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Electric set up advice


Peppers

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Sorry, I know I've sort of mentioned something about this before, and I'm being very on and off on the site at the minute, but between building a boat, being self-employed and writing a PhD, I'm finding little time to think straight!!

We're about to order all our electrical set up and just want to make sure we're doing the right thing before we go ahead. Please do offer suggestions - this part has been the source of a great deal of stress for us and is a little bit of a sore topic, so any help is very much required! 

We'll be liveaboard - running the usual 12v lights, charging phones, laptops, oven ignition, 12v fridge, pumps, a couple of kitchen worktop appliances every now and then - nothing too out of the ordinary but I would like to "future-proof" and not skimp now in order to find ourselves falling short very soon. 

In our shopping baskets at the minute are:

Vitally, I don't know how many solar panels to order. Ideally, they'd sustain the boat power wherever possible during summer. Strangely my OH seems to think the electrician who will be installing said we only need one panel (something to do with us having a big engine), which I'm certain I'm not understanding right. He said we should get this pack as it has a charge controller in it - would we need more than one charge controller though, depending on the amount of solar panels?

So...what do I have wrong, incorrect, missing etc. etc...?

Thanks so much all. 

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1 hour ago, Peppers said:

I would consider an mppt controller for the solar. 

solar calculator  

http://www.bimblesolar.com/solarcalc

Edited by rusty69
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Will you have  shore power available if so how about a battery charger or combined inverter/charger (multiplus ) ?

Amount of solar will depend on your energy use and budget. People with more knowledge than me will be along soon to help you with that I'm sure.

That solar kit looks expensive too me an equivalent setup from bimble is a lot cheaper http://www.bimblesolar.com/offgrid/12v/175w-dualbatt-pwm-kit

or a bigger panel with a mppt controller http://www.bimblesolar.com/offgrid/12v/260W-kit-mppt-mounting?sort=p.price&order=ASC&limit=75

But work out what you need first as you may wish to add panels later etc.

 

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You can't have too much solar IMHO. And fit an MPPT controller.

You don't say whether you will be CCing or usually attached to shore power. 140 watts of solar won't be enough if you are living aboard and expect a usefull contribution to your electrical needs. We have 700 watts and find that provides most of our needs throughout the summer. Bear in mind that on cloudy days, your panel will produce a lot less power. To produce electricity off grid is going to be expensive, either by engine or genny, and is likely to cost you around £1 per hour as a rough ball park figure. Solar of course is free after the initial costs. Even if you are attached to shorepower, electricity still costs. I find that I only need to have the shorepower switched on for only an hour or two a day to run power hungry items such as immersion, washing machine, iron, etc. So even having shore power available, solar is still a very cost effective option.

Having said that, solar will be pretty much useless for your needs in winter.

Ken

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Each time I read this type of post from a soon to be or new boater and find no power audit figures have been given experience tells me it may all end in tears. Especially when I see a 3000 Watt inverter, unspecified "work top appliances" and no mention of other mains powered equipment like a hair dryer, iron, vacuum cleaner etc. If there are to be many mains appliances in use then you need to look at getting a large alternator that can power them via the inverter, a Travelpower system on the engine or a separate generator.  A 3000Watt inverter at full output will draw about 300 Amps from the battery so with 440Ah of battery capacity that only gives you less than half an hour running from fully charged batteries. That sort of load is not very good for batteries.

If you do not want to run the engine then the engine and alternator size are irrelevant as far as solar specifications go. Until we see your power audit any sizing will be a guess so  until we get more info the answer must be "as much as you can afford or fit on the boat". Even so some times, even in summer,  it will not be enough. Its more a question of looking at solar as a charging helper rather than the main source.

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Unless you will have electric hook-up in the winter - or are intending cruising every day you really need to consider a 'Jennifer the Generator'. This will add between £2000 (Honda 2 Kw suitcase type, petrol) to £10,000 (built in diesel, water cooled, ultra-quiet 7-10Kw) to your fit out costs.

