recommendations for 12V / LED light / Dock project

latemr2

Hi - new to the forums!

I have a dock project here in the mid-west (lake of the Ozarks). The covered dock's roof is approx 20x25 with a small boat lift and swimming platform extending past the roof covered portion. There is a huge issue with the AC wiring supplied from the house. It needs to be completely overhauled or scrapped, it's dangerous! The present owners demand you cut off power, at the circuit breaker in the house, that feeds the dock, before you swim.

Instead of running 150 feet of buried conduit and wire, add ac fixtures, breakers, outlets, grounding, etc... I would like to use 12 Volt DC at the dock. It would be primarily used for lighting.

My current plan is to use around 100 feet of yellow LED rope light with a timer:
.53W per foot - leaning this way due to power consumption ( http://www.1000bulbs.com/product/1981/SIV-IFL75Y.html )
or
2.5W per foot - dimmable (http://www.1000bulbs.com/product/2038/SIV-IF75Y.html)

I plan on making my own reflector housings to squeeze as much light out of the rope as possible.

The dock lighting will not be used much. At the MOST, 3 nights a week for 4 - 5 hours. (mostly a weekend getaway retreat) Typically used for a couple hours on weekend nights.

There is a boat lift on the dock which can be addressed later as the small ski boat hasn't ran in years and is not a priority. I would like to factor in my battery size to accommodate a future 12V motor for the lift. Even with the boat running, the frequency of use for the lift would be once or twice on the weekend.

I would like to use one battery for ease of use but not opposed to using more. Storing it in a battery box on the dock somewhere. Unsure of what size and type. I would like to use one for the ease of hauling it in/out of the house every spring/fall when the dock will not be in use due to the winter months.

I would like to use a Solar panel to keep the battery power up but not sure on what size to use.

I am trying to avoid running AC to this dock as it would be expensive, time consuming, not really utilized much, ect... Using DC and solar just sounds like a lot easier and safer solution.

and recommendations, ideas, suggestions, improvements? Thanks in advance!

vtmaps

Re: recommendations for 12V / LED light / Dock project

latemr2 wrote: »

I am trying to avoid running AC to this dock as it would be expensive, time consuming, not really utilized much, ect... Using DC and solar just sounds like a lot easier and safer solution.

and recommendations, ideas, suggestions, improvements? Thanks in advance!

Welcome to the forum.

100 ft of 2.5 watt per ft rope draws 250 watts. If you run it for 5 hours that is 1250 watthours. On a 12 volt battery that is a bit over 100 amphours. You should try not to run the battery below 50% SOC (state of charge) so you need AT LEAST a 200 amphour battery. Probably a good choice would be two 6 volt golf cart batteries in series.

I have no idea how much energy the boat lift needs.

If you need an inverter for the lights (are they AC or DC?) you need to factor in an efficiency loss.

Now for charging the battery, you will need solar panels and a charge controller (CC). Not knowing your location, I don't know what sort of insolation you have. You will probably want about 400 watts of panel.

A 400 watt system is right on the threshold for recommending an MPPT CC with grid-tie panels over an PWM CC with 12 volt panels. Grid tie panels are cheaper per watt than 12 volt panels, but MPPT CC is more expensive than PWM CC.

--vtMaps

mike95490

Re: recommendations for 12V / LED light / Dock project

My suggestions:
Skip the rope light (pun un-intentional) and get a couple (or 4) of 50 LED Holiday Light strings (they should just now be coming on the market for the season) Each LED light string is about 5, maybe 10 watts. They will go all night for a couple of nights, on a cheap MSW inverter on a battery. even a 50w cig lighter inverter will drive a couple strings. They work great for camping and such.

A single Group 24 size deep cycle battery should last you a couple years, drag it back to the house once or twice a week to recharge. Or a 100W PV panel & small charger will keep it full.

When you get the boat working, and want the lift, use a 12V winch, and change your power to a pair of 6V golf cart batteries in series, and add another 100w panel for more charging. Use heavy gauge wire with hydraulic crimps to keep ohmic losses reasonable.

