DC Power Connectors

[eco-boat]

I've decided to run DC power lines around my boat. I want to use inverters at the point of use rather than have them near the batteries and then route AC cables around the boat.

The problem I have is I don't know what type of connector (plugs and sockets) to use for DC power circuits.

Is there a standard DC connector?

I don't want to use the standard cigarette lighter plug and socket from cars because I find them unreliable (they work loose).

Using standard AC plugs and sockets would add danger:- appliances could end up on the wrong circuit; and they are designed for no greater than 13Amp. This equates to 156W maximum on a 12v circuit. I need much more than that.

Does anyone have any suggestions on a plug/socket combination that would be suitable for DC circuits (with a sensible amount of power)?

 

Thanks in advance.

 

Mark

[b0atman]

The cabling would be expensive for the DC runs it is cheaper to run 230v circuits.

[Groundhog]

This sounds like a bad plan to me. The DC cables will be carrying far more current than the AC cables would be so volt drop will be a problem if you don't spec the cables right. Also as you presumably won't have an AC distribution board what are your plans regarding bonding the AC earth from each inverter?

[Keeping Up]

Does this mean you will often have multiple inverters running at the same time? If so that will be very inefficient as each one will waste one unit of standing current of perhaps 1 amp.

[nicknorman]

Not to mention requiring an RCD for each inverter.

 

All very un-Eco. More copper, more power wasted, and for what end?

Edited December 23, 2014 by nicknorman

[Pete & Helen]

I've decided to run DC power lines around my boat. I want to use inverters at the point of use rather than have them near the batteries and then route AC cables around the boat.

The problem I have is I don't know what type of connector (plugs and sockets) to use for DC power circuits.

Is there a standard DC connector?

I don't want to use the standard cigarette lighter plug and socket from cars because I find them unreliable (they work loose).

Using standard AC plugs and sockets would add danger:- appliances could end up on the wrong circuit; and they are designed for no greater than 13Amp. This equates to 156W maximum on a 12v circuit. I need much more than that.

Does anyone have any suggestions on a plug/socket combination that would be suitable for DC circuits (with a sensible amount of power)?

 

Thanks in advance.

 

Mark

 

The only advantage would be if it was just to run low current devices and where you think that a larger (standard fit inverter) would be drawing excessive current. I think most people understand where you are coming from. But if you are going to use more than one (local inverter) at a time then I would take advice from a Marine Electrician.

You would probably be better off getting 12v devices (tv, fridge, car phone charger,etc..) then sizing your single inverter to be as small as need be for anything else and only switching it on when required.

 

ETA. To answer your question though about connectors you could look at something like these which I believe are a more secure item

http://www.ebay.co.uk/itm/12v-24v-Male-Female-Din-Accessory-Power-Plug-Socket-Connector-16A-Hella-/370847369626?hash=item565839c99a

Edited December 23, 2014 by Pete & Helen

[system 4-50]

I've decided to run DC power lines around my boat. I want to use inverters at the point of use rather than have them near the batteries and then route AC cables around the boat.

The problem I have is I don't know what type of connector (plugs and sockets) to use for DC power circuits.

Is there a standard DC connector?

I don't want to use the standard cigarette lighter plug and socket from cars because I find them unreliable (they work loose).

Using standard AC plugs and sockets would add danger:- appliances could end up on the wrong circuit; and they are designed for no greater than 13Amp. This equates to 156W maximum on a 12v circuit. I need much more than that.

Does anyone have any suggestions on a plug/socket combination that would be suitable for DC circuits (with a sensible amount of power)?

 

Thanks in advance.

 

Mark

I don't see how you can have big inverters used in a plug-in way. They have to be hard-wired surely? My inverter has a massive cable kept as short as possible to minimise losses.

[Guest]

Doesn't sound like a good idea TBH. I agree with the poster who suggested using 12V devices where possible. I started out thinking I would have many 240V items on the boat, but now only have a washing machine, and fridge freezer, though that will eventually be replaced with a 12V one.

[bottle]

With all those inverters working, you would not need any heating on the boat...

 

All right probably an exaggeration but very wasteful and costly as mentioned by previous posts.

 

If you do want to do it then probably the best socket/plugs are DIN. Can be obtained up to 20 amps (12v)

 

These are 16 amp (12v) so approximately 190 watts

 

example link for socket

 

example link for plug

 

They 'lock' in

 

Edit: I am not advocating this, as it seems/is the wrong way to go about it.

Edited December 23, 2014 by bottle

[ditchcrawler]

Have you ever wondered why nearly all the boats that use any 240 volt AC appliance have one inverter as close as possible to the batteries.

[Murflynn]

typically mains power transmission uses high voltages like 250KV for long distances and 33KV for more local distribution, for the very reasons cited above.

 

It is simply quite impractical to do as you propose. And if you have such high capacity DC cables (like welding cables) to suit the load they would be very dangerous in case of a short or an accidental contact between + and - . Think what happens in welding - it would be similar.

[Alf Roberts]

 

(with a sensible amount of power)?

 

Thanks in advance.

 

Mark

I don't think you've understood the reason why 240v is used for power distribution

 

clue: power = voltage x current.

[alan_fincher]

I feel sure the message is done to death already, but this is just such a bad idea on all levels.

 

Even a very small inverter, (say 300 watts), will need to draw in excess of 25 amps at 12 volts, if working at full output.

 

None of the standard methods used to plug in 12 volts are really viable at those current levels, and the volts drop along even a substantially specced cable may well be enough that the inverter fails to work properly, (if at all).

