Small Cabin

# Posted: 25 Jul 2015 03:17pm - Edited by: MtnDon
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Quoting: HiLonesome

Do they need to be identical amp draw lights on any one circuit?

No.

Quoting: HiLonesome

I am only fusing the battery and the two outlets

The way you have the fuses positioned the wiring that goes to all the lights has no protection. Fuses are there to protect wiring from overcurrent events, not to protect the light or whatever. Fuses should be as close to the battery as possible, but not be exposed to any fumes/acid/gases from the battery. So I would place a main fuse near the battery but well before the buss bars. Then maybe a few fuses to break up the lights, etc into groups. The idea being to allow one branch fuse to pop but not plunge everything into darkness.

BlueSea has a large selection of blocks, fuses, etc.

Quoting: HiLonesome

parallel-wired (hence the bus bars, does that work?)

Except that buss bars are most often made to be either negative or positive, not both as illustrated. BlueSea Buss buss bars there are also other buss types.

BlueSea does make some dual buss bars but IMO, it is better to keep the positive and negatives separated whereever there may be danger of having one touch the other while aorking on it. (Yes, the power should be disconnected at the battery negative when working on a system, but that rule has been known to be broken.

# Posted: 25 Jul 2015 03:43pm
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Thanks MtnDon! I figured you would jump in on this one! I take your point on keeping + and - separated. Before I drew the diagram, I had purchased the BlueSea buss bars that are dual (- and + on the same bar), so I thought that was standard practice. I will add the fuses you suggest. With that many total fuses, sounds like a fuse block is the way to go. I should be ready to start the real world part--soldering, etc. Yet another learning curve, but that's half the fun!

# Posted: 25 Jul 2015 06:05pm - Edited by: MtnDon
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Quoting: HiLonesome

soldering, etc

Nothing wrong with soldering (unless performed poorly), but a good, ratcheting type, of terminal crimper makes quick, easy and dependable connections. Not the common $5 wire crimper tool available everywhere, but one with a ratchet and interchangable jaws if possible. The ratchet operation makes it impossible to under crimp the terminal.

Amazon has some. Ebay has many.

If you go that route make sure the tool is designed for the terminals to be used. IE, a terminal with an insulated collar requires a different tool than terminals with no insulated collar. That's where a tool with interchangable jaws comes in handy. There are kits available for 75 100 dollars. Last you a normal DIY lifetime and you'll always have a good connection. I wish I'd had one 40 years ago instead on only buying 10 years ago.

I would think about installing a disconnect at or near the battery negative. That makes disconnecting for safety easier than having to get a wrench out.

# Posted: 25 Jul 2015 06:13pm
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This one is very similar to what I have.

# Posted: 25 Jul 2015 06:28pm
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Ya I saw a youtube on the crimper tool...but they sure are proud of those things, compared to the walmart special. Spose a rental center would let me rent one for 5 minutes?

But cabins are like that, buy the tool that lasts a lifetime, the cheap tool, or hire it done. Hire it done usually=lifetimetool X 5, so that's pretty good math for the case you make.

# Posted: 25 Jul 2015 07:23pm
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Like Mtndon I'm a Big fan of BlueSea products for 12v stuff. Always surprising how they can be cheaper than the RV counter parts. If you really are going to use fewer lights than your diagram and it would be workable to co-locate switches, consider a combined switch fuze panel. May be easier to install although the look may not suit the cabin. Link below is an example only. Can't really search from my phone easily and the site is a Canadian store. Sitting here listening to the rain on the metal roof and watching the wind on the lake so not going to pull out the laptop.

panel

# Posted: 25 Jul 2015 08:14pm
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Yes the buss bars and cig lighter sockets I have already purchased for this project are BlueSea. I too like the marine stuff. Thanks for the link to that panel. Most of the lights I want are task lights with a switch on the base already built in, but not all of them, so I might well look at that panel option. For LED, is it better to buy LED fixtures/bulbs, or to buy a regular 110 fixture, and then get LED bulbs that will fit? Seems like I can't find styles I like just looking at RV type LED setups. Thanks

# Posted: 25 Jul 2015 08:24pm - Edited by: MtnDon
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Quoting: HiLonesome

regular 110 fixture, and then get LED bulbs that will fit?

