3 minutes ago, plonkster said:

In other words, 20k :-) And then I still have to make my own pole. What has set me thinking is that perhaps, this is a better investment than a big battery bank... and that is what the next windfall (aka December bonus) is tagged for.

Only if you have enough wind all year round  I know we have too many days with no breeze at all. And I'm in the 'burbs so I don't know if the neighbors will like the "russle" too much 

2 minutes ago, plonkster said:

In other words, 20k :-) And then I still have to make my own pole. What has set me thinking is that perhaps, this is a better investment than a big battery bank... and that is what the next windfall (aka December bonus) is tagged for.

you know, i was not sure if it was the right thing to do either, i intially had 12 x 260ah batts, then sold 4 thinking it was too many, which in summer perhaps was, but now i think 12 would have been good to utilize the turbine more and i suppose switch the kitchen over to off grid too.with the 2kw turbine i think i can do it but i dont want t go below 80% of battery capacity.i think with our winds in the Cape that the 1kw would be the better choice to use for "trickle" charging as the 2kw just cannot run enough and the batteries are full. So i think i am seeing wastage on the 2kw. all i need is to get one of my distant neighbors to send me some armoured cable and i could "supply" them...

I was going to suggest community supply but was a little scared of who was listening...  Thorne's Micro Grid

Do you have a spec sheet/flyer for the 1kw and 2kw you could attach for me please...  I'm like Plonkster...

32 minutes ago, Mark said:

I was going to suggest community supply but was a little scared of who was listening...  Thorne's Micro Grid

Do you have a spec sheet/flyer for the 1kw and 2kw you could attach for me please...  I'm like Plonkster...

Rotor Diameter (m)

2.8

Material and number of the blades

Reinforced fiber glass*3

Rated power/maximum power

1000/1500w

Rated wind speed (m/s)

8

Startup wind speed (m/s)

2.5

Working wind speed (m/s)

3~25

Survived wind speed(m/s)

45

Rated rotate speed(r/min)

380

Working voltage

DC24V/48V

Generator style

Three phase, permanent magnet

Charging method

Constant voltage current saving

Speed regulation method

Yaw+ Auto brake

Weight

70kg

Tower height (m)

9

Suggested battery capacity

12V/200AH Deep cycle battery 4pcs
Life time

15years

4.  Application principles

4.1  The wind turbine should be installed in an open and flat area without barriers nearby.

4.2  Off-grid wind turbine generating electric power is charged to the batteries group. When there is no wind, it consumes the electricity from the battery group. Therefore, after discharging, the batteries should be recharged timely, especially for lead-acid batteries. During the working, over discharging, over charging or after over discharging, the batteries cannot be recharged timely, the working life of the batteries will be reduced in above conditions. So, the users should regulate the consuming capacity of the electricity according to local wind condition and the electricity capacity generated by the wind generator.

4.3  After passing full wave bridge rectification, the 3-phase AC electricity generated by wind generator is output with DC power, usually are DC24V, 36V, 48V, 120V. The voltage of the battery group should be equal to the DC voltage of the wind generator (after rectification).

4.4 The input DC voltage of the matched inverter should be equal with working voltage of the wind generator (after rectification).

 

5. The maintenance of the wind generator

5.1  Checking, cleaning and lubricating all rotating parts one time per year.

5.2  Before rain season, cleaning outside and paint antirust grease on the surface of all fixed connecting parts once a year.

5.3  Lubricating and maintenance bearing of generator one time per operating year.

5.4  Cleaning, rust removing and painting all exposed parts one time per every two years.

2kw system:

Rotor Diameter (m)	3.2
Material and number of the blades	Reinforced fiber glass*3
Rated power/maximum power	2000/2800w
Rated wind speed (m/s)	8
Startup wind speed (m/s)	2.5
Working wind speed (m/s)	3~25
Survived wind speed(m/s)	45
Rated rotate speed(r/min)	380
Working voltage	DC24V/48V/120V/240V/300V
Generator style	Three phase, permanent magnet
Charging method	Constant voltage current saving
Speed regulation method	Yaw+ Auto brake
Weight	88kg
Tower height (m)	9
Suggested battery capacity	12V/200AH Deep cycle battery 8pcs
Life time	15years

 

Re battery temperatures. Outside it's 9 this afternoon. The batteries are sitting at 13.

Starting at a high of 17 ar 4pm, at 4am mine was 12deg.

The wooden crate must be helping for under a polycarbonate roof, it is as good as outside.

Question: When a battery states a cycle life of 1600 @ 50% DoD what performance will the battery be at? As much as medicines need to be at 90% or better at expiry surely a battery is not dead.

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As I understand it it means that a 200ah battery will effectively be a 100ah battery after 1600 cycles. At C20 at least. At C100 it might still pack quite a bit of life.

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1600 @ 50% DoD I guess is the expected cycles if you are talking Trojan's for forklift operators. They need reliability, and are going to argue with a battery supplier for less than that.

