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LV6548 output/charger source priority timer settings

wayne530

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Mar 7, 2022
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I'm not sure too many people are using this feature but after some back and forth with MPP Solar about odd behavior with the timer, I finally understand a little more about how it works and wanted to share it in case it helps anyone else. I am making some assumptions based on my observations - feel free to let me know if they're incorrect and I'll update the post accordingly.

tl;dr if using the output source/charger source priority timers in the LV6548 (and probably any other Voltronic-based inverter that has this feature), please treat the starting time as the top of the hour and the ending time as the end of the hour. Example: if you'd like USB priority from 7am to 3pm and SBU priority from 3pm to 7am, you should set USB priority start at 07 and end at 14, and SBU priority start at 15 and ending at 06. Do not edit/change setting 01 (global output source priority) after you've set a timer. If you have multiple inverters in parallel, for output source priority timers, you only need to configure the timer on the primary inverter. All of the secondary inverters sync the output source priority automatically. If you're using charger source priority timers, you must configure them on all inverters (thanks @DanielS for confirming this).

If you incorrectly use USB 07-15 and SBU 15-07, what you're actually saying is you want USB from 0700-1559 and SBU from 1500-0759, which as you can see overlaps. So what happens when you do this? The inverter accepts these values and does not perform any overlap detection. The last setting that is saved will be the active setting. If I set USB 07-15 first, then set SBU from 15-07, what I actually get is USB from 0800-1459 and SBU from 1500-0759. This is of course not exactly what I wanted as the transition from SBU to USB will now occur at 8am rather than 7am.

The way this works is that there is a 24 hour (from 0-23) table and in it, each hour is assigned an output source priority setting (USB is assigned the code 0, SUB code 1, and SBU code 2). When the clock ticks over to the next hour, the inverter checks this table and switches (if necessary) to the new output source priority. If my table looks like this:

2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2

it basically indicates SBU priority from midnight through 7:59, USB from 8:00-14:59, and SBU from 15:00-23:59.

When you update setting 01 (global output source priority), I believe that it essentially writes the selected value over all 24 slots in that table. For example, if I go to setting 01 and set it to USB, my table would look like:

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

When you update one of the output source priority timers, it takes the start time and iterates through the end time (inclusive) and sets the corresponding output source priority into the output source priority timer table. If I start with the above example (setting 01 set to USB), and then set an output source priority timer for SBU with start 07 and end 14, the firmware will overwrite those slots in the timer table and we'd have:

0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0

Each successive change simply overwrites the corresponding slots in this timer table. This is why you cannot edit/change setting 01 after setting timers.

When the start time and the end time are both set to 00, this seems to be a special case and is ignored. I think this means you can't set a timer to begin at midnight and end at 00:59, but if you've gotten this to work, let me know!

I believe the same applies to the charger source priority timer, if you're using that. There is also a way to view this table over the RS232 port (you'll need a USB to DB9 RS232 adapter). Please see the attached PDF for more instructions.
 

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Oh Voltronic...

I wonder if they do any data validation at all?

Could you please test with some or all off these cases?

USB_priority_start=0
USB_priority_start=+0
USB_priority_start=-0
USB_priority_start=-1
USB_priority_start=23
USB_priority_start=24
USB_priority_start=25
USB_priority_start=a
 
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Oh Voltronic...

I wonder if do any data validation at all?

Could you please test with some or all off these cases?

USB_priority_start=0
USB_priority_start=+0
USB_priority_start=-0
USB_priority_start=-1
USB_priority_start=23
USB_priority_start=24
USB_priority_start=25
USB_priority_start=a
The good news is that the input is limited to numbers 00-23 only. I can confirm that setting start to 00 and end to 00 is a special case and is ignored. Start time > end time works as expected by wrapping back to 00 after 23. For example, start 15 and end 06 is interpreted as the ranges 15:00-23:59 and 00:00-06:59.
 
