Narrowboat Electrician - Narrowboat Solar Installation

An almost typical narrowboat solar installation. But not without its obstacles.
Victron Smartsolar mppt and 140w Victron solar panels.
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Answer to fuse location - Always nearest the power source from the batteries, so needs to be nearest 12v fuse box where the cable diameter, and hence its current carrying capacity, reduces.

[@peterfarrell7675]

Man, I love the videos. So much info. Also great to see someone trying to explain so much in a simple way.

[@narrowboatelectrician]

Glad you like them! I must do some more!

[@andy_nye]

Excellent video Martin .. stay safe

[@narrowboatelectrician]

Cheers Andy

[@steveohagan665]

. Once agene very professional i like you the way you explain these things to us. tank you

[@narrowboatelectrician]

Thats really nice of you to say Steven.

[@davehopkin9502]

To reinterate the power in DC, many many moons ago, I worked for the Post Office Telephones and managed to drop a spanner across a 50v DC buzz bar, as luck would have it 90% of the bar was insulated, but my spanner found the couple of inches that was not insulated, the result a very loud bang and a case of flash blindness that lasted 10 to 15 minutes - the spanner? about 3" of the end gone, steel liquidised and gone.......

[@narrowboatelectrician]

Yeah Dave, can be scary stuff, remember ac swings past zero 50 times a second, dc is full on voltage, so power is much higher. I used to work on 250v dc back in the steel industry, that was powerful stuff. I think I need to do something on safety and the danger of dc voltages.

[@Dirt-Diggler]

I've melted spanners on a 12V battery before, it's not just the voltage it's the amps flowing that maketh the sparkly sparks 😁

[@davehopkin9502]

@@Dirt-Diggler In my case it was in a telephone exchange and the fuses beyond where I short circuited on the equipment rack were 100Amp, and there were at least 20 racks of that buzz bar, so god only knows what the upstream fuse was!!

[@Dirt-Diggler]

@@davehopkin9502 my electrical tool kit is mostly normal spanners but covered in shrink tube 👍 I'm a clumsy sod at the best of times 🤣 especially with today's LiFeP04 battery Banks 😮 fortunately i haven't shorted one of those yet 😁

[@raymondrobertson3869]

Very informative 👍👍🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@Dirt-Diggler]

Really enjoyed the vid chap cheers 👍 I do a little work here and there on boats but usually on road vehicles, mainly camper vans so all relevant info for me 🙂

[@narrowboatelectrician]

That explains the question I've just asked you on a previous post. Vans and boats are very similar, I have done a few vans for friends, but I'm so busy with boats I don't need more work. I only do three days now and a bit of part time on the hire boats. Glad the vids are of use to you.

[@Dirt-Diggler]

@@narrowboatelectrician same position myself, early 50's and starting to slow down and pick the jobs, fortunately my age is useful for a change as not many boat mechanics know 70s petrol engines, so for older fibreglass cruisers I'm in demand and no bloody computers to tend with 👍 But i still get asked to do solar mainly as i use my ex ambulance camper as a mobile workshop, Which attracts questions followed by jobs 😁

[@swsfrancais7289]

Thank you so very much for this video & a comprehensive overview of a PV system. I am a "rag & stick" boater & owner of an elderly vessel which I have carried out the rewiring myself. Learnt a lot here. The list of winter jobs to do with the electrics is lengthening especially with fusing!! You asked the question where does the fuse sits between the isolator & the battery - the answer is ....? Also your comment on pragmatism is much appreciated - some of the installation on my boat could be considered a bodge but now it's been renamed as "a pragmatic solution". Thanks once more & take care

[@narrowboatelectrician]

Hey, welcome, ah! Did I put the answer in the comments.....er no! Its quite simple - get the fuse as close to the power source as possible, as the length of cable to the fuse is unprotected should a short circuit occur. Isn't the solar panel a power source? Yes but when you short solar panels out they can only produce a given amount of current (Isc) so can never cause a fire if using cable that can carry that current. I use 6mm which is good up to 42A, so there is no risk here. Batteries on the other hand, can produce 1000's amps in a very short time. Hope that helps.