The alternative is to sit with your engine running for 3 or 4 hours per day and not moving

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48 minutes ago, Tony Brooks said:

I would add an ammeter to help you decide when to stop engine charging.

Definitely. It was the one glaring omission whatever solar setup/generator/travel power the OP needs. 

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Thank you for your extremely useful responses so far.

We will be CCing and not hooked up to shoreline power. 

With regards to a power audit @Tony Brooks I did a bimble calculator thing (screenshot attached). Apologies for not including to begin with. I

And thank you so much for mentioning the ammeter @Tony Brooks and @WotEver - I had not realised a smartgauge was not that. Any particular type of ammeter or is something like this ok? https://www.midlandchandlers.co.uk/store/product/ei-003.aspx

I have, of course, over-egged everything on the calculator, so perhaps 6 of the solar panels suggested above (http://www.bimblesolar.com/offgrid/12v/260W-kit-mppt-mounting?sort=p.price&order=ASC&limit=75) would work - presumably giving me 1560W of solar if it happens to be a glorious summer day :/

3 hours ago, Tony Brooks said:

experience tells me it may all end in tears. Especially when I see a 3000 Watt inverter

Can I ask why this inverter might be incorrect? I'm still struggling to get my head around what the 3000w bit means in relation to the inverter. My logic/sense tends to be a bit "surely the bigger number the better" which I'm sure is quite wrong, but hey ho I'm trying to learn.

Thanks again all for your invaluable knowledge so far. 

Screen Shot 2017-08-31 at 11.01.49.png

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Also the electrician doing our install says we have a large twin alternator on the engine. I just spoke to him and he said we've not got anything on the boat which warrants loads of solar. I think he's thinking this as we won't have a washing machine or dishwasher or hoover, but we do have technical equipment we need to use and so I'm concerned we will be underprepared.

I just did a "build your own" through bimble, which came up with the picture below. Any thoughts on this?

 

Screen Shot 2017-08-31 at 11.39.14.png

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There have been several threads on here recently from folks who have destroyed their batteries 'quite quickly' because they have not managed their charging regime. To my mind - as well as charging the batteries for the correct amount of time, there's been no discussion about equalizing  the batteries towards the end of the charge. This is essential if battery sulphation is to be minimised / reduced. For the ordinary user this can only be achieved by a charge controller such as an Adverc or Sterling or some other.

Not using lead acid batteries I'm quite happy to be contradicted on the subject - but it's painfully obvious to me....

 

  

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In my view that ammeter is better suited to a "boy racer" type setup, not accurately measuring charging current. I think that you need a digital one and you could do a lot worse than a battery monitor from the Nasa, Victron etc  AS LONG AS YOU GRASP THE FOLLOWING: - These monitors will give accurate readings of Amps, Volts, and Amp hours OUT. They also purport to show the batteries state of charge, Ah left, time left and such like but in most boaters' hands these are nor much more than lies and cause premature battery failure. That   will tell you when you can stop charging  from the Amp flowing into the battery while the Smartguage will tell you when you should start charging to prevent battery damage. Even so you should recharge every day.

How do we know what figures you put into Bimble calculator and what assumptions it made? Did you divide the inverter driven loads wattages by 10 rather than 12?. If not the calculation could be wrong. In any case I expect the power audit result to be expressed in Amp Hours not kWh. Sample calculations and charging/battery calcs to get a  starting point on my website in the course notes.

A 3000 Watt inverter means that you will have no need to limit the power of mains electric equipment you will gradually bring onto the boat and use. As long a such equipment is only used while the engine is running at speed and generating enough electricity to supply the loads then there is nothing wrong but as I explained at full output it will be drawing about 300 amps from the battery unless the alternator is covering it and that will go to a potentially damaging degree of discharge in about 20  minutes with fully charged batteries and far faster with old or partially discharged ones. You may well have it all sorted but experience here say the likelihood is that you do not. I suspect the large alternator probably has a 175 amp output if you are lucky. That would cover an AC load 1750 Watts, not 3000 Watts.

