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Solar Or Two Batteries


fatstu
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hi folks, i have to use a electric mask at night which is 3a max, so for many years i have not been able go anywhere without EHU, but the mask can be used on 12v. lots of sites i like have no ehu, and i always fancied rallying (lots without ehu) etc, so i have decided to run my mask on 12v with no ehu, hence i need to sort myself some power soloutions, so heres a couple of options i thought of but of course any better ideas taken on board,

 

2 x banner energy 110a leisure batteries, plus ctek msx 7000 charger ( around £300 ) 1 connected to caravan, 1 in the boot of car, change batteries when 1st gets low. .... OR

 

 

65 - 100w solar panel (plug and play pack so to speak ) which i believe to be around £400 plus 1 new banner 110a battery £100, ( by the way i like banner ).

 

i plan 3 nights stay as an example, and im not sure how to calculate how much my mask will actually use, i have led lights and no television so apart from the mask im not a heavy user, and as a ball park marker 8hrs per night for the mask.

 

am i right in thinking 8 hrs @ 3a max = 24a per night ?... x 3 nights 72a ? for just the mask, im only a simple man so no laughing if this is wrong. ....... LOL .

 

i have only put the estimated prices above for my own figures, this is not an exercise about money or savings, its about non ehu,

 

many thanks in advance, Stu

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First . .. is the 3A the current it will draw at 12v, or the current at 240v?

 

But yes, you're right - if its 3A at 12v, it will use 24Ah (Amp-hours) for 8 hours.

 

Although a battery is rated at (say) 100Ah, in practice you'll find it hard to get all the power out - the voltage will dip after about 50Ah. So your battery would last about 2 nights assuming no other load.

 

If you're going to do it on a regular basis, then a solar panel sounds a good way to go. If just now and again, I'd use a second battery.

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We have used two 110Ah batteries successfully for many years now.

 

One on one off as you describe.

 

When at home the one not being used is bench charged with a LIDL charger.

 

When away one is always in the car boot hooked up to the cigarette lighter socket for charging as we are out and about.

 

Of course the battery needs to be secured in the boot and charging wires need to be fused.

 

Interestingly we are now thinking of adding solar as well, I've recently seen (on here I think) a 68W Solar Panel that sticks to the caravan roof.

 

As previously stated the amount you are away non-EHU will dictate which path you choose. . I'm just pointing out that we have inadvertently gone via a staged route!

 

And we already had the LIDL charger anyway.

 

HTH

 

G.

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If you are hooked up at home and therefore the battery is fully charged before you leave home a solar may be enough providing it is up to replacing during the daylight hour what you use at night.

 

A good selection of solars are here and a phone call explaining your needs will probably give you a better idea whats required.

 

http://www. sunshinesolar. co. uk/khxc/gbu0-display/splash. html

 

http://www. sunshinesolar. co. uk/khxc/gbu0-prodshow/SS85WM. html This is a good offer at the moment (Monocrystalline) Best you can buy!

Ford C-Max and Coachman Festival 380/2 SE 2006    Motto  Carpe Diem

Still trying to find the perfect pitch. ..110 amp Battery+ 65 watt roof mounted Solar and 25 watt Wind Turbine. LED lighting. Status Aerial 315. Loose chattels marked with UV,. Safefill Gas Fitted.

 

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I also have to use a mask and if I was in you place I would actually do both. Second battery as a backup in case the other goes down overnight and a solar to recharge the overnight during the following day. Only charge one battery at a time so don't have them both permanently wired.

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thanks guys, all above taken in, just spoke to sunshine and a 85w freestanding monocrystalline panel with, bolt on stand, regulator, all leads connections etc is aprox £375, and i think as suggested i will cover all bases and get a couple new 110a batteries aswell, so 110a batt with 85w solar, and a 110a spare batt in the boot should have me well covered i think ??, and all for an acceptable budget of around £500.

i am pressuming with this setup i can charge the batteries at home (to full charge- ish) with the solar panel, so i will not need a batt charger aswell ????, or do i ?.

 

unless i get no further or better ideas i will purchase these at the weekend. also am i right to assume winter charging with a solar panel will be reduced by maybe 50 - 60 % ?

