Upgraded HF charge controller

[oztrich]

Hello!  Great discussion board.  Beginner (with a capital B) here.  Apparently, I slept through the electricity chapters in school.  But, I want to learn now, and have checked out numerous library books and read lots of websites.  Still, questions remain unanswered.  Please forgive the long post...

We have a remote weekend cabin we want to get some off-grid power to.  We're in the 'gathering parts and pieces' stage.  Not much power is necessary, mainly to run a fan, a small tv to watch the news and a light or two.  We've been hauling one battery back and forth to use and bring it back home to charge it up.  This is getting old!  

I've bought the Harbor Freight 45w solar panel set. I have 2 deep cycle (used) telco 12v 100a/h batteries that I will wire parallel. I've bought a Morningstar SunSaver 10L charge controller to replace the HF controller, due to the HF controller not having a diode, since we won't be around to unhook the batteries when the sun goes down.  I also have a 500w/1000w inverter that will be in the cabin.  We're going to build a shed to hold the batteries and (eventually) a generator, but mainly to mount the solar panels on, the cabin gets a fair amount of shade on the rooftop.  The shed will be approx. 15-25' away from the cabin.  The present panel wire connectors do not fit into the wiring slots for the new Morningstar controller, so I need new connectors (wire-ends).  The space for the wire connections to the controller are rather small.  What kind/where can I find end-connectors that are small, for the bigger wire?  I've been told that the wiring should be 10-2 stranded copper.  I'm fairly certain this wire will require some sort of end connector also, to connect it to the controller to the batteries.  Then there's the wire that needs to be connected to run from the shed (batteries) to the cabin.  This will need to run underground.  The person at Home Depot said I could use INDOOR 10-2 wire, but just run it thru conduit.  I'm not sure about that. I guess my main confusion is that I'm finding lots of info on how to do this...but not HOW to do this!  Can someone please point me to a book or website that is a bit more granular (pictures are good!) as to the actual physical connections of these components?

I've always been fascinated with AE, and this is the first opportunity I've had to try to apply it, any and all help is appreciated!

[willib]

welcome oztrich

 first off the solar panels 'should' ? have the diode built in to them.

i'm not sure if they actually DO or not , but they should.

[henjulfox]

Oztrich,

Welcome!

Time for a trip to Lowes, Home Depot, or whatever home improvement store you have in your neck of the woods. They should have everything you need.

To connect panels to the controller what you want are Fork Terminal connectors. They are color coded by wire size, I believe 10 gauge is Yellow. The connectors to the battery will be Ring Terminal connectors. Each typically come packaged 6 or 8 together for a buck or so. Last I checked they also sold kits of a hundred or so various connectors plus a crimper for $10 or so. Might be worth it for the next project.

To use them you strip a little insulation from the end of the wire, slide it in the end of the connector, and crimp it down. I use pliers, squeezing for all I'm worth. Test by pulling - you should not be able to pull it off.

Good luck,

-Henry

[Volvo farmer]

Welcome to the forum!

From what I can gather, you want to put the panels and the batteries in the shed, then run DC 25 feet to the inverter inside the cabin? 10 AWG is not nearly big enough for this application.

Here's a link to a voltage drop calculator.

http://www.currentsolutions.com/knowledge/vdrop.htm

500W at 12V is about 40A. Ideally, you want to keep the voltage drop at 2% or less. This would require #2/0 or even #4/0 AWG between the shed and the cabin. These wires are about as big around as your thumb and are very expensive per foot.

If you only have AC loads in the cabin, I would recommend keeping the inverter in the shed and running an AC line to the cabin, 10 AWG would be sufficient for 500W at 120VAC at 25 feet, and you don't need stranded. Alternatively, you could put the batteries and the inverter in the cabin and run 10AWG from the panels 25 feet away. In all RE systems, you want the batteries and the inverter as close together as possible.

As for connectors, aren't those Sunsavers wired with screw terminals? Don't you just put a piece of bare wire in there and tighten the screw? Seems like you'd just cut whatever connectors are on the wires off, strip the wire back and go. The manual says up to 10AWG will fit into those terminals.

I've installed some conduit lately. It's a pain. For a little project like yours. I'd get regular old 10-3 direct burial and put in a shallow trench. Code requires it to be 18" or 24" deep but perhaps there's no electrical inspectors with tape measures crawling around at your cabin.

[ghurd]

I too would use direct burial wire, and move the batteries into the cabin.

I would use "12-2 w/g sunlight resistant UF-B" for a few reasons. Its big enough, its a lot cheaper, water-proof compression conectors are available at Lowe's & Home Depot, it fits nice in a SS-10 without a connector.

A small tube of "Ox-Gaurd" (sp?) is next, its some goop to protect the exposed wire from corrosion.

I like to solder all connections except to the SS-10, then Ox-Gaurd.  Goop the end of the wire going into the SS-10.

I won't use crimp connectors because of corrosion, unless I solder them to the wire.

Its a simple operation. Make sure the electricial connections are sound. Use big wire for the inverter. Those Red & Green felt battery terminal washers from the auto parts stores are great.

G-

[oztrich]

You guys are FANTASTIC! The muddy waters are indeed clearing!

Aside from the cabin being extremely tiny, we wanted to keep the batteries away from the cabin for safety reasons. At some point, I may end up going to flooded batteries, which would off-gas more during charging and we didn't want that inside the cabin.  Worse case scenario, if something goes awry (battery explodes!), it would be somewhat isolated.  Am I being overly cautious?  Placement of the inverter was pondered, but not extensively.  I forgot about the voltage drop for DC runs vs. AC runs.

I could build a small lean-to off the side of the cabin to hold the batteries, putting the inverter inside the cabin on the adjoining wall.  This location is also shady most of the day, so it may be a better (cooler) environment for the batteries.  If I do that, I'll have an empty shed under the solar panels...maybe just a frame (pole) mount for the panels would be better.  But then again, you never can have too much storage space!  

I read that the HF controller should be disconnected from the panels after sundown, I'm not sure if the panels themselves have the diode or not.  I also read several people somewhat complaining about the buzz/beep it makes, plus the quality of that controller doesn't get very good ratings either. I decided to go with the popular recommended upgrade to the Morningstar.

Terminal connectors (how simple!) are the hint that I needed, I appreciate all the answers.  I wasn't sure if the 10-2 wire would fit directly on the screw terminals.  It looks pretty big at the store, but I haven't bought it yet because I wanted to make sure I got the correct size/type.  I'll look at the 12-2 and 10-3 wire today.  

Thank you for the opinions/suggestions/comments.  You've all been a great help!

Kelly

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"I'm trying to look at the trees, but the forest keeps getting in the way!"