Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Flight Crew Last 90 Days 10; Flight Crew Total 2626; Flight Crew Type 1060
Aircraft Equipment Problem Less Severe
Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Aircraft; Human Factors
Lost all electric power at cruise altitude of 11;000 feet in Baron 55.  Was on an IFR flight plan and was above clouds.  Having observed the voltage indicators as being '0' for both engines; I realized there was a good chance that the batteries were not charging and that I might be losing electric power.  That was about 20 minutes after refueling at ZZZ.  I grabbed my emergency handheld radio and attached it to my external antenna (I make sure to keep fresh batteries in my handheld radio).  I then tuned it to the frequency of the controller I was speaking with.  Within 5 minutes the panel went black and all electric was lost.  I did not try to recycle the alternator switches or change from voltage regulator #1 to #2.  Rather; I contacted the controller on the handheld radio and informed him that I had lost all electric and requested guidance to an airport so I could safely land and assess the cause of loss of electric power. The controller was very accommodating and directed me to ZZZ1.  He also called the airport to inform them of my having lost electric power and of my expected arrival there.  I followed procedure to crank the gear down (pulled the circuit breaker first) and landed safely and uneventfully.  The airport proprietor asked if I would like to have an aircraft mechanic look at the Baron; to which I responded 'please'.  The mechanic assessed the matter and concluded that I had blown a circuit for the alternators; causing the batteries to drain power because they were not charging. He charged the batteries enough so that the engines turned over and could be started.  The alternator switches had reset themselves; and the batteries recharged to the max.  Rather than continue flight and risk flying over the mountains at night; I elected to spend the night there.  The next morning the engines readily started; the alternators were charging and the voltage indicators indicated pulling a charge.  I safely returned to my home base with no problems with electric power.  Assessing the cause of the loss of electric power; I recounted that after refueling; I flooded the left engine during my 'hot start'; but before the engine quit due to flooding; I flipped the left alternator switch up.  Although I followed procedure to 'unflood' the engine prior to attempting restart; I failed to turn off the alternator switch.  I think that is when the breaker kicked (on both alternators) and prevented the batteries from charging.  For some reason; the 'alternator off' lights did not come on.  Prior to takeoff; I failed to see that no load was pulling on the voltage meters (either of them); and the batteries were therefore not charging.  Henceforth; I will make sure the alternator switches are off during the engine starting process and that I check the voltage indicators to ascertain that a load is being pulled on each side before takeoff.  Also; had I tried recycling the alternator switches during flight; and/or switched voltage regulators from #1 to #2; there is a good chance my power would have been restored in flight. I learned several valuable lessons. Glad I always carry a handheld radio. After [many] years of flying; this is the first time I have had to use it in an emergency.I called the aircraft mechanic and asked him to please send a 'return to service' logbook entry for my aircraft airframe logbook.  Upon receipt; I will make sure this entry is made in my aircraft logbook.
BE55 pilot reported a complete loss of electrical power at cruise altitude. The flight successfully diverted while using a handheld radio.