Portable Solar panel Or second battery.

Masman

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Hiya.I am thinking of getting a portable solar panel for when we wild camp.At the moment we manage about four days on 12v with one battery depending on wheather conditions.Would I be better off havind a second battery fitted and if so would it more or less double the time I could spend without the need to charge on 240v.Also my hab battery is now 10years old,still holds its charge.If I went down the 2 battery route would I need to but two batteries. as I was told that just adding one battery would be the wrong thing to do.Also if I go down solar route.what size wattage would I need.Any help most appreciated:thumb:
 
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Hiya.I am thinking of getting a portable solar panel for when we wild camp.At the moment we manage about four days on 12v with one battery depending on wheather conditions.Would I be better off havind a second battery fitted and if so would it more or less double the time I could spend without the need to charge on 240v.Also my hab battery is now 10years old,still holds its charge.If I went down the 2 battery route would I need to but two batteries. as I was told that just adding one battery would be the wrong thing to do.Also if I go down solar route.what size wattage would I need.Any help most appreciated:thumb:

Do you drive every day? If so, and especially if you have a good size alternator, consider getting a B2B charger. A 50A charger will refill a typical 110A battery in just over an hour of driving from 50%. The typical split charge relay found on most installations takes more like 12-24h and will only charge to about 80%.
 

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On our first night away to Scotland, the battery charger packed in. However, the solar panel I fitted did the job 100% for the next two weeks, without any problem, even though we were staying at locations for up to four nights. Not sure about winter, but it charged our single leisure battery well, in fact, the thing was fully charged before we got up in the morning. :thumb:

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scotjimland

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For lengthening your time off grid, first and foremost .. increase battery capacity .. as much as you can physically cram in.. there is no substitute..

After that, consider supplementing with a solar panel.. no matter how small (within reason) it will lengthen your stay.. the bigger the better , but not indefinitely unless the panels are supplying more or equal to what you are using..

Think on it like this.. a water annology .. the tap is a solar panel .. the basin the battery..

no point in running the tap indefinitely to store water if you only have a small basin to store it.. A big basin, even with a drip going in eventually fills.. unless you pull the plug.. or use more than the tap is supplying.

Can't have too much battery storage if you want to stay off grid.
 
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Techno

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Yup I just added a fourth ::bigsmile:
CA_06211421223402-L.jpg
 
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Do you drive every day? If so, and especially if you have a good size alternator, consider getting a B2B charger. A 50A charger will refill a typical 110A battery in just over an hour of driving from 50%. The typical split charge relay found on most installations takes more like 12-24h and will only charge to about 80%.

This sounds a good idea. Tell me more ?

When we are driving, only the vehicle battery gets charged. Would be great to get the leisure batterty (ies) charged as well :Smile:

How much are they ?

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Oct 24, 2013
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Hi. We have a 150watt solar panel fitted on roof. With 2 leisure batteries + the starter. This works really well. Power from solar panel constantly charging all 3 batteries. Can run fridge/freezer, TV. Without hook up for quite long periods. :thumb::thumb::thumb:
 
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Hi. We have a 150watt solar panel fitted on roof. With 2 leisure batteries + the starter. This works really well. Power from solar panel constantly charging all 3 batteries.[HI] Can run fridge/freezer[/HI], TV. Without hook up for quite long periods. :thumb::thumb::thumb:


I think your fridge /freezer will be running off mains hook up or gas, as the 12v side only works with the engine running.
I'm sure someone will correct me if I am wrong. ::bigsmile:
 

scotjimland

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I think your fridge /freezer will be running off mains hook up or gas, as the 12v side only works with the engine running.
I'm sure someone will correct me if I am wrong. ::bigsmile:

unless it's a 12v compressor fridge..... correct.

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Jun 8, 2012
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This sounds a good idea. Tell me more ?

When we are driving, only the vehicle battery gets charged. Would be great to get the leisure batterty (ies) charged as well :Smile:

How much are they ?

Basically they are full blown smart chargers like you would plug into the mains, but instead of 230V, they run on the 12V of your engine side with circuitry to disconnect when the engine isn't running. They aren't cheap, but are ideal for wilding where you move every day rather than staying in one place and going on bike rides (you'd have a caravan if you wanted to do that!) You don't have to move that far to fully charge your battery.

However, you need to get one of the size to match your alternator. Typically your alternator will be between about 60A and 120A. You'll want to leave at least 40A to run the lights/fans etc. I've only got a piddly little 60A alternator, so I stuck with a 20A charger. However, with a modern vehicle, you are quite likely to have 100A plus, so you could fit a 50A model quite comfortably.

