How to decide with Smartshunt to choose, 300 amp or 500 amp? 37 foot boat with three batteries, one for generator, one for house, one starter for 2 engines.
How much power do you need in your system?
Power / system voltage = current
Less than 300A → 300A shunt
More than 300A → 500A shunt
Thank you, yes that makes sense but perhaps I should have been more specific, how do I determine how much amperage in my system
As I wrote, it depends on how much power you need in your system.
You need to know how much power every device in your system needs.
Total power divided by battery voltage = current (+ 20% as reserve)
Or you calculate it the other way around.
300A x battery voltage = max. power
e.g. 300A x 12V = 3600W
What purpose do you intend for the shunt? I presume it is for monitoring the house battery?
What equipment operates from the house battery? Voltage and capacity of the house battery would also help.
I found that in the UK last week the 300A model was unobtanium and you had to get the 500A anyway. I hadn’t realised the 500A modal has M10 bolts instead of M8, so had to scrabble around for some suitably-massive crimps. Otherwise they seem nearly identical.