An FAA policy memo issued last week highlights the potential safety hazards associated with the rechargeable lithium batteries in electronic flight bag (EFB) portable computers. Noting that lithium batteries can pose a particular danger during recharging, the memo requires class 1 and 2 EFB users to test onboard battery charging to RTCA/DO-311 standards or add placards stating that no equipment containing rechargeable lithium batteries may be connected to aircraft electrical power. During overcharging, lithium batteries can heat and ignite, resulting in fire or explosion, the policy document warns. The results of the battery charge testing do not need to be included in the STC package for EFB installations, nor are they required to be shown to the operator’s aircraft certification office, according to the memo distributed last week by the agency’s aircraft engineering division.