[@narrowboatelectrician]

Consider becoming a member for continued tech advice.

[@davidcook380]

Great Stuff Martin mate

[@narrowboatelectrician]

Thanks so much David.

[@keithperrin1568]

Martin, found the Buy Me a Coffee link (I know, it was right in front of me, my wife says I can’t find things in the fridge either!). Anyway, bought you a coffee and look forward to following your channel.

[@narrowboatelectrician]

Cheers Keith, really appreciate that. Can't you find beer in the fridge? No other point looking in there is there?

[@stevanez5108]

Good video.

[@narrowboatelectrician]

Glad you enjoyed it, Lots more to come hopefully.

[@TheNomadicCrobot]

You made this look far to easy, great instructional video buddy, were just trying to work our boats energy out and its been nothing but a nightmare so far, thanks for your insight

[@narrowboatelectrician]

Thanks for the great comment. I have done so many boat solar jobs its generally quite straight forward now. I have a 1200w widebeam installation at the weekend so I'll try to film that one as its a little different.

[@havoctrousers]

I winced when you stripped that cable with your pocket knife! Have you seen the Knipex Ergostrip? It's perfect for round cables, I use one for flex, meter tails and the inner sheath of armoured all the time. Thanks for a really interesting vid, subscribing now!

[@narrowboatelectrician]

Hi Robin, thanks for the comment, I’m old school and have strippers in my tool bag. I guess it’s just become the habit. It’s not razor sharp, it’s quite dull so it’s easy to gauge the depth. Good comment thankyou

[@eddieMurphy11111]

my car started motor got stuck so I got a spanner to turn it I had a ring on my finger spanner in hand and turn the motor but I hit the spanner on the positive wire and the spanner in my hand was touching my ring and my ring caught on a bit off the engine which of course was earth ring melted to nothing and finger was badly burnt so I learn very quickly about how DC can be dangerous . I am enjoying your episodes and thanks for the video

[@narrowboatelectrician]

Scary stuff Eddie, I never wear rings or watches or bracelets when I am working for that very reason. The power stored within, even a small 12v battery, can be very high if shorted out. Lesson learnt there, but the hard way, I hope the effects were not long lasting.

[@Peteamareet]

I'm a retired spark. I have seen three lead acid batteries explode. I believe what happens is ignition od the (highly explosive) hydrogen gas that is emitted from batteries.

[@narrowboatelectrician]

Yes you are most likely correct, or the failure of the regulation valve, which was likely the issue I had as there was no explosion. Unvented hydrogen pools in high places, which in itself can be "interesting". What industry were you in Pete?

[@Dave-bu6bc]

As much as possible is the approach I've taken on the narrowboats I've done so far. Let the roof dictate the number of panels, and buy the highest wattage panels that will fit in the available space. Can't get a 4th house sized one on this 55 footer without either fouling the side hatch or fouling the pigeon hatch, so it's getting 3. Couldn't get a 3rd one on the little 36 footer I did last so it only got 2. Every boat I've looked at there's always a patch of roof that you can't put panels on, which can be used for climbing on where necessary, even if it means adding a folding step somewhere halfway down the side of the boat.

[@narrowboatelectrician]

Hi Dave, yes I agree mostly. And it does depend on the usage of the boat. You don't nee 2kw on a narrowboat when they only go out in the summer. I will always get the most on, but aesthetics do come into it, after all I am putting my name on it. Having said that, the customer can dictate exactly what they want and I'll try to make it happen.

[@keithweybury5212]

Hi Marty and the cap backwards does fit you. Great informative vlog and enjoy watching you work as I have a beer. Keith

[@narrowboatelectrician]

Cheers Keith, I need a cooler tool bag! Not sure that's professional, but when its hot I could murder a cold one.

