How to test an e-bike battery, There are five tasks you’ll need to do. First, prepare the battery by charging it and removing it from the bike.
Then, perform a battery load test with a multimeter. Using the same multimeter, then test the voltage, current, and resistance.
Compare all of those readings to what’s stated in the user manual to measure the battery’s health.
In this article, we’re going to explore the easy steps to test an e-bike battery right in the comfort of your home.
With nothing more than a multimeter, you’ll be able to keep a good eye on your battery’s health and know when the time will come to replace it.
What Tools Do You Need To Test An E-bike Battery?
To test your e-bike battery, the only tool you’ll need is called a multimeter.
A multimeter is a simple electrical measuring instrument that’s cheap and easy to get. You can find them at any hardware store or even online in both digital and analogue forms.
But what exactly does a multimeter measure?
It measures electrical values like the voltage, current, and resistance of electrical items like batteries.
More sophisticated multimeters will also test for other types of values. Still, those are not necessary for running basic tests on your e-bike battery.
Typically, a digital or analogue multimeter comes in the form of a handheld device with two probes.
When it comes to e-bike batteries, you’ll be pressing those probes against the battery’s terminals (the red probe onto the positive terminal and the black probe onto the negative terminal).
What Parameters Are You Testing In An E-bike Battery?
Whenever we talk about ‘testing an e-bike battery’, what we’re really referring to is testing the battery’s:
- Voltage
- Current
- Resistance
Let’s take a closer look at each of those parameters and what role they play in the health of your e-bike battery.
E-bike Battery Voltage
The performance of an e-bike is closely tied to its voltage. Generally, the higher the voltage of the batter, the higher the performance of the e-bike.
The purpose of testing the voltage of the e-bike battery is to ensure that it’s at or close to the correct voltage.
You’ll know this by comparing the voltage reading to whatever is stated in the user manual for the bike or the battery itself.
Simply put, if the voltage is too low, that’s a sign that the battery might be on its way out. You might have to replace that battery soon enough.
E-bike Battery Current
In simple terms, the current in an e-bike battery is the amount of electrical energy that flows through at any given time.
E-bike Battery Resistance
All batteries have a certain amount of resistance in them. However, that resistance should not be too high, leading to the battery overheating and the voltage (discussed earlier) dropping.
Suppose you test an e-bike battery and find that the resistance reading is far too high. If that’s the case, then that’s an indicator that the battery is wearing out and may need to be replaced.
The Quick Steps To Test An E-bike Battery
Here are the 5 quick steps you’ll need to follow to test an e-bike battery:
- Prepare the battery for testing.
- Perform a Battery Load Test
- Perform a Voltage Test
- Perform a Current Test
- Perform a Resistance Test
Prepare The Battery For Testing
One of the most important things you must do first is to prepare your e-bike battery for testing. Doing that will involve two tasks: firstly, you must fully charge the battery.
Once that’s done, you should remove the battery from the bike and set it on a flat work surface, like a workbench in your garage.
As you do that, make sure you have the user manuals or technical sheets for the e-bike and the battery. This will make it easier for you to refer to it later.
Here’s an important note: depending on the type of e-bike battery that you have, connecting the multimeter probes to it might be different.
For example, some batteries will have terminals directly on them to push the multimeter probes into.
For other types, though, you might need an adapter to do so.
Be sure to refer to the user manual or contact the manufacturer if you’re unsure of how to do this for your battery in particular.
Always remember two things: Firstly, every single test you do will involve connecting the multimeter probes to the same terminals. The only thing that changes is the setting on your multimeter.
And second, you don’t have to press the probes at all. It’ll still be able to get a good measurement purely by contact, so applying any pressure is unnecessary.
Perform A Battery Load Test
The first test that you’ll want to perform is a battery load test. Some multimeters may already have a dedicated function to perform this test.
So, if that’s the case for yours, all you have to do is turn the dial or choose that setting.
What this test is actually measuring is the amperes of the e-bike battery.
You see, all lithium batteries (the most common type of battery for e-bikes) will gradually lose their capacity as time goes by. That’s also true for batteries of all kinds.
On a long enough timeline, that amperage will drop so low that the battery can’t be used at all.
Think of this as a ‘general health test’ for your e-bike battery. As long as it hasn’t dropped too far from its original figure (which you can find in the user manual), then that means your battery is still good for now.
Perform A Voltage Test
Next, switch your multimeter over to its voltage measuring function. To be exact, make sure that the multimeter is set to measure for DC voltage, which is the kind that your e-bike battery has.
Then, connect the multimeter to the battery’s terminals. The exact measurements will differ depending on the type of battery that you have.
For example
| A 52 V e-bike battery should show a reading of about | 58 VDC to 42 VDC. |
| A 48 V battery, on the other hand, should show. | 54 VDC to 40 VDC |
Suppose the numbers are not within those ranges. If that’s the case, then that’s an indicator that the battery may be gradually wearing out.
Perform A Current Test
Whenever you hear someone tell you to test the battery’s capacity, what they’re referring to is the current test.
E-bike battery capacity is measured in milliamps x hours or mAH.
Again, whatever reading your multimeter shows, you should compare it with the user manual for the battery.
That way, you’ll know what the battery capacity is supposed to be when compared with what it might be right now.
Perform A Resistance Test
Lastly, you’ll want to switch your multimeter over to measure the battery’s resistance. Electrical resistance is what tries to stop the flow of electrical current through the battery.
That resistance exists in all electrical circuits, but it should never be too high.
As mentioned earlier, if the resistance is too high, the battery will overheat. More importantly, electricity will not be able to flow through the battery as it should, leaving you with even less voltage than usual.
Final Thoughts
As you can see from the steps mentioned above, testing an e-bike battery is an activity that involves several tasks.
That’s because the overall health of an e-bike battery is a combination of its battery load, voltage, current, and resistance.
If all of these numbers are where they should be, you can rest assured that your e-bike battery is still in good working order.
However, if those numbers indicate that your battery might be wearing out, then you’ll need to decide what to do next.
Replacing an e-bike battery isn’t cheap, which is why you’ll want to first check to see if it’s still covered by the manufacturer’s warranty.
It’s not unusual for an e-bike battery to die sooner than expected. Thankfully, a warranty will take care of that, and you should be able to get a replacement at no cost.
New vs. Refurbished E-Bike Batteries
However, if you need to replace the battery on your own, you’ll have to decide between buying a brand new one or a refurbished battery.
Refurbished e-bike batteries are more affordable, and they still have plenty of power to offer.
Still, you should always be sure to buy refurbished batteries from reputable sellers. The good ones will also offer you some kind of a warranty, though it won’t be as good as that of a brand new battery.
If, however, you’d feel more confident with a brand new, factory-fresh battery, then don’t be afraid to shell out more cash for one. It’s certainly worth the investment!
