Wiring for Portable battery charger and Shunt

Sharon_is_SAM

Quick question.  We have a solar negative pigtail to the load side of our Victron shunt.  We also have a portable battery charger that we have been hooking directly to the battery.  In light of the shunt, should we be charging with the portable battery charger with the negative on the load side of the shunt?  Does it make a difference with shunt function?

elbolillo

Ideally, you would connect all loads to the shunt. I did that with my Victron portable charger that had a quick connect.

webers3

For the shunt to function correctly, ie: provide correct battery status, ALL loads have to be on the negative side, including charging

Sharon_is_SAM

Ok.  So, if I charge the battery fully with the portable charger on the battery, then sync the Victron BMV, will the BMV SOC be accurate on discharge?

AnOldUR

Ideally you want a busbar attached to both the positive and negative battery terminals. Your shunt should be between the negative busbar and the battery terminal. All your wires, including the chargers should be connected to the busbars. 

At least that’s what I did. Someone corrected me if I’m wrong. 😑 

rfuss928

Sharon_is_SAM said:

Ok.  So, if I charge the battery fully with the portable charger on the battery, then sync the Victron BMV, will the BMV SOC be accurate on discharge?

Yes, that is a good process to establish 100% SOC and it makes no difference which side of the shunt you connect ground.  But, if you want the shunt to keep track of the portable charger contribution to the battery's state of charge in the future, the charger ground should be on the "load" side of the shunt. This will also allow you to monitor the portable charger performance.

Sharon_is_SAM

@AnOldUR - another way is to either attach a load side lead directly to the shunt or at the junction box.  We have done both.