No "Charge" current showing

[sailingharry]

My system has been working for about 18 months now, with no issues.  It is still "working" but I noticed an issue with currents.

This pic shows the SBMS0 main screen.  The LED digits are a Hall Effect ammeter summing my solar input -- it was there before the 'Dacus and it's nice to have.

You'll see that I'm producing 37.6A, and net power to the battery is 30.274A.  This makes sense since I'm probably using about 7 amps.

The problem is that I'm showing zero amps for both PV1 (the charge shunt, right?) and Load.  Battery Amps are read right on the main shunt, so that one is reading.  PV1 Amps are read on the charge shunt, so perhaps a problem?  But Load Amps is Battery-Charge, which somehow is adding to zero (30 Batt - 0 PV doesn't equal zero Load!).

I did pull the ribbon cable and reset, which is why the SOC is reading 47%.  I had the contactors open when I did the reset, so the shunts should have properly zero'ed.  It also probably explains why ADC2 is reading zero-ish (it's my Start Battery, and I need to do another reset with that disconnected.)

So, why do my Load and PV1 Amps read zero?

[Dacian Todea (electrodacus)]

There can be many reasons for PV not to show any current.

Did the PV1 showed corect current before the recent reset ?

What was the reason for the reset ? And was it done correctly ?

It will be normal to show Load as zero since the PV1 shunt is not working and Load is calculated at Battery current minus minus PV current so 37 - 30A = 7A

But since PV current is zero the Load will also show zero since current flows in to battery not out of battery and Load is supplied directly by PV array.

A photo of the Diagnostic screen will be useful to know what happened. Could be be reverse sense wires to PV1 shunt or one of the PV1 shunt sense wires disconnected or there was a current trough the PV1 shunt during last power up and so the zero offset calibration was done incorrectly. A photo of the Diagnostic will help with narrowing down the possibilities.

[sailingharry]

Both PV1 and Load did work correctly for many months.

I did the reset in an attempt to restore PV1 and Load readings.  They were both reading zero before.

I didn't realize that Load was limited to positive numbers -- that would explain it!   I do charge on the load side with my inverter, but that happens so rarely I probably never noticed.

I'm pretty sure that since everything worked before, it isn't a configuration issue.  I'm going to start troubleshooting by looking at the circuit from the SBMS0 to the shunt (of course, the wires to this shunt are upside down and can only be felt, not seen

 -- that's boats for you!)

Diagnostic photo attached.

[Dacian Todea (electrodacus)]

Is this a recent photo ?

As it shows 14.54A from PV1 and 14.4A going in to battery. It is slightly lower than 17.1A I see on the green display but not sure how accurate is that.

One thing I notice is that You have connected the EXTADC2 to battery+ voltage and it was connected to around 8V when you last powered on thus the bad zero offset calibration for EXTADC2 of 36977 instead of something around 32700. Your ADC2 reads now 5.205V the difference between 8V when you powered on and around 13.3V battery voltage.

Maybe you meant to connect the ADC2 to battery or maybe you shifted the shunt sense wires with one position or something similar.  

[sailingharry]

Just to close the loop on this.

Dacian indicated at one point that "load" won't indicate negative.  So if the math between "batt" and "PV" create a negative "load," it reads zero.  Ah!  It's simply no solar shunt.  That's a clue.

I removed the wires for the solar shunt from the shunt and the SBMS0, and reconnected them all.  Reset the SMBS0, and I have solar amps.  Just a loose connection someplace.

As far as the ADC2, that's worth pointing out.  I have to relearn this each time I reset the SMBS0.  That wire comes from a fuse block, and removing the fuse is not enough. It's one of those newfangled fuse blocks with an LED that lights up to show the fuse is blown.  In most cases, that's a good thing. Unfortunately, it lets through a lot of volts, even if near-zero current.  To get the SBMS0 to properly reset, you can't remove the fuse -- you have to physically remove the wire from the fuse block.