@wayne530 you an gentlemen and a scholar! I'll report back tomorrow if I can get these working tonight. Just so you guys know. I have a TOU plan here in Houston, TX. I just got the 2 LV6458s up and running earlier this week with 4x EG4 Lifepowers. My TOU plan is around $0.27/kWh from 9AM to 9PM and then completely free from 9PM to 9AM. No TDU or line charges and they even pro-rate the monthly TDU charge for kWh delivered off-peak. Give that we're in peak temps I'm not expecting the +20kWh to cover all 12 hours, but the ROI calculations that I did based off previous years consumption showed around 9 months of the year I'd only need 10-15kWhs. I've made it a couple days already with all my usage shifted off-peak. Anyway, the whole project started as an alternate to a whole house generator and morphed into an Energy Arbitrage system. I'm currently doing manual transition via Solar Assistant. Your work here will get me closer to this being more autonomous. Thanks again!
 
Free between 9pm and 9am? Wow.. we pay $0.18/kWh from midnight to 3pm and then around $0.47/kWh from 3pm-midnight. Your use case and initial motivations are pretty similar to mine! Started as whole-house backup, then realized I could buy during off peak and use battery during peak. Works well, but the battery bank is a bit oversized so with my current configuration of 16 hours running off battery per day, I can only get the entire bank down to about 70% before being charged up. I have to tradeoff between deeper cycling and paying off-peak prices to charge the bank and run loads, and I haven't figured out a good middle ground yet.
 
Just noticed something off... in Solar Assistant I'm showing the Inverter 2 is set to OSO charging, but Inverter 1 is still SNU... as we'd discussed I only input that in Inverter 1. Also verified with I input that timer setting I was set 16 = SNU with timer OSO 09 20. I'm not at home to verify if this is just an SA issues or if the inverters are both OSO right now.

With that said, I've been making it all 12 hours on Battery before transitioning.... that's right... 24 hours of free power basically!!!
 
Just noticed something off... in Solar Assistant I'm showing the Inverter 2 is set to OSO charging, but Inverter 1 is still SNU... as we'd discussed I only input that in Inverter 1. Also verified with I input that timer setting I was set 16 = SNU with timer OSO 09 20. I'm not at home to verify if this is just an SA issues or if the inverters are both OSO right now.

With that said, I've been making it all 12 hours on Battery before transitioning.... that's right... 24 hours of free power basically!!!
MPP isn't very clear about what settings are automatically synced between inverters and what settings operate independently. The output source priority is always synced from the primary inverter to all other inverters, which is why the configuration only needs to be input on the primary. I'm unsure of the charging source priority - perhaps this one is not automatically synced from the primary inverter? Would you mind doing some more testing and updating this thread? It might be the case that for charging source priority, you must configure both inverters independently. I don't have solar connected to my system at the moment, which is why I haven't played with those settings :)

Regarding my system - I have 6 EG4 5kw packs. I originally built the system to be sufficiently large to keep our normal loads running for a minimum of 24 hours with some headroom. I've tested it and get easily 36 hours with normal usage and 40+ hours with conservative usage. This was running in SBU mode. Unfortunately, in SBU mode, I can't control when bypass to grid and AC charging is started. It's based on the low voltage cutoff setting, which means it could happen during peak usage periods where I have to pay almost 50 cents/kWh. If I didn't care about when charging a 30 kW bank occurred, I would leave the system in SBU to get more complete discharging of the bank, but it's too expensive. Right now, I use the output source priority timer to use SBU from 3pm-7am (peak usage through the time I normally wake up - more on this later) and USB from 7am-3pm. When switching to USB, not only are loads shifted to grid but it also starts AC charging regardless of the voltage of the bank, and AC charging is quite loud (unfortunately, our inverters are in the garage almost directly below the master bedroom), which is why I set it to switch after I wake up. Using the current timer, I only get 16 hours on battery, which is only enough to discharge to 65-70% before charging starts again. As far as I can tell, with the current firmware, I either get more complete discharging (but potentially peak rate bypass and AC charging) on SBU or I can get incomplete discharging (but controlled AC bypass/charging time window) using the timer, but not both.