So at 1600 cycles I recon the batts are quite done as a bank. Maybe one or two out of the bank may still be good for solar experiments.

Googled that a RE battery will be at 80% of its new capacity at the end of its projected cycle life.

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...be that 1600 @ 50% or 3000 at 20% for arguments sale.

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1 hour ago, Gerald_db said:

Googled that a RE battery will be at 80% of its new capacity at the end of its projected cycle life.

I too have googled into that result. There appears to be two schools of thought:

1. How many times can I discharge it to x% before it only has 80% of its capacity left.

2. How many times can I discharge it to x% before it dies on me before it reaches x%.

By the first school of thought, a 200Ah battery with 1600 cycles to 50% will still have 160Ah left after 1600 cycles... and is therefore in relatively good shape!

By the second school of thought, after 1600 cycles, you have a battery that will be flat after withdrawing just 100Ah.

I've become convinced that the second -- more pessimistic school of thought --  is actually correct.

It makes sense to me on some level, because I would expect the battery to gradually degrade according to how hard it works. For example, a 100% DoD would basically "kill" the battery by day one, because on day two it will only have 99% of its capacity left, and so, within 100 days or so you will kill it. But cycle it more gently, and by day 1000 you only have a 160Ah battery left... but you don't notice since you still only use 50% of the original 200Ah, in other words, you still have 60Ah spare at the end of the day. What happens is that the "spare part" runs out at the rated number of cycles.

If you take that battery that's done its 1600 cycles, and move it on to another less demanding application that only needs 50Ah (out of the remaining 100Ah), you can in theory do another 1600 cycles before it will once again run out of space capacity, and then you can move it on to another less demanding application where you draw only 20ah and do another 1600 cycles... of course at some point, like the old engineering joke*, it just becomes close enough to dead for all practical purposes :-)

* A mathematician and an engineer discusses Zeno's argument. The mathematician explains that if a guy and a girl stands a certain distance apart and repeatedly halves the distance between them, they will never actually reach each other. The engineer replies: Yes, but they will get close enough for all practical purposes.

Interesting calculation crossed my screen. I was looking at these really cheap Stride batteries, and a number caught my eye: they claim 1600 cycles at 30% DoD.

http://www.sonopsolar.co.za/product/strirde-12v-deep-cycle-battery/

They cost R1376.55. That works out at R2.39 per kwh, which isn't quite grid-beating yet (about ten cents too much)... but they do surprisingly well despite the cheap and cheerful nature of the suggestion. That is IF they actually do the 1600 claimed cycles.

On 28/06/2016 at 9:15 PM, Gerald_db said:

@Manie. To use 1 bank of 48v and cycle hard and hope that there is a cost effective 20 year new generation battery in 3 or 4 years when they are tired or 2 x 48v strings that could ne good for 10 years or more is the decision to be made.

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Hi Gerald, keep in mind the max sustainable amps for T105 is approx 70A so 3.5kW max on a 48V system. Cheers

Hi Gerald, keep in mind the max sustainable amps for T105 is approx 70A so 3.5kW max on a 48V system. Cheers

Actually have gone for 3 strings of 8 batteries in the end which hopefully will allow a long life, low dod and max power of up to around 5kW on occasion.

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I attended a very informative lecture on energy yesterday. It was presented by a very knowledgeable industry energy consultant.
He does a lot of analysis on the energy market locally and globally, with particular interest in Eskom given their key role in energy in South Africa.
The bottom line is that it is virtually impossible to avoid significant further electricity price increases, as in a doubling of the current price. Apparently that is what is being actively discussed in the inner circles of government. Eskom is a business with a single shareholder, but given Eskom's dire financial situation they will require serious bailout, something our government is not in a position to do. 
Below is a short summary of the Eskom situation as it changed over the past 7 years (2008 - 2015), it was done using Eskom's annual report information i.e. as reported by them.

Revenue and cost
- Power sales decreased from 244 000 GWh to 214 000 GWh.
- Average selling price increased from 19.45 to 76.c/kWh.
- In the mean time Eskom is adding 22% to their capacity with Medupi and Kusile. The good news from this is that load shedding is probably a thing of the past (unless it is related to poor management of coal supply etc.), we should not be capacity constraint. In fact the facility capacity and demand is moving further and further apart. This makes the idea to build another 9600MW nuclear capacity even more ludicrous.
- In 2015/16 Eskom will buy 9 TWh from IPP's for R15.1bn, average price therefore R1.67/kWh. That is a gross loss of 90c/kWh. In itself the 90c/kWh loss does not sound like much but on 9TWh it amounts to R8.1bn per year.
- Over this period employees increased from 34500 to 48000.

