Solar Panels

SantiagoDR · Sep 6, 2015

Hello,

I have been playing around with a small 10 watt 12v solar panel, and use it to power a solar fan over my desk. If anyone has a panel or 2 for sale I may be interested in them.

Thanks

Don

Criss Colon · Sep 6, 2015

Contact "AE", she did have some solar panels I believe.

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AlterEgo · Sep 6, 2015

Criss Colon said:
Contact "AE", she did have some solar panels I believe.

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I do, but it's a whole system, panels/controllers/cables/connectors, etc.

Olly · Sep 6, 2015

Hi Santiago, We are looking for a used 130 Watt panel with V at Pmax of 30 ish volts. If I find one I will have a 48 Watt panel V pmax 17 Volts availalble. It is for our solar helper on the invertor batteries - it stops the trickle charge from the invertor .
The solar tops up the batteries and saves 30 to 50 kWatthours per month. No charge controller necessary.

Olly and the Team

SantiagoDR · Sep 6, 2015

Olly said:
Hi Santiago, We are looking for a used 130 Watt panel with V at Pmax of 30 ish volts. If I find one I will have a 48 Watt panel V pmax 17 Volts availalble. It is for our solar helper on the invertor batteries - it stops the trickle charge from the invertor .
The solar tops up the batteries and saves 30 to 50 kWatthours per month. No charge controller necessary.

Olly and the Team

I was thinking about getting maybe 4/6 of the 30 watt 12v (17v) panels or something of that sort that will fit in a carry on next time I go to the States. We got a quote of 17,000 pesos for one(1) 255 watts 24 volt system panel here in Santiago. They don't sell the 12 volt system panel at that particular place.

The reason for thinking the 12v system is to use it to help reduce the 12vdc wall warts, security cameras and recorder power usage which run over 100KW a month (Work my way up to full replacement of the 12 vdc adapters). I could maybe use the 24 volt system by using a 24vdc to 12vdc converter, but that negates some of the benefits due to the loss in the conversion of the voltage back to 12vdc.

Been learning a lot using my Kill-a-watt meter. Never thought about it before, but just 100 watts an hour, 24 hours a day, adds up to 72,000 watts or more a month.

windeguy · Sep 6, 2015

The Kill-a-Watt is a good tool to have in the DR to double check what you are using monthly.

SantiagoDR · Sep 6, 2015

windeguy said:
The Kill-a-Watt is a good tool to have in the DR to double check what you are using monthly.

I also bought a used power meter off the Internet for $29, and it verified that my meter from EdeNorte registers the same amount of power.

KateP · Sep 6, 2015

I know less than nothing about solar panels but saw a kit at Pricesmart today and they've got a large selection on their website. Here's the link in case it can be of help https://shop.pricesmart.com/dr/sp/search/solar#page=1

SantiagoDR · Sep 6, 2015

KateP said:
I know less than nothing about solar panels but saw a kit at Pricesmart today and they've got a large selection on their website. Here's the link in case it can be of help https://shop.pricesmart.com/dr/sp/search/solar#page=1

Thanks, I will look in to it.

MiamiDRGuy · Sep 7, 2015

I want to clear myself, if I ever purchase this one:

https://shop.pricesmart.com/dr/en/p...controlador-de-30a-e-inversor-de-2000w#page=1

It says only for like lights in the house, maybe few hours using fan and use laptop, routers etc ONLY but not for like A/C, Ref, right?

windeguy · Sep 7, 2015

Also looking into importing them yourself. They will have zero duty under Dominican customs laws (as would charge controllers, mounting hardware, cables, and inverters bought for such a system) .

A few years ago I had door to door shippers provide me with quotes. At that time I had them quote on importing the exact same panels from a vendor in the US that donP used in Samana from his chosen supplier. The total price including delivery to my door was far less than buying them here.

SantiagoDR · Sep 7, 2015

MiamiDRGuy said:
I want to clear myself, if I ever purchase this one:

https://shop.pricesmart.com/dr/en/p...controlador-de-30a-e-inversor-de-2000w#page=1

It says only for like lights in the house, maybe few hours using fan and use laptop, routers etc ONLY but not for like A/C, Ref, right?

I'm new at this but think I'm correct on the following:

1,200 Watt Hours would run my Universal fan on low speed (70 watts) for about 17 hours,
... if conversion to 110 A/C was 100% efficient.

