Broughton 2

So, if we are going to run a TV of 40'sh Watts it would be best not to do so through an 1800Watt inverter but through a seperate and dedicated unit of say 50Watt. Yes? Alan

You are correct of course, my figures are guestimates. Difficulty, for me, is that there seems to be differences of opinion as to efficiency of the various electrical converter units. For example, one supposedly qualified source told me that inverter efficiency varies according to load and at low loads it may even drop below 50%. Obviously I don't know the ins and outs of it and that's why I find it interesting and useful when people who are knowledgeable take the time to respond. Ta. Alan

It seems to me, for those who are running an inverter to power a TV that will otherwise accept 12V DC direct you may be wasting up to say 36% of your battery juice. Firstly, the inverter looses 20% (say) in converting from 12V DC to 230V AC and then the conversion back from 230V AC to 12V DC for the TV is a further loss of 20% (say) on the remaining, ie. 36% loss overall. That's a lot of juice to throw away! Someone please tell me I'm wrong. Alan

Seems there are opposing views on this topic (which is a good thing for any discussion) but no-one disputes the statement "If you never operate the TV when the batteries are being charged you should be OK." For reliability I like to keep things simple so on our boat we shall plug the TV straight into 12V and only switch on when engine is not running. However, unless someone advises different, we shall not be so constrained when charging batteries from the shoreline as I suppose there is less likelyhood of over voltage there. Is my supposition correct?

Thanks guys. Had the answer been that 12V regulation is required then a supplementary question was going to be about the efficiency of a small inverter, less than 100W, to run the TV at 230V AC compared to 12V-12V DC regulator/ converter. I shall do as you suggest (plug straight into 12V supply) but am still interested which of the inverter or converter options would otherwise be best, so if anyone would like to comment I'd be pleased to know. I suspect the 230V is anyway converted to 12V within the TV and if so then probably running from an inverter would be less efficient (or did I read somewhere that DC-DC converters are quite inefficient?). You see, I'm strictly clockwork and 'lectric gubbins ain't my bag. Alan

Many of the common-or-garden 15-17" mains TV's have 12V option socket. Are they suitable as they come or do they need 12V regulation:- (1) When engine not running and TV is powered from fully charged 12V batteries, ie. 14'sh volts? (2) When engine is running and possibly higher voltage will be felt? Anyone out there with practical experience of running without 12V regulation? Alan

The Waterscape/ British Waterways site is about as usefull as half a pair of scissors! I'm sure the info is there somewhere but finding it requires the services of a mystic. I Googled for it:- Address: Alrewas, Staffordshire, DE13 7DN Telephone: 01283 790236 Fax: 01283 791411 E-mail: enquiries.westmidlands@britishwaterways.co.uk Alan

Thanks Chris for the speedy reply. I didn't make myself clear did I (apologies) it was the wiring diagram that I was looking for, ref your Post No 28 to Mike. Can you point me to it? Regarding the Relay, I thought it was introduced to the circuit as a consequence to discovery the proposed Switch is AC not DC and likely would weld contacts in no time at all. I guess you had it in mind all along to incorporate a relay. Alan

Chris This Numpty cannot locate the wiring instructions (diagram?) you so generously posted and shall be grateful if you will either PM to me or indicate where to find the posting. My engine has two alternators coupled through a Sterling 'Alternator to battery charger, AB12160' and I suppose I simply repeat your circuit for each alternator(?). To avoid having a Relay can you suggest a suitable 12V DC Switch? It's a personal thing that I prefer simplicity with least number of components in any system wherever possible? Thanks Alan

I'm told vaseline is as good as anything else for protecting against battery terminal corrosion but what is the correct method of use? Should the vaseline be smeared all over the terminals before leads are fastened to them or should leads be fitted to dry terminals and the assembly then covered with vaseline, ie. is vaseline an electrical conductor or insulator?

Thanks again Dylan. Rather than connect the battery charger cables to battery terminals I may well copy your scheme and connect to battery side of the isolator. Same result but seems tidier. Alan

To which terminal of the main isolator is your positive connected, battery or input/output? Alan

Thanks Dylan. So, I hard wire the charger to the battery terminals and all is tickedy-boo. You may be interested to know Sterling supply a fuse in the negative cable as part the kit. However, whilst they also recommend additional fuse in the positive cable they do not supply that one. Odd?

Betamarine engines are Kubota based. You could do worse than give them a call to price replacement engine/ parts.

I'm fitting a mains battery charger (Stirling 1240CED model) and the supplied wiring diagram shows the charger to be connected direct to battey terminals not through a switch. Is this correct or should there be/ is it better to have a switch between the charger and battery (say in the positive cable) so the circuit can be broken when (1) the engine is running and battery charging is being done by the alternator (2) when the engine is not running and shoreline is not connected? My concern is that without a switch there may be a live DC circuit through the charger which may upset either it, the alternator or battery when the engine is running. Further, when the engine is not running and shoreline not connected would such live circuit (if it exists) flatten the battery by trying to make the charger work in reverse. Hopefully someone will tell me the battery charger is constructed in a way that allows it to be permenantly connected to the battery without the need for a switch and no harm will be done.

