erik.calco
Solar Badger
NOTE: Using this thread to track progress on tweaking LV2424 settings so that hopefully, in the future, someone with an LV2424 or similar MPP Solar inverter can benefit from it.
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I'll say, when I bought it, I had high hopes I could optimize for my requirements. But, wasn't sure. I have to say, I'm extremely happy with it.
I am configured off grid with manual transfer switches for 10 AC circuits. The LV2424 uses AC in. My requirements are:
- Utilize 100% of PV
- Keep batteries in relatively high SoC so I have plenty of juice when utility is down
- Have most critical loads continue to be on when grid is down, with ability to direct power to various other loads on an as needed basis
- No AC charging of batteries unless I have to catch up after grid being down.
Focusing on just the first two since the 3rd one is handled via a Relion transfer switch, the LV2424 has met my highest hopes!
The key is to always apply a critical load that is more than what PV can produce at any given time. While alone, this isn't 100% needed. As long as this is true, you will always use 100% of your PV. This is also true if your battery needs charging. But, the condition I try to avoid is having a full battery and load that is not enough to use current production.
To be sure, I only have 2 of my 6 panels online so far, and in a very inefficient setup. But, that is enough to monitor and tweak how the LV2424 behaves.
What makes this successful is the LV2424 seems to be "trickle" charging my batteries when not full even though the load is higher than production. That's what I hoped it would do. You can see that here:
Last night my battery voltage went to 25.4V. I consider 26.5V to be full based on how it behaves and has responded to this "trickle" charging. The inverter reading of 74% is wrong, so I just ignore that. Not sure if a full cycle would fix that, or if it will never correctly know the SoC.
It is also worth noting that when I did AC charging with 30A limit, if you happen to be watching it, it will hit a point where over about 10-15 minutes charging current will drop from 30A to 0A, which is what you expect when a battery is full. I suspect it then goes into float mode. If I had my way, I'd disable float as LiFePO4 doesn't need it. But, since I rarely use AC charging now, this isn't an issue. Just something to be aware of if you use AC charging a lot.
As for my critical load that is always on the inverter so stays on when grid goes down, it includes my refridgerator, a part of my living room with lights, outlets and charging for devices, and my servers, so my internet stays up among other things.
Here are my settings:
Charging source priority is Solar only. If I want to enable AC charging to catch up after the grid has been down, I can change that until they are full, then change it back to Solar only.
Solar power priority is Load-Battery-Utility. Since I'm maintaining a high SoC of the battery already, I want it to primarily focus on loads. As I noted earlier, it still trickle charges the battery, which has proven to be more than enough to get back near 26.5V.
Output source priority is Solar-Utility-Battery. This tells it to feed the load it can't take care of with Solar using utility. This is key to not draining the battery when utility is up. Note that I do see some low discharging in the evening, typically 1-2A, which is how it comes down to 25.4V. Not sure why it does that, but because I can limit it via the next setting, it's not an issue.
Battery re-charge voltage when utility is available is 25.5V. This is as high as you can set it. And, it's fine. I haven't figured it out, but I suspect the SoC of the bank is over 80% there, well within my requirements. This is the key that ensures my batteries stay high when I have no PV input.
Note that another reason I do this is because I suspect converting from AC to battery then back to AC is inefficient. Directing utility directly to loads, if it does not do these conversions, should be pretty efficient. I haven't proven it operates how I expect here. But, for now, I'll hope that's what it is doing until proven otherwise. So, minimizing battery cycling should prolong their life as well as maximize efficiency of utility power.
When I get all 6 panels online, I'll also be monitoring impact to my electric bill. It should go down some. We'll see.
_____________________________________
I'll say, when I bought it, I had high hopes I could optimize for my requirements. But, wasn't sure. I have to say, I'm extremely happy with it.
I am configured off grid with manual transfer switches for 10 AC circuits. The LV2424 uses AC in. My requirements are:
- Utilize 100% of PV
- Keep batteries in relatively high SoC so I have plenty of juice when utility is down
- Have most critical loads continue to be on when grid is down, with ability to direct power to various other loads on an as needed basis
- No AC charging of batteries unless I have to catch up after grid being down.
Focusing on just the first two since the 3rd one is handled via a Relion transfer switch, the LV2424 has met my highest hopes!
The key is to always apply a critical load that is more than what PV can produce at any given time. While alone, this isn't 100% needed. As long as this is true, you will always use 100% of your PV. This is also true if your battery needs charging. But, the condition I try to avoid is having a full battery and load that is not enough to use current production.
To be sure, I only have 2 of my 6 panels online so far, and in a very inefficient setup. But, that is enough to monitor and tweak how the LV2424 behaves.
What makes this successful is the LV2424 seems to be "trickle" charging my batteries when not full even though the load is higher than production. That's what I hoped it would do. You can see that here:
Last night my battery voltage went to 25.4V. I consider 26.5V to be full based on how it behaves and has responded to this "trickle" charging. The inverter reading of 74% is wrong, so I just ignore that. Not sure if a full cycle would fix that, or if it will never correctly know the SoC.
It is also worth noting that when I did AC charging with 30A limit, if you happen to be watching it, it will hit a point where over about 10-15 minutes charging current will drop from 30A to 0A, which is what you expect when a battery is full. I suspect it then goes into float mode. If I had my way, I'd disable float as LiFePO4 doesn't need it. But, since I rarely use AC charging now, this isn't an issue. Just something to be aware of if you use AC charging a lot.
As for my critical load that is always on the inverter so stays on when grid goes down, it includes my refridgerator, a part of my living room with lights, outlets and charging for devices, and my servers, so my internet stays up among other things.
Here are my settings:
Charging source priority is Solar only. If I want to enable AC charging to catch up after the grid has been down, I can change that until they are full, then change it back to Solar only.
Solar power priority is Load-Battery-Utility. Since I'm maintaining a high SoC of the battery already, I want it to primarily focus on loads. As I noted earlier, it still trickle charges the battery, which has proven to be more than enough to get back near 26.5V.
Output source priority is Solar-Utility-Battery. This tells it to feed the load it can't take care of with Solar using utility. This is key to not draining the battery when utility is up. Note that I do see some low discharging in the evening, typically 1-2A, which is how it comes down to 25.4V. Not sure why it does that, but because I can limit it via the next setting, it's not an issue.
Battery re-charge voltage when utility is available is 25.5V. This is as high as you can set it. And, it's fine. I haven't figured it out, but I suspect the SoC of the bank is over 80% there, well within my requirements. This is the key that ensures my batteries stay high when I have no PV input.
Note that another reason I do this is because I suspect converting from AC to battery then back to AC is inefficient. Directing utility directly to loads, if it does not do these conversions, should be pretty efficient. I haven't proven it operates how I expect here. But, for now, I'll hope that's what it is doing until proven otherwise. So, minimizing battery cycling should prolong their life as well as maximize efficiency of utility power.
When I get all 6 panels online, I'll also be monitoring impact to my electric bill. It should go down some. We'll see.
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