If you have just bought an electric bike or are perhaps thinking about buying an electric bike you might be thinking about batteries. For most of us, electric bikes are a relatively new idea, and we don’t yet know how to solve e-bike battery problems.
We’re going to help guide you through the world of electric bike batteries. In our guide, you’ll find out about different batteries, how to charge these batteries, and how to solve any common issues that may crop up with e-bike batteries. By the end of the article, you’ll know the basics and have nothing to fear about batteries.
What type of batteries are used on electric bikes
In the US and EU, there are two main types of battery fitted to electric bikes. They are Lithium Ion (Li-Ion) or Lithium Polymer (LiPo) batteries. If you go into Asia, and particularly China, you’ll see that the most common battery used are lead-acid batteries. China is a huge electric bike market, and only a tiny percentage of the bikes sold have a lithium battery fitted.
What is a Lithium Ion battery?
Li-Ion batteries are a type of rechargeable battery. A Li-Ion battery is usually much lighter than a similar sized battery, especially when compared to the much cheaper lead-acid type.
|A Li-ion battery can store 150 watts of electricity per kilogram. A lead acid battery can only hold 25 watts per kilogram.||They only last between 2 and 3 years from when they were manufactured. The time length does not matter how often or not they have been used.|
|A Li-ion battery can hold its charge well. It loses only a quarter of the charge that NiMH batteries lose.||They don’t like high temperatures. The warmer it is the faster they degrade.|
|They don’t need to be completely discharged before recharging.||If it gets fully discharged, it will deteriorate rapidly.|
|They can handle more charging cycles.||They are pretty expensive.|
What is a Lithium Polymer battery?
A LiPo battery is a Li-Ion battery that is encased in a soft polymer shell. The soft polymer shell allows the battery to be more flexible. That is the reason why they are becoming more popular for use on electric bikes. They allow manufacturers to come up with solutions that will enable electric bikes to look more like regular bikes than e-bikes.
Where to find new e-bike batteries?
One of the most convenient place to get new e-bike batteries is Amazon. You can find plenty of models or you can just get an universal one with the same specs as your existing battery. Check them out here (link to Amazon).
Another place to find e-bike batteries is eBay, but, it’s more risky as you can’t tell how old is a battery and they don’t come with any warranty certificate.
How do I charge an electric bike battery?
We will start with a word of caution about charging your electric bike battery. Never leave your battery to charge unattended. That means don’t try and charge your battery overnight as you sleep. Li-Ion batteries can burst into flames, the risk is low, but always make sure of your own and your families safety.
Another great thing to remember is that electric bikes will need to be fully charged before their first ride if you have bought an e-bike from your local bike shop they’ll hopefully have done this for you. If they haven’t maybe their customer service isn’t the greatest and you might need to try another store.
If you have bought your bike online, then your bike will have shipped with around 30 – 50% of a charge. Don’t get excited and pull your new bike straight out the box and go for a ride. Give it a charge first and then go for a ride. You’ll also want to make sure that you fully charge the battery for the first 5 charging cycles, this can be a long time so be prepared.
The do’s and don’ts of battery charging
- Never charge a battery that has been subjected to freezing conditions, especially if it is still frozen.
- Don’t charge a battery from a discharge port, this will bypass all the protection built into the battery.
- Never charge your battery after a ride, give it a few hours to cool down.
- You must never leave a battery unattended when charging.
- Try and charge to 80% and discharge until 20%. Doing so will give you the best battery life.
- When charging a battery to 100%, for more range, don’t leave it like that for more than a day.
- The reason for the 100% charge cycle for the first cycles is so that your battery can balance. It takes a few cycles to do this. It can take around 6 – 8 charge-discharge cycles for your battery to balance.
The break-in period
New batteries will have a break-in period. In this time what your waiting for is your battery to balance and settle. You use the first 5 or so of your charge-discharge cycles to complete this task. You don’t need to discharge the battery fully.
