There are 3 disadvantage's between the Smartshunt and BMV712. I don’t know if the IP65 one fixed the Bluetooth issue or not. I speak from experience after owning both.
1. Very limited range on the Smartshunt. Because the Bluetooth antenna is so close to the shunt and my battery bank- I was lucky to get 5 or 6 feet of Bluetooth range. The BMV712 has the Bluetooth antenna in the display- I would guess 25’ range.
2. The BMV712 has a relay port on the display- if you want to switch some stuff based on voltage or SOC - it’s useful. Otherwise no big deal.
3. VE.Direct port. The VE.Direct port goes to a Cerbo- (which is way cool and worth it). Both units have it - the Bmv712’s is on the display- while the Smartshunt’s is on the unit. Which is better depends on where you will mount the Cerbo. I don’t really use the display- I read everything off either my CCGC (old version of Cerbo) or the App - through Bluetooth. The display is mounted in a back corner of the cabinet- out of the way. But since it is close the my CCGX - it works out well.
The one advantage of the Smartshunt is it is a little bit cheaper.
Also, since your batteries are currently “outside” you may want to consider getting the temperature monitor for the Bmv712 & smartshunt- (same cable). This will allow the Victron smart solar charge controllers to know what temperature the batteries are at. There is a charge difference for hot & cold lead acid batteries. There is also a no charge for lithium’s below 32F. That cable is worth it - unless you have a Multiplus- it comes with a cable- then it’s just redundant. (My issue in my MotorHome is my Multiplus is a ways away from the batteries - so I couldn’t use the Multiplus supplied temp cable.
As long as the Bmv712’s is dry (maybe inside a battery box or just where the cables come through the trailer), it will be fine.
Good Luck