Edited to add:- If you did draw 300 Amps for 20 minutes it will take many, many hours of charging to put that back into the batteries - think maybe 10 to 12 hours of engine charging or maybe 4 hours early in the day from the engine and the rest, in summer, from SIGNIFICANT solar. 

I will be blunt, as you tell us you will be CCing in winter without a shoreline your electrician is talking through his nether regions. Solar will NOT provide enough power during the winter and may not in poor weather in the summer so more than one person has advised as much solar as you can get on the boat or you can afford. Either that or plan to run your engine everyday for several hours OR buy a generator.

No-one here has anything to gain by giving anything other than the best advice as they see iso have no reason to give bad advice.

36 minutes ago, OldGoat said:

There have been several threads on here recently from folks who have destroyed their batteries 'quite quickly' because they have not managed their charging regime. To my mind - as well as charging the batteries for the correct amount of time, there's been no discussion about equalizing  the batteries towards the end of the charge. This is essential if battery sulphation is to be minimised / reduced. For the ordinary user this can only be achieved by a charge controller such as an Adverc or Sterling or some other.

Not using lead acid batteries I'm quite happy to be contradicted on the subject - but it's painfully obvious to me....

 

  

 Modern Solar MPPT controllers do a regular equalise cycle and as standard this is set to about 14.8 volts for wet cells. However if it has a user setting then this could be set to 15 volts if  that was required.

It would not be good for any form of sealed cell battery to be equalised on a regular   basis because it would drive waer off and they can not be topped up.

Edited by Tony Brooks
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5 minutes ago, Tony Brooks said:

In my view that ammeter is better suited to a "boy racer" type setup, not accurately measuring charging current. I think that you need a digital one and you could do a lot worse than a battery monitor from the Nasa, Victron etc  AS LONG AS YOU GRASP THE FOLLOWING: - These monitors will give accurate readings of Amps, Volts, and Amp hours OUT. They also purport to show the batteries state of charge, Ah left, time left and such like but in most boaters' hands these are nor much more than lies and cause premature battery failure. That   will tell you when you can stop charging  from the Amp flowing into the battery while the Smartguage will tell you when you should start charging to prevent battery damage. Even so you should recharge every day.

How do we know what figures you put into Bimble calculator and what assumptions it made? Did you divide the inverter driven loads wattages by 10 rather than 12?. If not the calculation could be wrong. In any case I expect the power audit result to be expressed in Amp Hours not kWh. Sample calculations and charging/battery calcs to get a  starting point on my website in the course notes.

A 3000 Watt inverter means that you will have no need to limit the power of mains electric equipment you will gradually bring onto the boat and use. As long a such equipment is only used while the engine is running at speed and generating enough electricity to supply the loads then there is nothing wrong but as I explained at full output it will be drawing about 300 amps from the battery unless the alternator is covering it and that will go to a potentially damaging degree of discharge in about 20  minutes with fully charged batteries and far faster with old or partially discharged ones. You may well have it all sorted but experience here say the likelihood is that you do not. I suspect the large alternator probably has a 175 amp output if you are lucky. That would cover an AC load 1750 Watts, not 3000 Watts

I will be blunt, as you tell us you will be CCing in winter without a shoreline your electrician is talking through his nether regions. Solar will NOT provide enough power during the winter and may not in poor weather in the summer so more than one person has advised as much solar as you can get on the boat or you can afford. Either that or plan to run your engine everyday for several hours OR buy a generator.

No-one here has anything to gain by giving anything other than the best advice as they see iso have no reason to give bad advice.

 Modern Solar MPPT controllers do a regular equalise cycle and as standard this is set to about 14.8 volts for wet cells. However if it has a user setting then this could be set to 15 volts if  that was required.

It would not be good for any form of sealed cell battery to be equalised on a regular   basis because it would drive water off and they can not be topped up.

For effective use of solar it is to be hoped that the sun shines regularly and long enough to equalise the battery set?

Apologies - I'd ignored the sealed cell issue - don't they have some calcium salts in them to reduce the effects of sulphation?

 

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FWIW I have caught my old PWM controller doing an equalisation charge a few times but it does need the batteries to be all but fully charged.

