Why Are Battery Warranties Important on eBikes?
E-bike batteries are perhaps the most expensive ‘consumable’ on an e-bike and, despite the fact that today’s e-bike batteries are a world away in performance and quality from those around in the early days of the industry, they are complicated items that can occasionally fail. Even barring the unlikely event of total failure, a battery-specific warranty can be important in determining if a decline in battery capacity over a number of months and years falls within the acceptable, or actually triggers the warranty.
The good news is that as e-bike battery technology has developed and the terms of the warranties from most major e-bike battery manufacturers have become more generous and more specific as they have realized they can put their trust in the vast majority of batteries to perform well.
Of course, the flip side of this is that you should look after your battery in accordance with the manufacturer’s recommendations in order not to void the warranty. Check out our brief five-point advice at the end of this article on how to get the most range and life from your e-bike battery.
The Legal Stuff – First Port of Call?
It is worth quoting the United States’ Federal Trade Commission on the importance of warranties in the US:
‘When you make a major purchase, the manufacturer or seller makes an important promise to stand behind the product. It’s called a warranty. Federal law requires that warranties be available for you to read before you buy even when you’re shopping by catalog or on the Internet. Coverage varies, so you can compare the extent of warranty coverage just as you compare the style, price, and other characteristics of products.’
As you will see below, most major battery manufacturers make explicit their own battery warranties and all offer fairly similar terms, so in practice, these are what retailers and end consumers tend to rely on.
However, even though failed batteries should ultimately end up with the manufacturer for replacement your first port of call should be the retailer, whether they are your local bike store or online. If they are doing their job well they are simply best placed to be able to help you resolve the matter quickly and easily.
A bricks and mortar retailer may be especially reassuring and useful if you think your battery has lost more of its usable capacity than it should have done under the terms of the warranty; the main battery manufacturers’ batteries have the ability to record the number of charges they have received and a good dealer will let you observe the process and the readouts.
It’s also important to go through your retailer as you have a sale of goods contract with them and this could be a useful supplementary recourse if, for example the manufacturer went out of business.
Determining the Working Capacity of Your eBike Battery
By using a plug in energy meter (for example like this one) it is possible to get a very approximate idea of the capacity of your e-bike battery. For example it may be rated at 500Wh but e-bike batteries degrade over time and can also develop faults that will affect their capacity.
Firstly make sure your e-bike battery is empty by using it on your e-bike until power has run out.
Now recharge it as normal to full but use a plug-in power meter to measure the number of Wh taken from start to finish (ie as soon as the battery is full).
Not all the electricity shown as consumed by the meter will be going into the battery cells. For example, some will be lost by the inefficiencies of the transformer that drops the voltage down from mains 240V to whatever your e-bike battery requires.
All transformers vary but a very approximate working assumption is that 80% of the electricity from the power socket will end up in your battery. So to find out the extremely approximate capacity of your battery just multiply the Wh consumed on the plug in meter by 0.8 to give you a rough idea of its health.
It is a good idea to repeat this exercise several times to get an average reading.
Examples of eBike Battery Manufacturers’ Warranties
Bosch offer external batteries in 300, 400 and 500Wh, frame integrated batteries in 400, 500 and 625Wh and the remarkable frame integrated 1625Wh dual battery system. They are notable for the detailed nature of the warranty.
They warranty their batteries to hold a minimum of 60% of full charge capacity for 2 years or 500 charge cycles (whichever comes first). According to Bosch a charge cycle is a full discharge and recharge. A partial discharge and recharge only counts as such eg discharging and charging 25% of capacity four times will count as one full charge cycle. The battery management system records the number of charge cycles and the information is accessible to authorised dealers via diagnostic software.
Do note though, a good quality battery should give good range for much longer than 2 years – in fact Bosch themselves state that the battery should be good for around 8-9 years or 1000 full charge cycles.
Reputable drive systems like Bosch, Brose, Shimano and Yamaha should all use good quality e-bike batteries.
Brose produce their own brand of battery, the Brose 630 which is rated at 630Wh. Quoted weight is 3.8kg.