I have not looked extensively but I doubt there is much choice in LED's that have medium screw bases and operate on 12VDC.

What sort of criteria must the lights meet?

# Posted: 25 Jul 2015 09:06pm - Edited by: razmichael
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Actually lots of them. Search eBay or aliexpress for E26 base 12v bulbs and you should come across many types, color, Temperature and wattages Price is generally the same as 120 or 220. Way back about 4 years ago I ordered a 10 pack of 60 watt equivalent bulbs - the type that look like regular bulbs not the corn lights. I don't remember the cost but about average for the day. Get good quality ones as they are not all made equal. I picked up a ten pack of 120AC bulbs at a great price last year for the house and at least 4 of them have died. The 12v ones at the cabin are all doing great. I still have them mounted in those cheap contractor fixtures until my wife picks some better fixtures. With the regular base the options are unlimited.

Whether to use regular light switches is another discussion due to the slight risk of arcing and then fusing closed. Not a concern with the older switches that had longer throws but the new quiet ones are riskier. I did use regular but 20amp switches so may need to replace them in 20 years - I can live with that.

# Posted: 25 Jul 2015 09:19pm
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Meant E27 base.
Here is an example from the same seller I used 3 years ago whats_up_sun(11570)
(price has gone up).

ebay

# Posted: 25 Jul 2015 09:28pm
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Thanks. Sounds like regular fixtures with LED bulbs would work. MtnDon: Just looking for task lights for counter, table and reading for bunk. Maybe a porch light. What I don't want are white plastic rv fixtures that seem to be standard. I am looking at these for example:

http://www.amazon.com/Green-LongLife-9090110-Reading-Fixture/dp/B00D21RRUK/ref=sr_1_1 ?ie=UTF8&qid=1437873982&sr=8-1&keywords=rv+reading+light+bronze&pebp=1437873988059&pe rid=14S008Z5NSYKPKAM6MXM

# Posted: 25 Jul 2015 09:38pm - Edited by: razmichael
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For under counter you might consider ribbon lights as most of these are actually 12v. Generally the kits include the 120 to 12 adapter which you don't need. I put together my bits and pieces from Lee Valley as you can custom build including a dimmer. Works great for under the counter. It can be important to use a matching dimmer as dimming LEDs is not as simple as regular bulbs. Cheap dimmers will not save power.

# Posted: 26 Jul 2015 10:34am - Edited by: MtnDon
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I found 30 cm led strips on ebay. 12 VDC Cheap. Very nice bright lighting for a work counter with cabinets like a kitchen. But you do need to do some wiring.

ebay led

davestreck
Member

# Posted: 26 Jul 2015 11:33am
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I bought these so I could use standard 120VAC fixtures with my 12v system.

# Posted: 26 Jul 2015 07:33pm
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OK here is my revised plan, accounting for your suggestions MtnDon. Battery is fused in and fused out on the hot wire. All sub-circuits come off a fuse block now. So I just add the amps for each fused circuit and get use a fuse that is a little bigger? Thanks!

Bunkie_Solar_Wiring_.jpg

# Posted: 26 Jul 2015 08:03pm
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Quoting: HiLonesome

a fuse that is a little bigger

Yes / No.

For what you are doing it should be okay to simply choose the next largest fuse.... The NEC looks at it slightly differently.

In short the NEC has you add up the loads in amps and multiply that by 1.25. Round that up to the next size.

So 5.5 amps total x 1.25 = 6.875
If you are using ATC fuses the next biggest would be 7.5
Of course the wire size must be sufficient as well.

Remember you are protecting the wire not the light.

One more comment... many charge controllers have a definite sequence for powering up. Usually the battery is connected first. Then the solar panel(s). For that reason many folks will insert a breaker like the Midnite Solar MNEPV on the input and the output sides of the CC. It just makes it easier as the MNEPV breakers can be used as a switch.

