A Solar Installation Thread

[RVRoadTrip]

Originally Posted by mythplaced

Yea, our AMana residential refrigerator compressor did not like the "modifed wave" and let us know by puking....$800!

Certain electronics require pure sine wave inverters, I just didn't try to list any as my level of expertise in that category is limited. I'd venture to say that most modern electronics require pure sine wave... but that's only my opinion.

[jspande]

Actually, I believe that sine wave power is more vital to anything with a motor (such as a compressor refrigerator) than most electronics (except laser printers which apparently demand sine wave - of course laser printers are not a good choice for solar anyway due to high power consumption).

Motors will (at best) run hot with modified sine power, thus wasting power and shortening their life.

[RVRoadTrip]

I believe that jspande is correct about the inverters.

Also, here is a shot of everything ELSE needed for the installation except the wire.

[Rv'n]

Here is a question I have not seen asked. We are planning to go to Alaska next summer, May-Sept, and plan on doing a lot of boondocking. I am leaning towards solar power versus buying and using a generator because of the hours of sunlight at that time of year. Will we be ok with solar or should we buy a generator? At this time it is either or not both.

[RVRoadTrip]

Originally Posted by Rv'n

Here is a question I have not seen asked. We are planning to go to Alaska next summer, May-Sept, and plan on doing a lot of boondocking. I am leaning towards solar power versus buying and using a generator because of the hours of sunlight at that time of year. Will we be ok with solar or should we buy a generator? At this time it is either or not both.

Several variables are involved in this decision.

1) How much power do you consume per day?
2) How much battery capacity do you have (AH)?
3) How many watts of solar are you planning to have?

People that own generators will probably tell you that you need a generator, whereas people who have a properly wired and sufficiently powered solar setup will suggest solar.

As for me, I don't own a generator and don't care to. Solar does the job for me as I tend not to stay in places that require me to run the A/C. More reasoning was that generators will always require fuel, I have to have a place to carry that fuel as well as the generator, it needs regular maintenance and servicing, it makes a lot of noise, generators are not warrantied for 25 years like my panels are, no one sees my panels unless I tilt them up so chance of theft is minuscule, etc.

In summary, if you need more power than solar can provide, get a generator. Otherwise, solar is a good choice.

[Rv'n]

RVRoadTrip,

Thanks for the reply and the questions you asked me. I am just starting to research this but I am planning on at least 3 135 watt panels, at least 3 batteries, probably T 105's and my consumption I have to recalculate. Last calculation I must have done something wrong but I was up to about 6 panels, more batteries than I care to think about so I know that cannot be right. You have given all of us a great wealth of info and I want to thank you for that.

[Blue74]

I was up there in 94 for 2.5 month as a state park campground host, left Denver 4/15 got to Portland on 10/10. I had very low demand on the 12V system since I could not get TV and used the radio. I did use a small inverter (200 W) to charge the park handheld radio. All was fine till I moved north of Fairbanks in August and towards the end of the month the rainy season.

I have a 1000W Yamaha generator to use for the microwave and as a back up. With the colder temps and little sun I would fire it up to top off the batteries. And later on it was used on the trip south in September as I ran into 20 deg temps around Paxton and the snow started to fly. I have 3 Siemens panels I think is around 75W total it was what Camping World sold back in 93.

[RVRoadTrip]

OK, after 4 more trips to the local hardware store for things I thought I had but didn't have, I now have everything I need! Everything but the panels is installed and operational... the crazy panel mounts still have not arrived as of 09/30/2009. But on a brighter note, the UPS tracking says they will be here on 10/02/2009!

So here's a few more shots of the installation...

This is the Samlex 300-watt pure sine wave inverter and the charge controller mounted under the bed in the pass-through storage area. I did this so I could reach in the storage area and turn the inverter off an on as needed. I lined up the inverter so it's cooling fan blew across the heat sink of the charge controller. The inverter has a wire running from it to the other end of the camper where the TV sits. From here we can plug in the TV, the DirecTV box, our cell phone chargers, etc. while boondocking.



This ain't pretty in this shot but this is outside where the batteries are. This is the shunt where all the negative contacts are and you can also see the 50A fuse for the hot wire that runs to the charge controller.



And here is the remote display powered up. The default screen shows that battery voltage level and how many amps the system is drawing. The display shows way more information than you could imagine and has so many settings to allow you to configure the system just like you want it. With the remote display, I don't have to flip any jumpers on the charge controller itself, I can do it all from there.



Once the panel mounts arrive and I get those installed, I'll update this post. As always, much, much more information regarding the installation is available on our blog site.

