solar system for shed

[Freeesun]

Ya I've read with a mppt you can change the voltage. But those are expensive cc

[SunEagle]

Ya I've read with a mppt you can change the voltage. But those are expensive cc

Why do people think that building an off grid solar/battery system would be inexpensive? Nothing is for free.

[Freeesun]

Lol I'm just surprised at the price of everything even when trying to do it cheap

[SunEagle]

Lol I'm just surprised at the price of everything even when trying to do it cheap

The problem is if you buy cheap you get cheap. Most of the lower cost equipment may not last half as long as the quality equipment. That is why comparing the price of a quality off grid system should always look at running power from the house. In the long run it may be a lot cheaper then a good CC and multiply battery purchase.

[Ampster]

Lol I'm just surprised at the price of everything even when trying to do it cheap

I am continually surprised at the cost of electricity in California. When I drive by a PG&E crew setting a pole I know they aren't even trying to do it cheap. Occasionally i see an independent contractor doing the same task with half the crew.

[Freeesun]

I think I'm going to pull the trigger on a renolgy 100watt 12v panel. It says the output is 5.29 so I'm guessing a 50ah battery would work well with it. I'm going to keep my pwm cc and I'll be pretty much done.

[Freeesun]

I know everyone think a mppt is much more effective than a pwm but there's a video on YouTube that shows that they are both very similar in there outputs when compared side by side.

for a pwm cc do you think a 50ah battery would be good or should it be lower

for a mppt I know a 50ah should be good but in recent post people have said to lower the batter ah even more if I have a pwm

should I just connect my panel to my cc and wait until mid day to see what my max amps I'm getting are and size my battery to that?

[SunEagle]

I know everyone think a mppt is much more effective than a pwm but there's a video on YouTube that shows that they are both very similar in there outputs when compared side by side.

for a pwm cc do you think a 50ah battery would be good or should it be lower

for a mppt I know a 50ah should be good but in recent post people have said to lower the batter ah even more if I have a pwm

should I just connect my panel to my cc and wait until mid day to see what my max amps I'm getting are and size my battery to that?

IMO a PWM CC works just fine with a 12v battery and about 200watts of panels. Once you go with more wattage or a higher battery voltage a MPPT starts to make sense.

My concern is your 50Ah system may be small for your actual needs. But you will find that out soon enough if your battery starts to lose it's ability to fully charge back up to 100%

[Freeesun]

I keep finding more and more products the more I look. I just found a eco worthy 12v panel that has 160watt. And so far that's the biggest single panel 12v system I can find. So I'll probably end up going with that one just so I can get a bigger battery next time.

if I get a 40ah battery and use 25% of it that's 10ah which would be good for 4 led lights at 9w 12v for little over 3 hours on a full charge. If I get a deep cycle golf cart battery next and get 50% that'll give me light for 6 hours

but I'm still going to get the 160watt panel and buy a good size battery next time.

ive said this a bunch of times in the forum but I believe that this is it now. Can't belive how much I've learned lol and probably pissed people off

[Ampster]

I know everyone think a mppt is much more effective than a pwm but there's a video on YouTube that shows that they are both very similar in there outputs when compared side by side.

..... and I am am sure there are YouTube videos that show how different they are. It all depends on where you are standing.

[SunEagle]

I keep finding more and more products the more I look. I just found a eco worthy 12v panel that has 160watt. And so far that's the biggest single panel 12v system I can find. So I'll probably end up going with that one just so I can get a bigger battery next time.

if I get a 40ah battery and use 25% of it that's 10ah which would be good for 4 led lights at 9w 12v for little over 3 hours on a full charge. If I get a deep cycle golf cart battery next and get 50% that'll give me light for 6 hours

but I'm still going to get the 160watt panel and buy a good size battery next time.

ive said this a bunch of times in the forum but I believe that this is it now. Can't belive how much I've learned lol and probably pissed people off

Sounds like you are on the right learning curve. I am trying to help people not waste their money like I did when I built a solar/battery system for my "shed".

It contains about 360 watts of panels (expensive 12v type), 4 x 50Ah 12v AGM batteries wired in parallel (that was stupid), a 30A PWM charger (which reduces my panel wattage charging to about 240watts) and a Xantrex 600w pure sine wave inverter (probably the smartest purchase). Add to that a cart, wiring, fusing, combiner box, grounding parts, panel supports, etc.

I spent about $2500 and can only get maybe 600watt hours out of it a day. Please do not follow my example.

[Freeesun]

It's honestly extremely easy to get into the thousands when playing with these systems. Even when trying to do it cheap when you all set and done it'll be from 500-1000 for me.

just curious why did you buy 4 batteries for a 12v system?

[SunEagle]

It's honestly extremely easy to get into the thousands when playing with these systems. Even when trying to do it cheap when you all set and done it'll be from 500-1000 for me.

just curious why did you buy 4 batteries for a 12v system?

As I indicated. I was just stupid at the time and thought I knew what to do. I did not realize multiple parallel wired batteries was the wrong direction. I wanted AGM because I wasn't sure if I would be moving the system around or not but they are heavy and not very portable.

When these 4 50Ah die I will replace them with 2 x 6V 225Ah FLA type batteries. It is still a small system but I found out that running a 20Amp U/G power line from my main panel will be much cheaper then replacing batteries and going with a MPPT type CC. Live and learn.

[Freeesun]

so i went out and bought a 150watt solar panel from canadian tire. its a little big but i think itll do the job. now i think i got it all figured out and just want to make sure.

the fuse from my solar panel to my cc im going to be using a 15amp fuse with a in line holder.
i have a fuse box that im connecting in between my panel and battery and ill be using a 15amp fuse in there also
my fuse from fuse box to battery will be 20amp because my cc is 20 amp but i think i could get away with a 15 amp as well since my panel is 150 divided by 12.

is this all correct? and also i see that my wire size should be around 14 gauge but the wire on the back of the panel is pretty big not sure what size but its thick. do you guys think its alright to go down to 14 gauge?

[Tecnodave]

Free sun,

normally we use 10 ga. Wire on the solar panels to minimize voltage drop. If your panels have MC-3 or MC-4 connectors the easiest way is to get a p.v. extension cable twice as long as your run from controller to panel and cut it in half so at your panel you have a waterproof plug in connection. There are several advertisers on Amazon who pre make these cables as the connectors are hard to crimp unless you have the required crimpers. Greener World Stores, and Wire and Cable Your Way come to mind as to the source of these pre made cables.