[@Chris_In_Texas]

26:34 Glad you were ok with the exploding battery. I have seen that happen on a boat over here as well. The battery was over charged, and developed an internal fault, which then the charger tried to push more current into it, which then started a thermal run-a-way situation. At that point the amount of hydrogen gas it was venting into the area without enough ventilation built up to the point where it just found the ignition of a spark to set it all off. At least there was no fire, just blew the battery apart and a few windows out. Flooded cells can be very nasty when the have a fault. They should NEVER be used inside the cabin and only in vented areas. If anything an AGM battery will help almost fully eliminate the off gassing of hydrogen. This battery was located under a berth that was used for the bow thruster. I guess the owner didn't want to spend the extra money on an AGM and just used a flooded cell battery as it was much "cheaper" but didn't realize what could happen. That was in a 40' fiberglass cruiser here in the USA on an inland lake. Keep up the good work sir. 👍😎

[@narrowboatelectrician]

Thanks for the comment. Most people do not recognize the potential danger with batteries. I have batteries inboard, but they are gel batteries. The explosion I had seemed to be pressure only, yes that must of had hydrogen in it but there was no ignition luckily. I put it down to a faulty pressure relief valve within the battery. I get work up close and personal with LA batteries, and even though I was aware and careful before, hard lessons are remembered stronger. I have to flooded batteries in my van, they are being changed very soon. Keep commenting, good chatting.

[@maxnmilly]

Always use bootlace ferrules for stranded cable, and DC breakers not fuses on all installations for the DC side.

[@narrowboatelectrician]

Only really required on screw type terminals, not on clamp type. Which is what the controller has.

[@MicraHakkinen]

Another enjoyable video, thanks! I came across this channel only recently, but it's already one of the few where I clicked the bell :) If you will indulge my curiosity, the isolator you show around 11:50, is that rated for DC? I thought it looked a lot like the 100A Wylex 321FR, but as far as I can tell that's only rated for AC. And in my experience as a hobbyist, if a switch or isolator is rated for both AC and DC, the DC rating will be substantially lower than the AC rating.

[@narrowboatelectrician]

Hi Bart, yes, for sure. It generally relates to the switching capability under load. DC specific switches have a bigger gap between contacts to extinguish the arc. We do use some 240v switches for dc such as light switches as they are switching low current LED's. I have the conversation with the customer not to break under load, and actually the panels can be damaged that way too. We are only switching about 10A on the PV side so I know this will cope well, I have used them for years. Good point and question Bart, thanks for that.

[@chrisbeaubouef671]

Love your videos. Just realized today. I’m not subscribed. Sorted!! Anyway, is there any issue with galvanic reaction between the steel roof and the aluminium? Thanks! Happy New Year!! From Miami Beach, our hull is being made this year! You’re videos have been so helpful! We will definitely be reaching out when we get to across the pond in May!!

[@narrowboatelectrician]

Thanks for subscribing Chris, all helps! Mmmmm, dissimilar metals? Not something I encounter often but I would think the aluminum would be prone to corrosion if not protected where they touch. There is a research paper here that seems to confirm that ideaexchange.uakron.edu/cgi/viewcontent.cgi?article=2254&context=honors_research_projects Think a conversation with boat builder would be in order.

[@keithperrin1568]

Martin, love your videos. Hope you continue to build the channel. I know that making these videos is a lot of work. Hope you stick with it! I’m trying to figure out how to buy you a coffee but all I can find over there is your Moonshine page. Is that OK? Quick question in the meantime: you kind of skipped over drilling that hole in the roof under the roof gland. What did you use to drill it and what is that white plastic grommet you inserted in it? BTW I am planning a major upgrade to our boat electrics over the next couple of seasons and would love to engage your consulting services as I work my way through it.