[RVRoadTrip]

The tiltable panel mounts arrived today. Once again, the mounting holes were drilled incorrectly. I called the company and told them this was the second time and I would just re-drill the holes myself. They were nice enough to refund the entire purchase price of the mounts for my troubles. Here's what a pair looks like. I will try to get them installed tomorrow and have some completed pics.

[RamblingRV]

Originally Posted by Rv'n

RVRoadTrip,

Thanks for the reply and the questions you asked me. I am just starting to research this but I am planning on at least 3 135 watt panels, at least 3 batteries, probably T 105's and my consumption I have to recalculate. Last calculation I must have done something wrong but I was up to about 6 panels, more batteries than I care to think about so I know that cannot be right. You have given all of us a great wealth of info and I want to thank you for that.

T-105s are 6v batteries, so with a 12v system, you would need either 2 wired in series to get 225 amphours at 12 volts (total , or 4 wired series/parallel to get 450 amphours at 12 volts.

With 2 T-105s, you will have a total of 225 amphours, or 2700 watt hours (2.7 kwh) of storage space. Of that, you will never want to go below 80% DoD (Depth of Discharge) or you risk an early death to your batteries. Best to target under 50% DoD if you can. That means you would have 1350 targeted watt-hours available, or 2160 watt hours available at max safe DoD, in the 2x T-105 scenario. Twice that in a 4x T-105 system. However, please remember that efficiency must be taken into account. Battery based systems are not 100% efficient. I don't recall the figures, but as I recall, it is somewhere around 75-80%. So, take 80% as a rough guess, and say you target approx 1100-1700 watt hours per day in a 2x system.

Now lets go back to the panels and charging. If you have 3x 135watt panels, then you will have 405 watts of max input per hour, provided you aim your panels at the sun, less if pointed straight up. You need to take that into consideration. For these purposes, let's simply use the 405 watts per hour for now. You will then need to consider how many hours of full sun you will get at your location during the period you are there. Let's say 6 hours of full-sun per day. We also have to consider input efficiencies, of perhaps 80-90% after going thru the charge controller etc. Again taking 80%, you could count on 405 wh X 6 hours X 80% = 1944 watt hours input into your battery bank per day, assuming no rain, clouds, fog, etc.

Going back up to the top, if you figure you will never have a cloudy day, and you use less than 1100 watt hours per day, then you probably only need 2 panels and 2 batteries. Since this is not likely, and since you are already thinking about 3 panels, I would go with 4 batteries.

Before you do any of this, find out how much electricity you will be using. There are lots of websites about renewable energy that can help guide you. You will also find info about tilt angle etc.

Good luck...hope this helps.

R

[RVRoadTrip]

The wife and I finished up the solar installation this morning! It was exciting to see the meter light up when we flipped the switch to turn it all on. Here's a shot of the panels mounted on the roof. All the details of the installtion are (or will be very soon) posted on our web site at RV Road Trip - Solar Power Installation Walkthrough.

[jspande]

RamblinRV, excellent explanation but I believe there's one mistake. The 75-80% efficiency for batteries would affect how much electricity you must put into them (charge) to get the rated amp hours out. That is, it affects how many panels you need, but doesn't reduce the available amp hours for discharge.

However, if you're using an inverter to power 120vac stuff, then you need to factor in an efficiency of around 90% for a good sine-wave inverter, assuming optimal load. Inverters consume around 15-20 watts internally for a 1000-2000 watt model, so if you were only powering a 20 watt load the efficiency would be only 50%. So you don't want to run a big inverter 24/7, and if you want to power a clock-radio or something, better have it's own small inverter that would have a smaller residual consumption.

Also the battery amp hours would be reduced if you discharge faster than the 20 hour rate, so if you're running heavy loads, that needs to be factored in.

[RamblingRV]

Originally Posted by jspande

RamblinRV, excellent explanation but I believe there's one mistake. The 75-80% efficiency for batteries would affect how much electricity you must put into them (charge) to get the rated amp hours out. That is, it affects how many panels you need, but doesn't reduce the available amp hours for discharge.

However, if you're using an inverter to power 120vac stuff, then you need to factor in an efficiency of around 90% for a good sine-wave inverter, assuming optimal load. Inverters consume around 15-20 watts internally for a 1000-2000 watt model, so if you were only powering a 20 watt load the efficiency would be only 50%. So you don't want to run a big inverter 24/7, and if you want to power a clock-radio or something, better have it's own small inverter that would have a smaller residual consumption.

Also the battery amp hours would be reduced if you discharge faster than the 20 hour rate, so if you're running heavy loads, that needs to be factored in.

Yes, I believe you are correct. Thx for clarifying. In the end, it is best to either read and follow an authoritative book on solar installation or check with a pro, because there are lots of factors, and they vary somewhat by brand and model as well as latitude, season, mounting angle, etc.

RRV