 

 

 

Just been advised by sunshine solar suppliers of above panel i should expect panel to put roughly summers day = 28a into battery - winters day roughly 10a a into battery, that sound about right you think ? , if so then a back-up battery to change over in winter is a must for my useage,

thanks again Stu

Edited by fatstu
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Personally I'd keep an eye open for the Lidl/Aldi charger. . then for another £15ish you've bot all the bases covered!

 

G.

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Hi Stu.

 

 

 

 

If you are planning to go away for 3 nights without EHU, then the charger isn't going to help.

 

You can't really rely on the power from the solar panel as its outputs are unpredictable. Are you talking just summer trips or all year round ??

 

My thoughts are that you need enough charged battery capacity to run the van all weekend, with there being no chance of power running out for your mask.

 

You ideally need to do an energy audit on the van, add the drain from the mask and then calculate the needed battery capacity to achieve that.

 

I would use batteries in parallel rather than switching them. You might be able to put the additional batteries in the back of the car and connect an umbilical cable to your main battery.

 

Its possible to rig an alarm that will tell you if the batteries go below the "danger" level.

 

 

 

 

 

 

hi folks, i have to use a electric mask at night which is 3a max, so for many years i have not been able go anywhere without EHU, but the mask can be used on 12v. lots of sites i like have no ehu, and i always fancied rallying (lots without ehu) etc, so i have decided to run my mask on 12v with no ehu, hence i need to sort myself some power soloutions, so heres a couple of options i thought of but of course any better ideas taken on board,

 

2 x banner energy 110a leisure batteries, plus ctek msx 7000 charger ( around £300 ) 1 connected to caravan, 1 in the boot of car, change batteries when 1st gets low. .... OR

 

 

65 - 100w solar panel (plug and play pack so to speak ) which i believe to be around £400 plus 1 new banner 110a battery £100, ( by the way i like banner ).

 

i plan 3 nights stay as an example, and im not sure how to calculate how much my mask will actually use, i have led lights and no television so apart from the mask im not a heavy user, and as a ball park marker 8hrs per night for the mask.

 

am i right in thinking 8 hrs @ 3a max = 24a per night ?... x 3 nights 72a ? for just the mask, im only a simple man so no laughing if this is wrong. ....... LOL .

 

i have only put the estimated prices above for my own figures, this is not an exercise about money or savings, its about non ehu,

 

many thanks in advance, Stu

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Hi guys thanks again for advice been very helpful,

 

It would be nice if you let us know how you go after you have made your choice of Solar or Battery. It could help others with similar dilemma.

 

Take care and enjoy your Rallies. We do! :)

Ford C-Max and Coachman Festival 380/2 SE 2006    Motto  Carpe Diem

Still trying to find the perfect pitch. ..110 amp Battery+ 65 watt roof mounted Solar and 25 watt Wind Turbine. LED lighting. Status Aerial 315. Loose chattels marked with UV,. Safefill Gas Fitted.

 

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It would be nice if you let us know how you go after you have made your choice of Solar or Battery. It could help others with similar dilemma.

 

Take care and enjoy your Rallies. We do! smile.gif

thank-you and as soon as i have had a chance to buy and evaluate i will let all know how well, or not, it works, Stu

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As suggested, you should find out just how much 12v power you are likely to use before spending a lot of money.

If you fancy giving rallies a try contact your club (we use C&CC but I think that the CC hold similar rallies) to see which rallies you want to try. You may find that during the darker, cooler months of September and October some rallies visit sites where ehu is available which is just as well because although modern solar panels work with ambient daylight their performance drops off during autumn and winter.

If you decide that rallying is for you, as we did a couple of years back, you will probably find that most regular rally goers use solar power with one or two 110a/h leisure batteries.

We bought our 80 watt solar panel from this company. http://www. ebay. co. u. ..=item20bcb72d66

Although they often sell on Ebay Greener Electric are a reputable company based in Bromsgrove, their panels are not overpriced and they work very well under normal conditions.

Buy a solar charge regulator from Maplins http://www. maplin. co. ..egulator-266145 then budget another £50 for suitable cable, a cable entry shroud, some angle brackets and some Sikaflex and you could easily install a caravan or motorhome roof mounted solar panel for just under £300 which would give trouble free service for years to come.

If your d-i-y skills or state of health don't stretch to doing this job a mobile caravan engineer would be able to complete the job in around half a day.