[@narrowboatelectrician]

Hi Keith, that’s really nice of you to say, it’s good to know there are people getting something from it. There is a buy me a coffee for Narrowboat Electrician, but Moonshine lands in same pot eventually. Thank you. Happy to assist you when you are ready.

[@narrowboatelectrician]

The hole was already there, there was a Wi-Fi antenna that I removed. I normally drill through with a hole cutter, Starrett are the best ones. As the roof cover is sealed I drop a cut down 20mm cable gland to protect cables from chaffing.

[@keithperrin1568]

@@narrowboatelectrician Thanks. My solar cables right now are routed through a mushroom vent. That’s how the boat was when bought. One of the first things I want to fix. Start simple and move up :)

[@ssailes]

Great videos Martin as always. Have watched a few times but can't find any guidance on how you selected the cable size from the panels. What size cable should be used, or are most solar cables a standard size and type. Im on a widebeam and will have 4 panels of 360W/24v and a 150/100 Mppt. I was 'advised' that i should do two panels in series, and then those two series (2 x 360w) bundles in parallel to the mppt. thanks

[@narrowboatelectrician]

Hi Sean, I use 6mm double insulated solar cable as the MC4 plugs are only rated to 30A anyway. So I try and series the panels up so the voltage goes up and keeps current low. If the array is larger I will use series parallel again bumping up the voltage and keeping current below 30A. I have in some cases had to run two pairs of cables as I cannot get the current low enough. Use the Isc (short circuit current to get the individual current each panel could produce. They are going to be in the region of 15A each, so you would be way over is you paralled them. So two in series then in parallel with the other pair would be an option. But you are right on the edge to where I would be running another pair of cables or putting all in series.

[@stevejones9795]

Hi, great instructional video please can you tell me the make of all the components and where to get them. Cheers Steve

[@narrowboatelectrician]

Hi Steve, all Victron. Brackets, cable etc easy to source online.

[@chrisalfie3326]

Great channel Martin, helpful & informative, thank you. I'm planning to fit some solar panels soon and would like to use the black mounts you've used in this vid. Where do you buy these please?. Regards Chris

[@narrowboatelectrician]

Hi Chris, I always get them From Narian Solar on ebay. Copy this link. ebay.us/lTdKcW

[@chrisalfie3326]

@@narrowboatelectrician Thanks Martin, regards

[@MrCSutton]

Thanks for this, it's very useful. May I ask, if MC4 connectors are only good for 30A and I get the impression most panels come with them already fitted, if you want to connect extra panels in parallel, what can be done about the connectors? Most narrow boats seem to use them, and I've not seen any different types. Is it a case that really people are using them but overloading them, or can they actually cope with increased amperages? Thnaks very much.

[@narrowboatelectrician]

Hi, thanks for the comment. The ones I use are rated for 30A continuous, I wouldn't be driving them any harder than that as during charge cycles the current is prolonged at the higher level. You have spotted the issue when connecting in parallel, as the current can easily exceed the 30A rating. (note some are listed as a 20A rating so always check the datasheet) When you are using 6mm solar cable its current carrying capacity is approx 42A but as long distances can be involved back to the mppt controller, volt drop can come into play as currents increase. Yeah, all narrowboaters do is plug them all in together and not even think about the current capacity. Thats why, on larger controllers there can be multiple PV inputs to allow the running of a second set of cables.

[@MrCSutton]

@@narrowboatelectrician Thanks very much. I'm trying to sort out some panels for our boat and there do seem to be a number of such things that are important, but are apparently ignored by a lot of the articles and videos about them. Is there a particular brand of connectors and fittings that you can recommend please? Thanks again.

[@paulkozakiewicz]

Great video. Why do narrowboaters not earth solar panel frames? Just curious. Watched a few solar panels being fitted to narrowboat roofs and never see the earthing hole get connected.

[@narrowboatelectrician]

No we don't earth the solar panels. They are isolated from the roof when using plastic brackets.