I think the calcium is alloyed into the lead plates instead of the traditional antinomy. Some add silver as well.  This has the effect of raising the gassing voltage so if you have the  charging equipment that is capable you can charge at closer to 14.8 than 14.4. This in itself will reduce sulphation. This can apply to open wet cells a swell as sealed cells.

Some/many sealed batteries have a catalytic arrangements whereby the hydrogen and oxygen produced by gassing gets recombined back to water within the cell. However equalising at say 15 volts would probably overwhelm the catalyst so the excess gas would be vented.

I know some will disagree with me on this but I think the bulk of sulphation problems come from insufficient charging over a long period. Maybe not when we had 13.8 volt alternators but now most will go to 14.4 to 14.5 and some to 14.8 the charging voltage is getting close to equalisation values.

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1 hour ago, Peppers said:

Also the electrician doing our install says we have a large twin alternator on the engine. I just spoke to him and he said we've not got anything on the boat which warrants loads of solar. I think he's thinking this as we won't have a washing machine or dishwasher or hoover, but we do have technical equipment we need to use and so I'm concerned we will be underprepared.

I just did a "build your own" through bimble, which came up with the picture below. Any thoughts on this?

 

Screen Shot 2017-08-31 at 11.39.14.png

I didnt realise you were living on HMS Belfast......

 

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I am not sure of the dimensions of your boat, but these panels are roughly 1.6m by 1m, and your calculator above shows 7 panels, so if a narrowboat and you put the panels end to end with a 100mm gap between then, then they will be about 12m long, or close to 40 feet.  Do you have that much free roof space??

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7 hours ago, NB Ellisiana said:

You can't have too much solar IMHO. And fit an MPPT controller.

You don't say whether you will be CCing or usually attached to shore power. 140 watts of solar won't be enough if you are living aboard and expect a usefull contribution to your electrical needs. We have 700 watts and find that provides most of our needs throughout the summer. Bear in mind that on cloudy days, your panel will produce a lot less power. To produce electricity off grid is going to be expensive, either by engine or genny, and is likely to cost you around £1 per hour as a rough ball park figure. Solar of course is free after the initial costs. Even if you are attached to shorepower, electricity still costs. I find that I only need to have the shorepower switched on for only an hour or two a day to run power hungry items such as immersion, washing machine, iron, etc. So even having shore power available, solar is still a very cost effective option.

Having said that, solar will be pretty much useless for your needs in winter.

Ken

How about if you're mainly on shore power but want solar to subsidise your mains usage and also give you some usable power when you're away from the mooring? I haven't done a a power audit but when away from shore power my electrical requirements are relatively low as I switch the fridge to gas, most of my lights are led and I use a small flatscreen 12v tv when I'm away which only draws 1amp. I haven't included laptop use of course but I will soon be getting something to replace this 8 year old model which will hopefully be more power efficient. I also have a 3kW (2.6kW rated) generator to run my washing machine when away from the mooring and use this at the same time to run the battery chargers, immersion heater, vacuum cleaner, etc, if I've been static for any length of time and haven't run the engine. I don't believe in using batteries to run high power mains appliances. I only have 450a/h of domestic batteries but that's always been quite sufficient for me.

You mention only switching your shore power on when you need to run the washing machine. I pay 50p/day for the use of shore power whether I use it or not (yeah complete rip-off I know, but I just mentally add the £182.50/year to my mooring fee and then it doesn't seem so bad). I suppose I would do the same as you, switch my battery charger off (which is usually on 24/7) and keep the inverter switched on for mains power?

Edited by blackrose
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4 minutes ago, blackrose said:

How about if you're mainly on shore power but want solar to subsidise your mains usage and also give you some usable power when you're away from the mooring? I haven't done a a power audit but when away from shore power my electrical requirements are relatively low as I switch the fridge to gas, most of my lights are led and I ise a mall flatscreen 12v tv when I'm away which only draws 1amp. I haven't included laptop use of course but I will soon be getting something to replace this 8 year old model which will hopefully be more power efficient. I also have a generator to run my washing machine when away from the mooring and use this at the same time to run the battery chargers if I've been static for any length of time.