Prices are pretty expensive. About £200 for a 20A model, rising quite rapidly. However, for an avowed tourer, this might be all you need, saving money on a solar set up or additional batteries. I keep mine in storage and would occasionally like to go a few days without moving, so I'm glad I've got both.
 

eddievanbitz

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Yup I just added a fourth ::bigsmile:
CA_06211421223402-L.jpg

Only four? I have six plus two spare in another bank:winky: If your thinking about one or the other battery every time

Why worry about making more power whilst there, if you can arrive with sufficient for the stay?

Beyond that, then start thinking about ensuring that the batteries are properly charged when you arrive and perhaps the ability to recharge your batteries whilst your there

Eddie
 

Techno

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Only four? I have six plus two spare in another bank:winky: If your thinking about one or the other battery every time

Why worry about making more power whilst there, if you can arrive with sufficient for the stay?

Beyond that, then start thinking about ensuring that the batteries are properly charged when you arrive and perhaps the ability to recharge your batteries whilst your there

Eddie

However, some people might need to worry about weight. These batteries will be able 25kg each. Your 8 batteries might be about 200kg, which could be over half the available payload with some 3500kg vans. Just one battery with a solar panel and a B2B will, depending on the habits of the owner, often be enough to ensure continuous electrical power with no need for hook up ever, for under 40kg total mass, including cabling.
 
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Well that`s our 12th year & still loving it.
Hiya.I am thinking of getting a portable solar panel for when we wild camp.At the moment we manage about four days on 12v with one battery depending on wheather conditions.Would I be better off havind a second battery fitted and if so would it more or less double the time I could spend without the need to charge on 240v.Also my hab battery is now 10years old,still holds its charge.If I went down the 2 battery route would I need to but two batteries. as I was told that just adding one battery would be the wrong thing to do.Also if I go down solar route.what size wattage would I need.Any help most appreciated:thumb:

Fitting extra batteries is ok as long as you have the means to charge them up. as for going down the solar panel route, again that is ok but be aware that you will need to fit a solar panel with enough charging power to at least match your 12v usage.

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SUGGY

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I went with the 100 watt , portable (daylight ) solar panel idea on this van ....

what a pain in the butt , :Sad:

you are forever moving it about and trying to chain it to something
also when you put it away it was always in the way :Doh:

when we got to morocco i got a 140 watt daylight solar panel and mounted both units on the roof , sorted , :Cool:

i have 2 x 110amp batteries and i put an extrabattery isolator switch in so i can link the liesure and the engine battery so all are kept fully charged ,

at southport last week i was running the fridge of the liesure batteries / solar panels from 10 am to 7pm , the were showing over 12 amp in bright sun and 3.8 amp when over cast ,

From new year to now i have only had mains power to the van about 6 times , when electric was forced on us ( ie included in the fees ) ,

we have a 2kw inverter for the , Romoska , travel kettle , hair dryer , laptop n phone chargers , and Rice cooker ,

go for good quality daylight solar panels not cheep ones that are only good in direct sunlight , :Eeek:

Also you wont have to carry all the extra weight of extra batteries and save a lot of money buying / replacing batteries ,
 
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mapa

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This thread has caused me some head scratching. I've always been under the impression that when I drive my mh it automatically charges the leisure battery . but all this talk of b2b charges now has me worried. I've got a 2006 autocruise so my question is very simple.....is it?.......or is it not?......charging my leisure batteries whilst I am driving ?
 

Techno

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This thread has caused me some head scratching. I've always been under the impression that when I drive my mh it automatically charges the leisure battery . but all this talk of b2b charges now has me worried. I've got a 2006 autocruise so my question is very simple.....is it?.......or is it not?......charging my leisure batteries whilst I am driving ?

Yes but only a low amp charge as the alternator reacts to the starter battery voltage, so if fully charged the output will be minimal.

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SUGGY

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Yes but only a low amp charge as the alternator reacts to the starter battery voltage, so if fully charged the output will be minimal.

Yes it should charge your liesure batteries,

The MH should have the system that charges the engine battery first up to 14.4 volt approx then charge up the liesure batteries ,

i have a digital volt meter pluged into the dash board cigar lighter to read the engine battery voltage and another pluged into the liesure battery cigar lighter so i can see what voltage are in each batteries all the time ,

Simple ::bigsmile:
 

Techno

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14.4 volts is an alternator output voltage, this is not an indication of how many amps are being delivered. The amps will vary with the load on the battery or it's state of charge.

A battery to battery tricks the alternator into working harder by pulling the engine battery voltage down. This enables the liesure battery to get a huge charge depending on the unit selected. Without a BtoB you might only get a few amps.
 
