At $10 per panel, per clean and power at $0.25 per unit that's 40 units of generation just to pay to clean the panel. For most of us that's a month's worth or about 8% of the annual generation!

 

We've not cleaned our panels since January and I don't really see a drop in performance although it would be a gradual fall off so not really noticeable. I shall get the man to clean the panels this weekend and see if there's a sudden jump in production.

 

Of course our panels are on the car port, so no access issues.

 

Flame post removed.

 

Any bickering will be removed and holidays can be arranged despite the Covid lockdown.

 

4 hours ago, Crossy said:

Flame post removed.

 

Any bickering will be removed and holidays can be arranged despite the Covid lockdown.

 

Shouldn’t that be a quarantine period rather than a holiday? Or holiday then quarantine, maybe? ???? 

On 6/6/2020 at 8:31 AM, Crossy said:

 

Thinking about it ????

 

I've got a 5kW dummy load that's controlled by an Arduino (light dimmer type phase control) which works pretty well although not needed any longer. It shouldn't be rocket science to make a variable battery charger on a similar principle, or even just PWM the DC side to keep the net grid power at zero. Going to need over-charge protection etc.

 

I've not seen a battery only grid tie inverter so it might be better to just use a normal inverter and switch the normal load (lighting, TV etc etc) over en-mass and run off the batteries until they reach the low point and then flip back to mains power. This would also have the advantage of giving a UPS-like system to keep the lights on even with the mains off.

 

Going grid tie for this would be more elegant, need to source an inverter. Maybe look at inverters intended for wind?

 

EDIT This chap looks promising, grid tie that can run battery only. It has RS-485 too although it's intended to run with a dedicated sensor. https://www.aliexpress.com/item/4001054628033.html

 

 

 

Would a hybrid inverter with on/off grid not be better .

Something like this ...

https://www.aliexpress.com/item/32816291769.html?spm=a2g0o.productlist.0.0.5ceb32fbJfCivl&algo_pvid=8ace3204-2362-4be7-9ec1-15f08e035ab5&algo_expid=8ace3204-2362-4be7-9ec1-15f08e035ab5-2&btsid=0be3746c15917075398566461e3db5&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

They are available in Thailand also . Most models are hybrid off grid , meaning they charge the battery and put the rest in the consumer loads . If power goes off , then it works like a UPS . The on/off grid ones , like the 1 mentioned also lets you put the power back in the grid , besides having all the other options already , including putting the battery in the grid if you want to .

8 hours ago, sezze said:

Would a hybrid inverter with on/off grid not be better .

 

Indeed, but at a grand US plus duty and VAT it's significantly more expensive if you already have a grid-tie system.

 

I looked at the Sofar version (nearly 1500 US) but after factoring in batteries etc decided to go on-grid with zero-export set on meter reading days.

 

IF we ever get a no-reverse or electronic meter I'll look again at what to do. The UPS functionality is nice, but for us not essential, we already have UPSs on vital kit and a genset for long outages.

 

If going from new then yes, they are an excellent option IF you need the functionality.

 

On 6/5/2020 at 1:38 PM, Heppinger said:

Are you in Thailand? As i thought Thai power companies do not pay produces of solar power any money or even credit on your account when putting power back into the grid.  If this is the case than 10kw is overkill,  depending on how many air cons your running, a 5 or 6kw system would be enough.

Other than for one room you wouldn't get much conditioning for such a unit. An inverter a/c could help.

 

Figure out the load for how many rooms you want to cool and transfer that to a cost/benefit analysis. Then let your heart decide.