Small Solar System

Posted by John B on September 09, 2008, 05:25:39 PM

Patrick,

All of your negatives should be grounded.

The charge controller has the ability to turn your panels off if the batteries are full. However, there should be a breaker or fuse on the output of the solar panels going into the charge controller.

Posted by Patrick Guenette on September 10, 2008, 09:51:32 AM

Re: Small Solar System (Reply #21)

The company told me the solar panels had internal fuses for that. (So good for safety I guess, but if the fuse ever goes off, guess my panels are garbage as there's no access to the insides).

So if I run a ground wire from the negative terminal of one of the batteries to the earth, that should be ok? - Won't slowly drain power from the battery?

The batteries are hooked up to the inverter, with 4 gauge car battery cable (36 inches long), and the inverter itself had a ground port (which I grounded, about 24" into the earth).

So if I put a 200amp breaker one the positive cable from the battery to the inverter, and a ground from the negative cable, that should be good?

System is up and runs fine now (had 7.5 amps @12v generated in full sun yesterday afternoon), just want to make sure it's safe.

Called at least 5 electricians yesterday, and none of them wanted to come over to setup my system. All said they don't do those types of jobs..too "small" for them lol

Thanks,
Patrick

Posted by John B on September 10, 2008, 11:05:06 AM

Re: Small Solar System (Reply #22)

Patrick,

It wouldn't hurt to run 3 feet of ground wire (the same size that you used from the inverter to the ground rod) from the inverter's ground to the negative terminal of the battery.

This will not drain your battery. In fact, your battery is probably grounded already through the inverter. To test this, put your voltmeter across the battery terminals and then move the negative lead of the meter to the ground of your inverter and you should read the same voltage.

Glad to hear that you are up and running, but 7.5A @ 12V is only 90 watts which is not so good if you consider that you paid for 150 watts of power. It might be due to bad connections on some of the panels since your are tying ten of them together, but more than likely it is just the tolerance on a 15 watt panel where they wouldn't give you the same guarantee as you would get with a larger panel.

John

Posted by Patrick Guenette on September 10, 2008, 11:17:00 AM

Re: Small Solar System (Reply #23)

Thanks, I will do that for the ground.

So the fuse/breaker should go on the positive battery cable right? I just cut the cable and strip the shielding and install the breaker in between right?

Since the batteries are in parallel, doesn't matter which positive cable I use right?

Thanks again for your help, and yes now that I have my first "test" array up and running, I'll be looking to buy real panels.

Is this a good panel?:

http://store.altenergystore.com/Solar-Panels/150-Watts-Up-Solar-Panels/GEPVp-200-200W-18V-Solar-Panel/p3843/

5 of these would give me 1kw right?

Thanks,
Patrick

Posted by John B on September 10, 2008, 11:57:18 AM

Re: Small Solar System (Reply #24)

Patrick,

In this field every question will lead to another and you never stop learning.

A 200 watt panel is generally much larger and heavier than a 100 watt panel, so where it will be mounted is one consideration. Will you be mounting the panels on your own, or will you have assistance? Is your roof steep or high? Do you feel comfortable taking a 40lb panel up onto the roof by yourself? etc. etc. etc.

Generally speaking, I would look for someone who had similar panels in a similar location. IE. same latitude, as some panels work better in hot climates than others.

I have Evergreen 120 watt "B" panels. The "B" indicates that they have blemishes but the same power output and the manufacturer will generally sell them for ten or fifteen percent less than the regular price.

Once you start increasing the power then voltage is also a consideration. I have a 48V system which means that a single Outback MX60 Charge Controller can accommodate 3200 watts of solar panels. If I had a 12V inverter then I would need four MX60 Charge Controllers for the same system.

Will your system be grid-tied or stand-alone? Will you want battery back-up? Answers to both of those questions can affect the decision on which PV panel and/or inverter you go with.

John

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