You mention only switching your shore power on when you need to run the washing machine. I pay 50p/day for the use of shore power whether I use it or not (yeah complete rip-off I know, but I just mentally add the £182.50/year to my mooring fee and then it doesn't seem so bad). I suppose I would do the same as you, switch my battery charger off (which is usually on 24/7) and keep the inverter switched on for mains power?

We have been on our marina berth a lot this summer due to a number of reasons and have found that our electric consumption from the meter has been drastically reduced due to our solar array. We have a large fridge, two freezers and the usual gadgets of modern life so our normal electric consumption is fairly high. Solar caters for pretty much everything except the hot water which is provided by the immersion heater when either the engine or diesel heating system isn't on. We just switch the shore power on for about an hour or so per day to give us a tank full of water or when using high load items like the washing machine. Judging by the amount of prepay meter cards I have been buying this summer I would say my electric costs have been reduced by about 60-70% compared to my pre-solar usage. In cash terms that amounts to a saving of about £30 a month.

I have found that it is neccessary to switch off the shorepower (we have a Victron Multiplus inverter/charger) as otherwise the MPPT controller shuts down the panels as it senses the batteries are charged and the solar capability is wasted.

 

Ken

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5 hours ago, NB Ellisiana said:

 

I have found that it is neccessary to switch off the shorepower (we have a Victron Multiplus inverter/charger) as otherwise the MPPT controller shuts down the panels as it senses the batteries are charged and the solar capability is wasted.

Is there any way to get a controller to switch the battery charger off rather than the panels? 

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9 hours ago, Peppers said:

Also the electrician doing our install says we have a large twin alternator on the engine. I just spoke to him and he said we've not got anything on the boat which warrants loads of solar. I think he's thinking this as we won't have a washing machine or dishwasher or hoover, but we do have technical equipment we need to use and so I'm concerned we will be underprepared.

I just did a "build your own" through bimble, which came up with the picture below. Any thoughts on this?

 

Screen Shot 2017-08-31 at 11.39.14.png

Are you going to live aboard 24/7 365? If so yes we all have different wants/needs but no washing machine is fine for hobby boating but a pain for living full time. Even a small portable type is better than non at all.

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19 minutes ago, blackrose said:

Is there any way to get a controller to switch the battery charger off rather than the panels? 

You would need to get the solar charger running at a rate above the landline battery charger. I wonder if Nicknormans Empiribus system is capable of this???

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Thanks so much @Tony Brooks - is this the victron battery monitor type you refer to? https://www.midlandchandlers.co.uk/store/product/vv-024.aspx - would we need one of those for each battery? Full bimble calculator is below, I probably have made mistakes on there.

9 hours ago, Tony Brooks said:

A 3000 Watt inverter means that you will have no need to limit the power of mains electric equipment you will gradually bring onto the boat and use. As long a such equipment is only used while the engine is running at speed and generating enough electricity to supply the loads then there is nothing wrong but as I explained at full output it will be drawing about 300 amps from the battery unless the alternator is covering it and that will go to a potentially damaging degree of discharge in about 20  minutes with fully charged batteries and far faster with old or partially discharged ones. You may well have it all sorted but experience here say the likelihood is that you do not. I suspect the large alternator probably has a 175 amp output if you are lucky. That would cover an AC load 1750 Watts, not 3000 Watts.

I think he did say 175 amp output yes - does that mean a 3000 watt inverter is essentially pointless then, would we be better with a smaller one?

Also - we're on a 60ft by 12ft so should have the roof space for plenty of solar - to be honest I was thinking 6 panels rather than bumble's suggested 7. I was still thinking the 4 Leoch batteries too rather than the ones bimble suggested. 

Screen Shot 2017-08-31 at 10.56.35.png

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Inverter - There is nothing inherently wrong with a 3000 Watt inverter. The problems occur when it allows boaters to use mains appliances as if they were on land with no thought about how they are going to recharge the batteries. A smaller inverter limits you somewhat and forces you to think a bout what you are using.

