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What sized battery cable did you use?

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Battson

Well-Known Member
Joined
Jan 30, 2012
Messages
610
Location
New Zealand
Hey all,

I am interested to hear what sized battery cable you are using?

I am installing a Skytech Lightweight starter motor, which is of course the largest instantaneous demand on the battery cable. I emailed Skytech, and seemingly got a reply from the "GM" there (which was surprising) who told me to use 0AWG or at least 2AWG for the starter to battery connection. My battery is back under the seat for balance, so the cables are more than just a couple of feet long. Expected draw for cranking is between 180-280A (instantaneous, obviously, only for a few seconds). My battery is an Aerovoltz Lithium Iron Phosphate model, 410CCA & 12V.

I know many aircraft are using 4AWG which is what I'd planned on using, and going to look at the size 2 and 0 cables, they are more like overhead powerlines than battery cables, and would probably handle >100A continuously..... is the man at Skytech simply being conservative?
 

Battson

Well-Known Member
Joined
Jan 30, 2012
Messages
610
Location
New Zealand
Ahh chapter 11 we meet again...

For the voltages and currents involved it doesn't matter about the length for me, it's certainly no more than a dozen feet. But it does fall outside the chart's non-linear area, so there is no answer in AC43.13 which concurs with common practice, otherwise we'd all be using larger than 2AWG and I've never seen that before.
 
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TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
13,969
Location
Memphis, TN
I have seen people get away with smaller cables, but the engine has to be easy to start. If it keeps cranking, it just goes down from there. If you end up doing a flood start in a tight cowl on a hot day, you will wish you had the bigger cables if they are long.
 

BBerson

Light Plane Philosopher
HBA Supporter
Joined
Dec 16, 2007
Messages
14,299
Location
Port Townsend WA
I suppose it's not a matter of safety.
But 12 feet seems long to me. In cold weather the cranking amps will be more.
 

Battson

Well-Known Member
Joined
Jan 30, 2012
Messages
610
Location
New Zealand
Na 12 feet was in reference to the chart not to my installation. My install would be less than that by a decent margin. I know at least two guys with the same install in the same plane used 4AWG. What did you guys use??
 
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