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Hi all, completely new to planning solar and have been loving all the info on this site, my plan is to mostly DIY the install.

 

I live in a 3 bed duplex in Umhlanga and can’t do thermal water heating(too difficult to get all owners approval) but can do PV, my usage is +-20KW / day and I have an east west roof at 18 degree angle. Budget of around R100k, I’m looking at:

 

1 x Sunsync 5KW inverter.

12x panels (450 watts or so with 6 panels facing east and 6 west).

1 x 5 – 6kw battery, unsure make possibly hubble as I might want to add another at a later stage.

 

Apart from my oven(hob is gas) and aircons I want to push everything else through the inverter as essentials and link the geyser to the aux/smart port, geyser has full smart control(timing / temp / usage etc), I have installed a 1.5KW element in it and wrapped in a geyser blanket + lagged all pipes, my plan is to heat water twice a day(as currently) with PV heating during the day and then Eskom or battery(is this advisable) in the early hours of the morning if any battery power is left.

 

Any comments on running everything through the 5kw inverter, will make some changes in power usage at home during the day.

What would the best configuration be for wiring panels into the inverter?

 

I plan on placing orders for the main components in the coming weeks as I carry on with the overall design.

 

Thanks in advance for any advice.

 

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Hi @John Knowthe plan is good. The sunsynk is a pretty good choice since you have 5kw on the essential side while other brands have around 3kw on the essential side.

The solis 6kw hybrid is the same price and allows you to have three 2kw items on at the same time which is just shy of the performance of the sunsynk 8kw.

Either way both are good choices.

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Have you measured your peak usage, say you are running washing machine, TV, lights and dishwasher all at the sametime - if this is something you are likely to do.

The 5Kw Sunsynk is a very capable machine and with those panels you should be good to run the whole house on PV. I have a much smaller array than you and it manages to run the house with no issues. You COULD also leave the Geyser on Eskom before the Inverter then if there is excess PV and if the CT coil is installed correctly the PV can still power the geyser - then you won't need to use the Auv port.

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Thanks for quick responses, I am borrowing a logger this week and will do some detailed testing on my max loads if everything is on, we will also put some power managment rules in place so we dont max the inverter.

Im looking at 6 x 470 watt Jinko Tiger panels per bank east and west, this gives me 312 volts per bank will it be efficient or should voltage be a bit higher?

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@John Know, my 10c worth:

A 750W geyser element is available, which spreads the load and achieves ~6 deg C per hour, so it basically needs to be on all day, but on solar power.

Most of our 20 kWh daily household needs are met by the ~5kW solar input and 2* 5kW batteries, which are charged by noon on a clear day. I typically see solar input exceeding 1kW about 1.5h after sunrise (with north-facing rooftop panels), and supply also dips about 1-1.5h before official sunset. Your East-West mounting should trump this - although the peak power will be slightly lower than total capacity, it will be available for longer.

I looked at the Solis hybrid inverter too, and the specs are good for the price. However, Sunsynk includes the wifi antenna as a standard. While I enjoy tinkering, I also call in assistance when my knowledge is lacking and/or patience wears thin. Living in a remote location also influenced the decision, and reliable local support for Sunsynk by my electrical supplier won the argument for me. The same applies to the Shoto batteries, and they were a tad cheaper than Hubble.

The Sunsynk MPPTs work optimally near 370V. 312V is within 25% of 370V: (370-312)/(370-125). Start-up voltage is 150V, so a minimum of 3 panels required, but I would personally avoid operating too close to this limit. Two equally balanced inputs is a good compromise, but some adjustment may better suit your actual needs e.g. 7 or 8 panels for afternoon use, with 4 or 5 employed for morning use, or vice versa. (When does your family prefer to use large appliances? It is easier to accommodate than change such behaviour in the short term, should your design be able to accommodate it.)

All that said, do not allow the concern for the system to consume all other benefits. Enjoy it, and we look forward to hearing how you decided what your priorities were and how you achieved the desired results.

 

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Awesome info thak guys, think Im going to suck it up and just go for the 8kw Sunsync, now trying to find stock is another story for all the bits and pieces, Ill keep you guys posted once I have a list of what i can buy and finall design sizing etc 

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2 hours ago, John Know said:

Awesome info thak guys, think Im going to suck it up and just go for the 8kw Sunsync, now trying to find stock is another story for all the bits and pieces, Ill keep you guys posted once I have a list of what i can buy and finall design sizing etc 

Hi John

Excellent choices

I will send you a PM regarding stock, pricing and availability, if you want to

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Hi John, you won't be sorry about paying a bit extra and going for the 8Kv Sunsynk. You won't have to be wary that three big power users are on at the same time. I also have an East West orientation in Scottburgh. The geyser runs off the Aux output when the batteries are 100%. The flexibility brought on by the timer program makes sure that I never drain the batteries on a rainy day. Now and again I have to switch the Aux to grid after a few days of rain but otherwise I don't need to worry. I run a 24 BTU aircon with ease on hot days. 

East West 5 X 390 JA panels on each side.

8KV Sunsynk

2x Hubble 5.5kv batteries.

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On 2022/01/11 at 11:43 AM, John Know said:

Great, Tony will I be fine to start off with just the 1 X Hubble battery with the inverter? 

Which battery? It sounds obvious when said but this mistake is often made. The battery needs to be able to meet the demand of the inverter. If your 8kw inverter wants 8000Watts can the battery deliver? If the battery is say a 8kw/h model & it has a 1C rating then yes it can. If you paired the inverter with a smaller battery e.g. a 5kw/h then there's going to be a problem when the inverter tries to place a 8kw load on it. The battery BMS will protect itself & turn off the load. You don't want to risk it. 

