Wiring Lighting w/ Series or Not?

[cvick]

Hello guys, I just joined this forum for advice and guidance. I am very new to solar and off grid systems and will be asking for some basic assistance along the way. I just purchased a very small off grid cabin and am looking to install solar mainly for lighting. The basic design I am using should have plenty of additional power for my simple needs.

1. First off, when running 12v direct from the battery to the lights, is there a need for a special light bulb? I have read contradicting information. Can I not just use a standard 120v AC fixture and a standard 120v LED light bulb? Is there any downside to this? Can I put a standard 120v dimmer switch on a 12v system like this as well?

2. In reference to the actual wiring, I am wishing to install several lights independently of one another, ie. one in bathroom, two in kitchen, three in living area etc. Is it advised to try and run all lights on a series with a single positive wire connecting all lights within the cabin then back to the battery/charge controller and then use independent switches for each light? Or can I run independent wiring to each light and then back to the battery/charge controller? If the second is an option, how do I splice 4-5 separate independent lights into one positive at the charge controller?

Thank You,

VICK

[ButchDeal]

You will either need an inverter or to use DC 12V LEDs such as those available for RVs.
You will need fuses as well appropriate to the wire and loads.
What is the wire run length going to be? have you though about voltage drop in this situation?
You don't want to wire the lights up to the output leg of the ChargeController. Instead you will want a DC breaker box attached to the battery for the fuses mentioned before.
Though I suspect you are going to have too much voltage drop to be doing this at 12V anyway.

[SunEagle]

Well you won't be able to run a 120v AC light using 12V DC without having a DC to AC inverter.

If you plan to stay with AC lights then you can build a small distribution panel with 15 to 20amp circuit breakers to protect your load up to 80% of the breaker rating.

You can feed your DC lights from the battery through a small fuse box distribution system. You can find them on eBay or Amazon under automotive fuse wiring section.

And finally you can use the "load terminals" on that CC to run a very low wattage DC light. But be careful because most CC's can't have a "load" more than a couple of amps.

[AzRoute66]

Depending on the future plans, I think I might try to skip the inverter and model my power distribution and use like an RV, use DC lights, fans, radios, even furnace and refrig. I would not wire every device all the way back to the battery, I would use one pair of wires labelled 'cabin lights' and daisy chain them. I know you currently say it is mainly for lights, but once the lights are on most people look to keep the beer cold and the ears warm.

[cvick]

Thanks for the response guys. I guess the clarification that I needed was the distribution panel/circuit breakers on the outgoing side of the battery. I just wasn't sure how to run them. Now for further clarification regarding the inverter. I am trying to keep the system as simple as possible, as noted, at this point I am really just running lights off of the system with one small water pump. I am in design phase and have purchased neither so I can set up 12v DC or 120v AC using inverter. I know there are a ton of variables but in general: If I am trying to keep the system simple, what is the cleanest, most efficient way to power 6-8 lights on separate switches? Is an inverter necessary if I purchase 12v light bulbs and fixtures and wire direct DC for the entire system? Or is it silly not to use inverter convert to AC? For clarification, the distance from the battery to the first set of lights is roughly 12-14 feet. The other lights would be 18-25 feet pending exact location. This is from the battery to the actual fixtures. Thanks for your help and please excuse me if I am trying to so something that makes no logical sense. I am a fast learner but a little inept at the conversions of solar energy.

Thanks!

VICK

[cvick]

AzRoute66, thanks for clarifying. (This was my exact question above). If going to full bore 120v AC by inverting was necessary or I could keep it all DC and wire for this. My initial post I guess may have been unclear as I was essentially asking if I could run standard, 120v AC lights and fixtures on a DC system. From what I am understanding here the answer is no. What I am also understanding is that I can run a full on DC system if I purchase the correct fixtures and bulbs for a DC system. Of course now I am sure the distance of the wires may present a problem for DC?


Thanks!

VICK

[AzRoute66]

No problem with those distances, even with considerably longer ones should you want to add a wire pair labelled 'woodpile light'..

[ButchDeal]

is that 25 feet for the longest "Wire run" or from the battery to the wall where it will be.
you need to think of the wire run from the battery say up to the ceiling, across the room, down to the light switch, back up and over to the light.

You also should look up the price of DC lights, and DC rated switches, fuses, etc. You might find it rather cheaper to use AC and a small inverter.
If you want much more than a little power for the lights you would be better off with a 24V system though.

[SunEagle]

is that 25 feet for the longest "Wire run" or from the battery to the wall where it will be.
you need to think of the wire run from the battery say up to the ceiling, across the room, down to the light switch, back up and over to the light.

You also should look up the price of DC lights, and DC rated switches, fuses, etc. You might find it rather cheaper to use AC and a small inverter.
If you want much more than a little power for the lights you would be better off with a 24V system though.

Or possibly the use of 12v RV LED lights. I have maybe 36 of them little buggers through my Class A and they were all those tiny high wattage incandescent type before I swapped them out with LED type. I do not remember how many circuits I had but there were a few considering the number of lights.

[ButchDeal]

Or possibly the use of 12v RV LED lights. I have maybe 36 of them little buggers through my Class A and they were all those tiny high wattage incandescent type before I swapped them out with LED type. I do not remember how many circuits I had but there were a few considering the number of lights.

See post #2 in this thread....
I have 12V RV LEDs in my pop up camper as well but we tend to dry camp so conservation is important there.