70 watts x 17 hours = 1,190 watts.

You can do the math on what you would like to run and figure out what you would need.
Allow conversion to A/C at perhaps 85%. (Reduce produced watts to work with by 15%).
Remembering also, some days are cloudy or rainy, no Sun no solar power..

Any experts out there, your help would be appreciated.

windeguy · Sep 7, 2015

You are on the right track Don.

SantiagoDR · Sep 7, 2015

windeguy,

Let's talk batteries for my small mini solar panel:

For instance, if my battery is 12vdc / 7ah, exactly what does that mean?

... it's good for 7 hours of power at 1 amp?
... 1 hour at 7 amps?

... 84 watts for 1 hour?
... 12 watts for 7 hours?

All of the above / None of the above?

The purpose of the discussion is to determine how big a battery bank is needed for the power I need to collect from the solar panels, in order to run the equipment until the next solar recharge..

MikeFisher · Sep 7, 2015

SantiagoDR said:
windeguy,

Let's talk batteries for my small mini solar panel:

For instance, if my battery is 12vdc / 7ah, exactly what does that mean?

... it's good for 7 hours of power at 1 amp?
... 1 hour at 7 amps?

... 84 watts for 1 hour?
... 12 watts for 7 hours?

All of the above / None of the above?

The purpose of the discussion is to determine how big a battery bank is needed for the power I need to collect from the solar panels, in order to run the equipment until the next solar recharge..

all above is correct.
deduct a good percentage of "losses" due your cabeling etc.

Mike

MikeFisher · Sep 7, 2015

keep in mind that your solar panel provides a limited amount of "charge".
using too much battery capacity could mean that your "solar hrs" are not enough for your panel to fully charge the battery/batteries.

Mike

SantiagoDR · Sep 8, 2015

I think I need a new refrigerator, from 9pm last night until 5am this morning (8 hours of not opening the door) it used 630 watts, that's roughly 57KW a month minimum, with opening the door the KWs will soar. It's been connected to my 3.6kw Invertor for 17 years. I have been testing everything to reduce my usage and convert some things to solar.

kts78 · Sep 8, 2015

Our house is run entirely on 30 watt panels. I brought them from the U.S. 5 per suitcase, back when you could have 2 free suitcases. The system started out as 12v, but have since changed it to 24v by just putting two panels in series. We currently have 32 panels and this is enough power to run everything we use. Normally our battery bank (12 batteries) is fully charged by around 1:30.

windeguy · Sep 8, 2015

SantiagoDR said:
windeguy,

Let's talk batteries for my small mini solar panel:

For instance, if my battery is 12vdc / 7ah, exactly what does that mean?

... it's good for 7 hours of power at 1 amp?
... 1 hour at 7 amps?

... 84 watts for 1 hour?
... 12 watts for 7 hours?

All of the above / None of the above?

The purpose of the discussion is to determine how big a battery bank is needed for the power I need to collect from the solar panels, in order to run the equipment until the next solar recharge..

All of the above in theory, but in practice you want to limit the amount you take from the battery to protect its useful working life.

Think of the battery as being able to store 84 VA = 84 Watts

DC amps to watts calculation formula:

The power P in watts (W) is equal to the current I in amps (A), times the voltage V in volts (V):

P(W) = I(A) ? V(V)

So watts are equal to amps times volts:

watt = amp ? volt

or

W = A ? V

The maximum storage this battery can provide when newly broken in after a number charge/discharge cycles is 84 Watts.
To protect that battery from being damaged, the most you should take out if it during any discharge cycle is 50% of that or 42 Watts. If you go below 30% of battery capacity, you will damage the batters very quickly. We are talking flooded wet cell lead acid batteries here.

windeguy · Sep 8, 2015

kts78 said:
Our house is run entirely on 30 watt panels. I brought them from the U.S. 5 per suitcase, back when you could have 2 free suitcases. The system started out as 12v, but have since changed it to 24v by just putting two panels in series. We currently have 32 panels and this is enough power to run everything we use. Normally our battery bank (12 batteries) is fully charged by around 1:30.

Quantity 32 of 30 watt panels provides you with a maximum of 960 watts . Lets say you get 10 hours at that wattage, that would mean you get 9.60 kWh from the panels. About 80 percent of that will reach the batteries, but let's say as much as 8 kWh is available for use by you daily when it is sunny.

You are running everything from 8 kWh per day (or less)?

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