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Any auto sparkies?


roamingyak

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That would work, Mo. 

Plugging yourself in should work fine, along with a decent charger -though one of these aren't especially cheap. It would need to supply greater than the fridge is drawing, without knowing what model it is, it is hard to estimate that. But if, say, you were running at 5A to the fridge, and have a 5A charger, well the battery won't be getting much! Though it should maintain it adequately.

Any reason why the fridge doesn't work on 240V? If it is just a regular 3-way ex-caravan type fridge then it is most likely just the element, which is very easily replaced, and very cheap, that way you don't need to rely on the 12V side of things at all, which is not as efficient, and not thermostatically controlled in most cases -you can make your beer as cold as want then 😛 

Mind you, saying all that, if it is a 3-way, I'd be running it on gas, way cheaper than hookup if that is all you need it for, and stops giving your battery a hard time! :) 

 

 

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That will work Mo - there are some decent little smart chargers for cheap now which should keep up no problem.

Depends a bit on the fridge, but your typical Engel/National Luna/ARB only draws approx 2A.  Absorbtion fridges with the little fan blowing over a heatsink use a lot more.

A little 40w solar panel & controler will keep a fridge going over a weekend - probably costs the same as a low end charger and hookup cables...

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5 minutes ago, Eightpot said:

A little 40w solar panel & controler will keep a fridge going over a weekend - probably costs the same as a low end charger and hookup cables...

I don't know what the supposed output is.... but one of the cheapy little battery maintaining panels kept my CF50 running for 4 days at Rewind festival last year. And it was a pretty warm weekend in the tent.

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Thanks for your replies fellas, appreciated.

My fridge is a Waeco CF40 but I don't have the skills to test or repair the 240v side of it and I'm not inclined to pay a service agent probably the price of a new one to repair it 😂

I'll have a look at chargers out there and see what's about.

I'll take another look at solar too but I assume they only work if it's sunny.

Much obliged to you all

Mo

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Been watching this thread with great interest and have learned a lot as it was a question I was going to ask , as when the 90’s finished the 110 will be a camping weekends at shows / going fishing for days possibly week sort of vehicle as well as green laning and I would like to do the Pyrenees trip someday if I get the chance before I’m to old . So whilst looking round the internet and reading various threads most from Oz I came across this system the REDARC BMS1530S2 , please make sure your sitting down when you look at the price :D , also a stiff drink might be in order for shock

 https://www.portablepowertech.com/product/redarc-manager30-bms1230s2-uk/

but from what I can make out it does everything and tells you everything that’s going on charge wise . I did find a review of it from an Australian bloke and he actually had 2 one in each vehicle he owned . It actually makes the C-tek system look a bit ordinary, just thought I’d put the link up and see what you all thought of it because when I win the lottery I’m going to buy one or two :hysterical: .

cheers Ian 

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11 hours ago, Mo Murphy said:

I've always wondered why the aux battery on mine was not terribly durable and the charge never lasts as long as I calculate that it should. Thanks to this thread now I know.

When we tour each year we use proper campsites rather than wild camping (mostly because we're all older and lazier and campsites have a bar and sit on toilets 😊). We don't go anywhere particularly remote or beyond reach of civilisation. 

The aux will last fine running the fridge for a night, but if we stay anywhere for 2 or 3 nights without driving then it doesn't last.

Conceivably then, I could live with my inefficient cheap and cheerful split charge system if I were to pay for a mains hook up and stick a mains charger on the aux overnight (the 240v on the fridge doesn't work but runs fine on 12v). In the morning the bacon won't have gone off and the water and beer for the day will be nice and cold and the aux battery will be tip top.

I don't really want to fork out for solar or new fancy batteries and management systems so this sounds a cost effective solution for me.

Anyone see any faults with that apart from a campsite with no hook ups ?

Mo

 

As soon as the battery people told me that my aux wasn’t getting fully charged on my split charge connection, I bought a Ctek charger. I got the extra little socket with rings on the end and wired it permanently to the aux with the socket poking out under the passenger seat. Whenever I could I connected the charger, using a mains hookup at campsites but otherwise at home. The battery responded well.

