> >A shunt goes in PARALLEL with your ammeter, imagine your ammeter as a >narrow pipe, not much can flow thru it, the shunt is a larger pipe, so >most the flow is thru the shunt, and a small amount of current flows thru >the ammeter. The proportion of flow is fixed by the size of the shun. >Pete ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I checked my wiring diagram and my Tony Bingelis book so I think what I'm about to say is correct. I checked Mark's reference and it left me feeling a bit electrically challenged. To clarify the above statement from Pete a bit, the AMMETER is in parallel with the shunt with the shunt wired in series from the + side of the battery to the main electrical buss. All current from the battery to the buss goes directly through the shunt, not the meter. The meter simply detects current flow through the shunt and give you an indication on the amp gauge, + or -. The alternator or generator regulated output is wired through required relay contacts and circuit breakers directly to the main buss. If the output from the alt or generator exceeds the load on the main buss then the excess goes to charge the battery and the ammeter shows a + indication with the amount of amps going TO the battery. If the alt or generator output is less than the load on the main buss then the battery supplies the remainder of the required amps and the amp meter will show a - read in the amount of amps being drawn FROM the battery. The shunt range and meter range must be matched for accurate reads. For those of us with lower output alternators like my B&C with a 12 amp rating, a good quality Bosch 30/40 amp relay seems to work well to tie the alternator output to the buss. I'm using two of them, one to tie my alternator output to my main buss and another to tie the output to my backup battery buss. No problems in 265 hours. I got my relays from an auto sound system supplier. Auto Zone sells similar relays, made in Mexico, so you be the judge of quality. They would probably work well as the main buss relay also but I used a continuos duty relay from the C-150 I salvaged. If I were doing my wiring over I would use these relays to control all my high amp circuits like landing lights, position lights, flap motors, etc., instead of drawing the entire circuit load through a switch on the panel. The switch on the panel would simply actuate the relay. If anything I said here is in error, someone with more knowledge please correct me. Larry Flesner
