Corvair Powered: Where to put the battery?

[Tony4aro]

Hi All,

I know the Corvair engine is a little heavy... and I know the battery should be located rearward... but where exactly are you guys putting it? What kind of power cables are you using? and if it's all the way back in the tail... how big of a hatch did you need? (Pics would be great also)

Thanks for any help you can give.

[racaldwell]

For the cables, I recommend Fatwire from Pherihelion Design. Large copper coated aluminum wire for high current and very lightweight. They are used by Boeing, and me in my Xenos. Also an Earthx battery to help with the weight reduction.

I don't have a Corvair but a CAMit 3300 and put my two batteries next to the front side of the spar tunnel. They will be under the passenger's knees on the floor which is unused space otherwise.

Rick Caldwell
Xenos 0057 25 hrs

[GordonTurner]

I am putting my two batteries on the aft side of the crossmember that is the lower aft piece of the “baggage compartment”. I haven’t decided yet if access from the cockpit area will be adequate or if I will need a hatch.

Going to check out those wires Rick. Otherwise planning to use #2 welding cable.

Gordon

[GordonTurner]

Quick check reveals:

Perihelion fat wire is 8 GA, $3.50/foot, and claims to weigh 50% or so, probably relative to 8 GA copper.

8 GA sounds light to me, but not my field of expertise.

2 GA welding cable costs between $0.60-0.90 per foot. It weighs about 1/4 pound/foot, so that will definitely add up. 4 GA is about 1/2 the weight of 2 GA. You should do your own research, but I think starter cable is typically recommended at 2 or 4 GA. Note, NOT 2-0 GA which is way heavier.

The farther the battery is from the starter the more need for heavier gauge cable.

A welding shop will crimp on connectors with their hydraulic press. Alternatively Amazon has a range of crimpers for cable including little hydraulic ones. Obviously these crimps are super important….for good starting and to prevent loose high capacity wires getting loose.

Gordon

[Tony4aro]

So... Why 2 batteries?

[racaldwell]

For me, one battery is for engine starting and one is for soaring. I also can have the EFIS on during starting since the cross-connect switch is off during starting. Otherwise, the voltage sag may cause the EFIS to reboot during starting.

Rick Caldwell
Xenos 0057

[Tony4aro]

OK... in your case... that makes perfect sense.

[XenosN42]

For me, one battery is for engine starting and one is for soaring. I also can have the EFIS on during starting since the cross-connect switch is off during starting. Otherwise, the voltage sag may cause the EFIS to reboot during starting.

Rick Caldwell
Xenos 0057

Which EFIS do you use? I’ve used two MGL devices, and turn them on before engine start and have never experienced a reboot.