Options, get a cheap grid tie 200W panel and expensive MPPT charge controller, instead of 2, 100w panels & cheap controller. Price ends up being about the same.

Surfpath

Re: recommendations for 12V / LED light / Dock project

Welcome -I'm into creative lowpower DC lighting, so I'll give it a shot

LED is obviously the way to go. Your est. of 2.5 to .53 watts per foot is accurate, depending on the quality & quantity of the light. I've commonly seen & bought 15ft waterproof LED ribbon lights (warm white, 3000 or 5000 range chips) that consume ~ 22-26 watts per strip.

However, I think your 100 feet of light for a 20x25 recreational space is a little excessive and will only make your solar setup that more complex and expensive. Perhaps you really want to brighten up the dock though. But I still think you will be fine with less. I recently used just one 15-foot waterproof ribbon strip to provide ambient light for my 50'x11' porch (kill-a-watt meter: 24w).

My suggestion is to go with a dual system. Ie:
1) a fairly minimal (75w?) LED ribbon/rope setup for more gentle, indirect set of lights. You'll prob use these (90% of the time?) for most social events, family gatherings, etc. BTW I highly recommend looking for the best warm white LED and trying them out. I bought 4 examples of "warm" white LED GU10's for my house before picking the winner. Plus...

2) a pair of 12v flood lights (warm white again) for those occasional times you need more direct, but still pleasant, light for cleanup time, or put away dock gear time, or "where the heck are my rayban's" time. There is a highly rated & inexpensive 12v 10 watt water resistant LED flood on Amazon that I bought a few months ago [Chinese made - there are several sellers -Lenvo I think it's called). That thing puts out a tremendous amount of light for its size and has stood up to harsh conditions.

As per VtMapps, there are very different ways to power your needs. Cheapest: I've seen someone directly wire up their LED ribbon lights to a 12v battery, and use a 45 watt panel with a 5amp Morningstar Sunsaver charge controller. The lights may not last the longest, but the set-up's light on the wallet. It's prob best to factor in your proposed boat lift (power specs?) now. Perhaps it's not a big addition. I just googled up a solar kit lift on amazon that uses a 10 to 20 watt panel.

If the boat lift is not a big draw and if you adjust your lighting needs significantly I recommend something like the rugged suresine 300w inverter (low draw and even lower idle consumption), a relatively cheap (100 amp hr?) Sam's type battery, a 200 watt grid-tie panel, and a smallish MPPT controller like the Sunsaver).

Some quick math:
100amp hr battery (50% max dod) = 50 amp hr available or 600 watt hours available (should cover 5 hours using 75 watts)
200 Watts of panel at ~80% rating is ~ 160 Watts multiplied by, say, 4 hrs of decent sun means ~ 660 Watt hrs potential. In the case of a 12 Volt system this is a little over 50 Amp/hrs. It should feed a 100 Amp/hr battery (but then again are you using the lift frequently while charging?).

Perhaps a slightly larger panel & controller ($) is in order, but, again, I think you can do more with less in the case of this recreational lighting project.
Good luck, let us know how it goes.
SP.

Eric L

Re: recommendations for 12V / LED light / Dock project

There is a highly rated & inexpensive 12v 10 watt water resistant LED flood on Amazon that I bought a few months ago [Chinese made - there are several sellers -Lenvo I think it's called).

Not sure if this is the one you meant Surfpath, but I have one of these on my little 12 volt system and I agree it's an amazing flood light.

Surfpath

Re: recommendations for 12V / LED light / Dock project

Eric L wrote: »

Not sure if this is the one you meant Surfpath, but I have one of these on my little 12 volt system and I agree it's an amazing flood light.

Yes Eric, along those lines - chunky small solid build. Mine is off-white. The great thing about those LED floods is that they can take anything from 10v to 85v. Meaning line loss is potentially not as much an issue and, if necessary, they can interface with just about any (12/24/48v) DC system. They are not the 'warmest' of lights but they are very bright.

Latemr2 - jut gazed over my suggestions again, I think I gave you a sort of "econ," 'bang for your buck' recommendation. There are certainly more high tech and sophisticated ways to go.