Our first solar panel

[WotEver]

How about this?

 

Nice fat flexible 25mm.

 

Tony

[Cinimod]

How about this?

 

Nice fat flexible 25mm.

 

Tony

Thank you for the hint of checking out welding cable... that brings up many options on eBay - LINKY

(Just in case you have not guessed I like my eBay - Nectar points (1 per £1 spent) and eBay points too... )

[Cinimod]

30m of 25mm cable is going to cost me £80... so I am wondering if this is a good idea, or if using a 240v inverter is a better idea, especially as the wiring is already in the boat.

We have an 800w inverter, which will easily run everything I need - that I was considering running on 12v.

 

From what I have gathered - running stuff (solar panels or appliances) at higher voltage is generally better as the cables don't have to be as thick and there is not so much loss in the cable.

Is that a fair summary?

 

So my question is then - with regards inverters - We have a Sterling 1230 (30A 12v charger) and an IFONIX i-800 inverter (though I am not convinced this is working too well and may need replacing).

 

Is this a reasonable set up - or should I look at getting a combined charger / inverter and get an inverter with an output of 2KW or more - so we can run hair dryers and vacuum if we want!

(Though we also have a 2KW genny, which we can fire up for the odd household chore )

 

Then should my £80 be better spent on an MPPT unit for the solar panels - which seemed like a good deal;

They are the Maplins (LINKY) ones - which I am not convinced are so good now (at least the charge controller)

 

Seems like there are so many small variables to consider, but they all add up to a big power saving or loss, depending on which way you go.

 

Also - wondering if we should consider some more solar power, as now is the time to get best input... if so - who is best at the moment?

[WotEver]

From what I have gathered - running stuff (solar panels or appliances) at higher voltage is generally better as the cables don't have to be as thick and there is not so much loss in the cable.

Is that a fair summary?

Yes

 

But for 240V you lose up to 20% in inverter inefficiencies. Yet another consideration.

 

Tony

[Cinimod]

But for 240V you lose up to 20% in inverter inefficiencies. Yet another consideration.

Hmm... Indeed - the other problem I have with my inverter is that when you stick a load on it (not always, but sometimes) it seems to die... the little green light goes red and no power comes out... any ideas on how to sort that one - or at least how to find out what the problem may be?

 

OK so running on the too thin wire I have at the moment I get about a 3v drop when I put a load on the wire. (Slightly more) and when I work the AMP calculation this gives me about a 28% inefficiency, and I am using about 3.5AMP per hour more than I really need to be, so at the moment I am better off using the inverter.

 

Assuming that putting in 25mm wire will bring that down to negligible inefficiency, then it is a much better way to run.

I can get 30m of cable for £66.50 (delivered)...

 

Considering the cost of a good 2KW inverter (>85% efficiency) it seems to make more sense to buy the cable and use the 2KW LPG powered Genny for times when I need the 240v

Would you concur?

 

The next question then is - where is a good place to buy 12v outlets and also I guess I am going to need some 25mm connection blocks!

[EricMark]

A number of points

1) Panels connected in series need diodes across panels to stop if one gets shadow it getting a reverse feed.

 

2) The simple regulators if connected across battery without a blocking diode can try to regulate the alternator output and burn themselves out.

 

3) Normal clamp on meters will only measure AC amps. There are specials using hall effect that will measure DC but these are very expensive. There are also cheap hold in place type to measure DC only but most will use a shunt and a voltmeter shunt normally made of iron however with an inverter drawing 200A and a solar panel charging at 10A to use a shunt would really need a selector switch unless using a digital display.

 

4) Finally it seems all new rules coming out next year June time on use of solar panels and although they don't count with narrow boats it may change what is available.

 

All very interesting and I am sure my son will end up with a panel soon. Although if inverter is anything to go by it will stay in packing until after warranty has expired.

[blodger]

A number of points

1) Panels connected in series need diodes across panels to stop if one gets shadow it getting a reverse feed.

2) The simple regulators if connected across battery without a blocking diode can try to regulate the alternator output and burn themselves out.

 

3) Normal clamp on meters will only measure AC amps. There are specials using hall effect that will measure DC but these are very expensive. There are also cheap hold in place type to measure DC only but most will use a shunt and a voltmeter shunt normally made of iron however with an inverter drawing 200A and a solar panel charging at 10A to use a shunt would really need a selector switch unless using a digital display.

