Savannah battery location

[Phillip King]

Savannah battery location

 

Having trouble starting when battery voltage is slightly down ,have checked voltage drop when starting with fully charged battery losing 4.7 volts because of the leads we think. Battery is located at the rear of the plane. Has any body had the same issue?

 

 

[Kenny]

I moved my battery forward some time ago both improving start up and C of G , the leads we're shortened by about two thirds.

 

I mounted the battery behind the reserve tank accessing it through the inspection hatch underneath the fuselage .

 

The battery leads are not all that heavy and with all that length the voltage drop would be quite substantial.

 

Cheers

 

Ken

 

 

[Kyle Communications]

Ken is right

 

The standard cables are way too small for a rear battery. I shifted my battery from behind the pilot in my XL down to the rear to make my CG more tail heavy as the aircraft was nose heavy...well in my opinion anyway. I used much larger cables to do the extension plus a busbar connection where the battery was orginally. My engine swings over quite fast I also run a separate negative all the way from the battery to the starter solenoid base abd then onto the starter motor so not relying on the frame for the negative return. The cable is 4 guage from memory in size

 

 

 

[Phillip King]

Thanks guys for the info, great help will pass this onto the owner.

 

Cheers Phil

 

 

[paulh]

Ken is rightThe standard cables are way too small for a rear battery. I shifted my battery from behind the pilot in my XL down to the rear to make my CG more tail heavy as the aircraft was nose heavy...well in my opinion anyway. I used much larger cables to do the extension plus a busbar connection where the battery was orginally. My engine swings over quite fast I also run a separate negative all the way from the battery to the starter solenoid base abd then onto the starter motor so not relying on the frame for the negative return. The cable is 4 guage from memory in size

Hi, on your aircraft is the whole electrical system wired this way to avoid using the airframe as the negative?

Must assist in reducing the corrosion risk due to potential differences.

 

 

[David Isaac]

Guys,

 

May I respectfully suggest that you tidy up that wiring in that picture and if you intend to run wiring in that manner that it is properly loomed and attached to the fuselage so that it cannot move in a G inertia environment or vibrate against any metal edge. The wiring in that picture would have substantial movement both in flight and on the ground and I would hazard to guess will cause you problems in the due course. I hope the cables are double insulated otherwise they need to be installed within an additional sheath. Even if you run a separate negative earth to the engine remember the fuselage metalwork will still hold a negative potential and a positive wiring rubbing through will cause a real fire hazard. In that configuration I would definitely have a master solenoid at the battery that can be readily isolated in an emergency. Wiring must be aequately insulated, loomed and attached if you value your life.

 

 

[eightyknots]

Ken is rightThe standard cables are way too small for a rear battery. I shifted my battery from behind the pilot in my XL down to the rear to make my CG more tail heavy as the aircraft was nose heavy...well in my opinion anyway. I used much larger cables to do the extension plus a busbar connection where the battery was orginally. My engine swings over quite fast I also run a separate negative all the way from the battery to the starter solenoid base abd then onto the starter motor so not relying on the frame for the negative return. The cable is 4 guage from memory in size

I suggest that the two 4g cables along the length of the fuselage must help the CG as well as moving the battery to the back.