Wetkit

Ok, so took a quick pick of the solar panels on the roof...

On the photo it is 6mm cable. Since then I have upgraded to 16mm welding cable. First had to make sure about lenght and amount needed before I placed the order for the cabling.

Eish, did it take this long to do??? So with increasing the PV on my roof, I needed more space. So basically I had to swap the two solar geysers with my PV. All the old copper 22mm piping was replaced with the Cobra 15mm white pipe. This pipe works well and can also use the normal copper pipe fittings. Great advantage of these pipes is that they have way better insulation than the copper pipes. Reason for going smaller pipe is also to have less water in the pipe, meaning less heat loss. The single biggest problem I had with the automatic mixing valves (It is now law to install these with solar geysers) was the pressure. Basically if the hot and cold water were at diffrent pressures, the mixing valve did not work correctly. First option is to install the mixing valve right at the geyser output. This makes it easy as your cold water can be taken directly from the geyser feed. Problem with this is that the "cooler" water output now from the geyser takes a hell of a long time to get the pipes heated till you get warm water at the tap. 2nd option was to install mixing valves at each hot water tap. Not only is this costly, but again there is problems with the water pressure My 3rd option that did work was to use a single pressure valve to feed the geyser and the 2 mixing valves. I used 2 valves due to the distance between the kitchen and the bathrooms. The single pressure regulator also feed a 2nd cold water line going to each mixing valve. This ensure that the cold and hot water pressure is the same at each mixing valve. For now everything is working ok and nobody can burn themselves on the scalding hot water Thing is, sometimes you want HOT water for washing dishes, or that extra long soaking bath. Seems like 55C is safe, but just that tad too cold.

Hi Mike, Any more feedback on the Infini Hybrid unit? I am leaning more and more towards this unit. Just trying to figure out why other units is nearly double the price!?!?!

Right, so just an update for now... I have just recieved my CoC for the complete electrical system. What a mission that was!!! Stuff that was legal some years back is suddenly not legal anymore. Anyway, that's 100% sorted now, including a new and seperate earth for the solar panels. My old battries did take a bit of a knock now with the increased load. So, I did an extremely hard thing and installed a new battery bank. So, this is what the installation currently looks like. This is the 6V Trojan T-105 battries, rated at 225AH. This was all I could afford at this time. Idea is to buy another set in the near furture. Well now, guess what, I changed my mind yet again After running with this configuration for a week or so, I see that the battery bank is working way too hard. Even if I install another set of battries, I'm not 100% convinced that that will help. Increasing the PV capacity could also help, but then I need another MPPT. Well, so what is the solution??? My current solution is to sell my old battries, Invertor and MPPT. With those funds I hope to buy a Hybrid invertor. The plan is then to run the Hybrid as an UPS. Using all available solar power during the day while keeping the battries topped up. Battries will only be used when Eiskom power is out. My internal load shedding relay system is also working great and this will help not too drain the battries with unnessesary loads.

Optimizers is basically a MPPT per solar panel. Output still DC. Micro invertors is per solar panel, but the output is AC. The problem with both above is cost. Micro invertors will cost you nearly double what a single invertor will cost you. Yes, your efficiency will be way better with micro invertors, but electricity will have to cost R5/kwh to break even.

Nice

No, only do the solar panles in series. This should give you 24V, but your solar controller should then reduce it down to 12V for the battries.

What is your plan with this system? Just a backup power supply or would you like to ues it 24/7? Just remember @ 12V and 3000W you looking at 250Amp!!! 2A at 12V is only 24W, so that is really low for a 3000W invertor on standby load. It will never draw Zero amps, ok. I suspect your controller is a really cheap PWM unit from a firm in JHB selling cheap crap solar suff on the web Perhaps look at connecting your solar panels in series, to output a higher voltage. Perhaps when you draw power, the voltage drops too low and the solar controller shuts down?

With a solar panel you need a meter. With the panel facing the sun, measure the voltage on the terminals. This should give you the open circuit valtage of the panel. Now put the meter onto AMP's and measure again. This should give you a good indictaion of the max amps the panel can deliver. Now you just multiply the 2 readings, 80% of that will be about the max watt the panel can deliver.

Well, you can look at boating shops, as they normally have 12V pumps. Question is regarding the required pressure and flow you need. Electric motors like you have in a hand drill, with brushes, can be run from DC valtages.

@superdiy, please PM me that suppliers details!!! Sounds like a good deal

The best value for money 2V cell I have priced to date is the Deltec BI-XILF 23 tubular traction cell. Cost is around R3300 for a 600AH unit. At 2200 cycles at 50% DoD it is a good buy. Problem is the total cost! Next would be the Willard RT13, also 2V. Cost about R2400 for 400AH. Also 2200 cycles at 50% DoD. Problem is the total cost! Next on my list would be the Trojan T-105. Cost R2200 for 225AH @ 6V. Rated 1200 cycles at 50% DoD. Two strings of these will still cost less than the Willard RT13, but you have the same capacity. Thing is, it is nearly 50% of the life cycle time.

@superdiy, looks like a very professional product there Estimate on cost of one of those units?

Ok, so the more I am reading up, the more I learn So, bottom line is that not all batteries is created equal, even if it is in the same batch. Now when you parallel these, the minute small differences will grow bigger over time. Some strings might charge less and other more. How long this takes, I cannot tell. Solution might be to mix the batteries between strings every couple of months? Does sound like a lotta work

Welcome, and sorry to hear about your problems. Perhaps you can give us some more details regarding the system and the issues you having.