# Posted: 26 Jul 2015 10:51pm
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Many thanks MtnDon, I think I am in business

# Posted: 27 Jul 2015 07:18am
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Curious - for such a small system why not run your loads off the LOAD output on the controller rather than the battery? The Morningstar Sunsaver 10 can output up to 10 amps for lights and other smallish things and has the added benefit that it will shut down the loads automatically if you start to drain the battery (I have not checked the settings used by the controller).

At my place I use the the controller load circuit for things that I leave on when I shut down the rest of the system when away (security camera, motion sensor lights). This also provides low voltage protection to the batteries should something go wrong.

creeky
Member

# Posted: 27 Jul 2015 08:49am - Edited by: creeky
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i think razmichael makes a crucial point. use the controller for your power out source.

a simple automotive fuse box would allow for power distribution safely and easily.

the low amperage lights could easily be strung in a line as opposed to the diagram which shows each light going to the bus bar.

and, as MtnDon points out, you need a fuse (class T) at the batteries positive line out. as close to the battery as is feasible.

good luck.

LS1
Member

# Posted: 30 Jul 2015 06:32am
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I'm building a very similar system for my small cabin, renogy 100watt panel with their pwm 30w controller and a size 27 marine battery. I originally, like you thought a 12v system was the way to go, but after a while decided that adding a small fanless 120v inverter was a better solution for me. With 120v you can run regular old 14g romex, buy light bulbs at the grocery store if necessary and plug in any 120v appliances (radio, fan, etc., as long as they are under the wattage of the inverter). I believe the 120v system to be more cost effective (no 10g, busses, because of voltage loss) and easier to buy electrical components (switches, outlets, etc.). Cost and availability of 12v e27 bulbs, 12v fans, and such caused me to rethink the 12v setup.

# Posted: 30 Jul 2015 05:28pm
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To each his own...I am going with LED (higher cost no matter the system) and since it is such a small system, high efficiency (no inverter loss). I have an inverter I can plug into one of sockets if I need to, but right now I don't know what I would ever use it for. Mostly I just need minimal lighting; I won't have anything that creates heat. Of course one I try this for awhile, I may change my mind, and that's the beauty of building a bunkie before the cabin.

Creeky, by "strung in a line" for the lights do you mean wired in series? Also I didn't see a "type T" fuse any less than 225 volt in my initial search, is that size what you are talking about? There is conflicting info all over the web on solar wiring, particular on fuses and switches. Most little systems seem to have no fuses at all, but of course that does not make them safe!

Thanks to all.

creeky
Member

# Posted: 30 Jul 2015 06:52pm
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It is just to be safe

Your looking for a "class t" fuse. I was adding on to what MtnDon had already said. Your diagram shows the fuse before the battery and while a disconnect there is an excellent idea. It doesn't protect you or your system.

ignore the voltage. it's the amps you want to size for. I'm assuming your marine battery is around 100 amps?

http://www.automationdirect.com/static/specs/efuset.pdf

gives you some sizing and other info. a 300v 1-200 amp fuse would do it. You know. Probably 20 bucks to be safe. Not bad.

A short circuit turns your battery into an arc welder. So fusing your positive line off the battery is what most folks do as it ensures the battery doesn't discharge so rapidly as to burn things down.

"Strung in a line" can be wired in series or parallel. Are you putting switches on each light or one switch per bank of lights? Just trying to save you some wiring. Depending on your setup if you send wire back to a bus bar for each light that's more wire than if you put them in a parallel or series string.

And you could probably lose the two bus bars altogether.

Normally you'd go parallel but with led lights i doubt the draw would be so heavy as to dim the lights. you know. 4 8w bulbs ain't the same draw as 4 x 60w.

There are lots of good pics online for wiring a string of lights in parallel or series.

It'll be a nice system. Oh, and. as LS1 points out. A small pure sine inverter does up the cost. But you may find the system more flexible / useful / cheaper in the long run. (It can always be your first add on.)