input. Can you provide any more info as to how I should connect that device besides between the battery and the motor? All of this is very discouraging as you can imagine. I wonder if EJoe can weigh in and offer a any suggestions on this issue? it would be nice if they did. Thanks again
Gionnirocket
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- Y. O.
I did a quick search and I don't have encouraging news. Seems your battery is a Lipo and though great because of flexibility in size and casing, they're known for not having the longest life span... Further leading to the hypothesis that the battery is at the end of its usefulness.
Your bike is also a folding rear hub so I'm not familiar where you'd be able to tap the power connection for testing. But as Harry stated, it will probably be an exercise with the end result being the conclusion already suspected.
If you really wanted to test it you'd have to follow the wiring between the motor and battery and see where the most convenient place to intercept a connection is. The motor should have a connector at some point.
If I was in your position.. I would start contemplating a replacement. Give eJoe a shout and see what your options are. There are companies that rebuild batteries with new cells but they're not necessarily cheaper.
edit... I just clicked on another link and it said that the battery is Li ion... Which typically have a longer lifespan. That said because of the age of your battery I don't know which links are relevant. In the end I think you are still in the same place regardless.
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Ravi Kempaiah
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- Canada
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- Halifax
Harry, you are right.
@akakpaws
These guys do battery refurbishing. They have worked on many different kinds. Give them a call.
Selling Ebike Battery | Defective ebike battery
Replace your Defective ebike lithium battery online! We are selling Ebike Battery for replacements. Place your order! Visit us!
www.fthpower.com
I definitely will. Thanks for the information.Harry, you are right.
@akakpaws
These guys do battery refurbishing. They have worked on many different kinds. Give them a call.
Selling Ebike Battery | Defective ebike battery
Replace your Defective ebike lithium battery online! We are selling Ebike Battery for replacements. Place your order! Visit us!
Gionnirocket
Well-Known Member
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- USA
- City
- Y. O.
akak'...a few things to consider when replacing your battery.
If you go the rebuild route compare the brand and cells being used to the eJoe. Though the major brands are reliable there are some differences and there is plenty of info out there to be had.
Also check out the physical wear on your battery. Look at the case, connection points and the feel of any switch and/or charging port when used.
Then there's the shipping. Shipping a battery such as these can be a little pricey. It has to be packed properly and the box marked as hazardous which carries extra fees and carrier restrictions.
Not trying to push you away from a refurbish but in the end the price difference may be negligible and you'll end up with a pack with some used parts. I wish it was more cost effective as I'm all for recycle and reuse, but sometimes it doesn't make sense economically.This is an ever evolving industry so there might be some good deals out there.
Good luck and let us know what you come up with.
If you go the rebuild route compare the brand and cells being used to the eJoe. Though the major brands are reliable there are some differences and there is plenty of info out there to be had.
Also check out the physical wear on your battery. Look at the case, connection points and the feel of any switch and/or charging port when used.
Then there's the shipping. Shipping a battery such as these can be a little pricey. It has to be packed properly and the box marked as hazardous which carries extra fees and carrier restrictions.
Not trying to push you away from a refurbish but in the end the price difference may be negligible and you'll end up with a pack with some used parts. I wish it was more cost effective as I'm all for recycle and reuse, but sometimes it doesn't make sense economically.This is an ever evolving industry so there might be some good deals out there.
Good luck and let us know what you come up with.
Great advice and much appreciated GRocket. Thanks a lot.
My display does not give a voltage read out. It is a sub bare-bones arrangement.
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