# Battery Smart Shunt install advice on boat with 3 way switch 12v x 2 batteries **URL:** \ **Category:** DIY\ **Tags:** gx\_device, parallel, marine, beginner, cerbo\_gx, mppt\_controllers\ **Created:** [7 May 2026 15:50 UTC](https://community.victronenergy.com/t/battery-smart-shunt-install-advice-on-boat-with-3-way-switch-12v-x-2-batteries/57699 "2026-05-07T15:50:28Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![MSK](https://avatars.discourse-cdn.com/v4/letter/m/65b543/32.png) [@MSK](https://community.victronenergy.com/u/MSK)\ **Post date:** [9 May 2026 07:43 UTC](https://community.victronenergy.com/t/battery-smart-shunt-install-advice-on-boat-with-3-way-switch-12v-x-2-batteries/57699/2 "2026-05-09T07:43:57Z")
Hi all, I’ve worked out one of my issues/points thanks to another poster, [Shunt / battery monitor not reading the correct SOC/ Amps, missing solar, decreasing daily or other misreading problems](https://community.victronenergy.com/t/shunt-battery-monitor-not-reading-the-correct-soc-amps-missing-solar-decreasing-daily-or-other-misreading-problems/87) and the issues I was seeing was due to my connections for active devices still being mounted on the battery pole, and not on the load side of the smart shunt. I hadn’t considered that in order to be measured correctly, they needed to be moved and mounted to be shunt and not the battery. I have another question that I hope someone can answer. I will be installing nother 1000a smart shunt to he starter battery so that I can monitor both batteries independently, but my MPPT only has 1 supply out,can I busbar this and supply both batteries? Or will the MPPT get confused with the output it needs to supply? I’ve done a new diagram please could someone help? ![IMG_20260509_082805](https://europe1.discourse-cdn.com/victron/original/3X/f/f/ffd4a99c5e4122d7ae91fee008a62475e40d5fe7.jpeg) --- _[View the full topic](https://community.victronenergy.com/t/battery-smart-shunt-install-advice-on-boat-with-3-way-switch-12v-x-2-batteries/57699)._