To work the discharge of the battery should be around 1 volt slightly needs to be discharged. Do this slowly and don’t put any strain on the battery. Let it cool down and then charge it again. If you repeat this in a nice and relaxed manner you’ll have the battery balanced before you know it, it’ll still be a long process though.
There are a few things you’ll be wanting to do as during this break-in period. You’ll want to avoid stressing the battery, and you’ll definitely not want to hit the low voltage cut off point. You don’t want to get trigger happy and run your battery at high amp setting either.
The final note here is don’t let your battery get hot. Remember above where we said too high a heat and your battery will degrade. Don’t make that mistake right at the start of your adventures with your new electric bike.
After the break-in period
After the break-in period, you’ll want to charge your electric bike battery to around 80-90% fully charged. Then you’ll occasionally want to run the battery to 100% charged and do it 2 or 3 times in a row. Ideally, you should do this every 30 cycles, after a break of not riding, or bi-annually.
Following this advice should allow you to get the maximum lifespan out of your battery, and buying new batteries is not cheap, so it is worth the effort of doing.
What are the most common problems with e-bike batteries?
Electric bike batteries can have problems that fit into one of two camps.
- Charging issues. Your battery won’t charge or won’t hold a charge (you charge it for 10 hours and it’s still dead).
- Discharging issues. These come in two varieties as well, firstly your battery appears to be dead. You take it out and reconnect it and it works again. The second one is that a fully charged battery dies very quickly.
If your electric bike is being placed on charge and your battery does not seem to charge. It can be worth checking your charger first. There are multiple ways to do this. Some involve lightbulbs and voltmeters. I’m going to guess though that you want a simple way to check this.
How we’ll check to see if it is a charger issue is that we’ll try and power your electric bike with the charger. The first thing you’ll need to do is to remover the battery pack. You’ll now want to hook the charger directly up to the power wires.
If doing this makes the power display comes on and the motor spins with your wheel then it now looks like you’ve got a battery problem and not a charger issue.
How to test your electric bike battery
If the charger passes the above test, this does not mean it is not an issue with the charger though we’ve just made it less likely to be the charger, you’ll want to look at the battery. You’ll definitely need a voltmeter now. These tests will work for both charging and discharging issues.
On hardpack batteries, you’ll need to remove the battery from your bike. On the back of your battery, you’ll find 2,3,4, or even 5 terminals. You can plug your voltmeter into any 2 of these terminals to get a reading.
You’ll now want to check the adaptor port. To do this, you’ll need an XT-60 barrel adaptor. You’ll want to use the red lead to test the positive side of the adaptor, and your black lead can check the negative side. Doing this should give you a positive reading; a negative reading means that the battery probably has been miswired at the factory.
Soft pack batteries
On soft pack batteries, you’ll find that manufacturers have included an XT-60 adaptor. You’ll more than likely see 2 cables that look the same. The XT60 is the larger of the 2 cables. So now you’ll want to attach your voltmeter.
The one thing we haven’t done yet on the batteries is testing the charge port. On hard cased batteries this is a complicated procedure. It is very easy to short your battery. You might want to leave this one to the professionals.
On the soft pack battery, you’ll be using the smaller of the XT-60 adaptors, following the same rules as above.
You’ll now want to see your results. For the discharging port, after you’ve got you results you’ll want to check our results list below. Afterwards you’ll need to check your charging port results then or try a jumpstart, which we’ve nicely explained how to do in the section below.
0-27V on a 36V battery
0-35V on a 48V battery
0-38V on the 52V battery
0-44v on a 60V battery
0-55V on a 72V battery
In a similar fashion, the charge port also has a voltage similar to the above results your battery management system (BMS) may be tripped.
How to fix your electric bike
If you want to fix these issues, then you have 2 options again. You can take it to your local dealer and have them fix it, or you can make a little time and try and fix it yourself. The first step is to try and charge the battery properly.
Plug your charger into the wall. Some will allow you to select a 100% charge if it does go for that setting. Next, you’ll want to double check the battery charging procedure in your manual, and then plug the charger into your battery. If nothing happens, you’ll need to try and jumpstart the battery.