Common E-bike Battery Problems and How to Fix Them
There’s nothing worse than having to spend hundreds or thousands on an eBike only to have problems with its battery. Don’t get me wrong; e-bike batteries are built to last. but they’re still prone to failure if they aren’t adequately taken care of during their lifetime.
What happens if your battery fails?
Well, in this article, I’ve covered some most common eBike battery problems and how to fix them. So, if you’d like to know more. keep scrolling!
Ebike Battery Problems
When it comes to eBike troubleshooting, there are a couple of things that might be causing your battery problems, including:
- eBike battery pack swelling
- eBike battery not charging
- eBike battery not running for very long
- eBike battery pack not holding a charge
- eBike not turning on
- eBike not speeding up
Don’t worry, though. I’ll walk you through each one here!
eBike Battery Pack Swelling
If your eBike battery pack is swelling up, well, you likely have a pretty serious problem with one. or more. of the lithium-ion cells.
Some electric bike models use flat pack cells. and these are known to swell if they suffer some damage. On the other hand, the 18650 lithium-ion cells are far more resistant to swelling and, in turn, more reliable.
If you notice that your eBike’s battery pack has a bulge in it, be sure you turn off the power and carefully remove the battery from your eBike. It’s a good idea to recycle the battery; most cities have a place where you can do this.
Now, some eBike battery packs are positioned inside the bike’s frame. That makes it somewhat harder to notice if you have a swollen battery pack.
The only way to check if the battery is swollen is to drop the lower plate and take out the battery pack. Note that you’ll have to disconnect some cables before you do this.
eBike Battery Not Charging
If your battery isn’t charging, start by checking the following:
- Is the power turned on at the outlet?
- Is the charger working and outputting over 36 Volts?
- Is the battery hot?
- Is the battery charger port full of dirt?
- Has the battery been left discharged for several months?
- Has the fuse blown in either the eBike battery pack or the charger?
eBike Battery Not Running For Very Long
Lithium-ion batteries generally have a life of 700 charge cycles. They usually tend to lose full charge capacity over this mark.
That is entirely normal. and will, unfortunately, only get worse as time goes on.
Still, if you’re charging your bike every few days, you should be able to get many years out of your electric bike before you begin to notice the capacity of your battery is starting to degrade.
If you notice your eBike battery isn’t running as long as it used to, check the following:
- Is the battery pack being charged to 100%?
- Do you have a dragging of a disc brake?
- Is the terrain uphill?
- Are you assisting your battery by peddling?
- Are your eBike’s wheel bearings freely spinning?
- Do you have a short circuit in the battery, wiring, or motor?
Any of the scenarios mentioned above could lead to your battery discharging rather quickly.
eBike Battery Pack Not Holding A Charge
Lithium-ion batteries are good at holding a charge. However, like any other type of battery, they will slowly discharge over time.
If your eBike hasn’t been charged for a more extended period, it would be a good idea to give it a top-up. and see how it goes.
If you notice that you’re charging your battery, but it still discharges quickly without being used, you might have a short circuit somewhere or a faulty battery at your hands.
Here’s a quick test that can detect the problem:
Remove the battery pack from your eBike and charge it up on a bench. Once it’s fully charged, test the battery by leaving it off the bike.
If it holds a charge, the issue will be your electric bike. most likely a short circuit in the bike’s wiring or the motor. However, if it doesn’t hold the charge, your lithium-ion cell is faulty.
How Do I Know If My Bike’s Battery Is Charged?
Your battery charger will probably feature a LED light indicator that changes states depending on the bike’s battery level. It’ll go from red to green when the battery is fully charged in most cases.
However, in some chargers, the LED light will turn off completely when the battery is charged.
Either way, the point remains the same. you’ll have a way to track the progress while charging the battery.
Remember not to leave the battery pack on the charger longer than 24 hours, though.
Lithium-ion batteries don’t prefer being left on the charger. In the short term, this won’t hurt. but after a while, the battery’s capacity will go down.
You’ll also have an indicator of the battery’s current level on the battery pack itself or the speed controller. Some will use a 0-100% range, while others have a series of LED lights, depending on the model.
We can agree that e-bikes have come a long way since their first appearance. Granted, battery problems can occasionally happen, but most can be solved easily and quickly.
Hopefully, the tips I’ve outlined above will help you keep your eBike running fast. and for a long time. And remember:
The most significant danger to batteries of eBikes is excessive heat and low voltage. Make sure you keep your eBike battery topped up. and it will last for a very long time.
Can You Buy Replacement Electric Bike Batteries? How Much Do They Cost?
That was the humorous answer I received just the other day when I went to an electric bikes’ shop for my Mama and asked, “Can you buy replacement electric bike batteries? If so, how much do they cost?”
