question

oxdavey avatar image
oxdavey asked

Mppt 100/50 solar controller vs smart shunt

d9d8dfdf-8389-4fa2-a3bb-20c28d6171ba.jpegMy solar controller reads the batteries at 14.3v and goes into absorption while the smart shunt says 13.5v and at 83%. The solar controller is at the back of the boat while the smart shunt is right next to the batteries. Do I need to bring the solar controller next to the smart shunt to fix this as by the end of the day I am only getting the batteries charged to about 89%.

smart solar charging behaviour
1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·
Wire length and cross section?
0 Likes 0 ·
2 Answers
Paul B avatar image
Paul B answered ·

Whats happening is that when the solar is charging you are getting a voltage drop on the cable from the reg to the battery.


Best solution is to move the Regulator to be as close to the battery as you can get it. and make sure the wires gfoing from the reg to the battery are at least 6mm

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

JohnC avatar image
JohnC answered ·

Hi @oxdavey

You could network them, so the mppt can use the V from the shunt rather than it's own. You have a Cerbo (two?), so if they're connected there you can use DVCC to network the V. If not Cerbo connected, then maybe via bluetooth, although range may be an issue. Don't use both together.

But yeh, normally it's better to run the solar wires the distance as they're at a higher V, and have the mppt nearby the batts and the other elec kit.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources

Additional resources still need to be added for this topic