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New to solar and a 5 month crash course

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Hi everyone, I am glad to have found this forum (mainly due to trying to troubleshoot my system) and perhaps not surprisingly, found some answers and lots of really great info, and have learnt a helluva lot from reading through various posts.

Let me start with my current system as at yesterday. 5kw Deye inverter, 6x 330w solar panels (facing NE), and a Shoto 5.1kw battery with BMS. Still learning the ins and outs of this system.

My initial installation was done back in Feb '21 with a Growatt 5kw inverter, solar panels as above, and a Shoto 4.8kw (sans BMS) Li. The reason for my jumping into solar was threefold. 1. My suburb is affected by numerous unplanned outages ranging anywhere between 1 and 12 hours. 2. Get us through load shedding. 3. Reduce my utility bill with time.

I ran the system in SUB mode and the system seemed to work great. I did notice however that solar dropped every 3hrs and utility would take over for some 20minutes, after which solar would return. Weird I thought. Communicated this to my installer for troubleshooting (i have to add, the installer was super supportive during all of this). This issue was new to them and we started dabbling with settings. The battery not talking to the inverter was a massive issue for me. Sometimes the app would indicate the battery at 25%, only for the battery led to indicate 75% SOC. Issues aside, power outages came and went, and the system just worked (except for those random solar drop outs). Eventually the installer suggested it might be due to the battery comms. This was swopped out for a Shoto 5.1 with BMS. Connected it via CAN, and presto, communication and battery info is now correct.. but, solar in SUB is now completely throttled. Ie. During the day, the system used eskom power on SUB, and at night, the system would draw 5kw to charge the battery (ouch).. and this could not be set as the BMS controlled this. Curiously, in SBU mode, it worked as expected, except for the 90a utility charge rate to battery which was locked. Long story short, we initiated a return of the Growatt and installed the Deye. 

So far, it seems to be doing what is expected, and it appears more flexible ITO settings. Hope this is the end of all the tinkering. Although no real SUB and SBU settings. More like a flexible SBU from what I can tell.

Plans going forward, i think I want to add a second battery. This single battery cuts off at 35% SOC currently and carried us for some 6 hours last night (load around 650w, more or less of course), which I am quite happy with. I also want to add another 6 solar panels.

So in summary. So far so good with the Deye. Settings are configurable, and what is set seems to be what is happening. It does seem to need more hands on management of the settings to plan around the load shedding times, than the Growatt needed.

Some questions.

1. The battery doesnt seem to float during the day. Ie. It stays at 100%. I assume this is due to solar prioritising battery charge. This sound right? On the growatt there was a clear float between 95 and 100%.

2. Is 35% cutoff too conservative for a lithium battery? I know it could go as low as 20%.. i am also just gauging how long it takes to charge up during the day. From 07h30 to now it went from 35 to 75% SOC. I have all my times of day set to 35% currently. Switched 5pm to 9pm to 95 due to load shedding at 6pm.

3. I see a constant 20w draw from grid. Read on a different thread that this is to maintain the unit synced with grid? So this is normal behaviour then?

4. Curious what some of your battery charge settings would be for rainy/ cloudy days.

Thanks all. Looking forward to learning loads more

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Having made some small adjustments and now understanding the system setup with the times a lot better, i do agree that the performance of this Deye unit is very much what i expected from the unit. Performance is in line with the settings, and with the load shedding, charge times are just planned around the slots. Very flexible. I believe Deye and Sunsynk are the same machine largely, so I hear you Nightcrawlrrinc.


Edit. I also now know the answer to question 1.  Had the setting at 100%. By changing it to 95, it now cycles as needed.

Also, by selecting Priority to load, it basically acts like the SUB setting of the growatt.

Edited by GTP
Answer to ques 1 sorted
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