Hi Charlie,
I can verify the 40-45minute capacity of the PC680 at load. I had my system setup so that a contactor could be closed/open via a switch on my panel. I had read case of lead acid batterys exploding when an alternator "ran away" with too high voltages, so I installed the capacity to disconnect the battery from the Alternator.
During one trip to Texas from NC I stopped an refueled in Alabama. Approx 40 minutes after taking off, the engine started missing, I checked to make sure I had fuel going to the engine, even switched tanks this time. Missing continued so I turned toward Salema, Al where there was a old USAF training airbase. As I continued the missing kept getting worst and finally approx 5 miles out the engine quit. Continuing the glide I contacted the Airport and just had time to tell them I was making an engine out landing when I heard a click and the panel when dead with no lights, nothing! Made it dead stick into the airport and discovered while trouble shooting that the battery connect switch was in the disengaged position and battery voltage was down to around 6 volts. Yeah, I though to check the fuel but never thought to check that switch because after installing it - I never used it. I must have accidently hit the switch with my foot when exiting the cockpit at my refueling stop.
Yes, I immediatedly installed a switch guard after returning home. But, 40-45 minutes shoulds right for PC680.😄
Ed
------ Original Message ------
Sent: 7/31/2021 8:57:43 AM
Subject: [FlyRotary] Re: Airventure 2021
I took a slightly different path; I figured that if the alt quit, then the flight limit is how much the battery has in its 'tank'. A PC680 sized SLA is good for about 40 minutes with typical load from electronic injection. I've become a bit of a sissy in my old age; I want the engine to run until the fuel in the *gas tank* is gone. So, I made some brackets to add a 2nd alt; mounted where the air conditioner compressor lived in the car, and run off the 2nd pulley. Of course now, with it looking like Covid's going to outlast me, I'll likely never get to travel in the plane anyway, so I may just go back to the 40 minute limit & save the weight.
Charlie
I flew for a number of years with two 22 lb batteries without every needing the "spare". I then switch to a single Odyssey PC 680 17 lb battery and switched it out every 3 years (stuck used one in riding mower) and flew for over 15 years using this configuration. Never had a battery problem with either, but saved weight and money with the one battery.
But, my view is if you are not comfortable flying with a certain configuration, then don't. Fly with a configuration that you feel secure with and you will enjoy flying all the more.😄
Ed
------ Original Message ------
Sent: 7/30/2021 3:21:45 PM
Subject: [FlyRotary] Re: Airventure 2021
Le Roux, Agree a great product, but I am more concerned with the engine battery backup. Therefore I have 2 batteries . Since no longer flying instruments, I can still fly looking out the window, but if the engine fails --- Then you know what is trumps!! Neil. Realy nice product
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