voltage discrepancy

[jtdiesel65]

Hi,

I have absorb and eq set at 29.6 and 31. I noticed on both my classics that absorb voltage actually goes to 30.3. In other words it climes and holds at 30.3 rather than the 29.6 set point. I did an eq yesterday and noticed it was at 31.5, not 31. My bogart and inverter show the same, so it appears that the set points aren't being followed.

Any idea what might be going on here?

also any news on the new firmware with PV shade disablement?

thx

[Westbranch]

do you have a temp sensor?

[jtdiesel65]

They each have their own.

[Tinman]

Check your temp sensor. Mine caused voltage set inconsistencies until I mounted it differently. You can see my other posts where I changed it. Made an immediate difference.

[boB]

OK, so what is the output current.  Do you have a voltmeter to measure the voltage closer to the Classic terminals ?
Maybe there is a voltage drop from Classic to the batteries themselves.   The Classic will show a bit higher voltage
than at the battery terminals if there is a voltage drop but won't happen unless there is a good amount of current
through those wires.

As far as temperature compensation, EQ has its temp comp disabled by default but can be selected.
Even if the EQ temp comp is set to NO in the Temp Comp sub-menu (in the CHARGE menu), you can
go into that menu and press the VIEW soft right key and see what the Classic thinks the present
battery target voltage should be, compensated or not.

If the Classic's battery voltage reading is just plain off by a few tenths of a volt, going into the TWEAKS
menu will allow you to adjust that.  If it is due to a voltage drop of 1/2 volt on your battery lines,
I would think about making that wire larger or maybe the connections just need to be tightened
up some.

Usually, in MPPT mode, the voltage drop isn't a problem but if your system is holding the voltage constant
and not in EQ MPPT mode, then the voltage should be within a couple tenths of a volt.   0.5 volts is too high
I agree.  I didn't see a decimal point showing  31.0  vs  31.5 V, but assumed that's what you meant.

boB

[jtdiesel65]

I guess the eq isn't involved. Today the set point was 29.6 but was charging at 30.2. The temp menu indicated 13.3. So perhaps that is what I should expect. 

[boB]

I guess the eq isn't involved. Today the set point was 29.6 but was charging at 30.2. The temp menu indicated 13.3. So perhaps that is what I should expect.

Yes, maybe so.

  You know you can also set an absolute voltage limit in the Temp Comp menu, which is usually for sealed batteries.

In fact, it might be set to default of too low absolute voltage limit in some cases

boB