need advice on new system

System

Hi everyone, great site to bad i found it after i bought the system... hope someone can help,here's what i have I own a remote cottage that is water access only 15 minute boat ride, the place was builtin 1939, no hydro no water,lights stove and fridge are propane and seem to work fine. I wanted to add some power to supply lights ,tv and for toilet system that needs 12v for a fan. This is what i had bought 120w solar panel,30a charge controller and 4 6volt batteries for a golf cart(the only rating i got from batteries was 175@90amps) the batteries are hooked up in a series parrellel to acheive 12v, I used 2/0 tohook up batteries together, I also have 1750w inverter. the batteries are 20ft from panel wondering what you think about wire size for panel and I was possibly thinking of adding one more panel this year how would i do this....I hope to add more panels every few years. I wish i found the site earlier but thats history now. any remarks would be greatly appreciated thanks frank1 ( I use the cottage for 3or4 days every other week)

rplarry

Re: need advice on new system

Frank
It sounds like you are on the right track, your system sounds very much like mine when I started. I'm going to assume that your charge controller is not an MPPT charge controller and that it does not have capability of being wired as 24v in from the panels and 12v out to the batteries. If this is the case then your system is pretty simple. To add panels in the future just wire them in as you did the first panel, ie positive panel to positive on charge controller. The size wire to use is determined by the length of the run and the amps that will be used in the wire. You can mount a combiner box near your pv array and run the wires from the panels to the box and then run one larger wire from the box down to the controller, or you can run individual wires from each panel down to the controller. Either way you do it you just need to use large enough wire to get the amps to the controller with the least amount of loss. There is a really good program on this site that Niel put on here to help figure wire size. Should be easy to find. Hjope this helps,
Larry

System2

Re: need advice on new system

Hi larry thanks for the reply, I was also wondering if i can use 12v marine charger to charge up system, and would i need a switch to disconnect pv from system when charging. I was reading another post talking about how you take loads off batteries(bank) does this matter? thanks guys for the help in advance...frank

rplarry

Re: need advice on new system

Frank
Yes you can use a marine charger, and you do not have to disconnect the PV's. Both can charge the bateries at the same time. It is also not necessary to disconnect the DC loads, but having a load on at the same time you are charging will just lessen the charge amps and so it will take longer to charge your battery bank. If the loads are too great then you battery bank will not come up to the proper voltage. If possible you should have as few loads on as you can while charging. One of the mistakes I made when I was putting my system together was buying a cheap automotive charger. They really don't work well in a solar application. If I was to do it over again I would buy a good charger in the beginning and save all the money I spent on the stuff that does not work well. You're going to want a charger that allows you to set the Bulk, absorb, and float voltages and also has an equalize setting. I found that some of the best deals were the chargers that are built into inverters, such as the Outback and Xantrex inverters. You get a really good inverter and charger built into one.
HTH
Larry

Frank

Re: need advice on new system

This sounds a LOT like a family cottage we have: on an island and 3.5 mile boatride (after 10 miles on logging roads). Your system sounds like ours. Wire size seems fine; we ended up replacing our propane fridge with a Sunfrost when it stopped working and have no issues. You might find it helpful to use compact fluorescent bulbs if you don't already have them as they use a lot less juice. The original batteries in our system lasted ~5 years. Watch for trees shading your panel(s). Our system has a generator but we don't need it anymore (run it once/year to keep it exercised - use Stabil in the gas). It's nice not having to listen to the noise.