 

4) Finally it seems all new rules coming out next year June time on use of solar panels and although they don't count with narrow boats it may change what is available.

 

All very interesting and I am sure my son will end up with a panel soon. Although if inverter is anything to go by it will stay in packing until after warranty has expired.

)On 3 this is changing, the Chinese are producing more clamp meters with dc amps capability and, what I consider clamp on sare dc not ac.

 

On 1 I tend to agree it is worthwhile adding a diode to prevent future problems despite voltage/power loss.

 

Solar panels are intolerant of wrong polarity connection and also being connected when welding is going on

[Cinimod]

Does this mean in order to put the panels in Series, I really need to get out the soldering iron and create a connection board?

 

What sort of diodes would I be after? - Do they need to increase in capacity as you go down the line, or is it OK to use ones big enough to cope with max capacity all the way?

 

I am assuming this would be better.... at the moment the 4 panels in parallel should be MAX of 3.42A @ 17.5v... in Series I am working out that they would get up to 0.86A @ 70v?

However, doing the drop calc @ 3.42A over 5m the cable needs to only be 1.43mm (which I think it is) so looks like it would be an un-required effort?

If in series would it really only need to be 0.36mm cable? (over 5m)

 

Just dawned on me - @ 12m the cable thickness in mm needs to be the same as the load in Amps... doh!

It has also dawned on me that the 60w of solar we have is no where near enough... where is the best deal for more at the moment...

 

Thank you all you wonderful people for sharing your knowledge. Isn't the internet great!

[blodger]

The Chinese are doing the cheapest but need to be wary of import duties which bring them up to the same price as similar stocked in this country.

 

Search for blocking diodes on Ebay and (Damien Mitchel) does 30/40 amp ones with low volts drop (O.33) that nicely bolt onto (insulated) brackets/heat sink. You'll get 4 for a tenner if you offer.

[EricMark]

This is the diagram from the 17th Edition wiring regulations mainly to show earthing requirements. However it does show use of diodes. There is no reference as to size of diodes I understand the amendment due out this time next year includes more regulations as to use of solar panels. It seems with larger arrays there have been a few nasty accidents where light has fell on the array while some one was working on them. By the way 17th Edition does not cover narrow boats.

I wouldn't think the by-pass diodes need to be that big really only there for times when one cell gets covered so time would be low and heat sinks should be small. The blocking diode however will take much more and this would need ample heat sinks to stop over heating. I do remember working out heat sink sizes in University but books not to hand and not so easy anyway think I would go for ample and then inspect. Regulations say:- "712.512.1.1 Electrical equipment on the d.c. side shall be suitable for direct voltage and direct current. PV modules may be connected in series up to the maximum allowed operating voltage of the PV modules (UOC STC the PV strings) and the PV convertor, whichever is lower. Specifications for this equipment shall be obtained from the equipment manufacturer. If blocking diodes are used, their reverse voltage shall be rated for 2 x UOC STC of the PV string. The blocking diodes shall be connected in series with the PV strings."

 

One point though is diagram shows diodes first but with some voltage regulators the regulator also needs diode protection and each diode has volt drop of 0.6 volt so one does not want to add too many and I see no point in having them on pos and neg or both sides of regulator.

 

Do remember the regulations are valid also for the huge arrays found on commercial properties as part of their corporate image where they want to show the world at large how green they are and when they go wrong they are not too quick to repair as no one knows they are not working and some of the voltages produced with large arrays can be frighting.

 

This is not really a problem with sizes used on narrow boats. And one may find some of the diodes shown are already built into the array.

 

The same regulator was used for solar and wind charging and I know with wind the regulator just turns any excess power into heat and if put across battery they don't care where the power comes from and to sink the output from a 70A alternator is far more heat than they can handle and the have that expensive smell and smoke come from them. There were warnings with wind charger and I would hope where required they still have warnings on them.

[Mandy]

Can I just say that it is an absolute pleasure to read a post that is informative, courteous and on topic. Thank you Roger and all contributers. Now I just need to increase my brain power in order to understand all the technical stuff. I live on a no power mooring and solar panels seem to be the answer to my problems in keeping the batteries well charged, especially when I'm working all day. Thanks for all the info.

[Pretty Funked Up]

Anyone got a diagram for them in series and using diodes as Ericmark suggests?

[Cinimod]

Well I have my new cable in - that was an all day job!