Cable size for such a job is important, you'd need to buy 10amp 6mm automotive cable protected by suitable fuses for the cable run to the solar charge regulator in order to reduce the voltage drop caused by the length of cable used.

If you decide on solar power and need any advice on installation give me a shout and I'll try to help. :)

Edited by parksy
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I forgot to add that we'd never heard of caravan solar panels until we started rallying, the other ralliers showed us how their systems work and told us about Greener Electric which is not far from us. We collected our panel from their warehouse but they do mail order and their panels are fully guaranteed.

If you do give the rallies a try you will almost certainly be able to find good advice / tips from experienced ralliers.

 

I've got two 110a/h leisure batteries and I keep one fully charged at home using a c-tek deep cycle charger (similar models are available from Lidl at a fraction of the price)

We run our portable flat screen tv for the o/h to watch Constipation Street etc when off ehu and so far this year we haven't had to swap batteries.

I used my solar panel which we've had for just over a year as a free-standing unit and connected to the leisure battery with crocodile clips until July when I installed and hard wired the panel.

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I have seen people fitting the charge controller on the back of the solar panel.

 

I have even seen them being sold with the controller fitted on the back of the solar panel.

 

This means the cable run to the battery is where the voltage drop occurs.

 

Far better to fit the charge controller as close as possible to the battery and the voltage drop is then in the run from the panel to the controller.

 

I hope others will confirm this is correct good practice.

Ford C-Max and Coachman Festival 380/2 SE 2006    Motto  Carpe Diem

Still trying to find the perfect pitch. ..110 amp Battery+ 65 watt roof mounted Solar and 25 watt Wind Turbine. LED lighting. Status Aerial 315. Loose chattels marked with UV,. Safefill Gas Fitted.

 

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I hope others will confirm this is correct good practice.

 

Yes but not only for the reason you gave but also because any half decent charge controller will have local or remote temperature sensing to optimise the charge voltage for the temperature of the battery. A side effect of PV solar cells is they get very hot and with the controller sensing that it will needlessly back off the charging voltage. Result poorer charge and potential for battery damage.

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I have seen people fitting the charge controller on the back of the solar panel.

 

I have even seen them being sold with the controller fitted on the back of the solar panel.

This means the cable run to the battery is where the voltage drop occurs.

Far better to fit the charge controller as close as possible to the battery and the voltage drop is then in the run from the panel to the controller.

 

I hope others will confirm this is correct good practice.

 

Panels produce around 18 to 30+ volts (depending on make) to keep the power loss low from the battery to the controller, also a good controller has a temperature compensator built in, this monitors the battery's condition & chargers the battery accordingly, so having the controller as close as practically possible to the battery is the best position.

 

If the controller is stuck on the panel the heat the panel develops messes up the sensor so it can't monitor & charge the battery efficiently, also like Lefthand Down says you will have power lose along the the cables length :(

 

 

I wish I could type faster :lol:

Paul B

. .......Mondeo Estate & Elddis Avanté 505 (Tobago)

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My solar charge regulator is in the front o/s bed locker next to the leisure battery, rather than it being connected directly to the leisure battery it is wired into the charging circuit via a Sargent Connecting Kit for Swift caravans.

 

http://sargentshop. c. ..Products/WB2040

 

The cable run is from the panel which is fixed to the caravan roof to the controller/ regulator which is mounted on some plastic square section leaving a gap between the floor and the regulator in order to dissipate any heat which emits from the regulator.

 

A good MTTP solar charge controller has the potential to increase the efficiency of pv modules by between 10-30%.

 

The MTTP regulator / controller costs a minimum of £80, possibly more, but my feeling is that for a touring caravan owner who wants to go on weekend rallies in the summer here in the UK the initial cost might outweigh any potential gain which is why I recommended a bog standard but well engineered (German) pulse width modulator regulator which costs a maximum of £21, it would charge two leisure batteries if and when required and would definitely do the job :rolleyes:

No need to over complicate simple matters B)

Edited by parksy
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Hi guys, ok here goes, "basic set-up" solar panel, correct wiring running from solar panel to the reg/cont (thats mounted in battery box), from reg/cont correct wiring again to battery, ( all wiring 10a 6mm ). two 110a batteries (one in caravan 1 in boot) both fully charged with a ctek 7000 charger before leaving home, this would seem more than enough during spring summer.

