New-ish Classic and MNGP code update for trying

[Wizbandit]

New code is working perfect here...

[Vic]

This looks beautiful, Jim,  great work!!   Vic

[boB]

That's great, Jim !

Now we gotta figure out why Larry's is not quite getting up to the right voltage ?

I am playing ham radio this weekend but have a system at work I will look at monday.

[ClassicCrazy]

Bob - I still don't get the controller going all the way to absorb point.
I had Classic absorb set for 55.7 v today. But I also had the Hawkes Bay set to 54.2v absorb and forgot to turn it off for testing the Classic. There were loads on all morning.
As can be seen in the graph the Classic stayed steady in voltage and according to SOC filled up batteries around 54.2v.
I added the Classic reported Charge state and SOC to the top of graph screens.
I will need to lower the Absorb voltage and shut off the Hawkes Bay tomorrow ( if it is sunny).
But I did just use the Local Status app to force it into Absorb but it always goes back to Bulk. I am able to force it into Float .
Larry

[boB]

Larry, you should not have to turn OFF the Hawkes Bay.  It helps the Classic to get closer to its Absorb voltage setting which is higher than the HB.

BUT if the voltage readings for Classic and HB are off kilter, then I suppose the Classic could think it is in Absorb when it is not.


P.S.  HERE is a copy of an email from Steve Higgins from Surrette/Rolls batteries regarding lithium and Absorb settings for their batteries.  This was posted today on the RE-Wrenches mail list.

We worked together for years at Trace Engineering and also OutBack Power Systems and he has become quite an expert in his field.

boB


For many LFP batteries, while some say you can charge at the C1 Rate, most want you to charge at the C2 or C3 rate.   

While you don't have to get them full all the time like lead, as long as you are cycling regularly, it is still a good idea to get them to full regularly.   Now if they are a backup system or not being cycled, they should not be held to full all the time. This can accelerate damage to the cells.

Where we see the major mistakes are the absorb timer settings.   Too many people are setting the absorb timers too short, especially if they have parallel modules and are not running closed-loop communications, or the batteries can't communicate with each other or the chargers.

In these cases where you have 2,3,4... more batteries in parallel, the absorb timers can help balance them as the batteries that don't need balancing stop charging, while the cells that need the extra time get that time if you have longer absorb timers.

We advise for our LFP drop in's that you have the following.   Assuming that you are charging at least the C2 Rate.

1 Parallel Connection = 30-45 mins absorb timers.
2 Parallel Connections = 45-60 mins.
3 Parallel Connections 60-90 mins.
4 Parallel Connections 90-120 mins


Steve Higgins ⋅ Technical Services Manager
t +1.902.597.4020  m +1.206.790.5840
f +1.902.597.8447  e steve@surrette.com

[Wizbandit]

"But I did just use the Local Status app to force it into Absorb but it always goes back to Bulk."

That is a Local App "mis-print", it's not FORCE ABSORB it is really FORCE BULK...

[LilMT]

I am not certain about this but here is my understanding of the "Force" options in the local app.  I could be very wrong on this and if I am I hope someone corrects me - please.

The force float is used to "terminate" an active charge cycle, so if you are in bulk or absorb it will force down to float.

Force Absorb is to -bypass the midnight timer reset, so if needed you could perform a second charge cycle in a single day.  More like a rebulk setting than force absorb.  If you are already in Bulk and force absorb, I believe it will return to bulk.  If in absorb it will stay in absorb. If in float (after a full charge cycle), then it will allow a return to either absorb or bulk dependent on the battery voltage and you specific absorb/ float setting.  Not necessarily forcing the voltages to the battery to be set to your absorb setting but instead simply telling the midnite that it is okay to run another charge cycle even if the midnight timer has not been reached.

?

Again, I am basing this simply on what I have seen my classic do so please, those who know better, please correct my misunderstanding.

[Wizbandit]

I work for Midnite, have for over 10 years now.  I just wrote some code for the COMBOX to integrate CHARGE STATE from the New Hawkes Bay & Barcelona into the Classic's "Follow-Me" network. MODBUS register 4160 is where I force charge state in the Classic.  As you can see there is no "FORCE ABSORB" command, like I said, in the Local App is's a mistake.  We can force FLOAT or BULK or EQ.  Code 0x40 forces a new BULK/ABSORB cycle, BULK will always start and when the battery reaches the ABSORB voltage set point it will transition to ABSORB.  Sometimes this happens so fast the MNGP does not pick it up.  That's why ABSORB is not a "follow-me" stage, each Classic has to reach it's programmed ABSORB voltage independently.

ForceFloatF
0x00000020
Force battery charge stage to Float
ForceBulkF
0x00000040
Force new Bulk/Absorb charge stage and reset timers
ForceEqualizeF
0x00000080
Force new Equalize stage
ForceNiteF
0x00000100
Force a new day (saves daily logs, resets daily kW-H)

[ClassicCrazy]

Larry, you should not have to turn OFF the Hawkes Bay.  It helps the Classic to get closer to its Absorb voltage setting which is higher than the HB.

