apogee and main ejection charges. All Altus Metrum products are
designed for use with single-cell batteries with 3.7 volts nominal.
</para>
+ <para>
+ The battery connectors are a standard 2-pin JST connector and
+ match batteries sold by Spark Fun. Other vendors sell similar
+ batteries for RC aircraft using mating connectors, however the
+ polarity for those is generally reversed from the batteries used
+ by Altus Metrum products. In particular, the Tenergy batteries
+ supplied for use in Featherweight flight computers are not
+ compatible with Altus Metrum flight computers or battery
+ chargers. <emphasis>Check polarity before connecting any battery
+ not purchased from Altus Metrum or Spark Fun.</emphasis>
+ </para>
<para>
By default, we use the unregulated output of the Li-Po battery directly
to fire ejection charges. This works marvelously with standard
</listitem>
<listitem>
<para>
- RF interface for battery charging, configuration, and data recovery.
+ RF interface for configuration, and data recovery.
</para>
</listitem>
<listitem>