Take down the entire run of the roof section, drill through the bulk heads, run the cable, wire it in, put everything back... and still not finished...

 

Anyone care to recommend some good (not too expensive) LED lighting to put into the ceiling?

 

the problem I had is connecting the VERY THICK cable (finally worked out 25mm is the circumference and not the diameter!) to the socket at one end and the switch panel at the other. I have done this using a short run of 6mm cable - should that be OK do you think, or does it defeat the purpose of the larger cable? This cable is thicker than the cable from the battery to the swithing panel!

 

Ta

[johnmck]

Hi

 

I see Kings Lock chandlery have the below kit on offer!

 

No connection to the company, but any thoughts on this bit of kit?

 

 

SPECIAL OFFER 150 watt Solar Panel Boat Kit - 68 amp hours per day on offer at £827.99

 

John

[NB Willawaw]

A lot of these electrical jobs are very labour intensive, especially on existing boats.

As far as narrowboats are concerned, I've realised that the cost of paying someone to do it for you can often be prohibitive and beyond the reach of many boaters pockets.

Many boaters want to and can do, most of the job themselves. They sometimes just need a little help and guidance. These days, if people want panels or an inverter, etc fitted but don't know how to do it, I tend to visit the boat, make a drawing of how it needs to go, spec and often obtain all the bits that are needed and then just go to the boat once more at the end to wire it up, make up battery connectors etc and commission it. Experience often means that I can see an easy way of installing something that will save a lot of work and unnecessary parts.

This way, the costly hours, drilling through steel and running cables, are avoided and the boater gets a properly designed and specified installation for a few hours paid labour.

 

I haven't read all the thread, but 25mm is normally 25mm2 and is the cross sectional area, not the circumference.

 

 

 

Well I have my new cable in - that was an all day job!

Take down the entire run of the roof section, drill through the bulk heads, run the cable, wire it in, put everything back... and still not finished...

 

Anyone care to recommend some good (not too expensive) LED lighting to put into the ceiling?

 

the problem I had is connecting the VERY THICK cable (finally worked out 25mm is the circumference and not the diameter!) to the socket at one end and the switch panel at the other. I have done this using a short run of 6mm cable - should that be OK do you think, or does it defeat the purpose of the larger cable? This cable is thicker than the cable from the battery to the swithing panel!

 

Ta

[Chris Pink]

Hi

 

I see Kings Lock chandlery have the below kit on offer!

 

No connection to the company, but any thoughts on this bit of kit?

 

 

SPECIAL OFFER 150 watt Solar Panel Boat Kit - 68 amp hours per day on offer at £827.99

 

John

 

About twice what it should be.

 

Well I have my new cable in - that was an all day job!

Take down the entire run of the roof section, drill through the bulk heads, run the cable, wire it in, put everything back... and still not finished...

 

Anyone care to recommend some good (not too expensive) LED lighting to put into the ceiling?

 

the problem I had is connecting the VERY THICK cable (finally worked out 25mm is the circumference and not the diameter!) to the socket at one end and the switch panel at the other. I have done this using a short run of 6mm cable - should that be OK do you think, or does it defeat the purpose of the larger cable? This cable is thicker than the cable from the battery to the swithing panel!

 

Ta

 

I am unsure whether you really mean 25mm diameter cable (Are you trying to light up Milton Keynes?), when cable is specified the number usually applies to area ie 25mm². However most panels and the MC3 linking cables you can get are wired with 4.5mm ² cable.

 

Being someone who routinely overspecs cable i use 10mm² (which has a diameter of around 7mm with insulation). to fit this into smaller connectors, the best thing to do is to separate the strands at the connector and insert as much as is possible. resistance is proportional to length so the drop introduced by this (or your short tails) is minimal.

[Roger Gunkel]

Hi

 

I see Kings Lock chandlery have the below kit on offer!

 

No connection to the company, but any thoughts on this bit of kit?

 

 

SPECIAL OFFER 150 watt Solar Panel Boat Kit - 68 amp hours per day on offer at £827.99

 

John

 

Way over priced!! Have a look at Midsummer Energy's XM range Panels I have used one of their XM 100s for a few weeks and it has been very good, as has the help and advice. The Panel cost me £280

 

Roger

[barge sara]

Hi

I see Kings Lock chandlery have the below kit on offer!

No connection to the company, but any thoughts on this bit of kit?

