Tandem believes that there should never be a "bad battery".
Tandem batteries are modular in design and should rarely fail as an entire unit.
The Warranty provides support for our pledge that there should never be a “bad battery”. The modular design is important not only for the Warranty but also for any out-of-warranty service that may be required since individual components can be replaced at a fraction of the cost required to replace an entire battery.
If you have purchased a Tandem Battery, please use this link to register your battery.