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Jun 8, 2012
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This thread has caused me some head scratching. I've always been under the impression that when I drive my mh it automatically charges the leisure battery . but all this talk of b2b charges now has me worried. I've got a 2006 autocruise so my question is very simple.....is it?.......or is it not?......charging my leisure batteries whilst I am driving ?

Most motorhomes will have a split charge relay which will run the fridge and charge the leisure battery, but not very effectively. Certainly not enough to maintain its charge on the occasional drive to the shops or the next town.

It is unlikely that you have a B2B charger, as you would probably have bought it yourself and remembered it. Even if it had one before, any previous owner will probably have removed it, unless negotiated otherwise.

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SUGGY

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14.4 volts is an alternator output voltage, this is not an indication of how many amps are being delivered. The amps will vary with the load on the battery or it's state of charge

Maybe we should measure the internal resistance of the batteries and check the level of sulphate etc ,,,

The guy wants some suggestions / comparisons of solar panels etc ,

Not a load of technical bumffff . B S B Brains as they say :ROFLMAO:

But there again i am only an electrician :Blush:
 

Techno

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Maybe we should measure the internal resistance of the batteries and check the level of sulphate etc ,,,

The guy wants some suggestions / comparisons of solar panels etc ,

Not a load of technical bumffff . B S B Brains as they say :ROFLMAO:

But there again i am only an electrician :Blush:

I'm not retired :roflmto:

You were giving the impression that 14.4 volts indicated they were charged which it is not.
 
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SUGGY

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:ROFLMAO::ROFLMAO:

not retired as in still working
or
not retired as an electrician

it aint wot you say its the way wot you say it .....:Doh:

see you at misterton :Cool:

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SUGGY

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OK ,,,
By the way , thanks for the info on fitting the marcle air suspension , it came in handy when i fitted mine the other week :Cool:

see you at malvern :thumb:
 

eddievanbitz

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In simple terms, most European Motorhomes, when the engine is running has a cheap automotive relay which joins the engine battery and the leisure battery(s) together, irrespective of battery size type, condition or age.

On some Motorhomes the cheap relay is hidden in a big posh, multi function distribution unit, but it is just the same.

German van? Gel battery? Well despite what you believe, your expensive Gel battery is being connected to the wet, lead acid starter battery and being charged at circa 14.8 VDC

Of course none of this really matters as the charging set up, on most vans is so poor that due to inefficient cable sizing, there is so much voltage drop that it isn't a problem.

Every Motorhome is designed on a delivery van, a commercial vehicle. They are designed to be used by Bob the Builder or Fred the Florist. Stop start, Monday to Friday, with weekends off.

They then bought to be turned into Motorhomes, we add a fridge and freezer that works off the alternator when the engine is running and an extra couple of batteries, and we don't change or upgrade the alternator or engine battery.

Worse still, is that the chassis manufacturers locate the engine battery as close as possible to the alternator and then connect the two together with a thick cable to minimise loss.

The Motorhome manufacturers locate the batteries anywhere they like based on aesthetics and convenience, rather than electrical principles and then connect the whole lot up using wire that in some cases has a smaller diameter than my shoe laces:Doh:

Consequently many people arrive on site, with batteries that are only about 80% charged. Now given that good practice suggests that we should only dip into our battery(s) about 50% that's a waste of valuable power.

Do the sums on an easy example: you have a 100 Ah battery, you have 50 amps to use. If your battery isn't fully charged on arrival you only have 40 amps available to use:Eeek:

Now before everyone gets too upset, the average van works well for the average person. Most people will drive to a site, not travel too far too often, and will always try to get electric hook up if they can.

A few nights on CL's or parked on a friends drive in the Summer without electricity, when their demand on their 12 VDC system is minimal ( not sat inside with all the lights on, heating and TV for example)

With this type of usage, an inefficient battery set up is not a problem nor would it be noticeable to most people.

It is when you start doing things that the average person doesn't do, that you'll need to change your set up.

Installing a more efficient charging system for example. Most think, erroneously that a split charge relay charges the engine and leisure batteries separately, this simply isn't the case. As soon as the engine is running, all the batteries are in parallel. Simply running more appropriate cable will massively improve the charging situation, installing a higher rated relay, again will improve the situation, and ultimately installing a dedicated "proper" split charge device will give you the optimum.

So for example, if you have two 100 Ah batteries, and you arrive "fully" charged, using the same 50% rule you have 100amps to use, a opposed to 80amps using the same battery setup, but with a "standard" split charging system.

That's quite a significant gain.

Eddie

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