Although the majority of the systems include a battery temperature sensor (BTS), most systems had problems with them that compromised their accuracy. At one site, the BTS was plugged into the secondary (slave) inverter instead of the primary (master) inverter, with the result that no temperature adjustment occurred. At other sites, the BTS was installed incorrectly—cither lying on top of the battery lid or at the end of a battery bank, which also reduced its accuracy. At many sites, the adhesive on the BTS failed