BUT if the voltage readings for Classic and HB are off kilter, then I suppose the Classic could think it is in Absorb when it is not.


P.S.  HERE is a copy of an email from Steve Higgins from Surrette/Rolls batteries regarding lithium and Absorb settings for their batteries.  This was posted today on the RE-Wrenches mail list.

We worked together for years at Trace Engineering and also OutBack Power Systems and he has become quite an expert in his field.

boB


For many LFP batteries, while some say you can charge at the C1 Rate, most want you to charge at the C2 or C3 rate.   

While you don't have to get them full all the time like lead, as long as you are cycling regularly, it is still a good idea to get them to full regularly.   Now if they are a backup system or not being cycled, they should not be held to full all the time. This can accelerate damage to the cells.

Where we see the major mistakes are the absorb timer settings.   Too many people are setting the absorb timers too short, especially if they have parallel modules and are not running closed-loop communications, or the batteries can't communicate with each other or the chargers.

In these cases where you have 2,3,4... more batteries in parallel, the absorb timers can help balance them as the batteries that don't need balancing stop charging, while the cells that need the extra time get that time if you have longer absorb timers.

We advise for our LFP drop in's that you have the following.   Assuming that you are charging at least the C2 Rate.

1 Parallel Connection = 30-45 mins absorb timers.
2 Parallel Connections = 45-60 mins.
3 Parallel Connections 60-90 mins.
4 Parallel Connections 90-120 mins


Steve Higgins ⋅ Technical Services Manager
t +1.902.597.4020  m +1.206.790.5840
f +1.902.597.8447  e steve@surrette.com

I wish he would have mentioned some setpoints he uses .
My batteries are kind of messed up because as they get full the cell differential is too much.
I just got the Neey balancer which Off Grid Garage did video on. And I just hooked it up on my most out of balance battery and trying out today. It is a miracle worker compared to the bms to get the cells balance since it works at 4 amps from high to low cells - compared to bms bypassing only 75ma per high cell.
If the Neey work out okay - I may just put on in all my present lithium batteries to make them decent. Then I can set the controllers with a legitimate ending amps to make sure they get full.
I am still learning all the ins and outs about lithium.
But what he says could explain why my batteries stay in bulk - they just are not full yet.
Larry

[ClassicCrazy]

"But I did just use the Local Status app to force it into Absorb but it always goes back to Bulk."

That is a Local App "mis-print", it's not FORCE ABSORB it is really FORCE BULK...

Thanks - that makes sense about forcing bulk . I was just used to it  working more like force absorb when I had the lead acid batteries.

Larry

[ClassicCrazy]

I work for Midnite, have for over 10 years now.  I just wrote some code for the COMBOX to integrate CHARGE STATE from the New Hawkes Bay & Barcelona into the Classic's "Follow-Me" network. MODBUS register 4160 is where I force charge state in the Classic.  As you can see there is no "FORCE ABSORB" command, like I said, in the Local App is's a mistake.  We can force FLOAT or BULK or EQ.  Code 0x40 forces a new BULK/ABSORB cycle, BULK will always start and when the battery reaches the ABSORB voltage set point it will transition to ABSORB.  Sometimes this happens so fast the MNGP does not pick it up.  That's why ABSORB is not a "follow-me" stage, each Classic has to reach it's programmed ABSORB voltage independently.

ForceFloatF
0x00000020
Force battery charge stage to Float
ForceBulkF
0x00000040
Force new Bulk/Absorb charge stage and reset timers
ForceEqualizeF
0x00000080
Force new Equalize stage
ForceNiteF
0x00000100
Force a new day (saves daily logs, resets daily kW-H)

It will be nice to try out the combox when they become available.
Larry

[LilMT]

Thank you,

That makes much more sense of what I was seeing in my classic, and makes the charge cycle process, as well as the force processes clearer.

Thank you for correcting my misunderstand.

[Vic]

Will add, that when ' Force Float ' is used in the Local App, the Net Ah value is NOT set to zero, as would be the case, if the Classic went to Float, based on its Absorb termination settings.

Not a big deal,  just something to remember,  as this non-zero can affect the following day Wb values.

FWIW,  Vic

[ClassicCrazy]

Bob ,
I still don't understand why my Classic with the new firmware never shows Absorb for me.
Today it looks like it gets to Absorb voltage wise and dropped to Float voltage wise but it only ever goes back to Bulk . I had added the graph of charge state and think it is accurate representing what happened over time. The Classic is set to Absorb voltage at 54.2v  which is first peak in voltage. I think the second peak in the voltage is the Hawkes Bay going to Absorb  that I had set for 54.7v .  I just wonder why the Classic never goes to Float .
Example below in screen shot.
Larry

[boB]

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