If you look at the cost of the RV LEDs they are not cheap and consider the amount of light they put out (check the lumins) vs an AC LED that can be had for a buck or so at amazon.

pack of 12 800 lumens 120V LED bulbs for $23
https://www.amazon.com/gp/product/B01CAL19F6/ref=b2b_gw_d_simh_a1_0_p/168-1856586-6700950?ie=UTF8&pd_rd_i=B01CAL1EMY&pd_rd_r=0HRM9QW PFY6EZB0C0WDZ&pd_rd_w=ClZVf&pd_rd_wg=0TMlm&pf_rd_i =b2b-desktop&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0HRM9QWPFY6E ZB0C0WDZ&pf_rd_t=ABGateway&refRID=0HRM9QWPFY6EZB0C 0WDZ&th=1

pack of 5 x 650 lumens 12V LED bulbs for $15

https://www.amazon.com/generation-12-24v-Bright-Lumens-Reverse/dp/B017386GLS/ref=pd_bxgy_263_2?_encoding=UTF8&pd_rd_i=B017386GLS&pd_rd_r=9YS884JBHWAFXAR64BN7&pd_rd_w=TZ6hp&pd_rd_wg=KPtwm&psc=1&refRID=9YS884JBHWAFXAR64BN7

[AzRoute66]

I just looked a little closer at your drawing (nice drawing by the way). You have these lights running off of the 'Load' terminals of the charge controller. That is very intuitive, and in my opinion that is the way that it should have been envisioned by the industry from the start. Probably nothing wrong with it as long as you don't exceed the amperage rating of the controller terminals which is typically quite small - and it likely will protect your wiring. However, the typical installation would be to attach all loads across the battery, by installing a fuse box, breaker box, distribution box (whatever you want to call it). Run ONE thick wire from the positive terminal of the battery to this distribution box, and then wire pairs from the box to the various loads. Good idea to attach this one thick wire to the battery with a fused terminal attachment just because we all like that as the closer it is to the battery itself the better the protections. For the distribution box, in your case the first load will be a wire pair labelled cabin lights, fused/breakered to the gauge of wire you have selected to install. The remaining fuse/breaker slots in the box will be for your inevitable future expansion.

Also, I just noticed that ButchDeal pointed this out in post #2. Not trying to hijack his astute observation.

[max2k]

Depending on the future plans, I think I might try to skip the inverter and model my power distribution and use like an RV, use DC lights, fans, radios, even furnace and refrig. I would not wire every device all the way back to the battery, I would use one pair of wires labelled 'cabin lights' and daisy chain them. I know you currently say it is mainly for lights, but once the lights are on most people look to keep the beer cold and the ears warm.

are you suggesting to connect loads in series or to have multiple 12V 'branches' going off the battery to different sets of loads but each load would be connected in parallel? Even with latter solution 12V is bad for any sizeable distance as it requires significant current to do anything useful. 120W fridge would require 10A current which is not negligible over any distance.

on top of that he'd be locked into much more limited 12V DC world of consumer devices which will lead to much more costs over long run.

I'd highly recommend to go with standard 120V AC setup.for much better long term compatibility and 10x less wire ampacity requirements.

[SunEagle]

See post #2 in this thread....
I have 12V RV LEDs in my pop up camper as well but we tend to dry camp so conservation is important there.

If you look at the cost of the RV LEDs they are not cheap and consider the amount of light they put out (check the lumins) vs an AC LED that can be had for a buck or so at amazon.

pack of 12 800 lumens 120V LED bulbs for $23
https://www.amazon.com/gp/product/B01CAL19F6/ref=b2b_gw_d_simh_a1_0_p/168-1856586-6700950?ie=UTF8&pd_rd_i=B01CAL1EMY&pd_rd_r=0HRM9QW PFY6EZB0C0WDZ&pd_rd_w=ClZVf&pd_rd_wg=0TMlm&pf_rd_i =b2b-desktop&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0HRM9QWPFY6E ZB0C0WDZ&pf_rd_t=ABGateway&refRID=0HRM9QWPFY6EZB0C 0WDZ&th=1

pack of 5 x 650 lumens 12V LED bulbs for $15

https://www.amazon.com/generation-12-24v-Bright-Lumens-Reverse/dp/B017386GLS/ref=pd_bxgy_263_2?_encoding=UTF8&pd_rd_i=B017386GLS&pd_rd_r=9YS884JBHWAFXAR64BN7&pd_rd_w=TZ6hp&pd_rd_wg=KPtwm&psc=1&refRID=9YS884JBHWAFXAR64BN7

I agree with you. At least the AC LED lamps have come way down in price and are more bang (lumens) for your buck.

[Mike90250]

While you are still in design phase, and BEFORE you buy anything, calculate the AMPS each of your 20W (or whatever) bulbs are going to be pulling from the battery,
12V @ 20 W = 1.66 amps.. And when you know the Amps you can calculate the Voltage Drop in the wire, and plan for the proper size wire for the distance you are covering,

Design / Plan / Calculate

[ButchDeal]

While you are still in design phase, and BEFORE you buy anything, calculate the AMPS each of your 20W (or whatever) bulbs are going to be pulling from the battery,
12V @ 20 W = 1.66 amps.. And when you know the Amps you can calculate the Voltage Drop in the wire, and plan for the proper size wire for the distance you are covering,

Design / Plan / Calculate

and if you are planning more than one light per circuit you need to account for that as well. They should NOT be in series but parallel but you need to count on all of them being on at once per circuit and include the longest wire run length (length of the wire not point to point).

In looking at the LED bulbs available at 12V a good deal of them support 24V so consider doing the system at 24V to avoid paralleling batteries and give better options for inverters and expansion later.

And make sure you are using DC rated switches and fuses.