Ask an Expert

Q:On the Uni-Solar brand panels, what is the difference between the "top mount" and "bottom mount" panels? Besides price, of course.

A:

Uni-Solar makes thin film solar panels. As part of its thin film PV products, Uni-Solar makes "bottom mount" and "top mount" flexible and lightweight solar modules. The bottom mount panels are a smaller production run - hence a bit more expensive. Bottom mount panels are unusual but are made to address situations when the top mount connections cannot be used. In a bottom mount scenario, the MC connectors are accessed from underneath the panel instead of on top. The ideal setting for using these solar modules (bottom mount or top mount) is on metal seam roofs. As flexible "peel and stick" solar panels, these solar modules are heat tolerant and virtually unbreakable.

04-09-2010 by john Category: Solar Panels

Q:I was looking at solar panels here on this site and I noticed that the 60 watt Kaneka panels are very reasonably priced and have a voltage of 67 volts. This seems like it would be perfect for use with a Grundfos SQ Flex well pump. I ws thinking 3 of these panels for 180 watts would be cheaper than two 85 watt regular 12 volt panels. Any comments on this? Suggestions?

A: 

The Grundfos solar water pumps are 24VDC and will function above 129 watts from a solar array with a nominal voltage over 30V.  If you used the Kaneka 60 Watt solar panels you would need three panels to get above the requisite 129W. If you used 12V solar modules, you would need to use three panels as well to get the required nominal voltage. Another thing to consider is how far you need to pump at what volumes and to what head. If you have significant requirements, you may want or need to have more wattage. Perhaps the best thing for you to do would to buy two 24V nominal panels like the 200W Canadian Solar Module.  We would be glad to help you select a pump and pair solar modules to go along with it to meet your pumping requirements.

03-31-2010 by Bob A Category: Solar Water Pumps

Q:We have a pontoon with an inverter/charger on board for the microwave, tv, and refrigerator. What would I need to hook a solar panel up to that. and is it hard to do?

A:

If you already have a power inverter and a charge controller for your battery bank on board your pontoon, hooking solar modules into it would be a relatively simple process, and most likely an installation you could do yourself. Basically you would need to calculate your power consumption to size the solar modules to meet the energy load and battery bank requirements. Once that is determined you would select adequate solar modules, mounting, wiring, and a small combiner should be all that you would need.

03-31-2010 by aleta m Category: RV and Marine

Q:I keep a car in Vermont at my condo, and want to install a trickle charger for the battery because the battery keeps dying on me due to lack of use. The car is in one of those self-storage units and it doesn't have electricity and I'm thinking that I could power the trickle charge with a solar panel. Is that possible? My idea would be to put a small panel on the roof of the storage unit and run a cord from there to the car, a distance of probably 30 feet.

A:

A solar trickle charger may be a good solution for you. We sell most of these trickle chargers in connection with a boat or a recreational vehcile, but it will work for you as well. A solar trickle charger such as the Sunsei 22W charger will provide a consistent charge to your battery when you are away. The solar panel itself includes connectors and a blocking diode to prevent back drain from the battery through the panel at night.

The system you are looking at operates off of AC power and would require unnecessary equipment for your desired use. How long do you leave your car between uses? If it is less than 2 weeks and your car and the battery is dead, you may have bad battery cells and simply require a new battery. Another option is to simply disconnect the red battery lead while it is in storage. This will prevent the circuit from being closed, which is what drains the battery over long periods of no use. The clock and radio have a small draw that will eventually drain the battery but it will take 2 months. The solar trickle charger will prevent this for long periods of storage.

03-19-2010 by Brad Category: Solar Electronics

Q:i have a 30' trailer how many panels do i need to power up all .Also what kind ?

A:

Thank you for your inquiry regarding solar panels required for your 30' trailer, The number and type of solar panels for a recreational vehicle depends on your intended usage and anticipated energy consumption.  SolarTown generally recommends a pre-packaged solar RV kit. Generally to recharge the batteries from using inside lights and small appliances a 80 watt solar panel for a RV will suffice. If you take a look at the specifications for a 80 watt solar RV kit, you can click on the  RV and Boat usage calculator to help you determine your average consumption. You can use that calculator to determine what wattage you will need for your solar RV kit. We'd be happy to help you through this process.