In theory, Solar Assistant has the ability to control the output source priority on the inverters and it is reading data from the battery bank and the inverters. I've emailed Pierre (to no avail) about adding support for a lightweight eventing system (like IFTTT). This would allow me to stay in SBU mode if the battery bank was above say 50% SoC and to switch to USB only during off-peak.
 
MPP isn't very clear about what settings are automatically synced between inverters and what settings operate independently. The output source priority is always synced from the primary inverter to all other inverters, which is why the configuration only needs to be input on the primary. I'm unsure of the charging source priority - perhaps this one is not automatically synced from the primary inverter? Would you mind doing some more testing and updating this thread? It might be the case that for charging source priority, you must configure both inverters independently. I don't have solar connected to my system at the moment, which is why I haven't played with those settings :)

Regarding my system - I have 6 EG4 5kw packs. I originally built the system to be sufficiently large to keep our normal loads running for a minimum of 24 hours with some headroom. I've tested it and get easily 36 hours with normal usage and 40+ hours with conservative usage. This was running in SBU mode. Unfortunately, in SBU mode, I can't control when bypass to grid and AC charging is started. It's based on the low voltage cutoff setting, which means it could happen during peak usage periods where I have to pay almost 50 cents/kWh. If I didn't care about when charging a 30 kW bank occurred, I would leave the system in SBU to get more complete discharging of the bank, but it's too expensive. Right now, I use the output source priority timer to use SBU from 3pm-7am (peak usage through the time I normally wake up - more on this later) and USB from 7am-3pm. When switching to USB, not only are loads shifted to grid but it also starts AC charging regardless of the voltage of the bank, and AC charging is quite loud (unfortunately, our inverters are in the garage almost directly below the master bedroom), which is why I set it to switch after I wake up. Using the current timer, I only get 16 hours on battery, which is only enough to discharge to 65-70% before charging starts again. As far as I can tell, with the current firmware, I either get more complete discharging (but potentially peak rate bypass and AC charging) on SBU or I can get incomplete discharging (but controlled AC bypass/charging time window) using the timer, but not both.

In theory, Solar Assistant has the ability to control the output source priority on the inverters and it is reading data from the battery bank and the inverters. I've emailed Pierre (to no avail) about adding support for a lightweight eventing system (like IFTTT). This would allow me to stay in SBU mode if the battery bank was above say 50% SoC and to switch to USB only during off-peak.
Hmmmm... So I think I might be missing something so I'll take this in chunks.
  1. Are you not using the Charge Priority Settings are all? Meaning you can restrict to OSO mode when you want Solar only charging, that will prevent you from charging during Peak hours
  2. You mentioned AC charging is very loud... What output current are you charging with? Mine is really loud at 50A each but not too loud at 30A. You might be able to adjust down to help with the noise.
  3. "Unfortunately, in SBU mode, I can't control when bypass to grid and AC charging is started" Correct, sort of. You should be able to control the Bypass, but adjusting the "Back to Grid Voltage" I have min set pretty low at 49VDC. You should be able to restrict Grid charging by using the OSO during your peak-hours. That is what I'm trying to do exactly
  4. Regarding the Charge Priority Timer. So the USB to SBU worked by just doing that setting in Inverter 1. But oddly enough... this makes no sense. The SNU to OSO only worked in Inverter 2, even through I only input it in Inverter 1!!! I tried setting it in both 1 and 2 last night, and neither of them worked today and I had to manually transition them, so more testing on this one today.
 
I think you missed this in my previous post:
I don't have solar connected to my system at the moment
I think whether something is noisy is pretty subjective. I'm using the default max utility charging current 30A. I haven't adjusted it - haven't seen the need. I don't need charging to start at midnight. When it starts at 7am, it's still off-peak for me and it takes 2-2.5 hours. Off-peak for me is midnight to 3pm. I actually was not aware of the OSO setting - it seems like in my case, with no solar attached, this would essentially disable charging. I'll look at this and see if it can do what I need in conjunction with tweaking settings 12/13.
 
