Zero is issuing its second recall in a week, this time for insufficient waterproofing for the battery management system on certain 2012 models. The recall comes after a recall on 2011 and 2012 models for the brake light switch. The second recall, related to the battery, is a much more serious one for the electric motorcycle manufacturer.

According to documents released by the National Highway Traffic Safety Administration, the battery management system printed circuit board has insufficient waterproofing on its connector pins. Under wet conditions, connector pins may short circuit, potentially causing a sudden drop in power, increasing the chance of a crash.

Zero first first received reports of a problem in March 2012 from a dealer after a 2012 Zero S inadvertently stopped running. The dealer replaced the battery management system under warranty with a new unit which corrected the problem. Zero then began an investigation for the cause.

In April, Zero received another report, this time of a dealer’s Zero XU demo model which had problems charging. A replacement battery management system was installed under warranty.

After examining the faulty battery management systems on both reported units, Zero determined the problem was caused by a lack of sufficient waterproofing compound applied to the pins. The faulty pins had corroded from exposure to moisture, leading to short circuiting. Zero contacted the battery management system supplier requesting an improved application process for the waterproofing compound.

Later in April, two of Zero’s company-owned models, a Zero S and a Zero DS, experienced a problems after riding in heavy rain. Two more reports from customers came in May, involving a Zero S and a Zero DS.

Zero completed its internal investigation in June and began the recall process.

The recall affects 254 models including 2012 Zero S, Zero DS, Zero X, Zero XU and the low-speed Zero XU-LSM variant produced before April 13, 2012.

Zero will notify owners and dealers will repair the affected units at no charge.

[Source: NHTSA]