Your Bimble calculations taken at face value give a daily consumption of  465 Ah @ 12V. For optimum life you should not discharge most battery types below 50% on a regular basis so that implies a battery bank size of 930 amp hours - rather more than 4 x 110 Ah batteries - that is if your figures are accurate. I would want to see the amps drawn @12V instead of watts. Mains  appliances need their wattages divided by 10, not 12 to take inverter inefficiency into account. The bank size may end up larger if Bimble have not taken inverter inefficiency into account.

At times when away from a shoreline your solar will produce not much more than zero output so your systems need to be specced for that if you intend to CC. A 175 amp alternator will on average charge at about 80 amps over 3 or four hours. Then the average charge becomes much lower, ever decreasing, until it ends up at 10 amps or less. Lets take 4 hours - 4 x 80 = 320 Ah but you need 465 so you still have a 145 Ah deficit ASSUMING A 100% charge efficiency that you will not have. You have already run the engine for 4 hours so you need to keep going for ................. how long? may be another 4 hours or more. Probably longer because batteries do not convert 100% of the current supplied into battery charge. On many days sufficient solar will more than cover that second four hours so maybe you will normally only need to run for 2 hours per day and in summer not at all.

Everything depends on your electrical use. Without the data from your equipment all I can say is that flushing the toilet for 2 hours a day looks a lot to me. For  12V fridge the 30 Ah consumption looks a bit low to me but as the highest consumption is likely to be in summer when solar is better that may not matter. I think my very old Lenovo laptop has a 90 watt power supply so those look bit high to me. Your camera recharges in just one hour? You are going to be running 20 lights for a full 7 hours? We generally only have 2 to 4 on at any one time. Why do you need powered speakers?

I note no radio, TV, hair dryer, electric iron, vacuum cleaner. All of those are common on boats that use an electric bread maker. Even it not at the start they gradually creep aboard.

I have been trying to get you to think deeply about your electrical consumption, battery bank size, and charging arrangements/regime. I have also been trying to get you to accept your electrician may not be correct in his assertion. As its a wide beam it looks a good candidate for an onboard diesel generator. Then you have far fewer restrictions because that will supply your needs when solar can't

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20 minutes ago, Tony Brooks said:

Your Bimble calculations taken at face value give a daily consumption of  465 Ah @ 12V.

To emphasise the figures Tony gives above, the 'rule' for working this stuff out is..

  1. What is my daily consumption?
  2. How can I replace this daily?
  3. I need a battery bank around 2.5-3 times number 1 

Numbers 1&2 need to be played around with until they balance. If you can't achieve 2 with your current plan then you either have to work out how to reduce 1 or you need to rethink 2. Only when you've done this can you consider 3. 

22 minutes ago, Tony Brooks said:

As its a wide beam it looks a good candidate for an onboard diesel generator. Then you have far fewer restrictions because that will supply your needs when solar ca

This is looking to me like your best bet :)

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Wow, you've made this so much clearer for me, thank you so so much. I've just spoken to the other half about diesel generators and we think we will definitely go down this route. If it looks to be too much for our budget for now, it will become our Christmas present to ourselves later in the year! I'll start looking into these this afternoon, but for now, as for the rest of my "shopping list", how does this sound based on the wonderful advice you've all given so far. 

4 x 160amp batteries: http://www.alpha-batteries.co.uk/leoch-160ah-agm-leisure-battery/

Victron 3000w inverter: https://www.midlandchandlers.co.uk/store/product/vv-015.aspx

Smartgauge: http://www.smartgauge.co.uk/smartgauge.html

Battery monitor: http://www.12voltplanet.co.uk/victron-bmv-700-multi-function-battery-monitor-1-batterybank.html

One of these as it comes with the MPPT controller: http://www.bimblesolar.com/offgrid/12v/260W-kit-mppt-mounting?sort=p.price&order=ASC&limit=75 - then I'm going to speak to bimble about 5 other solar panels that I could get, and how many controllers I would then need.

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