Good day to all.

Two quick questions to the experts on the forum with regards to my RCT-AXVMII-3K inverter. During the day I run the small flat we are in on solar as we do not use a lot of energy consumption. Normal about 200W - 600W and then about 2300W maximum when using the kettle, AF or microwave and then only for a short period of time. Geyser and tumble drier is still directly on utility. Gas stove and kettle (1500W), air fryer (1300W) and microwave (1200W) are not used together but one at a time.

1. Why does my fridge light have a slight flicker in it while on solar and not when it is on utility? Have tried it on all three settings (Utility and solar, Solar, utility and battery as well as Solar, battery and utility) but it stays the same with the flicker. The moment I go to utility, and it bypass this slight flicker is gone. I have read in one of the threads there was someone else who also had this but when he changed to SUB it stopped, mine however does not.

2. When on utility the floating voltage of my batteries is on (27.2V) and the inverter shows the battery voltage as 100%. However, the moment that I switch to solar it shows the batteries as only on 77% full while on the floating voltage. Only if I change my floating voltage settings to 28V while on solar, it will charge the batteries to 28V and then show it as 100% full. I am using Lithium's, and this does not make sense.

Thank you and hope someone can assist with answers to these two questions.

If you're using voltage settings to manage your battery I can safely assume you do not have BMS communication between battery and inverter. In that case, your inverter is "guessing" the State of Charge based on voltage alone, which doesn't really work for lithium batteries.

14 hours ago, Gerald1958 said:

Good day to all.

Two quick questions to the experts on the forum with regards to my RCT-AXVMII-3K inverter. During the day I run the small flat we are in on solar as we do not use a lot of energy consumption. Normal about 200W - 600W and then about 2300W maximum when using the kettle, AF or microwave and then only for a short period of time. Geyser and tumble drier is still directly on utility. Gas stove and kettle (1500W), air fryer (1300W) and microwave (1200W) are not used together but one at a time.

1. Why does my fridge light have a slight flicker in it while on solar and not when it is on utility? Have tried it on all three settings (Utility and solar, Solar, utility and battery as well as Solar, battery and utility) but it stays the same with the flicker. The moment I go to utility, and it bypass this slight flicker is gone. I have read in one of the threads there was someone else who also had this but when he changed to SUB it stopped, mine however does not.

2. When on utility the floating voltage of my batteries is on (27.2V) and the inverter shows the battery voltage as 100%. However, the moment that I switch to solar it shows the batteries as only on 77% full while on the floating voltage. Only if I change my floating voltage settings to 28V while on solar, it will charge the batteries to 28V and then show it as 100% full. I am using Lithium's, and this does not make sense.

Thank you and hope someone can assist with answers to these two questions.

I don't have any flicker on fridge LED on battery or solar. 

On the 2nd point I would think that you float keeps battery high. The moment you add solar it goes out of bypass and when running on SBU mode the battery voltage drops. This makes sense if you load is higher than what you get from PV and uses current from the battery as well. 

@ madness_za thank you for the reply. It might be the issue as the lithium's currently being used does not have the option for a coms cable. I am currently busy at the moment looking to buy two new 24V batteries with coms which will give me more than enough stored energy than what is needed daily but will be very handy for "a rainy day" in future.

Edited October 1, 20241 yr by Gerald1958
Needed to incorporate name. Cannot reply directly with answer quoted.

20 hours ago, Scorp007 said:

I don't have any flicker on fridge LED on battery or solar. 

On the 2nd point I would think that you float keeps battery high. The moment you add solar it goes out of bypass and when running on SBU mode the battery voltage drops. This makes sense if you load is higher than what you get from PV and uses current from the battery as well. 

The light in my fridge is a normal small globe and not LED. I have not picked up any flickering on the LED in my deep freezer. Was just concerned as my fridge is nearly 18 years old that it might not be too compatible with solar and inverter. As it is still working perfect with no issues, I would not like to replace it unnecessary.

As for the 2nd point of my question I think that the answer has been given by madness_za. Will see what it does with the new batteries that I am looking at to buy when there are direct coms between the batteries and inverter.

What's the size of your solar array?

3 hours ago, madness_za said:

What's the size of your solar array?

I have 5 x 550W Jinko panels up totaling 2750W. I would love to add 2 more but is out of space on the garage roof this is the only place that does not get shade till about 17H30. Efficiency is roughly about 78% to 80% during the day. Below is an example of a bit earlier when the wife used the Air frier today.

Re the flickering: My wild guess is that this is an older model, and some of the capacitors have dried out. If you are handy with electronics, you could replace some  power supply capacitors (see this post). In this particular case, it might be the two large bus capacitors, which are unfortunately a bit expensive to replace, especially with good quality parts, so it's hard to justify as a "just in case".

I vaguely recall a post about fixing flickering, but a quick search of the repairs and hardware modifications index doesn't bring up anything.

You could just ignore it. It's not clear to me whether this is an indication of impending failure or not.

On 2024/10/06 at 3:42 AM, Coulomb said:

Re the flickering: My wild guess is that this is an older model, and some of the capacitors have dried out. If you are handy with electronics, you could replace some  power supply capacitors (see this post). In this particular case, it might be the two large bus capacitors, which are unfortunately a bit expensive to replace, especially with good quality parts, so it's hard to justify as a "just in case".

I vaguely recall a post about fixing flickering, but a quick search of the repairs and hardware modifications index doesn't bring up anything.

You could just ignore it. It's not clear to me whether this is an indication of impending failure or not.

Thanks for the reply and sorry for answering a little late. I did a check on my deep freezer which is "new" (3 years old) compared to my fridge which is 17 years old but still going strong. The LED in the freezer does not flicker so I managed to get a 11W LED fridge globe and exchanged it with the normal 15W globe in the fridge and the flicker is gone. ALL globes in the flat are LED and don't flicker so want to just for the heck of it change one of the bedside lamp globes with a normal globe to see what it does.

Thanks to everyone's input in this. Glad I don't have to replace my trusty old double door.

Had the same issue of fridge light flickering. Was fixed when I sorted my Earth/Neutral bond