Solar Panels

[laurieash]

Thinking or gettig a solar panel to keep caravan battery toped up when using it on Holidays, What size do i need,any tips as i Know Jacksh.t about them.
Laurie.

 

[briggie]

Thinking or gettig a solar panel to keep caravan battery toped up when using it on Holidays, What size do i need,any tips as i Know Jacksh.t about them.
Laurie.

solarman 216 is the man to ask :thumb2

 

[R1cho]

theres a few trickle charge ones on the bay like this http://cgi.ebay.co.uk/12v-Solar-Pan...60476312443?pt=UK_Gadgets&hash=item3ca5991b7b dunno if they any good tho, was thinkin of getting one myself, you buy it first and let me know :lol:lol

 

[96terrano]

But what if it's not sunny:doh

 

[R1cho]

But what if it's not sunny:doh

you shine a torch on it :augie :lol:lol:lol

 

[laurieash]

theres a few trickle charge ones on the bay like this http://cgi.ebay.co.uk/12v-Solar-Pan...60476312443?pt=UK_Gadgets&hash=item3ca5991b7b dunno if they any good tho, was thinkin of getting one myself, you buy it first and let me know :lol:lol

Nar dont bother with the little ones i have one there crap.
Laurie

 

[laurieash]

But what if it's not sunny:doh

you come south of the border to get out of the mist:lol

 

[geoffdown]

you come south of the border to get out of the mist:lol

i have a 80w pannel with regulator charging a 110ah lessure battery went to the lakes 4 2weeks with no ehu and it kept battery full at about 9-10ish each morning and we do use alot of gagets 19" led tv 12v, 2 laptops phones, gps for walking then all the 12v the caravan needs i.e lights water pump i have a device called a nasa charge/discharge device fitted to battery show how many amps charging and discharging and tells how lon the battery will take to charge or discharge at that rate on sunny day 80w pannel would kick out 4amp an hour on cloudy day just push 1amp but it works for us we now only go to caravan club cl sites with no ehu and pay £3-£6 a ite for two of us not bad really hope this helps oh the pannel cost £169 del from ebay:thumbs

 

[solarman216]

I am not up with the smaller stuff, other than the £60 fold out thing from Maplins and did not rate that very highly at all, you will need to spend £200 plus to get something reasonable, but it does depend very much on your requirements, you need to get an amp hour rate of usage per day for your comfort and then rate a battery to give that rate for the number of days you will need it, but it is a very complicated calculation that really can only be done on an individual basis, I had a narrow boat and talking to other boaters they were either lying or they went to bed at 7.30 pm as they were saying they could manage 24 hours on two 100 Ah batteries, I had 800 Ah traction batteries @ 12 volt and could only go 48 hours without running the engine, but each to his own, but it is very complicated, if you want long battery life and short engine run time, = charge time and even then it is not straightforward every now and again you need an equalization charge which car alternators cannot provide, this is not hear say, I run on batteries here and have done for over 8 years, the controllers to manage my battery system are not cheap, but then I expect to get 15 years plus from my batteries, OH and when choosing batteries go for wet with top up facility, I use around 30 ltrs of distilled water a month, I will stop here as I could go on for ever, suffice to say batteries take a very long time to fully understand, Rick

 

[Duggysdad]

Solar energy is free

Free power, but costs are high to start,before I purchased mine I did lots of reserch and ended up with a ready made up pannel of 40 wats wich was recomended if I needed to be without hookup for more than 3 days.
mine was £240 all in all I do when I unhitch from the car is plug this into the 12v system and my power is free and all we do is go on C.C. cl or ccc cs wich are £3 plus, in a year I expect it to have payed for itself.
That is good for the envirament and may pocket as these things last a long time.
Hope this helps you!

 

[4wheel]

Don't know if this will help.A good few years ago we made a wind charger from an old alternator.Used the plastic fan from a car and some other bits and pieces and as I recall it did the job. Quitelot of fiddling about though.Perhaps there is a wind charger available out there at a reasonable cost?:clap:nenau

 

[rustic]

This season we have 3 x 10 watt panels and a regulator on the boat charging an 85Ah battery.
Last season, without the panels we flattened the battery on several occasions

When on the boat we do supplement the charge from an outboard engine.
However we are cruising less these days and the 30 Watts keeps the battery well topped up over a week.

Most panels will give a charge even in just daylight, but the angle to the sun also makes a difference.

You will need a regulator (for panels over say 10 watts depending on battery capacity) otherwise you will over charge the battery and it will loose water.

 

[rustic]

Don't know if this will help.A good few years ago we made a wind charger from an old alternator.Used the plastic fan from a car and some other bits and pieces and as I recall it did the job. Quitelot of fiddling about though.Perhaps there is a wind charger available out there at a reasonable cost?:clap:nenau

The Sturmey Archer "in wheel dynamo" from the old bikes are often used as wind generators, plenty of info on the web, so they sell at quite a premium when sold on ebay.

