Solar conversion, bit by bit

[abudabi]

I don't have a few 100k so want to slowly but surely start converting over to solar. I've done the std things already (solar geyser, gas hob, CFL/LED bulbs etc.)

Can it be done (without loosing money by having to buy a better inverter or controller or whatever at a later stage) and if so, how would I go about doing it and what should I be looking out for?

Thanks

 

[Gaz{M}]

Not an expert, but logic tells me that you probably can't build up in small bits and pieces, only larger chunks. It will also cost more in the end.

But I imagine that you would have to buy an inverter and charge controller big enough for your final needs up front, which is going to be expensive. You could probably add strings of solar panels in smaller batches over time (say 1kw each) and batteries can definitely be added later, to save some money up front, but then the repayment period on your inverter etc. becomes that much longer.

What is your goal? To save money on grid power? or for backup?

 

[The_Traveller]

Not worth it imo.

Wait for the municipalities to allow feed back into the grid and offer rebates, then start buying into Solar.

 

[richjdavies]

In my (biased) opinion. The next step is to monitor EVERYTHING. With good monitoring you can actually figure out what you need, rather than having to 'thumbsuck' the size of everything. More importantly it lets you focus on what you do now that costs you money and then figure out a way to eliminate those users and/or substitute.

The problem you have with inverters etc. and trying to take things one step at a time, is as others have described - you'll be either overbuying the inverter (i.e. buying a 20kVA unit, when you only have generation capacity to do 2kVA), or you'll buy a 2kVA unit and then have to replace it at each step.

You need to be clear about WHY you are doing it?
(1) Independence from the grid?
(2) Saving money?
(3) Being green?
Those are VERY different goals and going after (1) means almost certainly NOT saving money in the short-term. Moreover going after (3) means you probably would be less interested in things like Battery storage that achieves (1) and (2) but doesn't help with (3).

As with any strategy, you need to know what the goal you have in mind is, before setting off on a path! Particularly an expensive one.

 

[richjdavies]

Wait for the municipalities to allow feed back into the grid and offer rebates, then start buying into Solar.

Ah yes, the eternal wait. I've been told every year for the past 5 years that "in the next few months Eskom will come up with a framework to let us feed-back into the grid". Right now, given they aren't even willing to connect up the large-scale REIPPp guys that they have contractual obligations to connect, so I don't think anyone is really considering it at Eskom. The peak of 'eskom allowing LV feed-in' was probably last year some time, just before load-shedding was solved. Now both Eskom and the Municipalities have the opposite problem on their hands (too much power, not enough people buying it!) - it's been described by Chris Yelland as a bit of a vicious circle - as prices rise, more people go off grid, meaning the produces have to charge more for the same power, causing more people to go off grid.

We're definitely near the point right now - with the Rand Strong and Solar Cheap... and power likely to continue increasing in price in the future, that Solar probably does make sense for lots of people. Certainly on the larger-scale end, you can produce power for less than R1/kwh. It's just whether you will use that power - so for Homeowners, probably not, but for businesses that use power during the day (and weekends!) it's probably already worth covering your roof.

However -- there ARE municipalities that do let you feed into the grid - Cape Town and Drackenstein are 2 I'm pretty certain of. However, in almost all cases that FEED-IN amount is much LESS than what you pay when you are taking from the grid. As such, it still makes more sense to consume the power whenever you can, and possibly storing some, rather than 'using the grid as your battery'.

 

[abudabi]

Thanks chaps!

I guess the goal is more to save money on grid power. Even if its only break evenish in the short term for longer term rewards. If a by-product is some form of backup for when the grid goes out, happy with that.

 

[GoB]

Check whether you can save 10%+ per year without using batteries.

Personally I would look at the hassle/risk and only consider 20%+.

For me that is replacing 100% of my hot water for <R18k, or running a solar pool pump for <R18k.
Not realistic yet.

 

[treeman]

From my little experience and reading, one should not add new batteries to older batteries as they have already started to use up their life cycles. You can set up a small system 24V and up to 2.5kW and dedicate it to a certain task..e.g. lights pool pump. At a later stage you can add a 2nd system 48V to handle 5kW.