Aut / Winter would be shorter stays away without ehu.

Useage. ..

mask 3a max per hr on 12v = 24a per night, plus led lights, water pump, etc, no tv, im guestimating first fully charged 110a battery would need changing after second night ?, second fully charged battery on for minimum one more day and one more night to be on the safe side, this in in aut / winter with little help from solar panel, so would you agree 3 nights in winter should be fine ??.

Four or maybe five nights in summer months when the 80w solar panel is doing its thing ( say 25a a day charging battery ? ). aux things like phones i-pad etc charged in car, if the above are roughly correct im more than happy with investment, please feel free to pull apart anything above that you think incorrect or stupid, due to my lack of understanding my posts may sound like a 5 year old has written them. ..... for this i appologise, im just trying to break it down as simple as possible.

once again thank-you very much for everyones help / input it has been invaluable, Stu

Edited by fatstu
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Is the solar panel free standing and connected by two pin connectors on a free lead or is it fixed and hard wired?

Edited by Lefthand Down

Ford C-Max and Coachman Festival 380/2 SE 2006    Motto  Carpe Diem

Still trying to find the perfect pitch. ..110 amp Battery+ 65 watt roof mounted Solar and 25 watt Wind Turbine. LED lighting. Status Aerial 315. Loose chattels marked with UV,. Safefill Gas Fitted.

 

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Hi Stu,

I've sent an email to Greener Electric who hopefully will provide some further advice about the power output of an 80 watt solar panel.

It's always best to make absolutely certain before you buy that a product is the right one for you, I can offer advice on the practicalities of installing a solar charge system but real facts and figures about the power output are much better than any guestimates that I would make.

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Is the solar panel free standing and connected by two pin connectors on a free lead or is it fixed and hard wired?

Hi, none of the above has been purchased yet, as soon as there seems to be " a best way " i will order the batteries, charger, and solar panel, many thanks, Stu

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Hi Stu,

I've sent an email to Greener Electric who hopefully will provide some further advice about the power output of an 80 watt solar panel.

It's always best to make absolutely certain before you buy that a product is the right one for you, I can offer advice on the practicalities of installing a solar charge system but real facts and figures about the power output are much better than any guestimates that I would make.

Thank-you kindly for putting yourself out to help me, i am very greatfull, i was told by solar soloutions to expect "approx" 25a per day input to the battery on a bright summers day, and 10a per day in winter, from there 85w mono solar panel, so i look forward to greener electrics estimate, to see if they are similar, Stu

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You're welcome Stu, off ehu camping / caravanning can be great, away from the beaten track or on rallies with fellow like minded caravanners.

I haven't yet had the information that I was after from Greener Electric but if we divide watts by volts we arrive at the total amperage.

In this case we have 80 watts divided by 12 volts which would give a figure of just over 6. 5 amps.

Solar panels however lose some of their output, this can be as much as 50% which still gives a useful charge rate of around 3 amps per hour in good to ideal conditions. This would confirm the information supplied by Solar Solutions.

Within 8 hours your 25 amp usage could be replaced. Of course conditions are not always ideal but there are more than 8 hours of daylight available during the lighter months from March until the beginning of October. Solar panels still generate power when in ambient daylight, obviously direct sunlight gives a quicker charge but if the day is dull or cloudy the panel is trickle charging the battery.

No power is generated during darkness and good solar panels are fitted with an internal bypass diode which prevents the battery current from draining back to the panel during the hours of darkness.

An 80 watt solar panel would provide a charge for over 16 hours at the height of summer away from shade (such as underneath trees) which would be adequate to keep your leisure battery fully charged.

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Be very cautious with solar panels and their stated power.

 

An 80W panel will never provide a battery charge at 6. 5A in practice.

 

I would estimate that 3-4 Amps is doing well and that will only be when the sun is up and high enough above the horizon - obviously a lot shorter hours in winter.

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Be very cautious with solar panels and their stated power.

 

An 80W panel will never provide a battery charge at 6. 5A in practice.

 

I would estimate that 3-4 Amps is doing well and that will only be when the sun is up and high enough above the horizon - obviously a lot shorter hours in winter.

 

Which is exactly what I wrote earlier :)

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