Ok, so I asked Company A to help me with the electrical canges and they said fine, no problem. Come the day of the install, nothing The boss comes back 3 days later to say there was a death in the family. Sorry to hear, but you could at lest have texted me!!! Anyway, found another company, RL Elektries. The guys came round and I showed what needed to be done. They sent me a quote and couple of days later the job was done!!! Eish, it was not cheap, but for me to do all of this by myself? Propably 10 years ago. Still waiting for their quote to get the rest of my house up to spec. Could be scary??? So now the 2 x stoves, 3 x Aircons, Solar Geyser and general house plugs is on Eksdom power. The rest is on Solar. I did have a bit of a hiccup with the microwave. Basically when the perculator, microwave and toaster is running at the same time, the invertor pukes and die. According to the manual and the invertor software, it should re-start automatically, but this does not happen So had to move all those device's back to Eksdom power. The DB is divided into 2 sections, Orange for normal power and blue for invertor power. The blue section is divided into 3 sections again. Section 1 is like pure UPS loads, like DSTV and lights. Sec 2 is like less important loads like dishwasher, pool pump, ect. These loads will be dropped automatically when Eksdom power is off. Sec 3 will still run via the invertor and battries with an eksdom power failure, but if solar power is low as well, these will also be dropped automatically via the MPPT. This is stuff like the fridge, freezer, garage doors, ect. The idea of all this is too use the least amount of Eksdom power during the day, still have the protection of the invertor for all my important equipment and also have reserve battery capacity to run during a power failure. The MPPT tells me now that I am using 20kwh per day now At least I can now play around with the circuits to get the right balance solar power, eksdom power and backup power.

MPPT is rated 60Amp and chager on inv is rated 75Amp, so coverd there. The only thing I can pick-up from the web is they say to try and stay with max of two strings. Reason for this they say is that any fault on a single battery in a string, will cause the other other battries in that string to overcharge. With multiple parallell strings this can result in the other strings to also discharging into that faulty battery, resulting in increased fire risk. Some sites also mention that the outside battries of multiple strings might charge more and work harder due to copper losses. Each string also needs it's own fuse or protection device.

Hi Guys, I need to start looking at replacing my existing battery bank. Currently I have 2 banks of 48V at 100AH in each bank, but the battries is over 10 years old now. If I have to size my new battery bank correctly, I would need about 800AH or more. Problem is that it is way to costly right now. I'm happy to run with 400AH. Now, I can do it with 4 x 100AH parallell strings, 2 x 200AH strings or a single 400AH string. Thing is, with multiple strings, I can buy a new string say every 3 to 4 months. With a single string, I would need to save for at least a year Now the question is, if all the battries have the same specs, which configuration would be better in the long run? Multiple smaller strings or single big string?

Getting back to replacing bad cells.... My UPS guy reccomend we replace a complete string if one battery is bad. The one bad battery can cause the other cells to overcharge. We have also lost a complete ups due to a fire caused by a bad cell Also the new cell will react diffrently than the new cells. That could cause the new cell to overcharge again. That is the main reason for a warrenty. Replace everything!!! But again it is easy for a corporation with loads of money to do that, but can you afford to do that?

I would say it is more a question of AH size vs battery size. The bigger the AH rating, the lower the voltage of the battery become. I think the goal is too keep the weight down to below 100kg. So, 600AH you only going to find in 2Volt cells. 100AH in 2Volt is not worth it, so they pack it in a 12V cell.

Hi Steggo, I think Mike had a 3kw Micro Care unit for sale. To go onto life line with your power you need to be below 450 units per month for at least 12 months, AND your property needs to be valued at LESS than R350,000. I think the City of Cape Town brought in the last part to screw over the middle class

While reading up on Power optimizers in another topic, they did make some interesting reading. If you suspect you will have problems with shading, you could look at seperate MPPT controllers for each individual string. So instead have having a single 100Amp MPPT, you could have 4 x 30Amp MPPT's. So, once one panel in a string goes down, it will not pull the other strings down too.

Ok, so if I understand this correctly, the Power Optimizer is actually a per panel MPPT? Personally I do not believe it will give you much gains. Where is will help though is when you run large serie strings with shaded area's. If a single panel on a large string is pulled down due to shading, the complte string will go down. Looks like this optimizer will help to prevent this. With our small systems I think the cost will be far too high, like with string invertors. It is a brilliant idea, but the cost is just If you running 4 strings, why not just have a single but smaller MPPT controller for each individual string? The output of all the MPPT's is then combined onto your battery bank without any further combiners. This actually makes more sence to me, especially if the strings face diffrent directions or diffrent PV panels is used between strings.

There is loads of options now available for heating water. Directly heating the water via heat exchange, like with vacuum tubes. Retro fitting existing geysers with vacuum tubes. Retro fitting existing geysers with solar PV power. Changing the element??? No way can that save power. Heating 100L or water by 10 degrees will always take the same amount of energy. A larger element will just do it in less time. The PV option is good for problem locations where the roof is not suited for external geysers etc. My grip is just once all the water is heated, the extra energy is wasted Retro fitting is a good option, as long as you realise the system constraints, like small water storage volume. With solar you want to heat as much water as possable!!!