Then I added a 100W panel and used the Ctek controller and never looked back. The move from coolbox to fridge, CFX35W was an enormous step (in £ too) but last year in Ireland with 4/5 of the trip in rain and cloud we never hooked up to the mains at all and the batteries have been fully charged and hold up well. 

Edited by Peaklander
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Having waded through hundreds of web pages I came across a sensible site that said you need an intelligent dc to dc battery charger, and having done some more surfing found this!

https://www.ebay.co.uk/itm/Ring-RSCDC30-DC-To-DC-Smart-Battery-Charger-30amp/153013066455?epid=28017010179&hash=item23a04a1ad7:g:Rp8AAOSwqaJaYNLx

A wee bit cheaper than the Ctec unit, you can charge all battery types from the cars alternator / battery and it has a solar panel inlet too!! And if you're thinking it might not be as good as the Ctec.. buy 2 and have a spare, it's still cheaper that the Ctec!!

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Chaps,

Having done some reading to try and get my head around electrickery and charging and aux charging and split charging et al last evening, I really can't see why people have shot down miggit's suggestion of a second alternator.

It really does seem to be a simple solution to me !

I don't have expensive fancy batteries nor fancy alternators. And I've never found alternators to be particularly unreliable, but they are really easy and cheap to repair if they do break. Seems to be a use for those little old 45 amp alternators that people replaced.

It just seems to me that if the aux battery has its own supply from an alternator then all the weaknesses of split charging are removed, the aux alternator is sensing the state of charge of the aux battery and providing the appropriate charge to fully charge the battery - no middle men ! 

It strikes me that while it does seem overkill, it's simple, direct and if you make your own alternator mount and use a common belt, cheap.

Have I really misunderstood your arguments against ?

Mo

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@Mo Murphy,

Aside from the arguments about reliability, it is all about efficiency.

To efficiently charge a lead acid battery (read this as: allow you to get more into a battery in a given time span so it doesn't go flat overnight on you), you need a better battery charging profile than what a simple alternator can provide.

This is a good read: https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery 

As you say it does come down to cost, I couldn't justify any of the systems on in this thread, apart from maybe the Ring one Miggit found, but would only consider it if I were building a camper with built in solar, and future capability for charging lion/lead crystal type batteries. By the time you add up separate devices to do all the rest of the stuff and your time, it could well be worth it.

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@Bowie69

Thanks Pete, an interesting read particularly regarding the 3 stage charging process and how important this is.

However, this all seems to refer to external charging and I'm puzzled that if an alternator is not the best way to charge a battery then how do most batteries last so well in most cars ?

Having said that, mains charging via a smart charger seems to be a reasonably cost effective and efficient method of running the fridge over several days at a single location and be able to leave the site with a full battery for the next journey. 

Cheers

Mo

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3 hours ago, Mo Murphy said:

Chaps,

Having done some reading to try and get my head around electrickery and charging and aux charging and split charging et al last evening, I really can't see why people have shot down miggit's suggestion of a second alternator.

It really does seem to be a simple solution to me !

I don't have expensive fancy batteries nor fancy alternators. And I've never found alternators to be particularly unreliable, but they are really easy and cheap to repair if they do break. Seems to be a use for those little old 45 amp alternators that people replaced.

It just seems to me that if the aux battery has its own supply from an alternator then all the weaknesses of split charging are removed, the aux alternator is sensing the state of charge of the aux battery and providing the appropriate charge to fully charge the battery - no middle men ! 

Nothing wrong with a second alternator,  but there's not much wrong with using a single one either. 

The cteks etc only put out 20-30 amps, a single alternator can produce way more, and more than easily charge two batteries.  The argument for the dc-dc chargers is that they can take a battery all the way up to its full capacity, which alternators can't  (supposedly..) as an alternator starts to drop the voltage when the battery nears fully charged.

