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Posted: Fri Jul 10, 2015 9:17 am
I've dabbled with small solar panels in the US, but here in the Philippines it seems like it could really be cost savings due to all the sun. I've searched on the internet a few companies here that have grid-tie and off-grid systems, but I really haven't seen any in actual use. Does anyone have any experience here with solar power or know of someone that does? thanks in advance.
Posted: Sat Jul 11, 2015 3:17 pm
Welcome Alice. I'm not sure that we have any members from the Philippines but there are plenty of posts about PV, both grid tied and off grid, for you to look at.
I'm off grid with a small pv array, a diesel generator, a 12V battery bank and an inverter. How you powered your system would depend on your demand: whether you just want lighting, lighting plus refrigeration or how many appliances you want to run. There are descriptions of the whole range or scenarios elsewhere on this site.
Posted: Sun Jul 12, 2015 10:24 am
If you are grid tied in most places you need to satisfy many regulations regarding who and what can be installed. Basically mains elec from any source is AC and comes in waves of voltage 50 or 60 times per second. If you add a generator such as solar, you must generate in sync with the supply or power is wasted and things expire. In the UK there is some money to be made from grid tied, so it's an incentive, but almost all of these installations will not operate if there is a power failure. Off grid, you could make a small amount of power for lighting and entertainment, but not enough for heating. There is no practical way to store enough to get you through 24 hours without big expensive batteries.
Posted: Fri Jul 17, 2015 5:01 am
In the Philippines they probably only want lights, a fridge, a computer, phone charger and TV and radio so with a small battery and inverter installation they could get that quite easily. 1.5 to 2 kW would do for the lot.
Posted: Fri Jul 17, 2015 5:47 am
Ken, I didn't know you were off grid. Would appreciate some more info on the spec of your set-up, and how it performs for you. Cheers.
Posted: Fri Jul 17, 2015 6:55 am
We been off grid for 33 years now. The SEB, as it was at the time, wanted to charge us £17,750 for the equipment and connection and then they were going to charge us a monthly rental for the equipment as well. We told them where to go and have been off grid ever since.
We've now got two Lister 6kW diesel gennies, one running and one standby, which we run for two 5 hr sessions per day on a timer. They charge 6 no. 2V ex MOD batteries through a 3kW ship to shore inverter/charger. When the genny is running the charger charges the batteries and sends 240V straight though to the mains circuit in the house. When the genny goes off the charger instantly switches to inverter mode and sends 240V into the house using the batteries for power.
We also have 880W, 8 x 110W, of PV on the roof which also charges the batteries through a 60A solar charge controller. I've got two more 110W panels to go on the roof but I've recently reread the controller literature and is says that we should have a 20% margin on the PV no load current so I'm not sure whether to put them on the current controller.
We have two separate mains circuits in the house, one for when the genny is on with standard sockets and the other for when the inverter is working with non standard sockets so that visitors can't plug in high powered equipment and blow the inverter. The earth pin on the plugs has a protrusion on the side and is smaller which prevents plugs being used in the wrong sockets.
Posted: Fri Jul 17, 2015 10:41 am
While being impressed with your set-up, Ken, I can't help thinking that generators are not really "off-grid" - just on a different kind of grid, quite possibly less efficient. Just saying, no disrespect intended, keep up the good work.
Posted: Sat Sep 12, 2015 1:16 pm
Generators are indeed a variety of being grid reliant, on fossil fuel extraction and delivery instead of the electrical grid.
However the moderate use of a diesel generator can be very helpful indeed at times of low renewable input or exceptional demand.
Or put another way, to meet 90% of your electricity demand from renewables is relatively easy, but to reliably meet 100% can be very expensive.
A renewable energy system to reliably meet 100% of your energy needs will require a lot of capital tied up in wind turbines or PV modules that are not in fact needed MOST of the time.
For a household sized off grid system it usually makes sense to provide 85% or 90% of the electricity from renewables, with the balance from a diesel generator. The diesel fuel use is modest and enough may be stored for several years use.
For a very small, low budget system a generator is unlikely to be viable. In such cases some standby FF lighting is a useful backup at times of low PV input.
A very basic system could supply lighting for a remote dwelling for MOST of the year, but might be inadequate in mid winter. LPG or oil lamps could be most useful for perhaps a couple of weeks each side of the winter solstice.
The FF use is modest and enough for some years is easily stored.
Posted: Sat Sep 12, 2015 2:29 pm
batteries help. Also other systems of electrical storage.
Posted: Sat Sep 12, 2015 2:44 pm
johnhemming2 wrote:batteries help. Also other systems of electrical storage.
Off course, and batteries are unavoidable in any common type of off grid renewable energy system.
In a domestic system there are economic limits as to battery size. It is usual to size the battery to meet most needs under most conditions.
A battery large enough for rare and exceptional events would be unreasonably costly and bulky.
It would be usual, in a largish system to use a generator when the battery state of charge drops to say 50%
In a small system without a generator, when the battery gets down to say 50% it would be usual to strictly limit use of electric lights and to use oil or LPG lighting until the battery is better charged.
If off grid, one can to an extent modify consumption patterns according to power availability. Examples include pumping water into an elevated tank, grinding grain, or sawing wood, when power is plentiful.
Storing the water or flour or sawn timber will usually be cheaper than storing power in batteries and pumping, grinding or sawing on demand.
Posted: Thu Nov 05, 2015 6:09 pm
Posted: Mon Dec 19, 2016 9:05 pm
Generators aren't completely off the grid but they are at least "some way off the grid".
Posted: Wed May 17, 2017 3:28 pm
They're not "time-critical" like the grid though so are off-grid in the sense that you can have bought the fuel ages ago.
Posted: Wed May 17, 2017 4:08 pm
RenewableCandy wrote:They're not "time-critical" like the grid though so are off-grid in the sense that you can have bought the fuel ages ago.
Welcome back from the dead.