question

jeffp avatar image
jeffp asked

Battery charge disagreement between shunt and smart controller

I'm adding panels and a smart controller to an RV that already has a lithium battery and a smart shunt.

So far I haven't been able to get the battery to receive charge. The controller shows incoming voltage at ~22v and no current on the solar side, ~14.2 volts and no current on the solar side, and that system is in absorption mode.

The smart shunt shows the battery at 13.2v.

I've checked the current to the solar controller with a multimeter and (at the time) it showed ~8A at ~22v.

Questions:

-why would the system show being in absorption mode, but no current on either the solar or battery side?

-why aren't the battery charge values in agreement between the shunt and the controller?

SOC
3 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

jeffp avatar image jeffp commented ·
I should've added, I've connected the solar controller battery negative to the system side of the shunt, and the solar controller battery positive to the load side of the breaker connected the battery's positive terminal.
0 Likes 0 ·
jeffp avatar image jeffp jeffp commented ·
just checked and saw that I misstated in first post - s/b ~14.2v and no current on the battery side of the controller
0 Likes 0 ·
jeffp avatar image jeffp jeffp commented ·

it's fluid! so another update... I didn't know about the VE Direct network, so I've set up a network and added both devices - the controller is now correctly receiving voltage from the shunt

the voltage on both is now 13.3v, and the controller indicates that it's now in bulk charging mode...

but both the solar and battery side say 0 current, the battery state of charge is 73% (from the shunt) - I've read where the current on the solar side *could* read 0 if it thinks that the battery is fully charged, but it's not, and the controller thinks it's in bulk charging mode...

so why are both the solar and battery showing zero current?

0 Likes 0 ·
1 Answer
pwfarnell avatar image
pwfarnell answered ·

You most likely have a poor connection between your controller and the battery. Get you multimeter out and check for poor connections, every crimp, terminal and switch.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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