[@andyleese4583]

Stranded cable into screw terminals - I understood bootlace ferrules would be needed? Or is that just a preference?

[@narrowboatelectrician]

Hi Andy, They are not screw terminals, they are clamp type

[@royblackburn1163]

It's best practice to use crimps on stranded cable even with clamp type connectors.

[@andytaylor7318]

What's the best amount of batteries to have for the solar panels.Only have 2 on my boat and thinking of getting solar but think 2 batteries are not enough?

[@narrowboatelectrician]

Hi Andy. As always, it depends. But as a rule of thumb, most narrowboats would have 4 x 110Ah batteries and if you were just out in summer months, 500w of solar. Of course liveaboard off grid is a different matter.

[@markwebster2056]

I am fitting a largish solar array on my widebeam to make use of all available sunlight and anticipate an excess of power after charging batteries. Is it possible to fir a solar dump (Iboost/Eddi) to divert to either immersion or oil filled radiator or can a Victron do the same as i read that it can and it can't. With Eddi/Iboost they are geared to firring between consumer unit and meter in houses but obviously there's no meter on a boat (thankfully).

[@narrowboatelectrician]

Hi Mark, Victron don't have that on their mppt controllers. They have a "load" output but that is used for switching off a load when batteries get to a set lower limit. Not for a dump load.

[@sleepyrabbit1446]

Surely you should have ended with "time for bed", rather than time for a cider. Very informative. Thank you for taking the time to film and share your work.

[@garethevans8424]

Hi, very informative, are you local to Rugby? Need some work on our narrow boat 👍👍

[@narrowboatelectrician]

Unfortunately I’m in Gloucestershire

[@mwhitcombe]

Why no cable ferrules on the multi strand cables? I understood in your past videos that with these cables, ferrules were recommended.

[@narrowboatelectrician]

Hi Martin, they are on screw type terminals, but the mppt and isolator have clamp type connectors. I will show that difference in a future video. well spotted though.

[@lextownsend8748]

Hi Martin, a potential narrowboat buyer.. What are your recommendations regarding flexible panels compared to the rigid type. Also, flat mount or angle bracket mounts?

[@narrowboatelectrician]

Hi Lex. IMO, flexible are twice the price for half as much power, Cables are always visible, When removing you'll destroy panel and paint. On the mounting its proven that flat is best average. And with tilters, do you want to move them every hour? Also what the chance of being 90 degrees to the path of the sun as they only tilt one way.

[@isabellstraughan1593]

Could you do a vlog on inverters ?

[@narrowboatelectrician]

I’ll be wiring up a Victron Multiplus 2 sometime this week. Anything specific?

[@isabellstraughan1593]

@@narrowboatelectrician ........ just types of inverters and their applications re narrowband/campers .

[@markmangan845]

😎😊👍

[@narrowboatelectrician]

Cheers Mark

[@stevemumbling7720]

Please note, not a snarky question. Why connect the solar panels in series rather than parallel? if they were in parallel the total voltage would be far safer, and if one panel failed the other two would continue to provide power. In series if one panel fails that's your lot, no solar power. I'm sure there must be a good reason for this arrangement, but I can't figure it out.

[@Dirt-Diggler]

Usually series if better with an MPPT controller 🤔 they like a higher voltage ?

[@narrowboatelectrician]

As dirtdigger said and expanding - the higher the voltage, the lower the current. Lets say three of those panels an produce 10A, in parallel thats 30A (in series 10A), right on the limit of the connectors and volt drop is going to come into play over a long length of cable. The down side if one of the panels is in heavy shade, the total output is reduced.

[@stevemumbling7720]

@@narrowboatelectrician I get it. So for a house roof with a short cable run parallel would be better. I could always fit heavier connectors. Thanks.