Now, if there is anything my late pappy warned me about, it’s salesmen who are too familiar, funny, and full of jokes.
“Son, such salesmen are dangerous, always put your guard up when dealing with their kind!” Pappy had warned me at his last breath.
You can therefore understand when, immediately after the salesman had responded in such fashion, I, as they say, “turned and ran” out shouting,
“I will be back, I just need to go and ask the professor-by which I meant Google, of course!
Below were the professor’s responses to my questions.
Can you buy replacement electric bike batteries?
Without perhaps being as familiar as the salesman at the electric bike shop had been, Prof Goggle treated the question as if I was asking whether the sea contains fish?! As a result, he could not wait to get to my next question.
Anyway, in a nutshell, Prof. responded with a loud, YES, you can buy replacement electric batteries-that’s why they are apparently called-R-E-P-L-A-C-E-EM-E-N-T!
Though you should not be in a hurry to buy one of your electric bike’s (also known as an e-bike), the battery has not yet started to give you problems or play up. This is because, on average, a good quality e-bike battery should and can last for hundreds of cycles. If used averagely, this could mean several years.
However, as with most man-made things under the sun, in due course, electric bike batteries need and must be replaced, especially as their life span nears its end.
Finding all this not only the most informative, but interesting as well, I asked one of the questions I know must be foremost in some of your minds- cost?
How To Tell When To Replace an Electric Bike Battery?
Fast as lightning, the response came back.
Signs that your electric bike’s battery is about to bid you farewell or reaching the end of its life-span is mainly when it and you can’t reach the distances you used to cover together. Fortunately, certain high-quality batteries like B—-h come with a battery management system (BMS) fitted in the battery. This BMS will usually keep you informed and updated about your electric bike’s battery current capacity as well as how much charge cycles it has gone through.
Should you happen to have access to the UK’s electric bikes network, then you can have your e-bike’s battery examined and assessed. It offers battery diagnosis (refundable against a replacement battery or recell if required). The ETS reports that it has stocks of Battery Management System chips that can be used on certain packs, usually on older e-bikes. So, should your e-bike be first-generation like Mama’s, then get in touch with the ETS and enquire.
That question satisfactorily answered, I next turned to the all-important question when it comes to new technologies-the cost of e-bike replacement batteries!
How Much Do They Cost?
Cheap Means Cheap Quality
While the battery on any electric bike will need replacement after some time and use, but if you take care of your battery to extend its useful life as long as possible, you’ll find shopping for a new e-bike battery is a very rare occurrence.
However, “Forewarned is forearmed”. Instead of beginning with a list of the of e-bike replacement batteries, Prof started by warning me about the cheap batteries and their places of origin.
According to Prof. Goggle, “There are many cheaper battery options through direct sellers from China, but these batteries will be of lower quality and could have some of the following issues”:
- Although Japan, South Korea, and to some extent Taiwan, try to manufacture quality products, reportedly China is unknown for quality especially 18650 cells.
- Apparently, most so-called “name brand” cell packs coming from out of China are sometimes, in fact, made up of clones that perform badly cells or re-wraps.
- Such rewrapped batteries will normally not last for very long.
- BE WARNED, rewrapped or low-quality batteries can also have a higher potential fire hazard.
Given the above, “Buyer beware” or you will pay dearly for what you cheaply paid for!
The battery on an electric bike is one of the most expensive components to replace. Compromising quality for affordability will generally result in lower quality, shorter lifespan of the battery, and lower performance.
That said, Prof. turned to some of his picks when it comes to some of the best e-bike replacement batteries on the market.
Whether in the market to replace an old e-bike battery, as with almost everything these days, knowing its cost is vital. How much do e-bike replacement batteries cost? Let’s look at Prof’s chosen few.
Yamaha E-Bike Batteries
Yamaha has integrated, rack-mounted and frame-mounted options ranging between 400Wh and 600Wh. Their systems appear on Haibike models and in the US on their own branded models.
Bosch brand battery packs are some of the most expensive, with ranging from 670 – 920, with an average cost per Wh of capacity around 450.70/Wh.
Shimano STEPS batteries range in price from 500 – 800, with an average cost per Wh of capacity around 450.40/Wh.
Last but not at all least, off-brand batteries with high-quality cells (Panasonic or Samsung typically, or sometimes LG) have an average cost per Wh for a capacity of around
Frequently Asked Questions and Salesman’s Answers.
Q1. Which battery is best for an electric bike?
A. Lithium-ion (Li-ion) batteries are the best option for e-bikes. Although lead-acid batteries are significantly cheaper, they’re three times as heavy as their li-ion equivalents.