Liabilities
- Liabilities (excluding equity) increased from R104bn to R480bn.
- The above figure excludes another R300bn to complete the current power stations in build. It also excludes off balance sheet financing from power purchase guarantees to the value of approximately R200bn to IPP's.
- Moody's rating downgraded from A2 to Junk. They cannot find any financial institution to borrow them more money unless underwritten by the government. Let's ignore the fact that the country's credit rating is on the brink of being downgraded to junk. This will seriously affect Eskom and the government's ability and cost to finance debt.
- Last year government made an injection of about R23bn into Eskom financed by selling the proverbial family silver, government Vodacom shares.

A very sobering summary. This brings us back to the price of electricity. It doesn't take a rocket scientist to figure out that servicing the escalating debt cost (let alone repayment of the principal) is going to be a serious challenge given the dropping electricity sales. Government is in no position to finance it, especially in our economic condition. All of us applaud NERSA when they cut Eskom's requested increase to a "mere" 8%, this is however not realistic, it is simply delaying the breaking point.
Some people might argue that the consumption will increase but if electricity prices increase to an average of R1.20/kWh (Eskom price, not consumer price) electricity consumption will probably fall even further.

So, I think with battery prices dropping, efficiencies improving and what electricity prices will have to do, the breakeven point is probably not far off for almost all battery types.

Just to add a last point, Eskom is a serious risk to South Africa. They are strategic enough and BIG enough to sink us.

Very interesting Cobus.

Seems to me based on your post, just a little more patience is required for personally I would like to done and go off-grid, with Eskom as backup.

But the poor, who get lifeline power, is going to suffer even more.

Sent a 'vonkpos' to CoC saying that they should consider giving solar a boost by allowing us to feed back at no cost with CoC picking up the cost for approving the connections.

When we buy back the price should be their Eskom costs +10% profit. 

This is on the proviso that we feed back X% to the grid for free to use by Municipality as they see fit - distributed "Eskoms".

Obviously the metering must be top notch, T&C's will apply and all problems have to be seen as opportunities.

 

Ps. Sorry for calling you Chris the other week. 

6 hours ago, cvzyl said:

I attended a very informative lecture on energy yesterday. It was presented by a very knowledgeable industry energy consultant.
He does a lot of analysis on the energy market locally and globally, with particular interest in Eskom given their key role in energy in South Africa.
The bottom line is that it is virtually impossible to avoid significant further electricity price increases, as in a doubling of the current price. Apparently that is what is being actively discussed in the inner circles of government. Eskom is a business with a single shareholder, but given Eskom's dire financial situation they will require serious bailout, something our government is not in a position to do. 
Below is a short summary of the Eskom situation as it changed over the past 7 years (2008 - 2015), it was done using Eskom's annual report information i.e. as reported by them.

Revenue and cost
- Power sales decreased from 244 000 GWh to 214 000 GWh.
- Average selling price increased from 19.45 to 76.c/kWh.
- In the mean time Eskom is adding 22% to their capacity with Medupi and Kusile. The good news from this is that load shedding is probably a thing of the past (unless it is related to poor management of coal supply etc.), we should not be capacity constraint. In fact the facility capacity and demand is moving further and further apart. This makes the idea to build another 9600MW nuclear capacity even more ludicrous.
- In 2015/16 Eskom will buy 9 TWh from IPP's for R15.1bn, average price therefore R1.67/kWh. That is a gross loss of 90c/kWh. In itself the 90c/kWh loss does not sound like much but on 9TWh it amounts to R8.1bn per year.
- Over this period employees increased from 34500 to 48000.

Liabilities
- Liabilities (excluding equity) increased from R104bn to R480bn.
- The above figure excludes another R300bn to complete the current power stations in build. It also excludes off balance sheet financing from power purchase guarantees to the value of approximately R200bn to IPP's.
- Moody's rating downgraded from A2 to Junk. They cannot find any financial institution to borrow them more money unless underwritten by the government. Let's ignore the fact that the country's credit rating is on the brink of being downgraded to junk. This will seriously affect Eskom and the government's ability and cost to finance debt.
- Last year government made an injection of about R23bn into Eskom financed by selling the proverbial family silver, government Vodacom shares.

A very sobering summary. This brings us back to the price of electricity. It doesn't take a rocket scientist to figure out that servicing the escalating debt cost (let alone repayment of the principal) is going to be a serious challenge given the dropping electricity sales. Government is in no position to finance it, especially in our economic condition. All of us applaud NERSA when they cut Eskom's requested increase to a "mere" 8%, this is however not realistic, it is simply delaying the breaking point.
Some people might argue that the consumption will increase but if electricity prices increase to an average of R1.20/kWh (Eskom price, not consumer price) electricity consumption will probably fall even further.

So, I think with battery prices dropping, efficiencies improving and what electricity prices will have to do, the breakeven point is probably not far off for almost all battery types.

Wait, 9TWh?

As, in 9 Terra, or 9,000,000,000 Kw!

That's 2,250,000 x 250w Solar panels! Damn, I guess we should start buying solar panels