 

SPECIAL OFFER 150 watt Solar Panel Boat Kit - 68 amp hours per day on offer at £827.99

 

John

 

I've just fitted two 100 watt panels on a friend's boat.

Cost for two panels, Steca 20A controller, cables, connectors etc. was £435.00

Panels from 1000suns. Controller from Free Solar Energy on Ebay.

Could have been cheaper still if I was prepared to use a cheap Chinese import controller.

 

Edited to add:

1000suns are cheap but certainly don't do help and advise and tend to take 2 or 3 weeks to deliver.

Edited July 13, 2010 by barge sara

[Cinimod]

About twice what it should be.

 

I am unsure whether you really mean 25mm diameter cable (Are you trying to light up Milton Keynes?), when cable is specified the number usually applies to area ie 25mm². However most panels and the MC3 linking cables you can get are wired with 4.5mm ² cable.

 

Being someone who routinely overspecs cable i use 10mm² (which has a diameter of around 7mm with insulation). to fit this into smaller connectors, the best thing to do is to separate the strands at the connector and insert as much as is possible. resistance is proportional to length so the drop introduced by this (or your short tails) is minimal.

 

The cable is spec'd as 25mm - it is welding cable - very good price from eBay.

Thanks for the advice on the 'tails' - this is what I have done, though I may shorten one end a bit more.

 

It is working though, as I am able to run both the TV screen and laptop at the same time, but the battery drain still seems rather too high.

I need to do some calculations, but it seems to be draining faster than I would expect.

[Roger Gunkel]

Edited to add:

1000suns are cheap but certainly don't do help and advise and tend to take 2 or 3 weeks to deliver.

 

I had one panel from them that works fine, but had absolutely no reply to further enquiries, and requests for information have gone unheeded despite a string of promises.

 

Roger

[barge sara]

I had one panel from them that works fine, but had absolutely no reply to further enquiries, and requests for information have gone unheeded despite a string of promises.

 

Roger

 

Yes, 1000 Suns are an absolute pain to deal with, but the last two 100 watt panels I bought were £336 the pair including delivery.

Worth a bit of grief for that price!

They seem to respond better to phone calls than email.

[Cinimod]

I appologise if this is a little off topic, but it is to do with power still

 

We have 4 x 110ah batteries - which I calculate to be 440ah...

We also have a smart guage and I like to be able to see how much % and v are available.

 

If we are at 81% and showing 12.3v and I am drawing of 7a/h (about 1.6%) I would anticipate being able to get about 19 hours of power before getting to 50%... however, am I correct in assuming that as you use battery power the voltage will drop, which means I will end up using more AMPs?

 

So instead of it lasting 19hours, the power will only last about 15hours before I hit the 50% mark...

Even so - the battery seems to run down a lot faster than that (at least according to the SMART Guage)

 

I would really like to get some sort of panel that records the AMPs in and out (and potentially voltage) to an SD card (or similiar) so that I can see how well the batteries are performing. I am guessing if my batteries seem to be going down too fast, there is a potential problem, which I am a bit dissapointed about as we only got them new in January!

[WotEver]

Yes, you should theoretically get around 19 hours with those figures (the voltage drop of around 0.2V is negligible so ignore it). You're running below the 20 hour rate, so in reality you should actually get slightly longer.

 

However, what if your figure of 7A is incorrect? How are you measuring it?

 

Tony

[Roger Gunkel]

I don't make a habit of getting involved in battery discussions as there are others with for more knowledge than me, however, there seems to be a discrepency in your figures. 12.3 volts as far as I am aware would be 60% not 81%. If you have actually got 81% showing, then your voltage should be about 12.5v. The trouble is, it depends on when, where and how you are seeing those readings. If you have a steady 7ah drain with intermediate surges from pumps etc, your voltage reading could be showing a surface reading which will recover to a true reading once the power drain has stopped.

 

No doubt someone with more technical understanding will reply shortly

 

Roger

 

(edited to say, "Sorry Tony my typing is slower than yours!")

Edited July 16, 2010 by Roger Gunkel

[WotEver]

Don't apologise, Roger - you've made a good point that I'd completely missed. I was purely working on 81% down to 50% and had entirely bypassed the voltage readings. You're right, they don't tally. 12.3V is pretty darn close to flat - around 60% as you say.

 

So I'm guessing that we can assume once again that it's a case of insufficient charging and SG hasn't had a chance to sync itself up correctly - that sound about right, Gibbo?

 

Tony