3 panel (180 watts) charging issue

[MKHPhillips]

I have a 3 panel system (180 watts) that I have created (normal 3"x6" cells) and I am trying to charge 2 camper batteries (12v total) in cold NY. There is a 12 amp charge controller in between the panels & batteries. Connected to the cold batteries is a 3000 watt Tiger inverter, which is running a 13 watt light bulb for a dog house. All wires (from panels to batteries) are 18 gauge. Issue: the panels do not seem to be charging the batteries as much as they should be. The 13w bulb uses 312 watts a day and the panels should be generating about 900 watts a day (5 hours). I checked each panel and they produce between 19.5v - 21.5v in cloudy weather. Do they not produce as much wattage during cloudy cold weather, even though they are at 19.5v - 21.5v? Should the batteries & inverter not be in cold weather? Does anyone have any ideas what the issue may be? See the attachments. Thanks in advance.

[Mike90250]

In cloudy weather, they will still produce voltage, but very little amperage. In cloudy conditions, I expect they will be 10% of rated watts, so you are looking at 18W harvest. Sorry. Also, some of the cheap charge controllers, are junk, and do not work. That can also contribute to the problem.

[MKHPhillips]

Mike90250, thanks for the info. I don't know much about the quality of charge controllers and found this one on ebay. What would you consider an average charge controller?

[Mike90250]

Look for a Trace C-12 Simple, reliable cheap, rugged. Any of the low priced offerings from Morningstar are good too. Many different versions, light timers, dual battery configurations, but still reliable, solid units.

Meantime, keep the batteries charged somehow, if below 70% for more than 24 hours, they begin to sulphate, and loose capacity.

Mike

[capesolar]

MKH-
My concerns for the design of your system are many.
1) Wiring a 180 watt array with 18 guage wire will not work well. In fact, the wire may act as a fuse and burn. The wire needs to be much heavier in order to handle the current. You have about 10 amps of potential charge at 12 VDC. Try #10 wire if your distances are 15' or less.
2) Why are you using a 3000 watt inverter to run a 13 watt light bulb? Is the light being used for light or minimal heat for the doghouse? If it is for light, consider a 12 VDC LED light. It will draw a fraction of what an incandescent will, and you dont need a massive inverters consumption at minimal load (they operate the least efficient at loads like this).
3) Does the light need to be on 24/7? If not use a photo eye with DC lighting to only turn the light on at night. rRght off the bay you'll cut your consumption by 50%.

In doing fast math with your system as it stands, your 180 watts of panels will produce abour 360 watt hours / day. You will only get about 2 hours a day of peak sun in the northeast in winter. Add the efficiency losses of some charge controllers and the efficiency losses of your inverter at low power levels, to the high consumption of incandescent bulbs and the combination will lead to a system that wont work well for your needs.
Your system is simply "out of balance". If balanced properly, it will work just fine.

Hope this helps.
Capesolar

[MKHPhillips]

1) Is the 18 gauge wire ok from the panels to the controller? and just increase the wire size (to 10 gauge) from the controller to the batteries? The wires do not seem to be hot when I touch them.
2) That is the only inverter that we have. The main intent for the 13 watt bulb is to heat the dog house a little bit at night. We shut it off during the day (7am - 4:30pm). Maybe I can find a small 12v heater, to eliminate the inverter. I added another picture.

Thanks for the help.

[Mike90250]

For heating, you could just use a 1157 auto bulb. Use the taillight filament, need more heat, wire up a 2nd or 3rd one. The brake filament runs too hot to leave on all the time.
Then forget the inverter.
Using solar electric for heating is VERY expensive. Via a battery, you only heat with about 5% efficiency. If you used solar to heat water, you are about 35% efficient. Maybe just use a hot water bottle?

[capesolar]

1) Is the 18 gauge wire ok from the panels to the controller? and just increase the wire size (to 10 gauge) from the controller to the batteries? The wires do not seem to be hot when I touch them.
2) That is the only inverter that we have. The main intent for the 13 watt bulb is to heat the dog house a little bit at night. We shut it off during the day (7am - 4:30pm). Maybe I can find a small 12v heater, to eliminate the inverter. I added another picture.

Thanks for the help.

MKH-
You should connect the solar panels together using 10 AWG wire, + to +, - to - for all 3 panels, then run 1 pair of #10's to the controller, then to the battery.
Since your intention is for minimal heat, an 1156 or 1157 automotive bulb, as Mike mentioned will work fine. This will eliminate the need for an inverter. If you want you can add a small DC photo eye to turn the light on / off automatically.
Good luck -

[netttech]

For providing heat/comfort in a dog house buy a roll of Refletix (20-$25, could be other names also) from any home improvement store. It's a roll (different sizes) of 1/4" aluminum faced bubble wrap.

It reflects 99% of radiant heat (body heat). Line the dog house with the product, especially under the bedding. Guaranteed the dog will be very warm.

I started using this product when my son was in boyscouts on cold weather camp-outs. A single layer either in or under the sleeping bag (works either way), is like laying on an electric blanket. Two layers in a sleeping bag (slide in between the layers) & we easily camped out in zero degrees. We received the polar bear patches every year.

It works immedately when you sit/lay on it. I used it in my house remodel & have a piece cut/shaped for my car seat. It works great & a lot cheaper than solar panels & batteries.

Your dog will not want to leave the dog house on cold days.

Good luck!

[capesolar]

Sounds like a great idea / product. Thx.

[nodetihw]

18 gauge wire is only rated for 4 or 5 amps the most, that is why they put it on lamps. 10 gauge wire is 30 amps, 12 gauge is 20 amps, 14 gauge is 15 amps, 16 gauge is 7amps, 18 gauge is 4 to 5. The larger the wire number the smaller the amperage. Anything other than this you are starving the supply. Stranded wire can handle a little more but not that much difference. Kick up the wire sizes it should be alright. I live in upstate NY also but watch your standard electrical code. Don't starve any of the wiring.
Good luck.Don

[MKHPhillips]

These are all excellent ideas. I am glad I joined the forum for advice. Thank you all. I was also thinking about creating a small wind turbine to charge the batteries since I only receive about 10% of charging (with the solar panels) when it is cloudy. I will have to do research just like I did when building the solar panels.