New-ish Classic and MNGP code update for trying

[ClassicCrazy]

Larry, What happens if you disable the Hawkes Bay from charging ?

How much time is your Absorb set for ?

Also, did we figure out if you are using any temperature compensation ?

And you did select Lithium battery type, right ?

I am working on another revision that may or may not help ?

When you see the battery voltage at NEAR Absorb but still in MPPT, you might press the MNGP's soft-left or soft-right  keys to verify that the PV input voltage is picking the proper Vmp.

If you are using Solar mode, you might try Legacy P&O ?

Sorry for all the questions but I just need to make sure I know what's going on.

At this 54V area, does the Classic read close to the right voltage ?  Same with the HB

Absorb was set for 54.2  16 minutes absorb time.  no ending amps
I have disabled Hawkes Bay in past but don't think I saw any different results.
I will turn off the pv to Hawkes Bay tomorrow.
Zero temperature compensation and yes it was set to Lithium after I did firmware update.
It was reading close to the battery voltage. I had set the absorb lower on Classic than Hawkes Bay and even after the Hawkes Bay pushed it up it still didn't go to Float. I am going somewhat by what my monitoring reported in that graph where it showed  it went to absorb but then went back to bulk - so maybe that absorb was some kind of error on my monitoring.
I just changed it from Solar to Legacy PO mode so will see what happens tomorrow.

So for tomorrow this is what I will have Classic set for ( Hawkes Bay pv off until batteries are full)
Legacy PO mode
Absorb 55.2v
Absorb Time 15 minutes
Float 53.8v   
zero temp comp
zero ending amps

Larry 

[boB]

Absorb was set for 54.2  16 minutes absorb time.  no ending amps
I have disabled Hawkes Bay in past but don't think I saw any different results.

OK, I am seeing what kind of looks like starting 54.2V rising up to 54.35 V  for several minutes  and then it stops and goes to Float ?

How long is that time that the voltage is at 52.2V to 53.35V ?   That isn't 16 minutes, is it ?

If you set the Absorb time for longer, does that time widen up maybe ?

I am working on tightening up the voltage range again BTW.  I noticed that the Classic would Absorb at the set point V  minus  0.1 volt.   For lithium battery selection, the Classic is allowed to go back to Bulk MPPT mode at 0.3V below set point, but right now, for you with the -0.1V offset, it would be -0.4 V  below set point to go back to BULK MPPT.

This will be better in the next day or two for you.

boB

[ClassicCrazy]

Absorb was set for 54.2  16 minutes absorb time.  no ending amps
I have disabled Hawkes Bay in past but don't think I saw any different results.

OK, I am seeing what kind of looks like starting 54.2V rising up to 54.35 V  for several minutes  and then it stops and goes to Float ?

How long is that time that the voltage is at 52.2V to 53.35V ?   That isn't 16 minutes, is it ?

If you set the Absorb time for longer, does that time widen up maybe ?

I am working on tightening up the voltage range again BTW.  I noticed that the Classic would Absorb at the set point V  minus  0.1 volt.   For lithium battery selection, the Classic is allowed to go back to Bulk MPPT mode at 0.3V below set point, but right now, for you with the -0.1V offset, it would be -0.4 V  below set point to go back to BULK MPPT.

This will be better in the next day or two for you.

boB

I have never seen the Classic go to Float on it's own using this firmware. No matter what I have tried it stays  in Bulk or goes back to it after Absorb.  There was no float time on the Classic at all today. But I will watch and see what happens tomorrow.
Larry

[boB]

I have never seen the Classic go to Float on it's own using this firmware. No matter what I have tried it stays  in Bulk or goes back to it after Absorb.  There was no float time on the Classic at all today. But I will watch and see what happens tomorrow.
Larry

Well, you have given me some things to look at.

On my work bench, I see the Absorb timer working normally and going to Float like normal.

BUT maybe  something changed between the one you have now and what I have now ?

Making sure the NEXT one you get works better !

Saw your video of the BMS in that battery box....   If that is just a passive (resistor based) balancer then maybe there is an open dump resistor ?   OR bad transistor that turns the resistor on ?

boB

[ClassicCrazy]

I have never seen the Classic go to Float on it's own using this firmware. No matter what I have tried it stays  in Bulk or goes back to it after Absorb.  There was no float time on the Classic at all today. But I will watch and see what happens tomorrow.
Larry

Well, you have given me some things to look at.

On my work bench, I see the Absorb timer working normally and going to Float like normal.

BUT maybe  something changed between the one you have now and what I have now ?

Making sure the NEXT one you get works better !

Saw your video of the BMS in that battery box....   If that is just a passive (resistor based) balancer then maybe there is an open dump resistor ?   OR bad transistor that turns the resistor on ?

boB

The battery bms has passive balancers. I think just small bleed resistors of about 50 to 75ma each so it can do each cell as needed. But with cells out of balance like mine are , it will never do that job for 100 ah cells. So I took Off Grid Garage advice and bought a Neey 4 amp active balancer. It only does on cell at a time but can dump a lot of power quickly from high cells to low cells. I made a video on that which I should post.
Not sure which video you watched about battery - this might be a second video https://youtu.be/Oz8bZhvrA6s
Larry

[ClassicCrazy]

Here are results of test today so far at 12:30 pm
I think what may be going on is that the batteries fill up and then the current ramps down to zero because of that ? So cell voltages wont rise higher maybe and never get to absorb voltage.
The two batteries I have on now are really not cell balanced very well so that doesnt help - you can see the differential is pretty high. But still if I was to put on my other battery charger I think it would run the voltage up higher even if they were full , and then cut off.
Now it was sunny , then got a bit hazy out here - but still the Classic SOC shows it getting to about 100% at same time current is tapering off to zero ( batteries full) .
The voltage offset was not very good on this today - I have it set more so that it would be about right at 56v .
Anyway here are the graphs .

[ClassicCrazy]

Bob,
I went back to the last regular Classic firmware from Midnite because it works better.
It lets all the power available to the batteries, and then will go to float.
Your newish lithium firmware just would not go to Float. I had watched it go to Absorb and then back to Bulk. With the regular firmware I know it sometimes wouldn't reach the Absorb setpoint and would go to absorb before that , but I could compensate for that by setting a higher setpoint . I know you pointed out in the other post that someone had said people don't set a long enough absorb time, but what I see on my batteries is that by the time they get to the voltage the cells are full. Any longer time than that and they wont accept any more current anyway once they are full.

The Neey cell balancer I installed on the most imbalanced battery I had, seems to have worked. It is battery 2 in this graph.The batteries did jump up to 150mv differential at peak, but I think that will come down if I tweak the absorb voltage down. Or else that is normal cell differential at the peak ( I am trying to look that up).
Larry

 

[boB]

OK Larry.  Thanks.

I will have another one to try soon.  Maybe not this week though.

Appreciate your tests.  I have been working on this code though and have found a couple of things and one of them may be related to what you are finding.

Thanks !

boB

[ClassicCrazy]

OK Larry.  Thanks.

I will have another one to try soon.  Maybe not this week though.

Appreciate your tests.  I have been working on this code though and have found a couple of things and one of them may be related to what you are finding.

Thanks !

boB

Always happy to test the new firmware. Enjoy the summer while it is here !

Larry