Which brand & model are you looking to buy?

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On 2022/01/11 at 11:43 AM, John Know said:

Great, Tony will I be fine to start off with just the 1 X Hubble battery with the inverter? 

The answer is YES! you can start with just one and build from there when funds allow. If your inverter wants 8kw and the battery can't handle that, it will take from the grid. Even my cheap Growatt does that when my bank is low on juice

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19 minutes ago, hoohloc said:

The answer is YES! you can start with just one and build from there when funds allow. If your inverter wants 8kw and the battery can't handle that, it will take from the grid. Even my cheap Growatt does that when my bank is low on juice

Ok but when there is load-shedding what is going to happen?

Edited by WJP
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14 minutes ago, WJP said:

Ok but when there is load-shedding what is going to happen?

when there is loadshedding, avoid using electric stove, oven, geyser and heaters. Avoid using multiple power hungry appliances at the same time and you should be fine. All you need to do is just to be aware of your loads and aware that you are on loadshedding. I survived for a long time with just 4.8kwh battery bank made up of 0.5C batteries and 2 x 5Kw inverters. A 5.5kwh , 1C battery will do just fine

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On 2022/01/11 at 11:43 AM, John Know said:

Great, Tony will I be fine to start off with just the 1 X Hubble battery with the inverter? 

Great choice with the SunSynk 8.8K inverter. I started with the same, and only one Hubble AM-2 5.5kW battery.

All you need to do is in the battery settings make sure you set the battery "Discharge Amps" to 100A.

This will make the Inverter limit it's battery draw to the max of the battery without, causing the battery BMS to shut the battery down.

But the inverter WILL shut down if there is load shedding and NO solar (night time), and the load is greater than 5 kW. No problem, just switch the inverter on again (Green button on side), and watch your loads during load shedding.

When funds are available, get a second AM-2 battery, and update battery "Discharge Amps" to 185A (MAX), and you can then supply the full output of your inverter from batteries.

I am currently running my SunSynk 8.8K inverter, with 2x Hubble AM-2 batteries, and have no trouble at all.:)

Note* With Eskom power available, you can pass through up to 12 kW of power on the SunSynk 8.8K on the essential side. But DON'T push more than 12 kW. I have ALL my loads on the essential side, and have taken it to just under 10 kW. 👍

Edited by TimCam
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43 minutes ago, WJP said:

I appreciate the logic but is it maid, guest & wife proof?

jip! in my case, I have installed a simple relay with two NO and two NC contacts. On the NO contacts, I have my stove and the geyser and on the NC I have connected a pilot light. When the grid is available, the relay energizes and the NO contacts closes, keeping my stove and geyser powered. when the grid goes, the relay is de-energized, disconnecting the stove and geyser. The pilot light switches on indicating power cut, so no one will use multiple appliances at the same time knowing that there is no eskom. That is the rule in my house. in the kitchen, the clock on the oven powers off and anyone in the kitchen knows that if no clock on the oven, you can not use the kettle and microwave at the same time. Or use the washing machine and dishwasher at that time. Long story shot, there is a work around to the issue of using a small battery. 

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10 minutes ago, hoohloc said:

jip! in my case, I have installed a simple relay with two NO and two NC contacts. On the NO contacts, I have my stove and the geyser and on the NC I have connected a pilot light. When the grid is available, the relay energizes and the NO contacts closes, keeping my stove and geyser powered. when the grid goes, the relay is de-energized, disconnecting the stove and geyser. The pilot light switches on indicating power cut, so no one will use multiple appliances at the same time knowing that there is no eskom. That is the rule in my house. in the kitchen, the clock on the oven powers off and anyone in the kitchen knows that if no clock on the oven, you can not use the kettle and microwave at the same time. Or use the washing machine and dishwasher at that time. Long story shot, there is a work around to the issue of using a small battery. 

Yip, I use a buzzer, so there can be no mistakes. 😂 Even the neighbors know the power has gone down. 😆

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Amazing replies thank you, this is fast becoming a black hole for money but I'm pretty set on the 8kw Sunsync with 2 x hubble AM2 5,5kw batteries, panels Im stil a bit unsure, I was given a decent price by ART solar on their 550 watt panel, Ive read mixed reviews on their panels but I like that they are local and I can physically go see someone as they are up the road from me, if their are not any seriously negative comments on the panels I may go for them?

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On 2022/01/10 at 7:21 AM, John Know said:

my plan is to heat water twice a day(as currently) with PV heating during the day and then Eskom or battery(is this advisable) in the early hours of the morning if any battery power is left.

I do this, but for me it introduces a danger period. My heat pump kicks in at 7am. If there is solar by then, then all well and good, but on overcast mornings like this morning my battery very quickly hits the allowed DOD and I start drawing from the grid. If there is an outage then - with my inverter - I need to either turn off the geyser, or take a chance on allowing the battery to be depleted. It would probably last an hour. 

There are never perfect solutions, but maybe you can plan a little differently here and change the run time for the inverter (or maybe the Sunsynk is smarter than the Goodwe). The worst case scenario now is bad weather and load shedding. When I know we have load shedding I pay more attention to weather forecasts and I look at the load-shedding schedule and may decide to top my battery up a bit round about 4am if we are going to have early morning shedding and it looks like the sun will not be shining too brightly.

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I have my geysers on CBI Astute timers. They kick in at 13:00 and turn off at 16:00 but the geysers usually turn off by themselves after 1 and a half to 2 hours. Then they are on temp. The water then is still happily hot enough to use the next morning at 07:00. This is 2 x 200L geysers. If its not too cloudy the PV power the geysers all the way otherwise my Sunsynk pull some power from eskom.

I don't see the need to start the geysers twice a day as i only use hot water in the mornings.

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