03-18-2010 by mono m Category: RV and Marine

Q:I have a fifth wheel trailer that I want to add two solar panels to. The Solar panel I am looking at use an MC4 connection. The connectors are available, the crimping tool that is required is $300-$600--quite prohibitive given I have only 8 or so connections, Do you know any way around this problem of crimping the conectiion with a factory crimper? I don't have a connector to look at so I am guessing as to how they actually crimp.

A:

If your panels have MC4 locking connectors, a crimping tool probably is not necessary. This is the type of connector sold on a majority of solar panels these days. If it is a non-locking connector, then our only recommendation is to rent the tool or borrow one from an solar installer.

03-18-2010 by Gene K Category: Solar Panels

Q:We have a 30' motorhome. What size wattage panel(s)do we need?

A:

Regarding the solar panels required for your motor home, the wattage depends on your intended usage and anticipated energy consumption, rather than specifically how large your RV is.  We would recommend one of our pre-packaged solar RV kits. To recharge the batteries from using inside lights and small appliances, generally an 80 watt solar panel will suffice for your RV home. You can click here then click the ‘Specs and Features' tab  to download our RV-Boat Usage Calculator to help you determine your average consumption, and size the panels accordingly. We'd be happy to help you through this process.

03-11-2010 by Gary W Category: RV and Marine

Q:Is there a consolidated source of Loans (green energy loans) that residents can use to help offset the cost of a system. I understand incentives, but they only help about 40-45 percent. I still need to come up with 37K of which I will get back another 5 k next year in taxes....all other incentives my installer will float for 12 monthes. But I am still on the line for 37K

A:

The high upfront costs is the major conundrum facing the homeowner who wants to go solar. You are right that these costs are the major impediment to growth in the residential solar market. Most homeowners will obtain a traditional home equity loan or HELOC. 

Don't let the financing blues get you down. Help is on the way.There are some new mechanisms that are available in a growing number of places around the country. Check to see if your city or county offers PACE financing. And in some states there are new solar leasing programs.

02-27-2010 by Anthony Category: Solar Panels

Q:I am working with human aid projects. I have got a question from Tanzania. They have an old 12V-freezer SANTOS SOLAR 165. I think it is like your SunDanzer 165. Question: How many 50Watt solar panels is needed to run this fridge without disturbance and what battery is needed. 

A:

There are several factors that will influence how many watts you will need to run a solar refrigerator or solar freezer. The two most important factors are the ambient air temperature and number of sunlight hours per day. In general, solar refrigerators or solar freezers require anywhere between 50-100 watts. Thus, you would need one or two 50 watt panels for your solar refrigerator or freezer to run properly. The variables outlined above would dictate the size of the battery required, but a 12V battery with 50-100 hours should provide enough reserve power for 2-3 days. We get many requests for help in designing these kinds of solar energy systems for developing countries where electricity is not readily available. And a solar freezer or fridge is an excellent solution. We would be happy design you design your system. 

02-24-2010 by Ulf E Category: Solar Outdoors

Q:What are the differences between the the various solar panel connectors and how are they chosen?

A:

Module connectors are typically connected together with external, exposed connectors. Most solar modules sold today come with MC connectors on the back of the module - MC for 'multi contact'.

There are 2 different types of MC connectors. Older connections were commonly MC Solarline 1, which is a non-locking connection. MC Solarline 2 is slightly different in that it is labeled 'DO NOT DISCONNECT UNDER LOAD', and offers a tab-and-slot mechanism to lock the connection more securely. MC2 connectors can be unlocked by hand, although there is an additional sleeve offered for MC2 connectors that requires an unlocking tool in order to separate the connection. The extra sleeve technically makes this a 3rd type of connector, although it is essentially an MC2 connection.

The primary requirement of all solar connectors is that they meet the NEC Code, specifically article 690.33.

01-08-2010 by Larry L Category: Solar Panels