Twin 914'2 w dual batteries

Rogerio,

Attaching a mechanical pump to the gearbox is an interesting option that I have never seen before.  Do you know where to obtain the parts to perform this alteration? I'm not sure I would go this route but it is worth considering.

Ryan,

Adding lighter weight batteries is definitely a consideration as the batteries in the plane are several years old and will probably need replacing soon anyway.

Thank you both, Tim

Bill,

The real question I am trying to answer for my particular plane is the fact that she's fat.  The original builders did a superb job of construction. They did such a good job and added so many "extras" that I am trying to figure out if there is anything I can modify safely to get her slimmed down a bit so I can have a better useful load.  I have never seen an Aircam with a three axis autopilot but, this one has it. She also has 4 landings lights, an extra slick and thick paint job (which is always extra weight), an absolutely crazy amount of instrumentation and wiring which adds quite a bit, etc, etc. 

I would never make any type of alteration that would affect safety of flight but I simply did not understand, until now, the proper rationale for the dual batteries. 

Thank you,

Tim  

You probably currently have two 15-20 Ah batteries.

A single 20-30Ah Lithium battery would be an option unless the Once in 10 million hours, Dual Generator failure scenario is going to keep you up worrying.

50% more than your current single battery capacity would be recommended.

Tomorrow when I am back at the airport, I will confirm this for sure.

Tim

Be a bit wary of Li-ion batteries. My original lithium battery (on a 912 ULS) died one day in 2018, for a reason I have never been able to determine.  As you may know, dead lithium batteries are not easily (or generally) revivable.  That battery, of a very particular size to fit in my battery tray, came from Italy.  Because of its capacity (10Ah), it could not be shipped by air, so I was looking at many weeks of waiting (in prime flying season) for a new one.  So I switched over to a small Odyssey lead-acid battery, which was easy to get and simple to recharge, if necessary.  Ya, it required a bigger tie-down strap, and weighs about six pounds more, but I have never had a problem with it since.