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Renogy 48v Solar Inverter Charger. Can't change switch-to-utility setpoint.

lux

lux

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Hello -

I've been using this inverter for about a year, but I've come across a problem that I can't figure out. Here is the situation:

I'm running the inverter in hybrid util + solar charging. My solar array is not big enough to fully power all my loads (1200watt array), but I have 2) 48v 50ah batteries as well.

In situations where I'm running a heavy load, the inverter uses all the solar power, and starts depleting the battery ... BEFORE the battery completely depletes, I'd like to switch to utility. However, the "switch to utility setpoint" (option 4) is set to 44.0v ... the default, and I can't change this! I'd like it to be set to say 48v, where the battery is about 20% capacity, but when I change the setting, it always reverts back to the default, 44.0v ... the problem with 44.0v is that it is TOO LOW, and at that point, inverter disconnects the battery and starts charging it, and it doesn't run loads anymore.

Does anyone know how to change this setting? Happy with the inverter otherwise, and these batteries have been great for a year now.
 
lux said:
Hello -

I've been using this inverter for about a year, but I've come across a problem that I can't figure out. Here is the situation:

I'm running the inverter in hybrid util + solar charging. My solar array is not big enough to fully power all my loads (1200watt array), but I have 2) 48v 50ah batteries as well.

In situations where I'm running a heavy load, the inverter uses all the solar power, and starts depleting the battery ... BEFORE the battery completely depletes, I'd like to switch to utility. However, the "switch to utility setpoint" (option 4) is set to 44.0v ... the default, and I can't change this! I'd like it to be set to say 48v, where the battery is about 20% capacity, but when I change the setting, it always reverts back to the default, 44.0v ... the problem with 44.0v is that it is TOO LOW, and at that point, inverter disconnects the battery and starts charging it, and it doesn't run loads anymore.

Does anyone know how to change this setting? Happy with the inverter otherwise, and these batteries have been great for a year now.
Click to expand...

Some inverters have a limited range of adjustment. Does the manual indicate you can adjust it higher?

There may be another setting that must be set higher than the cut off, such as an alarm voltage, e.g., if your alarm voltage is at 46V, and you try to set cut-off to 48V, it may disregard it. Look for any other settings related to low voltage.
 
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Wow, that is a low set point. Can the BMS be set higher. I know the best setting philosophy is to have the inverter Low Voltage set point be higher than the BMS but this situation may call for drastic measures. Or as @sunshine_eggo suggested, there may be another setting on the inverter that is limiting this setting.
 
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Wakintx said:
Is this the Renogy AIO off grid from SRNE? If so, I think different threads said solar assistant allowed settings to be changed...
Click to expand...
Heh, I'm not sure what an AIO, SRNE, or Solar Assistant is ... so I'm going to say "no". I'm using the Renogy 48v Solar Inverter Charger + 2x Renogy 48v 50ah batteries.
 
sunshine_eggo said:
Some inverters have a limited range of adjustment. Does the manual indicate you can adjust it higher?

There may be another setting that must be set higher than the cut off, such as an alarm voltage, e.g., if your alarm voltage is at 46V, and you try to set cut-off to 48V, it may disregard it. Look for any other settings related to low voltage.
Click to expand...
Thank you! I think this was the problem. I swear I had tried this before, but tried again, and it worked.

For anyone else with this same problem:

- I set user setting 14 (Low Voltage Warning) to 47.6 (instead of default 43.6)
- I was then able to set user setting 5 (Utility to Battery Power setpoint) to 48.0 (instead of default 44.0)

This sets the inverter above the BMS low voltage cutoff.

I expect now when voltage drops below 48v, utility charging will take over and charge it until it is at 50.5 (From setting 5, which I also changed earlier). At that point, it should switch back to solar. I think I will have to wait until tomorrow to find out if this is working right. Will post an update.

Here is the manual.

Thanks all!
 
I used 50.5 because that was the voltage when the battery was about 80% ... the battery charges FULLY at night when there is no solar input. Still tweaking these settings though! The problem is that the inverter is under the couch, and it is very hard to reach/read the display (I have to use a mirror, everything is upside down at arm's length!)

I'm going to keep tweaking it though
 
Ampster said:
I had assumed they were LFP in a 16S configuration. What is the chemistry and how many cells in series. That may affect what the appropriate Low Voltage setting is as well.
Click to expand...
it's 15 strings. LiFePo4, and charges at 54v constant. The specs are here on the last page of this pdf manual:


BTW, I see mixed reviews about Renogy stuff, but these batteries are really nice and haven't degraded much after over a year of heavy use. Max Capacity is 99.27% of the original capacity. At this rate, it would be like 15 years before they are down 10%.
 
I think it was set to 44v, because originally this product shipped before the 48v batteries were out. So it was set for AGM batteries by default. They really should note this in their documentation, because you would think the 48v charger would be paired with 48v batteries by default.

The 48v battery seems be in the 20-80% capacity range at about 47-51v range ... I'm trying to keep my eye on it as it charges, to see if I can get this just right on the next shot so I'm not stuck under the couch all afternoon.

I know some people feel strongly about renogy, but aside from not being able to easily see the display and the crappy description of these settings, it's been pretty good, and the whole system was relatively cheap. I full time in the RV, so it is used heavily.
 
lux said:
btw, how do you get the voltage range from the number of strings?
Click to expand...
I think in terms of individual cell voltages. My system parameters are 3.1 volts on the low side and 3.4 on the high side. For a 15S (15 cells in series) pack that would be 45.5 Low voltage and 51 volts on the high side. My low side is conservative because I want some reserve in case a power outage happens just as my pack reaches the low side. I also want to increase pack longevity by using less of the capacity. Your mileage may vary.
 
lux said:
btw, how do you get the voltage range from the number of strings?
Click to expand...

A string generally refers to a number of items in series, so the battery is essentially one string with 15 cells in that string.

Multiply or divide by 15 as needed.

50.5 is 50.5/15 = 3.367V/cell, which should get you to 70%+
 
Ok, I'm now testing out the settings I changed .... this is completely annoying.

So as discussed earlier I couldn't set the "Change to Utility Set Point" until I changed the "Low Voltage Alarm Voltage" ... but not I've found another problem.

It seems you can't set the "Low Voltage Alarm" at the same setting as "Change to Utility Set Point" and it also doesn't let you set "Change to Utiliity Setpoint" higher than "Low Voltage Alarm". So

Low Voltage Alarm must be > than Change to Utility Setpoint

This seems to make sense, but in practice, what is happening here is that the low voltage alarm starts going on off the inverter ( when voltage is 48.4 used for testing), but doesn't switch to Utility until battery reaches 48.0v ... so I have to listen to this annoying alarm?

There must be a better way.
 
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