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Why BMS Interfacing reduces e-bike battery warranty cost

When a consumer considers claiming warranty on an e-bike battery, all needed is to request the dealer to accept the claim as the dealer has a legal obligation to handle this.

Sending the battery to a service center was (and is in most cases) the only option when the dealer has no appropriate battery test facilities. As e-bike lithium batteries are labeled as dangerous goods, there are significant logistics costs involved in shipping, paid by either the battery manufacturer or the OEM. In both cases these expenditures are high compared to battery cost. This article describes how unjust warranty claims can be avoided and how warranty handling costs can be reduced by interfacing BMS’s with battery test systems.

Unjust warranty claims

A common reason for e-bike battery warranty claims is that the user emptied the battery and failed to recharge before winter storage. When, after the battery has been sent to a designated service center, the manufacturer’s BMS recognizes deep discharging the claim will be denied, but the battery then needs to be returned to the consumer via the dealer. Additionally, European e-bike producers reported that on average 20% of warranty claims are unjust because they still have a higher than warranted capacity.

High logistic costs or risks

In both cases –due to dangerous good surcharges- the cost of (legal) shipping & handling can even come close to the value of a new battery in some markets; a position that calls for a sensible solution. Failing to report lithium batteries is not a solution as it imposes liability to senders in a magnitude that could be fatal for small and medium organizations.

Trending: Involve e-bike dealers

Battery Condition Test Intl. Ltd. pioneered the concept to involve e-bike dealers in warranty eligibility evaluation by designing a battery tester that is so easy to use and fully automatic that every untrained e-bike dealer can perform battery testing. When dealers perform a warranty test with this system, the test report provides evidence to the customer (end user) when the capacity of the battery is higher than the warranted minimum. When the BMS can be read by the test system, the test report can also document any user mistreatments that affect warranty. This saves unnecessary shipment and is therefore in the interest of the battery manufacturer or their e-bike OEM customer.

How to implement BMS Support

Battery Condition Test’s e-bike battery analyzer is currently unique with an implementation program:

  • After signing a non-disclosure agreement, manufacturers provide the communication protocol, a description including the desired texts on the test reports as well as samples of the batteries. In case of secured batteries, access codes will need to be provided.
  • Battery Condition Test evaluates the BMS and approves this when that BMS offers enough warranty related information. The R & D costs of the BMS interface are generally waived.
  • After completion, the manufacturer receives a sample of the custom BMS interface and is requested to approve the test report –which texts are based upon their input-.
  • Upon approval of the test report, the BMS interfaces are produced including custom cables and made available for ordering.
Why BMS readers are not an option

E-bike dealers are reluctant to learn, use and pay for test systems that are unique to one particular brand.

Moreover, BMS’s give a rough capacity indication, at best within +/- 10%. Unlike battery analyzers with <2% accuracy this is –by far- unsuitable for warranty eligibility judgment, while BMS readers are usually also not able to produce a (convincing) test report.

The dealer’s position

For the e-bike dealer, battery warranty issues are not a major concern as all associated costs are born by the battery manufacturer or the e-bike manufacturer. Their only concern in this respect is to provide a faster service to their customer as warranty cases take time, which can run up to weeks during peak times.

The main reason why e-bike dealers are buying battery analyzers is to judge the value of the batteries of to-be-traded-in e-bikes, a situation that becomes more and more common in Europe. Being able to provide their customers with evidence (a test report) that a battery rather than a vague “not so good” is key to them. The second motivation is to provide customers with well documented replacement recommendations.

The manufacturer’s position

Who pays the bill for warranty costs differs but whatever the arrangement may be, the customer needs to pay for these costs. Hence, manufacturers with high warranty costs suffer from a reduced competitive position or profit. Major e-bike system vendors BionX and TranzX and major battery vendor Varta Microbatteries chose to have their BMS interfaced. Several important names are in the pipeline.