Brose told EBR this battery is guaranteed for 700 full load cycles with 60% remaining capacity at the end of the warranty of 2 years.
Shimano STEPS mid-drive system has its own brand batteries in 418, 504 and 630Wh sizes. All have external versions and the larger two capacities have frame-integrated versions as well.
On their website Shimano outlines their impressive warranty; ‘As with every modern battery, capacity will decrease due to charging. Shimano guarantees a remaining battery capacity of 60% after 1000 charge cycles. Your dealer can determine the remaining battery capacity for you’ which certainly implies the battery guarantee could easily extend beyond two years, even for a rider e-biking regular and quite long distances.
For compatibility between Shimano mid-drives, batteries and battery mounts check out the table here, but note you will need the correct product numbers for all three elements.
Yamaha offer 400, 500 and 600Wh capacity batteries and like other main manufacturers only offer their largest 600Wh capacity as a frame-integrated option.
Yamaha’s US website says ‘The drive unit (including the motor assembly, housing cover, internal gears, motor control unit assembly, drive axle assembly, and torque sensor assembly), battery, rigid frame, and rigid front fork will be warranted for a period of three years’ but this warranty excludes ‘Normal deterioration, including the gradual decrease of battery capacity over the three year warranty period as long as the battery capacity is still 50% or more of the initial capacity before the warranty expiration and the total number of battery charging cycles is 700 or less.’
Bafang make their own brand batteries that come with Bafang motor systems that come ready fitted to e-bikes from a number of manufacturers with capacities ranging from 200Wh to 820Wh.
Bafang told EBR they will repair or replace the battery if its capacity falls below 60% within 2 years. The warranty period for total failure is 3 years. Both warranties are only valid to the original purchaser with a purchase invoice.
Examples of eBike Manufacturers Warranties
Outside of the large motor system manufacturers above a host of smaller e-bike manufacturers sell their own branded batteries and offer their own guarantee. A good idea on the purchase would be to get a written clarification as to what drop in capacity within the guarantee period constitutes a defect, as this isn’t clarified in every smaller manufacturer’s warranty.
From the US
Pedego batteries are covered by a 5 year prorated warranty.
- During the first 3 years of service – A defective battery will be repaired or replaced at no cost to the customer. The warranty period for a repaired or replaced battery remains unchanged based on original purchase date.
- After the first 3 years of service – A prorated credit, based on months of service, will be applied toward the purchase of a new battery. Batteries purchased at pro-rated cost will have a new 5 year warranty based on the pro-rated purchase date.
- No cash reimbursement will be made.
Batteries are covered under the general warranty terms which state ‘All Rad Power Bikes……are protected against all manufacturing defects in material or workmanship for one year after receipt of the ebike by the customer’. They list all items on the bike that are covered by the warranty and the lithium ion battery is included.
BULLS offer a general warranty of 24 months on their e-bikes but qualify this for the battery:
‘There is one limitation for E-bike batteries. Since rechargeable batteries are wearing parts, the warranty period is only 6 months. However, BULLS offers an additional voluntary extension of this warranty for the battery to 24 months if the defect is due to material or processing errors. The voluntarily extended warranty does not include labor costs or transport costs for conversion. It is limited to the replacement or repair of the defective part.’
Easy Motion offer a wide range of styles and guarantee their own brand battery packs for two years or 400 charge cycles, whichever comes first.
This warranty applies to 2012 and newer model bicycles.
From the UK
Batribike / Promovec
Their basic Promovec battery warranty is two years from date of purchase covering manufacturing defects or reduction in capacity below 70% during this 24 month period.
They also offer an extended warranty of 5 years on similar terms as above – they say ‘the cost will vary depending upon the model of battery. Current costs are between £158 for a 10.2 Ah (365 Wh) battery to £220 for a 15.6 Ah (560 Wh) pack.
So before your next e-bike purchase be sure to check out the battery warranty terms.
Stay tuned for more e-bike news and reviews and thanks for reading!