So if we believe all the claims from the electronic charger companies, you can have a battery that charges all the way but slowly for $$$$, or an alternator charged battery that charges quickly to 90% for $.

Maybe worth chasing the difference if you're only using battery power and need to wring every bit of juice out -practically, if you have a solar panel of adequate size it just doesn't become an issue. 

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If you're just going to be using a second wet battery then either split charging or the excellent suggestion of a second alternator (can't remember how thought of that :D) are both good solutions.... As far as charging the second battery to a reasonable level both methods need input from the engine, and as such a dedicated alternator will do the business quicker than a split charger.... and if you go for a big alternator then much much quicker. I'd have thought that a truck size battery would be more than ample for your requirements... but it comes down to available space.

As far as solar goes, you're going to need a big one to counteract a fridge, but good old fleabay has some 100w caravan ones... if you've got a compressor type fridge it should be able to top the battery up nicely, if it's a cheaper 3-way type with on moving parts (bar the door) I think it will struggle as they have quite a high drain... as many a tin tent owner has found out leaving the caravan plugged into the car without the engine running and the fridge on 12v:blink: From memory they pull upwards of 30 amps... you'll need a lot of headlights to get that sort of drain!

If you're going for a leisure battery or agm / optima type the you'll need the smart charger, as a normal charging system doesn't output either the voltage or variable rates needed, and will end in premature failure and tears!

The biggest question you have to ask yourself is how long do you plan to stay square wheeled  for at any one time... if your touring then keeping everything working won't be a problem, if you're staying put for a few days/weeks/months then you'll need either a large solar panel (assuming you're going south of the UK!!) or you'll have to run the engine for a period of time.

Oh and on the subject of solar panels I've just bought one for my 'ang' 'over as I don't use it enough in the summer to keep it charged... part of the blurb said that it had to be disconnected from the car during starting as it can cause a surge and fry the panel... not a problem for me as it'll be on the dash in the way.. not so simple if it's glued to the roof.... However the addition of a 2 way relay wired to the ignition would disconnect the panel when the engine is running !

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20 minutes ago, miggit said:

and as such a dedicated alternator will do the business quicker than a split charger.... and if you go for a big alternator then much much quicker

Hmm, no, I don't think so. A bigger alternator will only charge a battery at the current the battery is willing to accept at its current charge level.

A split charger won't charge slower, unless it is one of the really naff ones with a diode causing a 0.7v drop across the VSR.

One 100A alternator can supply ample power to charge four 'normal' lead acid batteries at a time.

23 minutes ago, miggit said:

if you've got a compressor type fridge it should be able to top the battery up nicely, if it's a cheaper 3-way type with on moving parts (bar the door) I think it will struggle as they have quite a high drain... as many a tin tent owner has found out leaving the caravan plugged into the car without the engine running and the fridge on 12v:blink: From memory they pull upwards of 30 amps... you'll need a lot of headlights to get that sort of drain!

Clearly it will vary depending on model/size etc, but as a rule of thumb, the three-way caravan type fridges use around 4 times the power of a similar compressor style fridge. The most I have ever seen a 3-way fridge drawing (according to spec sheet) is 12A, and most are around 9A. It can't possibly be more than 20A, as that is what the 12S supply from the car is fused at normally...

25 minutes ago, miggit said:

If you're going for a leisure battery or agm / optima type the you'll need the smart charger, as a normal charging system doesn't output either the voltage or variable rates needed, and will end in premature failure and tears!

... and even with a 'normal' lead acid battery you will get better efficiency with a DC-DC smart charger, the battery university link above explains this.

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2 hours ago, miggit said:

 

Oh and on the subject of solar panels I've just bought one for my 'ang' 'over as I don't use it enough in the summer to keep it charged... part of the blurb said that it had to be disconnected from the car during starting as it can cause a surge and fry the panel... not a problem for me as it'll be on the dash in the way.. not so simple if it's glued to the roof.... However the addition of a 2 way relay wired to the ignition would disconnect the panel when the engine is running !

