Morningstar TS-MPPT-45 Battery Sense Connection

ddegange

Hello.  I just installed 2 Kyocera KU265 panels on my boat with a Morningstar TS-MPPT-45 CC.  The run from the panels to the cc is about 25 feet.  I have 3 AGM batteries connected in parrellel and the closest one to the cc is about 7 feet so I connected the cc there.  Can the battery sense wire be connected to the same battery terminals as the battery connections to the cc?

vtmaps

Welcome to the forum,

The battery sense wires help the controller to know the battery voltage regardless of the voltage drop in the wiring.

It sounds like you have your batteries spread out a bit.  This will make it difficult for them to all have the same voltage drop.  The voltages will be correct at the battery with the sense leads.  Batteries closer to the controller (than the sense leads) will be overcharged, and batteries that are farther will be undercharged.

--vtMaps

ddegange

Thank you.  I wasn't sure if putting the battery sense wire on the same terminal as the charge wire from the cc would have any affect on the battery sense voltage reading.  

inetdog

Putting the sense wire on a connector which is in turn attached to the battery terminal will pick up the voltage drop between connector and battery. But it should only be millivolts of difference.
If possible, you should attach the sense wires separately to the battery terminal, but that is not always easy. Against the lead on the other side of through bolt from the main lead on a flag terminal should be perfect.