Gradual Migration to Off-Grid Possible?

[Jon Siko]

Can someone advise whether it's possible to take a step-by-step approach to getting off-grid? I'm currently using between 25-30 kWh per day of which 50% is because of the geyser. I'm hoping to do the following migration over 18 months:

Step 0: Reduce Load - approx R 33,000 in month 0
   1 x  replace Electric Stove with Gas Stove    
   1 x  replace 200L Geyser with Evacuated Tube Thermosiphon Solar Water Heating Geyser/Kit
Step 1: Battery Backup System - approx R 55,000 in 7 months
   1 x  Hubble AM-2 110AH 5.5kWh Lithium Battery
   1 x  SunSynk 5KW 48V Hybrid Inverter
   1 x KETO Battery Disconnector with 125A Fuses
Step 2: Battery Backup System - approx R 30,000 in 4 months
   1 x  Hubble AM-2 110AH 5.5kWh Lithium Battery
Step 3: Solar Panels - approx R 20,000 in 2½ months
   4 x Canadian Solar HiKu 380W Solar Panels
   4 x Tile Roof Mounting System
   Cabling

Repeat Step 3 x 2-3 more times

Total cost (Steps 1-3): R 145,000

(or R 8,000 x 18 months)

[RiccoS]

Step 0: Gas, good move, solar geyser uuuhmm, ask yourself do you use most of your hot water during the day.  See Step 1

Step 1: Good choices, there is however more to it than just battery disconnect, think splitting your DB into 2, essential and non-essential side.  Extra earth leakage, breakers, cable, etc.  Cable is getting ridiculously expensive these days.

See Step 0 on the geyser comment, Sunsynk inverter is bi-directional and if you have enough panels it can supply the non-essential side of your DB with excess solar aka geyser, unless you use a lot of hot water during the daytime.  If not I would use the solar geyser money towards more panels.

Step 2: Again good choice just keep in mind your first battery would have cycled a few times by now.

Step 3: You will need more panels for this inverter, 4 will barely get you into the voltage range of the MPPT.

On the solar geyser, my parents have one and every time we go and visit they need to manually override the element or change the settings.  You see my kids bath/shower after the sun set and we usually take a shower around 5 in the morning so from the time the kids had a bath until we took a shower in the morning you do not have sun and therefor you are using the element and Eskom to warm the water.  Then during the day when nobody is using hot water I've seen it going up to as high as 77 degrees, surely that amount of heat and pressure cannot be good for a geyser.

I'm also running a Sunsynk 5kW inverter and 2x 4.8kWh batteries, the past weekend we had a 41 hour outage  my 2 batteries was good for 18 hours and the dishwasher also ran at some point because I set it to start after load shedding during the night and then the power never came back on.  I'm in the process of installing 16x 370W JA Solar panels and will be able to start giving you real life stats in the next two weeks or so.  First string to be switched on hopefully today.

[zsde]

Some thoughts on the matter after having gone pretty much down the path of similar ideas.

Did a flat panel geyser conversion around 4 years ago to bring down the costs of Eksdom. Works great in summer when one doesn't need so much hot water and iffy in winter when one does need it. Yes, it helped in reducing electricity cost. In retrospect I should have rather invested that money in a second inverter, but that was not on my mind at the time. Only went PV last year, and there is no substitute for heating water as quickly as a geyser element. 
Using my solar during the day to power the geyser to it's max of 65C that the Geyserwise controller allows. Have adapted bath and shower times to use the available hot water. Also have a dedicated gas geyser shower should it be required. Haven't used it in two years. 

Had been on gas stove for over 7 years before I installed the PV. The convenience of instant heat and the historical affordable gas prices made it a primary object to get off the grid. Gas prices since have doubled and there is no more real saving except the assurance that one always has heat to cook for as long as you have gas. I am actually now retrofitting this to a electric/gas combo stove. Why? During the day I have huge amounts of spare electricity from my panels. So in daytime I shall use the electric plates and outside solar power times use the gas. Why pay for gas when the solar gives me "free" electricity?

Put some thought into more solar panels.
I would prioritise the Inverter, battery and panels first and start with at least 3kW of Solar Panels. That would allow you to heat your geyser in the daytime from the start. The planned cost for the thermosiphon I would rather use towards more PV.
 

[Scorp007]

Such a project would be interesting for a number of us and yes you will get twice the answers to those giving their input.

@zsde

I agree in a big way with you. Good to learn from your journey.

 toto why fit tubes if you can use the end state Sunsynk to power the whole house loads for free during sunshine.

As the Sunsynk can start saving the geyser(elec) power use from day 1 I would do the inverter and 4 panels from the sstart.Make it 5 to be sure. It can run as a grid tied(125V to run and 150V to start) without the added cost of bbatteries.No splitting of DB yet. To be done when battery is added.Yes it might sounds funny as you need grid and we are having little of it. The fact that tubes only heat during the sunshine period i would at least want to heat water a few times like over the festive season with visitor.  Yes there won't be back up but that can follow shortly out of savings as the geyser is the single most power hungry item. An option will also be to use a heat pump that can easily be run even from batteries for a quick splash and dash if needs be. Maximum of 1.5kw needed.

After this there would be a good saving and the rest can follow.

Edited June 30, 2022 by Scorp007