[@stevemumbling7720]

@@Dirt-Diggler Thanks. I have a back up battery bank at home that is floated with a mains to 13.8v DC supply. I have a Plantronics PL20 solar controller and was thinking of getting a couple of solar panels to keep them floated rather than rely on the mains power. I think parallel would be best for my application.

[@Dirt-Diggler]

@@stevemumbling7720 I don't think there's any hard and fast rules 🤔 it's all about the individual installation, i have 4 X 100W panels in parallel due to shading where the van is parked for storage but i still use an MPPT even though the voltage is low ( 25V) mainly cos most PWM controllers don't have dedicated LiFeP04 settings and after spending £800 on a battery I want to look after it 😁 In contrast in my shed i run a PWM as the batteries in there are sealed lead acid and the charge perimeters are fine for them.

[@Chris_In_Texas]

11:50 Hello, quick question are you 100A isolators rated for DC current? Many aren't rated for DC power only AC, might want to check the spec sheet or it should have the DC ratings on the switch itself. Many people I have seen here in the US just use whatever switches they can find for the DC side of solar arrays and come to find out that they do NOT have a DC rating on them and can only be used with AC power. DC is way harder on the switches and can cause premature failures. Just thought I would let you know to check. Granted 500 or even 1KW isn't much power in the grand scheme of things, but none the less it can be an issue.

[@narrowboatelectrician]

I have used these isolators for quite a while, rating for DD refer to the load breaking capacity (due to increased arc sustainability) and is the current carrying capacity is the same for AC or DC. Having said that I am running this at 10% capacity which in my experience is fine, and never used to break the circuit under any load.

[@Satters]

what is the DC rating of that isolator?

[@narrowboatelectrician]

As you are most likely aware, not all switches get a dc rating. It is way over voltage and 10x overcurrent. I I have deemed it suitable. The only issue is breaking dc loads not carrying them. So as we should break solar circuit on power anyhow (as it can damage panels) the customer knows to cover panels before disconnection. This is perfectly acceptable.

[@midsocsec]

Hi Martin. Briefly, i have a 70' narrowboat with 3x 110ah Leisure batteries. I am about to buy/ install 2 x 410w solar panels and victron MPPT etc. Just wondered if you think this will be worth installing, as we are in a marina with EHU 9 months of the year. Been losing sleep thinking about it!

[@narrowboatelectrician]

Hi Steve. Solar inputs even on shore power, less obviously. But will pay huge dividends when you go out.

[@midsocsec]

@@narrowboatelectrician Thanks Buddy, that's what i thought. So looks like i have to spend some money!! Thanks for the reply.

[@narrowboatelectrician]

@@midsocsec look at my store www.kingfisher-marine.co.uk and aim for around 500w for a narrowboat

[@HenryOCarmichaelSmith]

Is that isolator you've used for the panels rated for use on DC?

[@narrowboatelectrician]

Hi Henry. Not specifically but here is the logic. Current carrying capacity is same for ac or dc. DC rating is down to arc quenching capacity requiring wider contact gaps. In this case max current is 10x below capacity and not to be operated in full sun, so not breaking any load current. It’s there as a bib n braces approach to allow you to work on the mppt. Most likely will never be operated. Not unusual to use ac switch gear on 12v. Domestic light switches as an example.

[@HenryOCarmichaelSmith]

​@@narrowboatelectrician I know what you're saying, but what if that is ever operated in an emergency under load it might weld the contacts closed and with no other means of isolation you've got a problem.

[@narrowboatelectrician]

@@HenryOCarmichaelSmith not with solar matey. No more than 10A can ever flow in that side of the circuit. I’d never use these on any battery circuit I promise you.

[@MachielIedema]

flat brackets on a curved roof. 🤔 sad to read that viewers take your advice serieus.

[@narrowboatelectrician]

Such a nice comment. Lets say goodbye now shall we.. Serious is spelt this way.

[@narrowboatelectrician]

Im just off to order some curved ones!