Q2. Range, how far can you go on a full charge?
A. Range Estimates! Every company, website, and salesperson struggles with this. On one side, you have the desire to claim the best-case scenario as it makes the best sales pitch, but on the flip side, if it looks too good to be true, it usually is. The fact is this, expect typically 20 miles / 32 Km from an average 6 to 8 Lb Lithium battery, that is the universal truth and pretty much the most honest statement a company can make.
Q3. How can you influence service life?
A. To get the longest service life out of a battery, eBikers need only to follow a few simple rules in respect of protection, transport, and storage. They include storing the battery in a dry environment and protecting it from direct sunlight at a room temperature of around 50°F (10°C) to 68°F (20°C). The ideal charging level for a battery is between 30% and 60%. Ideally, the battery should be recharged at room temperature. When transporting an e-Bike, it is important to remove the battery from the bike and store it safely in the car.
Q4. How do you dispose of an old battery?
The dealer will ensure that Bosch Power Packs are disposed of in an environmentally sound way free of charge. Disposal in the United States is handled by CALL2RECYCLE at (877) 723-1297.
Feeling that all my FAQs had been more than satisfactorily and professionally answered, I bought Mama’s electric bike a replacement battery.
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Normally, new high-quality electric bike replacement batteries will cost anywhere between 500 to 900 plus depending on the brand and capacity. Usually, this would be for a battery with a capacity of around 400wh to 700wh. Name brand battery packs are characteristically more expensive when looking at cost per Wh of capacity versus high-quality off-brand battery packs.
How to fix Phylion ebike battery not charging. COMMON PROBLEM. EASY FIX
Remember, should you buy your e-bike replacement battery online, always add additional shipping costs to the final total. Shipping batteries, especially Lithium-ion batteries, are complicated and will usually increase your shipping costs by an additional 40-50 depending on the destination amount. Most battery packs only have a 1-year warranty, so think carefully about where you purchase your e-bike battery from.
My primary research over, and with some time to spare before returning to the e-bike shop and its familiar salesman, I googled some Frequently Asked Questions to test the salesman.
When I thought I had been informed enough about e-bike replacement batteries, I this time went to interrogate the salesman. The visit went something like this….
What is in an electric bike battery?
A typical lithium-ion electric bike battery is comprised of two main components – the individual lithium-ion cells and the battery management system.
These cells are slightly larger than an AA battery and are named due to their size of 18mm x 65mm. They are used in high-drain devices due to their superior capacity and discharge rates.
Typically these cells will have an average voltage of 3.7v and around 3000-mAh capacity. These cells are then combined in parallel (to increase capacity Ah) and series (to increase Voltage) to create a larger battery suitable for the higher power demand of an electric bike motor.
For example, in a common 48V / 15-Ah pack there would be a total of 65 cells (3.7v, 3000 mAh). These 65 cells would be combined in parallel in groups of 5 to get 15 Ah (3Ah x 5 cells), and these 13 groups of the 3.7v packs would be combined in series to get a nominal 48 V (13 x 3.7v).
In contrast, the most popular battery pack for a Tesla has 7,104 individual 18650 cells!!
Battery Management System (BMS)
The battery management system is the ‘brains’ of the battery, which helps keep the individual sub-packs within a larger battery well balanced to improve the longevity of the battery. It helps with charging (limiting the amount of current) and discharging by limiting the number of amps that can be drawn out of the pack.
Some BMS can also monitor for higher temperatures and limit the battery to prevent overheating and damage to the cells. Some can also connect to your phone via Bluetooth to provide more detailed battery information and have an on/off switch for the battery.
I’ve written about how long a battery will typically last in this post here, but generally, a new battery will last about 1000 charge cycles.
How Do I Replace My bike battery?
Many manufacturers provide replacement batteries for there bikes, which is important to consider when shopping for an ebike is how easy it is to replace the battery. Some batteries are built into the frame and take quite a bit of work to remove and replace. Others simply clip out of the frame or rear rack and a new one put in its place quite easily.
This is one disadvantage to a purpose-built ebike – you are generally tied to the manufacturers battery replacement pack, which is generally quite a bit more expensive than more generic alternatives. If you build your own electric bike with a conversion kit or assembling the parts yourself, you have a lot more choice in what battery you use, it’s quality, capacity, and ultimately it’s price.
Here are a list of several bike manufacturers’ battery packs and their pricing (check your local dealer or online for the most recent prices).
estimated as of December 2019
If you’re buying a battery online, remember to account for additional shipping costs. Shipping batteries, especially Lithium-ion batteries is complicated and will usually increase your shipping costs by an additional 40-50 depending on the destination. I’ve written about shipping your own electric bike battery as an option if you plan to take your electric bike on a plane.
