FixAMess

I have a 150l geyser and tubes, retrofit. It works perfectly, but as above, one needs to increase the amount of water , a 300l geyser is good for a family of 4.
If only the 2 of you, 200l will be enough,  we use 150l for 2, 1 bath and 1 shower....
In summer I get temps of 70C on a N facing roof, in winter 45-50C.
The cost was approximately R15K , all in. I used a geyserwise system to control temp and pumping etc.
I had a flat panel, threw it out in favour of the evacuated tubes, much more efficient in my setup.
Hilton did my solar water, tube setup, he's reliable and knowledgeable. Hilton Melck. [email protected]
 
 

Perhaps the easiest way to explain is by using examples of unbalanced systems.
One example is when you have too much PV compared to the battery capacity. If you put 4 x 100Ah batteries into a 48V system, it has a total capacity of 4.8kWh. If you have low load or no load during the day, it would be silly to install more than about 1kWp of PV (maybe a bit more), because most of it will go to waste. 1kWp is sufficient to generate up to 5kWh a day.
The batteries also want to charge at no more than 20A (about 20% of the Ah capacity... and technically I'm pushing it, 15A is better), so going over 1kWp increases the danger of overcharging your (lead acid) batteries.
Similarly, a 5kW inverter on that same 4.8kWh bank is also not balanced. The battery will not like more than a 0.2C discharge rage (again, 20A), so 1kW is about the maximum continuous power available to you, maybe 2kW for a few seconds.
Sometimes people will buy the oversized inverter with the plan to upgrade the batteries later. That is fine, it is an imbalance you can manage. Many so-called solar installers may however sell you a system that is underbatteried without telling you such things.
There isn't a fixed ratio, but as I explained above, you can do some simple math to see if a system is completely ridiculous or not. In my experience, people tend to under-battery their setups (cause batteries are expensive). Also note that Lithium Iron Phosphate batteries have higher charge and discharge rates (typically 0.5C or even 1C), which does allow a higher ratio of PV or inverter to battery capacity.
And just in case you haven't picked up on the C notation, 0.5C means half the Ah capacity, so if I discharge a 100Ah battery at 50A, that is a 0.5C discharge rate, and the same when I recharge it.
What that means is that I can charge and discharge a LiFePO4 battery at least twice as fast as lead-acid (and often even more), which means I can have twice the PV and double the inverter size without getting out of balance.