I think you missed this in my previous post:

I think whether something is noisy is pretty subjective. I'm using the default max utility charging current 30A. I haven't adjusted it - haven't seen the need. I don't need charging to start at midnight. When it starts at 7am, it's still off-peak for me and it takes 2-2.5 hours. Off-peak for me is midnight to 3pm. I actually was not aware of the OSO setting - it seems like in my case, with no solar attached, this would essentially disable charging. I'll look at this and see if it can do what I need in conjunction with tweaking settings 12/13.
Right, I don’t have Solar either. But I don’t want any charging to happen during peak hours, so the OSO (Solar only) prevents me from charging during peak hours, even if my batteries don’t last the entire peak hours.
 
@Skypower, @wayne530 has done a lot of testing see above….an update on my end…. This sounds crazy but it seems that if you configure OSO xx yy in Inverter 1, it will copy to Inverter 2, but won’t work in Inverter 1, but works in 2. If I set OSO in Inverter 1 and 2…neither works…. If I sent OSO in Inverter 2 it copied to 1… but then didn’t work in either. Something is different about the Charge Priority timer that doesn’t make sense.
 
Post in thread 'Mpp lv6548 off peak timer'
https://diysolarforum.com/threads/mpp-lv6548-off-peak-timer.36750/post-534616
What I posted on another thread and thought it would be relevant here too.
Forgot to mention that the timer control is done only on the master inverter but charge current is changeable and combined at whatever each inverter has been set to. Charge current can be changed while the timer is active.
 
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@Skypower, @wayne530 has done a lot of testing see above….an update on my end…. This sounds crazy but it seems that if you configure OSO xx yy in Inverter 1, it will copy to Inverter 2, but won’t work in Inverter 1, but works in 2. If I set OSO in Inverter 1 and 2…neither works…. If I sent OSO in Inverter 2 it copied to 1… but then didn’t work in either. Something is different about the Charge Priority timer that doesn’t make sense.
Have you done the RS232 debugging in the attached document to verify it is set correctly in both inverters?
 
@wayne530^ @DanielS
Thank you for sharing this information.
Helped a lot to understand observed behaviour.
I'm just asking myself if there are other commands than QT and QOTTP to read out inverter data.
Does anybody have documentation for the communication tool?
 
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Did anbody test if setting Start & End time to identical values will allow to set a 1 hour period?
eg. will Start=16 and Stop =16 switch on at 16:00 and off at 16:59?
Or is this forbidden like Start = End = 00 as mentioned in the initial post?

If Setting "16" is set to "OSO" (only solar) and I want to change it to "SNU" ( Solar & Utility") e.g. from 16:00 to 17:59 is it then sufficient to just set the Charge Priority Timer for SNU to 16-17 or do I also have to set the Timer for OSO to 18-15?
If I understood correct Setting 16 will set all the 24 slots in the table to "OSO"
The Timer settings for "SNU" will then overwrite the corresponding slots in the table, all the others will stay on "OSO".
So in my understanding it should not be necessary to in addition set the OSO-timer.
Is my understanding correct or did I miss something?


Did anybody check if the Command Tool and the described commands also work for Voltronic Axpert models (eg. VM IV)
 
@wayne530^ @DanielS
Thank you for sharing this information.
Helped a lot to understand observed behaviour.
I'm just asking myself if there are other commands than QT and QOTTP to read out inverter data.
Does anybody have documentation for the communication tool?
I asked MPP Solar's support team for more commands but they never replied. I'm not sure why, since the information could really help us troubleshoot issues locally before reaching out to their support team. If anyone has more information on additional commands, I'd love to aggregate that into a github project for the benefit of everyone.
 
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