Can You Have an old battery “repacked”?
What is “repacking” exactly? Basically, this is when the housing or container holding the old/worn out batteries is kept, but new cells are placed in the old housing. This is done so that you get a “new” battery that fits your bike or built-in battery pack.
There are quite a few forums and sites advertising the possibility of repacking an existing casing to replace an aging or broken battery pack. Several manufacturers discourage this practice like Bosch stating:
High-quality lithium-ion batteries like the Bosch PowerPacks are complex, finely-tuned systems the repair of which requires special expertise and elaborate production facilities. That is why a defective battery must in nearly all cases be replaced.
Some providers claim they can recondition batteries. Bosch strongly advises against this because the safety and optimum interaction with the Battery Management System cannot be guaranteed in this case. In addition, there is a safety risk and opening or modifying the battery may invalidate warranty claims.
And their claims and warnings are reasonable I think. To be sure if you undertake this endeavor your warranty if any left will surely be void.
- You’re really trying to keep costs down, especially if the brand name battery pack replacement is quite expensive
- The model of electric bike you own is no longer supported or it’s hard to get replacement parts. This can happen with outfits that go out of business or with older models
The dangers of repacking a battery
How to test an electric bike’s BMS/charging system
When the charging system of an electric bike fails, it means one of a few things:
- Supply failure: The charger might be broken (not delivering voltage or current necessary to charge)
- Mechanical failure: A connector wiring inside the battery might be broken,
- Cell failure: Some of the cells inside the battery may have failed, or
- BMS failure: The battery management system may not be operating
To get to the core of the problem, you have to test everything one by one.
The first (and easiest) thing to test is the charger. You measure the output voltage. For a 52V battery like mine, it should be supplying about 58V. For a 48V battery it should supply around 54V.
After you measure the output voltage, you do what’s called the light bulb test — where you use an incandescent bulb hooked up to the outlet. This is easier in America (or Japan I guess) where the voltage supply is 110V, but it still works with 220V bulbs.
How to check your E-bike battery and signs that your battery is damaged.
You could also test it with an automotive bulb if you have one. But it might blow!
Second, test for mechanical failures. Probe around with a multimeter and make sure you read operating voltage in the places where you should.
Also, open up your e-bike battery and check all the wires are intact, and that none of the solder joints have broken. Bikes get beaten up and it’s possible — likely — that a joint will fail at some point, especially if your battery has gone flying across the road because you forget to lock it (guilty! Actually I lost the key for a while. )
Finally, you have to test the internals of the battery.
I did a suite of tests that Luna Cycle said I should do
- Opened it up and tested all the wires and connections
- Did a BMS battery reset
- Tested voltages across the pins — making sure every individual cell was operating correctly
One trick for testing voltage across the pins of the BMS is that they’re often coated with silicon. You should scrape it away gently before checking the voltage.
How does the BMS of an e-Bike battery fail?
A BMS is a delicate issue. There are actually people who believe in charging batteries without a BMS, like this guy on YouTube:
If jumping your BMS is unsucessful, you can do more extensive testing on your battery pack and on your BMS.
Watch the video below. The core of it is to check individual cell voltage (confirming they’re in the 3.6-3.8V range), making sure no cell is dead. If it’s dead, you can replace it, probably for about 15-20 of parts (and. a spot welder and some nickel strips).
Look at the number of pins and the style of connector at the top of the BMS.
It seems a lot of BMS manufacturers have an informal agreement as to what the connector should look like. This is good news!
The second rating to look for is the current rating. My bike is rated for 50A peak, so I found a controller that promised to get to that spec.
I would treat current ratings on eBay with a grain of salt. It’s possible they might be truthful, but it’s possible they’re wildly exaggerating. Given they’re so cheap, get the biggest spec one you can reasonably afford, assuming it’ll be a weak point.
Installing the new BMS
There are three steps to installing the new BMS.
Firstly, remove the connector at the top. Mine is a 14-pin connector; you might have 10 or 12 pins or some other number. This should be a plug-and-play replacement for your current BMS.
Secondly, use a low-power soldering iron to de-solder the three connectors at the bottom.
Finally, use the soldering iron to connect the wires to your new BMS.
You should now be ready to power up and give your repaired battery a go. If you’re lucky, like I was, then your charger will whirr to life and your battery will take a full charge.
Optional — I realised, as I was writing this, that there was a chance I could have destroyed the BMS again! The battery was discharged, and a surge might have fried it.
Luckily, this didn’t happen. But you should consider perhaps directly recharging each cell of the battery pack if you have a 3.6V battery charger available.
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