solar hokup help needed

[cedric]

Hi everyone<br />I just bought these solar panels from amazon. 2-pack 140watt panels<br /><br />http://www.amazon.com/gp/product/B007VPQP5Q/ref=ox_sc_act_title_1?ie=UTF8&amp;smid=A21XZF4K65PP5Y<br /><br />I need advice on the connectors and which controller to buy that would give me the best bang for the buck. I will be charging three 105ah deep cycle batteries from wallyworld.<br /><br />I have a small Toyota classC RV that I will mount these on.<br />I need to find out what kind of charge system is in the RV. I am not sure how to investigate this. The rv has one house battery in the back at 105ah.<br />I don't know if it charges only when the AC 120v is plugged in from my house or if it also charges from the alternattor also.<br /><br />Any advise or direction would be appreciated.<br /><br />thanks

 

[SoulRaven]

with two panels the easiest way to connect them is via a junction box... ya run the + and - lines of both into the junction box per instructions (very simple)... Then run the lines from the junction box to your controller... Do not forget to use marine grade wire for all outside wiring...<br /><br />By using a junction box you dont need special connecters...<br /><br />As for a charge controller you will need an MPPT controller, myself and many use the BZ line of controllers... I can say they are the best in answering with a human tech every time and have a very quality product and warranty... You will need the BZ500 model due to wattage/voltage of the panels...<br /><br />http://www.bzproducts.net/id2.html

 

[peacetara]

Hi Cedric.<br /><br />This is a VERY simple layout diagram, to give you an idea.<br /><br />You will want to follow Soulraven's advice for what to get solar controller wise, and junction box wise.<br /><br />This assumes:<br />&nbsp; 1) All of your 3 batteries are 12 Volt batteries.<br />&nbsp; 2) all the red in the picture is + (positive)<br />&nbsp; 3) all the black in the picture is - (negative)<br />&nbsp; 4) All the purple are things you have to buy/get and connect together.<br />&nbsp; 5) the Green are special weird things you have to do, to make it all work safely.<br /><br />The picture should be pretty self explanatory.&nbsp; You are connecting the 3 batteries up in 'Parallel', which means the voltage (12V) doesn't change, and in essence you are making 1 large 315 amp hour 12V battery, all the + or positive are wired together, and all the - (negative) are wired together.<br /><br />You can also install fuses on the other side (where the 12V lighter plug and inverter are, lots of 12V lighter plug style things have fuses built into them, so you are probably ok, but it never hurts <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br /><br />Anyways, I hope this picture helps you imagine how everything lays out.<br /><br />With Love,<br />Tara

 

[cedric]

WOW<br />thanks so much for the information and especially the diagram!<br />I think I get all the hookup details except what size wire to use.<br />I know the battery connections are usually very large but what about the wires from the junction/connector box?<br />thanks again for the advice<br />cedric

 

[peacetara]

The wire from the Solar Panels to the junction box, you will want to get from your Solar Panel people.&nbsp; Chances are it's a MC3 or MC4 connector, so you will want to get outdoor/marine grade cable from them.&nbsp; Since you only need the connectors on 1 end (since inside the junction box, you will just use bare wire screwed into their holders) you can probably get away with 2 'extension' cords for the solar panels, and then cut them in half (so make sure you get them 2x longer than you need).&nbsp; They will be a heavy duty rubber cable I bet, as that is what mine are.<br /><br /><a id="tinymce" class="mceContentBody " dir="ltr" href="http://www.freesunpower.com/wire_calc.php">here is a calculator</a> to help you. This one errs on the side of caution, which is always a plus, and recommends a little bit bigger wire than you would absolutely require, but that's not a bad thing!&nbsp; It depends on the amperage, the voltage and the length, which is why you want to use something like the calculator above. Well it actually depends on a bunch of technical grossness, but let's skip over those insane details, yes? <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle">&nbsp; Since the junction box would be inside, you don't have to have heavy duty, outdoor rated cable, from the junction box to solar charge controller which is nice.&nbsp; Basically the shorter the cable, the smaller (and cheaper) it can be.<br /><br />Make sure the junction box you buy can handle that size wire (they will have a AWG rating, and will have an amperage rating).&nbsp; I'm by no means an electrical expert, everything I learned is from working at an electrical supply shop thru HS and sucking the knowledge out of everyone that worked there, and then became a sales person for them, helping people with their electrical confusions.&nbsp; I haven't done that for many years, but I learned a LOT!<br /><br />Anyways, good luck!<br /><span id="tinymce" class="mceContentBody " dir="ltr"></span>

 

[peacetara]

P.S. the cheapest way to buy wire, is not at Lowe's or Walmart, but to go to an electrical wholesaler or electrical supply house and ask them to cut it for you. They almost always sell to the public, and are usually very knowledgeable, will have all sorts of cable in stock, and have pretty much everything you need I bet.&nbsp; The options at walmart/Lowe's/Home Depot/ etc are very limited.&nbsp; They may not have the MC3/MC4 cables tho.

 

[cedric]

new update: I cancelled the order for the two solar panels. I think I bit off more than I wanted so I cancelled the order before it shipped. I also measured on my roof and found that two panels that size would fit on one side but it might make it difficult to get at everything up there that may need seal maintenance. I am looking at this panel from Grape <br /><br />http://www.amazon.com/Grape-Solar-G...348938081&amp;sr=8-2&amp;keywords=grape+solar<br /><span>10 year limited power warranty on power output</span><span>Panel Dimensions: 40.8-inches x 20.7-inches x 1.38-inches, weighs 16.3-pounds<br /></span><span>High cell efficiency PV solar panel with quality silicon material for long term output stability and reliability.<br /></span><span>Rigorous quality control to meet the highest international standards<br /></span><span>32 back-contact monocrystalline Si solar cells (approx. 20%)</span><div class="content" style="margin-left: 15px;">&nbsp;</div><br />I still would like to buy the mppt controller type. I have seen a few in the $150 range that also include a 400 watt inverter. Similar to this one. <br /><br />http://www.amazon.com/HQRP-Inverter...13&amp;keywords=hqrp+mppt+controller+inverter<br /><br />Will this work in an rv system? I'm sorry I am usually very tech savvy but it seems the more I read about solar systems the less I understand.

 

[SoulRaven]

Solar will work on anything from barns to goat powered carts, they are a system that has nothing to do with their application but provide power via the sun for you to use... As for cabling, this will depend on the voltage coming out of the solar panel(s), the higher the voltage, the lower the amps and thus a smaller gauge wire can be used... The MPPT controller takes the higher voltage and converts it to 12V, this then increases the amperage into the battery from the controller... This is the formula to use W/V=A, W will stay constant, so the variables will equally be between the A and V... As the V rise the Amps decrease equally and visa verse... It is very simple, and in keeping it simple is the key dont over think things...

 

[peacetara]

I'm with @soulraven. But if you don't feel comfortable, that's fine.&nbsp; I think the Winter RTR in January there is a solar panel class.&nbsp; The other option is, try to find one of us near to you, and see if we can help, or pay someone to do it for you.<br /><br />It seems kinda complicated, but it isn't that bad.<br /><br id="tinymce" class="mceContentBody " />With Love,<br />Tara