T&T: Battery monitor

[StWillett at aol.com]

I am getting ready to order a Xantrex Linklite battery monitor, I'll  be 
connecting it to the main bank which is 2 8D batteries serving house and main  
engine start functions. since it can monitor 2 banks I'll hook it up to the  
generator start battery also. 
The unit comes with a 500 amp shunt, I see other shunt capacities are  
available. I am not sure how the 500 amp rating is determined or if the 500  amp 
size supplied will be ok for my application.   I am not on the  boat now so don't 
know the exact ratings of the 8D's.  The product   description mentions " a 
new shunt selection is available to measure currents up  to 1000 amps 
respectively"
When the 8 D's die I 'll probably go to golfcart batteries and add a  
separate main engine start battery (group 31 size) which I will then monitor  instead 
of the genset battery.
  The boat is equipped with 12V windlass and bow thruster, no  inverter.
So, my question is, will the standard 500 amp shunt suffice for  the above 
application?
Thanks for your help and suggestions,
 Steve Willett 
Monk 36, Gumbo
Thibodaux, Louisiana
**************Feeling the pinch at the grocery store?  Make dinner for $10 or 
less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001)