Jump to content

Hallo and please put me on the right track

Recommended Posts

Hi there. 

I am planning my first solar upgrade in December. 

I have 2 schools of thought. My biggest consumption of electricity is my swimming pool, bore hole and geyser. The geyser I have placed on a timer to heat the water for only 4 hours a day.  2 in the morning and 2 at night. I will install a panel to heat the water and circulate it with a pump to reduce the losses more. I know the timer is not the most efficient way.

My plan was to replace the pool pump with a complete solar pump with 2 panels that will drive the pump. This is going to cost around R15k. My second option is to purchase a Hybrid Inverter and panels that will drive the existing pool pump and then also use the same inverter to run my bore hole pump on weekends. 

I can then add batteries to the system as time goes by. 

Personally I think the second option will be the best because if I add batteries later on I will be able to use it as backup as well 

The problem is the capital outlay. I only have around R17k for the system. I need an inverter that will drive a 1.5kw pump (current borehole pump) and enough panels to supply the inverter to run. 

I calculated that I need 6x300w panels to have enough power for starting the pump IE:1800w 

Will you please direct me to a shop where I will be able to purchase a inverter and panels that will be within my budget.

Eskom is becoming more and more unreliable and i believe we all should look at a backup plan. I don't have any at the moment. not even a generator. I have managed to lower our bill a lot by installing a gas hob and replacing all the lights with LED's With 2 teenagers in the house it is difficult to get it lower because they do not switch things off. 

If i can change my big consumption items I will be able to reduce my consumption more. I have managed to go below 15kwh per day if i do not run the pumps but with summer coming i had to start up the pool and bore-hole and are using close to 25kwh per day. i want to reduce my consumption to below 10 If possible.


Thanks for the great forum. i have read a lot today before joining


Link to comment
Share on other sites

You could consider changing the pool pump motor to a smaller size if possible , or install a speed drive . And while you're at it I'd swop the filter sand to clinobrite, you use less chemicals and it's easier for your pump to circulate the water. If the solar pump option is too pricey. Then again if you don't use the pool often , let it go green and then nuke it on a Friday so you can swim on the weekend.

  As for the bore hole I'm not sure what solar option would be best. 

Though the right size solar geyser and heating pannels might eat up a fair portion of the funds. For sizing of the geyser you can work on about 70 litres (minimum)of hot water per person. Otherwise there isn't enough solar hot water and you're back to Eskom.

Link to comment
Share on other sites

IMHO - The most benefit will come from sorting out the geyser first, Solar Electricity is still very expensive, but Solar Water heating is cheap enough now, and you will be able to get rid of 4hours of geyser power (anywhere from 6kW to 16kW per day dependant on your current element size).

1. Obviously, your geyser has to be Solar compatible. You can't do Solar Water heating with a normal geyser.
2. Buy a GeyserWise (There are some slightly cheaper products but they really don't work as well) - If you are going to need to pump (most systems/setups do) then a Geyserwise Max, otherwise a GeyserWise TSE will work (be careful, I have had to change because I thought I could get away with the cheaper model). The only and biggest negative with a GeyserWise is their completely UGLY control panel (seriously, hide it somewhere out of direct site!)
3. Evacuated tubes are relatively cheap, and can be installed by most plumbers (even those with limited solar experience), but I do advise that if they think you only need 12 tubes, multiply it by at least 50% (18 tubes). My logic behind that is that your geyser can get hotter than you want, but you have to turn on power if you need to just get it to shower temps if your setup is not heating enough. Adding to a Evacuated tube array needs an almost new install. If you find it getting far too hot, especially in Summer, then it is a simple process to remove a few tubes and keep them in your garage.
4. Pump for Solar Water Heating (Geyser) - My thoughts here are to use a pump with a 10Ah battery, a cheap charge controller and a smallish solar panel. Think about it, unlike normal electricity, the pump only needs to operate when the sun is shining and the tubes are getting heat... At night the pump will not operate at all anyway... The GeyserWise Max has a proper temp controller and a relay to operate that pump when ness (see item 1)

Now the tougher more expensive stuff... This might not save you money in the long run, but will get you on the Solar Electricity track:
1. You can always start with the small stuff in your house that already runs off 12VDC (You will be often surprised how much)... Alarm Systems, Automated Gates, Downlighters, Intercoms, Portable Phones, DSTV, Some Laptops, CCTV systems +++. A nice powerful 12V battery bank, that is charged with a few small panels can make a huge difference. As an example I have 200W worth of panels whose sole job is to keep a reliable 100Ah battery charged via a realitively cheap Ellies Controller, I have a 12VDC bus that runs off this battery that runs through my house. I keep a cheap battery charger (Midas special) on standby to charge the battery if I have had limited solar power for a few days. But that battery operates Constantly powered small LED strips inside my house (never dark), My DSTV (before we abandoned due to cost), my Gate/Intercom, and Alarm. Admittedly I have a cheap, cheap Voltage monitor on the battery that sits near my desk to make sure the voltage never drops below 11.5V, but I only look at that once or twice when I get home from work (It only tells me if I need to turn on the battery charger - don't want to be without alarm/lights/gate when you wake up in the morning).
2. Your budget is already way too small to replace the big electricity consumers in your house otherwise. A borehole pump and pool pump are huge power consumers. Second only to a heating element (Geyser/Stove/Oven/Dryers), anything with a motor usually is one of your largest consumers. As mentioned, try reduce it's load as initial trigger (I bought a lower power kettle for example, since it's instant on power was lower). Simple math - A borehole/pool pump has a hellava kick at startup, and a small solar electricity setup will trip. Again, my estimates are that you need to work at about 4-5x the actual power of a motor to calculated it's initial startup (obviously better equipment and better motors behave better, but this is just my opinion). What this means is that if you have a 0.75hp pool pump, you have to cater for it's startup power for anywhere from 1-30seconds (7.5hp or 5.5kW). You will have to pay quite a lot for an Invertor that can handle that load, and also the Batteries that will need to take that load - and be able to last through that heavy cycle repeatedly.
3. Avoid the loads I mentioned above (2) from being on your Solar plan. Almost everything else like lighting, computers/laptops, general household, can be run on Solar Electricity for much lower values. Even starting with just changing your lighting to LED instead of Incandescent will save a big chunk.

Not trying to dissuade you from going with Solar, in fact I am hoping you do go the route (even if only to stick it to the man:D). But I would prefer that you do it within your mentioned budget. I have been stung by bad advise, bad suppliers, wrong information, etc and it has cost me a lot more money than it ever should (4x more). (Feel Free to read the Blogs on this forum - KLEVA's Lessons Learned). But I cannot advise you strongly enough to do the Solar Water Heating route first - you will see and appreciate the benefits far better.

Link to comment
Share on other sites

Sorry, quickly getting back to the cheapest panels - As of today, the cheapest panels I have found are from ArtSolar in Durban (one of the few/only local manufacturers). They have a 72cell 330-350W panel at decent pricing (about R2k). Everything else carries an import cost which makes them expensive. Quality wise it's a bit difficult to say if they are the same as any imported product from CanadaSolar/Renesys/and many others, but the cost difference needs to be kept in mind (I have 5 from them, but they are new so how long they last and their continued output is still to be experienced).

Batteries - Depends on usage. At the moment I see the users on this forum ravining about the Polyntech (sorry if spelling is wrong) and also various Lithium types. It is going to depend not only on the Invertor you eventually choose, but also the way you need to use them - PS: These are normally, and should be, a MUCH bigger expense than the actual invertor you choose.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...