Wire size

[Juan]

Quick question:

what should be size of the wire connecting the alternator and the starter solenoid. Mine is #14. Shouldn't be #10? Should I change it? Does it matter?

Thanks,

Juan

[Clay Greene]

Blue Sea Systems has an excellent chart and an online tool for determining the wire size.  You'll need to know the amp output of your alternator and the distance between the alternator and the starter. 

As an alternative, you might consider removing that jump wire and running the AO directly to your house battery bank.  Your batteries will recharge more efficiently and you won't need to worry about frying your alternator diodes if someone turns the switch to or through "off." 

[Stu Jackson]

clay's right, but if you want to leave your current battery/alternator/starter wiring intact, then the larger wire wouldn't hurt.  It's a short length, but carries heavy current for a very short period of time to start the engine.  Bigger is better.

It's all explained here, Figure 2, from the Electrical 101 Topic:

OEM 1-2-B Switch Wiring History  http://c34.org/bbs/index.php/topic,4949.msg30101.html#msg30101

[Ron Hill]

Juan : Just make sure it's tinned "marine grade" wire!! 
I solder and crimp for both the best electrical and mechanical connection. 

Personally, I'd use a piece of #8 gage.

A few thoughts

[KWKloeber]

Juan,

I used 8 AWG, with heavy duty "starter" lugs (1/4" and M8).  Power lugs are overkill.

RC recommends 6 AWG because he says there's no good crimper for no. 8 lugs.

Don't forget also about grounding the alternator frame ground (#10 stud) to the bell housing (M8 bolt.)


Ken K

[KWKloeber]

Why will they charge more efficiently?

Ken

Blue Sea Systems has an excellent chart and an online tool for determining the wire size.  You'll need to know the amp output of your alternator and the distance between the alternator and the starter. 

As an alternative, you might consider removing that jump wire and running the AO directly to your house battery bank.  Your batteries will recharge more efficiently and you won't need to worry about frying your alternator diodes if someone turns the switch to or through "off." 

[Clay Greene]

Power loss over the length of the wire.  The factory set up sends the recharging voltage from the alternator to the starter and back from the starter to the battery switch and then from the battery switch to the house battery.  There is one wire used for both delivering charge from the battery to the starter (through the battery switch) and for recharging the batteries from the alternator.  Running a wire directly from the alternator to the battery bank reduces the distance the charge needs to travel.  We also changed the gauge of wire from 4 AWG to 2 AWG so there was additional improvement there as well.