 

A higher power inverter would make things proportionally worse.

And all that is without addressing issues of safe earthing and RCDs, which have already been mentioned.

 

I can't think of any single offsetting factor that would ever make this a good idea, if I'm honest.

[smileypete]

I think some of the responses illustrate why people get 'turned off' by CWDF... a bit more tact wouldn't go amiss

 

cheers, Pete.

~smpt~

[Alf Roberts]

I think some of the responses illustrate why people get 'turned off' by CWDF... a bit more tact wouldn't go amiss

 

cheers, Pete.

~smpt~

 

A little over-sensitive this morning Peter?

 

I think the responses give a complete picture of why it's not a good idea without being rude at all.

 

Perhaps you'd like to give us your idea of the model reply to what is a complete non-starter?

[Chalky]

I started typing up an explaination of why it's a bad idea to distribute power at a low voltage and why by using a higher voltage you will significantly reduce the losses in your system. It's been discussed on here several times before and a search will quickly find them.

 

What I have on my boat

 

Batteries in engine room -

50mm csa power feed from batteries to 12V fuse boxes

12V power to all lights - 10mm csa to feed 60W tunnel lamp

 

50mm csa power feed from batteries to 240V inverter,

240V (rated at 800W) to 240V fusebox 2.5mm csa then to fridge (2.5mm csa) and socket (2.5mm csa)

 

25mm csa from 12V fuse box to fusebox in middle of boat. This feeds 2 12V sockets 6mm csa and water pump 6mm csa. Also for 12V fridge if I ever fit one.

 

If you want to distribute via 12V then step up locally then it's your boat. What I would suggest is you calculate the size of the cables you need to keep the losses low and then cost the system up. You'll find that one single inverter close to the battery will be very significantly cheaper than a 12 bus bar and multiple inverters.

The only time that a system of the type you propose is used is in high integrity systems where single point failures must be avoided and cost is not an issue - think aerospace and life support systems and you're in the right sort of area.

[smileypete]

I think the responses give a complete picture of why it's not a good idea without being rude at all.

 

Perhaps you'd like to give us your idea of the model reply to what is a complete non-starter?

 

clue: post #2.

 

cheers, Pete.

~smpt~

[Guest]

I think some of the responses illustrate why people get 'turned off' by CWDF... a bit more tact wouldn't go amiss

 

cheers, Pete.

~smpt~

In some cases I agree, but to be honest can see no really abrasive comments here. To my mind people have taken the time and trouble to explain to the OP why the idea might be impractical. Their advice is offered freely and based on experience.

Don't forget that many of us are posting on phones these days which can make the posting style seem a little "abrupt" at times; a trait I have noticed on this and other forums.

People are trying to help/advise in their own way.

[Guest]

 

clue: post #2.

 

cheers, Pete.

~smpt~

This is where you lose me. Post #2 is straight to the point and similar to what I would put if on my phone. Others have then built on this post (which is correct IMHO) and added their own personal experiences. I see nothing different here to the many other forums that I use.

 

[Murflynn]

 

clue: post #2.

 

cheers, Pete.

~smpt~

get a life!!

 

Merry Xmas

[nicknorman]

Anyway, not sure it matters since OP hasn't returned.

[Eeyore]

I've decided to run DC power lines around my boat. I want to use inverters at the point of use rather than have them near the batteries and then route AC cables around the boat.

The problem I have is I don't know what type of connector (plugs and sockets) to use for DC power circuits.

Is there a standard DC connector?

I don't want to use the standard cigarette lighter plug and socket from cars because I find them unreliable (they work loose).

Using standard AC plugs and sockets would add danger:- appliances could end up on the wrong circuit; and they are designed for no greater than 13Amp. This equates to 156W maximum on a 12v circuit. I need much more than that.

Does anyone have any suggestions on a plug/socket combination that would be suitable for DC circuits (with a sensible amount of power)?

 

Thanks in advance.

 

Mark

Hi Mark

Anderson plugs would seem like a sensible choice for your requirements.

Genuine and pattern Anderson plugs are not always compatible, make sure to buy only from one manufacturer.

A few links:

http://www.andersonpower.com/products/multipole-connectors.html

http://www.ozautoelectrics.com/automotive-connecters/anderson-plugs.html

 

I see from your profile that you like to do things differently; hope it works for you.

 

Steve (Eeyore)

[MtB]

Anyway, not sure it matters since OP hasn't returned.

 

 

Prolly can't get online as his inverters won't work...

 

 

MtB

[alan_fincher]

 

clue: post #2.

 

cheers, Pete.

~smpt~

Post #2 hardly starts to cover it though, does it?

 

If it were just down to post two, you might be tempted to think it wasn't an unreasonable idea provided you could get your hands on lots of very heavy gauge cable at low cost, (which, of course, it still wouldn't be).

 

If anybody is going to answer a question like this, it seems entirely sensible to me to spell out fully what the (many) issues are with such an idea - which is exactly what has happened.

[nicknorman]

Post #2 hardly starts to cover it though, does it?

 

If it were just down to post two, you might be tempted to think it wasn't an unreasonable idea provided you could get your hands on lots of very heavy gauge cable at low cost, (which, of course, it still wouldn't be).

 

If anybody is going to answer a question like this, it seems entirely sensible to me to spell out fully what the (many) issues are with such an idea - which is exactly what has happened.

Quite right, you have to be cruel to be kind (sometimes).