Decided over December that working from home and load shedding does not mix well. Also see the maintenance at Koeberg plant having a major impact on the grid this year. Discussed with my installer and got the following:

Deye 5kw Inverter
1 x Shoto 5.12 kw Li-ion battery
6 x JA 540w Panels

The installation was completed with future expansion planned for end of this year. Additional 6 panels and one more Shoto Battery.

Also looking at replacing our stove with gas in the next couple of months. Oven for now will have to stay, it's a duel Defy thermo fan oven. Decided to join this forum as I would like to expand my knowledge about alternatives and get some ideas on maximizing my solar installation.

Welcome to the forum and congrats on your system.  Yeah, another battery will be a great addition. 

Currently the inverter is set to keep the battery at 80% SOC. During the last load shedding round the SOC dropped to 40% after 5 hours of load shedding overnight so we still had some juice left. One more battery will definitely put us in the clear if we have extended load shedding and / or other electricity problems.

System is grid tied, plan is not currently to go off-grid. We are seeing small savings on electricity although the idea was rather to focus on backup and expansion. 

Welcome 🙂 

Load shedding is not totally unpredictable, you generally get some sort of warning and it doesn't really make sense to keep the batteries fully charged when they could be saving you some money that you are currently giving to Eskom.

Depending on how much power your house uses at night, I have my batteries set to start discharging at 00:00, they reach 20% SOC by +-6 in the morning, at which time they usually start charging again.  

The only time we would really experience any unannounced load shedding is if it is totally overcast at 6 in the morning and we have load shedding. 

During periods of load shedding, I just set the battery to only discharge to 50% at night and it still only starts discharging after 00:00 so an easy setting to change. 

Is a good idea to put all your heavy loads that are not time sensitive smart timers where possible so as to get them to run during the day when you can power them directly from PV i.e geysers etc

 

If you are making it through load shedding no problem at the moment, then the savings you would make getting another battery would take years to pay for themselves, >6 typically.

Doesn't really make sense to go off grid at this stage if you have the grid option but is pretty easy to work out what makes sense as you have all your power usage data from the inverter. 

Probably better of getting more panels to ensure that you still make enough power on the more marginal overcast days.

@Sc00bs, I also only have 4.8 kWh of batteries and agree that it would take a very long time to recoup the cost of another 4.8 kWh battery, so spent money on some more panels and now running aircons during the day with no worries 

@Tariq I think you may have been the one who pointed that out to me about a year ago when I started the whole Solar thing 🙂 

Another possible focus point is retrofitting of of these to your geyser.

Cost is R7200, works even on most cloudy days (uses uv), pick one that suits your water needs 10-30 tubes versions are available.

A great way to implement these to to add a secondary tank (empty 200L geyser), the tube collector heats the secondary tank up, which acts as a buffer between the tube collector and the main geyser. As hot water is used in the main geyser, a circulation pump tops up the main geyser from the buffer storage tank. The result is the main geyser stays at temp with additional hot water transfer typically taking minutes.

Edited February 19, 20224 yr by Nitrious

On 2022/02/18 at 6:33 AM, RyC said:

Currently the inverter is set to keep the battery at 80% SOC. During the last load shedding round the SOC dropped to 40% after 5 hours of load shedding overnight so we still had some juice left. One more battery will definitely put us in the clear if we have extended load shedding and / or other electricity problems.

System is grid tied, plan is not currently to go off-grid. We are seeing small savings on electricity although the idea was rather to focus on backup and expansion. 

You should consider cycling your battery every day to at least 50% to increase longevity. Unlike lead acid, Lithium does not like to be at 80% plus for any great length of time.

Have a read of this topic as it was discussed in quite a bit of detail there as well.

 

 

Much appreciated for all the comments and advice. Will start implementing some of these and feedback. Reason for thinking of adding another battery would be to cover current load for 12 hours overnight. If there ever was a major crisis. 

Had a chat with a friend last night and he also suggested above pipe system to assist with geyser. 

Edited February 19, 20224 yr by RyC

I too have 1 battery and it takes us from midniight to 6am at which point we are at 35% SOC... PV kicks in and by 10am battery is charged. Doing this i have cut our Eskom bill by R2000 this month

Before you add the tubes consider using that money to get more panels and then add your geyser to the essentials grid. Then using a timer, qhen your battery is charged, use the excess PV you are generating to heat up geyser. 

Also ++ on the cycling... if not everyday then every 2 or 3 days 

Congrats on the system btw. 

Changed settings so SOC drops to 50% between midnight and 5. When we have loadshedding I'll change to make sure we are fully covered. 

How important is it to charge to 100%?

I have noticed that between the inverter and BMS the battery is charged to 100% every couple of days (irrespective of the 80% setting currently in place) 

It dépend of what area you are, if you have more sun hours or not. You should know how many Wh or KWh you can produced per day. After that you can compare to your consumption and chose if you upgrade de battery, solar panel or both. 

On 2022/02/19 at 7:55 PM, mzezman said:

I too have 1 battery and it takes us from midniight to 6am at which point we are at 35% SOC... PV kicks in and by 10am battery is charged. Doing this i have cut our Eskom bill by R2000 this month

Before you add the tubes consider using that money to get more panels and then add your geyser to the essentials grid. Then using a timer, qhen your battery is charged, use the excess PV you are generating to heat up geyser. 

Also ++ on the cycling... if not everyday then every 2 or 3 days 

Congrats on the system btw. 

Just a question. What is the reason for having 2S and 9 x parallel strings on your Sunsynk?

21 minutes ago, Scorp007 said:

Just a question. What is the reason for having 2S and 9 x parallel strings on your Sunsynk?

Maybe i got the notation wrong - its 2 strings (1 for each MPPT) and each string has 9 panels 

13 minutes ago, mzezman said:

Maybe i got the notation wrong - its 2 strings (1 for each MPPT) and each string has 9 panels 

Good.

Hi,

This is my first post on the forum.  I have a 5KVA Deye with a 5.1KVA Dyness Lithium Battery.  I have just added a second battery

I have set the dip switches according the the manual and the Communication cable is installed between batteries.

What settings do I need to change on the Inverter?

• I have increased the Battery capacity from 100Ah to 200 Ah
• The Dyness manual tells me to set the to set Max Charge/Discharge current to 50A X qty of Batteries, so I have set it to 100A
• STart = 30%, Grid Charge Current 40%, Grid Signal off
• Lithium Mode = Dyness, Shutdown 20%, Low Batt 20%, Restart 40%

Is there anything else I need to set?

Thanks

Greg

 

 

 

 

1 hour ago, Greg Perkins said:

Hi,

This is my first post on the forum.  I have a 5KVA Deye with a 5.1KVA Dyness Lithium Battery.  I have just added a second battery

I have set the dip switches according the the manual and the Communication cable is installed between batteries.

What settings do I need to change on the Inverter?

• I have increased the Battery capacity from 100Ah to 200 Ah
• The Dyness manual tells me to set the to set Max Charge/Discharge current to 50A X qty of Batteries, so I have set it to 100A
• STart = 30%, Grid Charge Current 40%, Grid Signal off
• Lithium Mode = Dyness, Shutdown 20%, Low Batt 20%, Restart 40%

Is there anything else I need to set?

Thanks

Greg

 

 

 

 

nothing else you need to change - seems to be all set