Solar Power Generator

I am not saying that is the best way to do it. Personally I use "12 volt panels" on mppt chargers with 12 volt battery systems.
Even with the top end of the voltage range Morningstar and Midnight still claim around 90% efficiency.

Actually if for some reason you had to have a longer distance between your solar panels and battery then you would want to use higher voltage. Another reason might be to tap into a preexisting grid tied setup, that normally operate at 48 volts and higher. that is the only situation I can think of besides getting free or almost free 48v panels and you have a 12v system where you would run panel voltage substantially higher than charging voltage.

 

i have 2 battery systems
One in the shop trailer, and one at the house .
The shop trailer bank is driving an inverter the provides AC power via 100' extension #12 cord to the house and a battery charger on that bank .
If I need AC power in the house, I can add another inverter on that bank as needed. (I still use city power for high demand appliances/equipment )
Transmission over any significant distance is best done at High voltage .
That was the simplest way I could do it .
I do have a third leg which is 6 volt for LED lighting through out the house.
My batteries ar all Golf cart 6 volt deep cycle , so I can configure the system in any fashion I need, in 6 volt graduations.
Don't forgive the mess , it something I'm working on.but this is my shop trailer , the mast you see at the left font corner is my wind mill. There are other solar panels off it's front of varying sizes ,
My amp meters inside show me how each one is doing through switches on each component.

 

I have a cheap and dirty Harbor Freight 45 watt system that I bought for $139 on sale and a Tractor Supply deep draw battery. Comes with panels, charge controller and a couple of 12 v flouresent lights and I use it in the greenhouse for lights, charging a 12 v battery for my sprayer and back up water pumps. Have used a good converter to power my laptop from the 12 v battery. They are on sale this week or so for $119. Are they good, no, are they super efficient, no, will they power you house, no, but it is a good cheap way to get your feet wet, are very handy for emergency lighting, are a small complete package to put in a faraday cage, and all the car-rtv 12 volt stuff will run off the battery. I have 400 watts of solar, with a good controller, deep charge batteries, good converters, etc, but 95 % of my use has been the cheap 12 v system. Use in the greenhouse, use it to keep my tractor, lawn mower batterys charged, use a battery to recharge power tool battery, etc. Could do the same thing with a 100 to 200 watt panel to make a small very handy solar power system that is easily moved.

 

The nice thing about solar power, or any DC power for that matter for charging batteries is that the only value one need concern them self is the voltage of the charging media is greater then their battery voltage . Every single panel can be a different brand and watt out put .
All make a contribution.
Most every panel is of a different age and make and model ,so by watching the amp meter as I switch on each panel, I can see it's contribution . Each switch is a 3 position center off. The little 3 amp meter is used for testing individuals.
A while back panel #3 finally was no longer making any reasonable contribution, so I replaced it . it was an 50 year old ARCO the resin on the face is yellowing and reducing the effectiveness of the panel.
I can check the battery bank in the same way and switch out a bank that is failing ,till I can deal with it properly .
One important thing about solar panels is that when they are not making power they are drawing power , do it is important to have a diode in line to prevent this loss .
The diode is matched up to the rated amp out put of the panel . A diode allows the energy to travel in only one direction.
If you need a 3 amp diode and only have access to one amp diodes, bundle three one amp diodes together parallel . one can make things far more complicated but I don't find it necessary for the gains and losses involved.

 

Actually you need to also be concerned about charge rate if you care about the batteries lasting a long time.
Normal charge rate for a flooded lead acid deep cycle bank is 13% of the 20C rate.