Thanks Allan, I had no idea what a Redline was and I think now I understand what you are about. Nonetheless, to avoid additional plugs, sockets and dedicated RCD I would still like to know if there is a changeover switch that would connect the charger through the AC panel RCD/ Breakers when shoreline is selected, then disconnect when inverter is selected. If such switch exists it would(?) simplify things. I think I'm asking for something that doesn't exist but it's interesting to hear what you guys have to say. As a newcomer and fitting out my first boat I find this site very informative. Nice folks who give up their knowledge so freely are to be cherished.

If I understand you diagram correctly it seems an excellent scheme where we have two AC circuits, (inverter powering the auxilliary AC circuit only and the charger being run from shoreline main). However my boat is a deal more basic than yours, having only a single AC circuit and therein lies the problem. Alan

And that takes me back to where I started. I want to simplify, whilst maintaining all safety, through a single (better) change-over switch.

Thanks Yoda but I can't vizulise your suggestion. Do you mean to incorporate an additional switch ("break before make switch") in the input wiring to the changeover switch? Would your scheme mean onboard power (DC 12V say to lights) would be denied when switched to Inverter? I wouldn't want to loose DC circuits simply because I'm plugged into the shore. There must be several ways to arrange a suitable change-over switch. Imagine for example a switch having two elements stacked one behind the other and operated by a common spindle through both elements. The first element could be the standard arrangement for a change-over switch but the second, additional, element would have only two connections (Live and Neutral) connected in series with the output from the battery charger fuse/breaker of the AC panel. Contacts in the second element would be aligned so that when 'shoreline' is selected they would make a circuit to the charger but, when 'inverter' is selected the contacts would move to open and the charger would be isolated. Job done? Probably I've not described my switch very well, let's call it a two element stacked switch, but if anyone does recognise either it or something like then please shout now because my simple mechanical mind tells me it would greatly simplify the charger-inverter circuitry. Alan

Is there an AC changeover switch available (shoreline/ off/ inverter) that will isolate the battery charger circuit when the inverter is selected? Such a switch could easily be made but does any manufacture actually offer one? When we have a battery charger and inverter in the electrical system it is necessary to prevent the batteries trying to charge themselves through the inverter (yes?). One way is to have an on/off switch to the battery charger but some of us will forget to use it and the result may not be too good. A fail-safe method is to wire the battery charger in parallel with the main circuit (from the shoreline socket as shown on the excellent ‘Smartgauge’ web site) but this means we have an extra circuit with it’s own consumer unit (RCD and fuse/breaker) dedicated to the charger. If we had a changeover switch of the type suggested we could have a fail-safe system, simplified electrics and save the cost of an additional consumer unit. Or have I got it all wrong? Alan

You seem to be travelling same route as me (Webato, skirting rads and room stat.) but I've not yet finished my installation. My reason for incorporating a room stat is to avoid wasting electricity pumping water round the system when the room is at the set temp. (whereas timer control alone will continue to pump water until it times out. For the room stat. I've been advised it can be done simply by wiring the stat into the timer out cable and before the heater unit. Provided the timer is active (timer set to on) the heater will see no difference in the off signal (break) it recieves and will go into its shut down mode as normal. When room stat remakes the heater will think it's being fired up by the timer and go into ignition mode (again provided the timer is still set to on). I haven't tried it yet but all sounds reasonable to me. Let me know how you get on. Alan

As an aside, can I say I've suffered (more often than is reasonable) with marks on paintwork left by the soot from chimneys of boats upwind. Can I make a plea that whatever we burn we do so cleanly as possible. I even had one guy putting the flue brush through a chimney he was holding not three foot away from my boat. Took ages to clean it off.

Thanks Dylan. Good point about fuses being there to protect cables rather than components. I made sure all cables are rated well in excess of the fuses used. I would still like to know if the various fuse types have operating differences that suit particular applications. Alan

I'm bewildered by the number of different DC fuse types there are and whether or not some are better suited for one purpose or another. Can anyone help me to understand? For example, when I bought my sailaway it was fitted with a 250amp ANL main fuse. For the life of me I cannot imagine why it should be so large a fuse and am thinking of replacing with a smaller one based on total capacity of all the fuses used in the various circuits, but am I missing something about ANL fuses that I ought know about? Also, I recently bought a Sterling 40A battery charger which came with a 60A 32V fuse (which I think(?) is AUE type fuse). Why a 60A fuse for a 40A charger and what's with the 32V? Apart from ANL and AUE fuses there are AMT, AEQ and goodness knows how many other types available. Why and what, if any, are the differences?

Confirmation of the above, if needed. Jabsco pumps (ITT Industries) seem to agree with Waterways World (or did WW get it from Jabsco?). Either way, instruction sheets that come with their new pumps recommend "sanitizing" using "common household bleach" at a rate of 100 ml of bleach to every 100 litres of water, leave for 4 hours, drain then purge the plumbing of all sanitising solution. Doubling the strength of the solution will halve the time to 2 hrs. Alan