Shunt installation with dual battery

[ahw3617]

Hi folks, my basic question involves inserting a shunt and battery monitoring system into a parallel dual battery arrangement. Both batteries have load coming from them and I was wondering if I have to move all loads to a single (say primary) battery, effectively leaving the secondary battery with only the parallel cabling in place. The shunt would then take all cables on the primary negative terminal to one post with the other post going to the primary battery.

A simpler installation though possibly incorrect would be to just insert the shunt into the negative arrangement of one of the batteries and hope by magic that the load coming from the other battery is also being measured (cuz they're in parallel) by the shunt. Please help me understand if simpler would work? or if I have more work ahead of me . many thanks....

 

[sunshine_eggo]

Hi folks, my basic question involves inserting a shunt and battery monitoring system into a parallel dual battery arrangement. Both batteries have load coming from them and I was wondering if I have to move all loads to a single (say primary) battery, effectively leaving the secondary battery with only the parallel cabling in place. The shunt would then take all cables on the primary negative terminal to one post with the other post going to the primary battery.

A simpler installation though possibly incorrect would be to just insert the shunt into the negative arrangement of one of the batteries and hope by magic that the load coming from the other battery is also being measured (cuz they're in parallel) by the shunt. Please help me understand if simpler would work? or if I have more work ahead of me . many thanks....

All loads from the battery bank would have to come from the load side of the shunt:

It's good that you can recognize your own magical thinking. No such thing as magic...

It is NEVER desirable to pull from both terminals unless you have carefully balanced the loads. Shunt, or no, you should re-wire for shared current best-practices.