There has been much discussion regarding the newer style, lightweight starters that use permanent magnets as the basis of their technology. To understand some of the issues, we must first understand one basic design characteristic of a permanent magnet lightweight starter: it needs a lot of power to get started! Since most permanent magnetic starters are derivatives of small automobile engine starters, their motors are first found in automobile chassis where batteries are substantially larger than typical light aircraft batteries and hence, have more available power. When these designs were adapted to aircraft, they failed to take into account the smaller batteries typically associated with light aircraft (25 amp-hour batteries and smaller). Permanent magnet starters typically draw between 30%-40% more energy than their larger, older style counterparts that they typically replace. This has left the entire aircraft electrical system, including the electronic ignition system, competing with the starter at the beginning of the flight cycle for power.

Most electronic ignition systems, Electroair’s included, require a minimum amount of power available in order to operate correctly. In the case of the Electroair EIS, the minimum system voltage required is 8V. If the system voltage falls below that value for any length of time, the EIS will not function properly and can potentially cause the engine to ‘kick-back’. This event can happen during the start-up of an aircraft engine using a permanent magnet starter if, for instance, the battery is not a peak charge. It is strongly recommended that an operator of one of these starters with an EIS always keep a full charge on their battery. Other suggestions that have come from some starter manufacturers include adding a dual battery to support the starting requirements. Electroair also supports the idea of a dual battery system, in particular, for potential emergency situations. This solution, however, has to be balanced with what the original weight considerations of the aircraft were in the first place.

One other alternative which has the benefits of a lightweight starter and does not have the draw backs of permanent magnet type starter is to use a series wound starter. Such an example is the starter built by B & C Specialty Products of Newton, KS. The B & C starter uses a series wound motor as the drive unit and draws much less power than a permanent magnet starter and is less susceptible to problems inherent to permanent magnet starters – like hot starts. A hot engine reduces the effectiveness of a permanent magnet starter. The B & C Starter has been used very successfully with electronic ignition systems. Of course, good battery condition and good grounding are vitally important for trouble free operation.

Another remaining solution to the low voltage problem associated with permanent magnet starters is to remain with the old style, Prestolite or Delco starter. These are heavier, obviously, than their counterparts, but there have not been significant problems reported about their operation with an electronic ignition system.

Please contact Electroair technical support if you are experiencing any starting problems. There are several solutions available.

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