 

[laurieash]

I am not up with the smaller stuff, other than the £60 fold out thing from Maplins and did not rate that very highly at all, you will need to spend £200 plus to get something reasonable, but it does depend very much on your requirements, you need to get an amp hour rate of usage per day for your comfort and then rate a battery to give that rate for the number of days you will need it, but it is a very complicated calculation that really can only be done on an individual basis, I had a narrow boat and talking to other boaters they were either lying or they went to bed at 7.30 pm as they were saying they could manage 24 hours on two 100 Ah batteries, I had 800 Ah traction batteries @ 12 volt and could only go 48 hours without running the engine, but each to his own, but it is very complicated, if you want long battery life and short engine run time, = charge time and even then it is not straightforward every now and again you need an equalization charge which car alternators cannot provide, this is not hear say, I run on batteries here and have done for over 8 years, the controllers to manage my battery system are not cheap, but then I expect to get 15 years plus from my batteries, OH and when choosing batteries go for wet with top up facility, I use around 30 ltrs of distilled water a month, I will stop here as I could go on for ever, suffice to say batteries take a very long time to fully understand, Rick

Like you say Rick its a can of worms ive opened.need to find out what battery i have then usage, would a Lesure battery or a terrano one be better?

 

[solarman216]

Like you say Rick its a can of worms ive opened.need to find out what battery i have then usage, would a Lesure battery or a terrano one be better?

there is no such thing as a leisure battery, they are start batteries and call themselves something different, a start battery, you can only take to 50% discharge without damage, a full traction battery can go 80% and will do this 350 times a year for more than 15 years, but cost a lot more, a start battery will only survive a few tens of full discharges before failing, so it really depends on usage, for a caravan used only occasionally, and not taken below 50% then you may well get two or more years from it, but simply get the cheapest battery you can find, wet flooded with caps, if you go for sealed, and they tend to be dearer, then you can only charge it at a slow rate 5 amps or so or you will loose electrolyte and will not be able to top, gell batteries are another matter altogether, hope that helps, Rick

 

[kitchenman]

Maplin do a wind charger
http://www.maplin.co.uk/50w-telescopic-vertical-axis-wind-turbine-396269

 

[laurieash]

there is no such thing as a leisure battery, they are start batteries and call themselves something different, a start battery, you can only take to 50% discharge without damage, a full traction battery can go 80% and will do this 350 times a year for more than 15 years, but cost a lot more, a start battery will only survive a few tens of full discharges before failing, so it really depends on usage, for a caravan used only occasionally, and not taken below 50% then you may well get two or more years from it, but simply get the cheapest battery you can find, wet flooded with caps, if you go for sealed, and they tend to be dearer, then you can only charge it at a slow rate 5 amps or so or you will loose electrolyte and will not be able to top, gell batteries are another matter altogether, hope that helps, Rick

Rick i have a wagon battery dont Know what the AH is as stickers are off it, so would that be better than a 110 leisure. it wont fit in battery box but not bothered about that. Laurie.

 

[solarman216]

Rick i have a wagon battery dont Know what the AH is as stickers are off it, so would that be better than a 110 leisure. it wont fit in battery box but not bothered about that. Laurie.

only way to tell is fully charge it, that is to 15.2 volts (it should be gassing well after around 14 v) this makes sure the electrolyte is well mixed, then apply a load say 10 amps (check with meter) and see how long it will supply that load till the voltage drops to about 11.5 volts off load, this is not as straight forward as it sounds as when the load is on it is giving a false reading of actual battery voltage, so you have to guess a bit and say with 10 amp load on take the voltage to say 11.0 volts then remove the load and check the battery after half an hour, if it is above 11.5 then there is still some amps left to use, the total hours drawing 10 amps will give yo an accurate number of Ah this battery can supply, Rick

 

[rustic]

The total hours drawing 10 amps will give you an accurate number of Ah this battery can supply, Rick

Just to clarify Rick's great post,
So if it supplies 10 amps for 11 hours it's capacity is 10 x 11 = 110Ah


This may not be the batteries original Ah rate, as the battery may have deteriorated.

I have used 2 old head light bulbs as the load, but you need to check the current as the current will be lower as the battery voltage drops.
This test you can do on old leisure batteries, but for an 85Ah battery I would use only one headlight bulb.



Do a table. Measure the voltage and current say every half hour at first.
Time..........Current.......... Voltage


You'll be amazed at how poor a 2 year old leisure battery actually is.


Battery tests are normally done on a 20 hour rate, so an 85Ah battery will supply 85 divided by 20 = 4.25 amps, so it should supply 4.25 amps for 20 hours. On a good day, fully charged battery at the right temperature etc.

It doesn't mean it will supply 42.5 amps for 2 hours though.

Safety issue.Just to add, be aware that the headlight bulb gets very hot, so ensure it is in a safe place.

 

[Hilltop]

The Sturmey Archer "in wheel dynamo" from the old bikes are often used as wind generators, plenty of info on the web, so they sell at quite a premium when sold on ebay.

The output of these is only 6 volts AC and would have to be transfomed UP and then rectified to DC to charge batterys




.