Solar panels (aside from little plug in dash-top 5w jobs) must be run through a solar control unit, not wired directly to a battery.  They put out 20-25v so will fry your battery...

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The unit linked to above, the RSCDC30 is a bit cheaper than the ctek D250SA (£190 v £220 plus pp). It looks good value but one thing to note is that it doesn't provide any top-up into the engine battery which the ctek does but only if the aux battery is fully charged. Also it's bulkier which might or might not be an issue. It does look as though you can monitor the Amps being pushed into the battery though and that's a nice comfort point.

The other point is that it doesn't matter how many Amps you have spinning out of the alternator, if the voltage of the aux battery is nearly but not quite at alternator volts then very little of that available power will actually arrive into the battery. If you load the alternator with a heated screen or two plus a few headlights then there will be even less chance of that top-up occurring.

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19 hours ago, Bowie69 said:

The most I have ever seen a 3-way fridge drawing (according to spec sheet) is 12A, and most are around 9A. It can't possibly be more than 20A, as that is what the 12S supply from the car is fused at normally...

OK so lets keep the maths simple.... we'll assume that the fridge has a 6 amp draw and you've an average sized battery, 60 Ah, that's 10 hours of running and it's dead in the water.... and that's at lower than average drain.. I'm not trying to scare peeps but if you leave the tint tent plugged into a car that's not running for a few hours it can have a very big effect.

17 hours ago, Eightpot said:

Solar panels (aside from little plug in dash-top 5w jobs) must be run through a solar control unit, not wired directly to a battery.  They put out 20-25v so will fry your battery...

The stick on kit that I saw had a regulator / controller with it, as you say it will end in tears if you plug a large panel into the battery directly, especially on days like the ones we had a few weeks ago!

 

16 hours ago, Peaklander said:

The other point is that it doesn't matter how many Amps you have spinning out of the alternator, if the voltage of the aux battery is nearly but not quite at alternator volts then very little of that available power will actually arrive into the battery. If you load the alternator with a heated screen or two plus a few headlights then there will be even less chance of that top-up occurring.

Surely if your battery has nearly the same volts as the alternator this would mean that it's nearly fully charged... why would you want to charge a charged battery? The man wants to power a fridge, I don't think that they are  a voltage critical piece of equipment... do they make smart fridges, for tents?

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17 hours ago, Peaklander said:

The unit linked to above, the RSCDC30 is a bit cheaper than the ctek D250SA (£190 v £220 plus pp). It looks good value but one thing to note is that it doesn't provide any top-up into the engine battery which the ctek does but only if the aux battery is fully charged. Also it's bulkier which might or might not be an issue. It does look as though you can monitor the Amps being pushed into the battery though and that's a nice comfort point.

I didn't realise that you can run the Ctec as a standalone unit, all the ones for sale had the Smartpass 120 thingy bolted on which doubles the price!  ... not so bad then !

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6 minutes ago, Bowie69 said:

6 amps is hardly 30!

Besides, a 12S socket should only be powered when the engine is running, so that situation should never happen unless a bodger has been at the electrics.

A 12s socket has a direct feed from the battery of the host... if it was switched then there wouldn't be a problem, but most don't come with warnings or a relay :o

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21 minutes ago, miggit said:

A 12s socket has a direct feed from the battery of the host... if it was switched then there wouldn't be a problem, but most don't come with warnings or a relay :o

That is exactly what I am disputing. Any 12s socket from back of the car is normally relayed to be only when the ignition is on, i.e. the engine is running.

All the kits I have ever fitted have always relayed the feed, so if you have had experience of them being permanent live, then I suspect a bodger had been at it.

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When I responded to the OP @roamingyak, I pointed out that the smartpass unit is only needed when there’s a big bank of aux battery not a single one. I run it alone.

About ‘nearly’ at alternator volts, the problem is that it only ever gets ‘nearly’ charged and over time this will lead to early failure. 

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