series or parallel?

[bprender]

Im wiring lighting and electronics right now. basically lighting. Can I wire four lights in series to turn on with one switich? or should I run a hot and a ground for each from one switch? is there a difference? Is one more efficient or just better in general? Thanks guys

 

[dorchard]

Re: series or parallel?

You should wire these in parallel. Most likely, these bulbs are designed to operated at your boat's native voltage (most likely 12V). If you wire these in series, each will only have a fraction of the voltage delivered to it.<br /><br />You can still have one switch to operate them all--that will be no prob. Hopefully this ASCII art schematic will serve the purpose of showing you how to wire this.<br /><br />

(-)----------|------|-------|<br />             |      |       |<br />             3      3       3<br />             3      3       3<br />             |      |       |<br />             |      |       |<br />(+)---/ ---------------------<br /><br />(-) : Battery Negative<br />(+) : Battery Positive<br />3 : Light bulbs<br />/ : SPST (Single Pole Single Throw) Switch

I am very new to boating, but as a Computer Science student, I know a bit about electronics.<br /><br />It may be customary in marine applications to use a DPST (Double Pole Single Throw) switch instead of SPST, im not sure, but the same principle will apply.<br /><br />There is laws of electronics called Kirchoff's Laws, that can be applied in the following way:<br /><br />If you want 2 or more devices to have the same VOLTAGE applied across them, wire in parallel.<br /><br />If you want 2 or more devices to have the same CURRENT through them, wire in series.<br /><br />I think you will find that parallel will dominate in most all cases.<br /><br />Sorry if I insulted your intelligence--it was not intentional. I just get excited about being able to explain things I know to people in a community where I am a newbie ;-)<br /><br />If you need any clarification on anything I have said, send me an email: dan DOT orchard AT centerpointmgt DOT com<br /><br />Replace the DOT with . and the AT with @. This is to reduce the amount of spam I get from bots scanning the web.<br /><br /><br />--Dan

 

[Dunaruna]

Re: series or parallel?

Dan, ease up a bit, you've just lost 75% of the readers <br /><br />He didn't mean' serial' (I think), he want to piggy back 4 lights.<br /><br />Bprender, what are the lights and what wattage are they?<br /><br />Aldo

 

[Realgun]

Re: series or parallel?

Good explaination dorchard.<br /><br />Wire from hot to the switch your using.<br />Wire from switch to first bulb + Another wire from bulb + to next bulb + and so forth.<br />Wire from ground on bulb to ground on bulb back to ground. <br />Voltage will remain the same for all bulbs. Otherwise you get 3 Vs at all four bulbs.<br /><br />Also if 1 goes out when your wired in parallel the others will still work.

 

[crab bait]

Re: series or parallel?

take a wire from the switch to the first lite's black wire.. <br /><br />then go from that black wire to the next lite's black wire.. <br /><br />an again,, on to the next lite's black wire<br /><br />an so on..<br /><br /><br />next,, take a green (or white) wire from a good ground ( negitive battery post ) to the first lites white wire.. <br /><br />an so on .. just like the 'black' wire..

 

[18rabbit]

Re: series or parallel?

Originally posted by Realgun:<br /> Also if 1 goes out when your wired in parallel the others will still work.

There it is right there.<br /><br />Wiring in series means when one light goes out they all go out. Then you get to figure out which bulb is the one that fried.<br /><br />Wiring your lights in parallel means when one light fails it will be the only one not shining.

 

[amirm]

Re: series or parallel?

The schemes suggested are indeed parallel when it comes to the light bulb, but series wrt to wiring. If the connection to the first light goes bad, the rest will not work either. My preference would be to run four seperate sets of wires to the switch and ground unless the lights are closely located. This way, it will be a lot easier to figure out any problems with one of the lights later.<br /><br />Of course, the above can get expensive if you have a big boat but for a smaller one, the difference in cost should be minimal.<br /><br />Amir<br />P.S. I had not heard of Kirchoff's law since I left engineering school some 20+ years ago. Dan, you are making me feel old .

 

[crab bait]

Re: series or parallel?

ROTFLMFAO..<br /><br />yeah,, that's sooooo is a better way to do it..

 

[Realgun]

Re: series or parallel?

Carb I believe thats just to many wires to fool with for lights.

 

[amirm]

Re: series or parallel?

Crab Bait, as the new guy here, I need to provide some comic relief, don't I ? <br /><br />Seriously, we all have different philosophies when it comes to boats or this board wouldn't exist. Mine is that if I am going to work on my boat instead of using it or paying someone else to do it, I am going to do things first class. For me, the idea of 8 screws (or worse, butt connectors) causing the last light in the chain not working is not a good one. Others surely will have a different standard.<br /><br />As a funny coincident, I was working on my new boat yesterday and dropped the ceiling panel to run a couple of speaker wires. There are two cabin lights there only 3 feet apart and I found that the builder had ran separate lines for each! As I suggested, in these situations even I would opt for sharing the same wires due to close proximity. They had ran separate sheathed wires for each to a junction box in the console.<br /><br />Now, this is a high-end builder and mostly produces boats for the military and as such, their work is first rate and over designed (ALL the wiring in this boat is sheathed and encased in wire looms!). But it enforces the point that running separate lines for lighting is not a crazy idea…<br /><br />Amir

 

[demsvmejm]

Re: series or parallel?

Amir,<br />What is the difference of making the connection at the light or at th eswitch? You still have a connection, you simply have moved the location of it. As for your craft, perhaps on another model or trim level the two lights are switched seperately. I don't see where the added complexity or weight makes it anymore "First class." It's just wasteful. No matter where the connection or splice is, it still is a potential for failure. Just my $.02

 

[Richard Petersen]

Re: series or parallel?

A neat and correctly squeezed on lugs at the ends of the wire are the most important part of the job. Lights that operate from the SAME voltage are are always wired in parallel. Wattage and the # of + or - wires to be commoned and distance will determine if they run back to the switch seperatly or share a common wire.

 

[crab bait]

Re: series or parallel?

well, since you went to electrical engineer school .. an you seem to be highly intelligent.. an your 'high end' boat has lites wired as you suggested.. that's all the proof i need.. an from this day forward,, all my boat lites will be wired this way.. thanks for the good tip..

 

[ron7000]

Re: series or parallel?

forget how he wires them,<br /><br />series <br /><br />parallel <br /><br />it all in how he makes the connections<br /><br />you are going to solder them aren't you?