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cymro123

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Just a question from a newbie. Bought a new van with a new battery I think you call iut a 110a. I keep my van on the drive but will need to move it with a mover once a week to get the wheelie bins through, then move it back up. My question, how long will the battery hold it's charge. How often will i need to recharge it.

 

Thanks.

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Depends on what current drain is on it, example any alarm?

Depends on what amount of "moving" is involved, incline etc.

 

If without any drain and a simple side shuffle then a good battery should not need recharging for several months but I would explore recharging it every month. Ideally I would put in on a good "smart" charger; even the one sold by Aldi and similar one from Lidl are quite good enough. This could be left on 24/7 or on for a few hours monthly.

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Thanks, no alarm, only mover required. on a bit of a slope so I'll take your advise and charge it monthly.

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As stated by JTQ, the frequency with which you will need to recharge your battery will obviously depend upon the amount of moving that is done, bur be aware that movers can take a fairly hefty current when moving a caravan on an incline. For example the Truma SE mover on my caravan can take a current of up to 120 Amps (60 Amps per motor). So even with only a short move for the 'weekly wheelie bin shuffle', the caravan battery will benefit from a recharge on a weekly basis, as discharging a battery to below around 50% of its theoretical capacity could shorten its service life.

 

You do not state what make and model of caravan you have, but be aware that some caravans have a combined PSU/Charger, which provides power to the 12 volt items in the caravan and also charges the battery when the caravan is connected to a mains supply. The maximum output voltage of a combined PSU/Charger is restricted (by EU Regulations) to 13. 8 volts, and this will only re-charge your caravan battery to around 80% of its true capacity, and also will not eliminate the inevitable sulphation of the plates in the battery cells, which will eventually reduce the efficiency and capacity of the battery. Using a 'smart' charger as suggested above, would eliminate this and greatly extend the useful life of your battery.

 

Regards,

David :)

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David

 

I'm curious - where are you getting this 80% charge thing from ?

 

I've also read it somewhere else on this forum ?

 

This is not my experience in my day job - does it have any scientific backing or is it a statement that is being passed from person to person and just accepted as fact ?

 

The maximum output voltage of a combined PSU/Charger is restricted (by EU Regulations) to 13. 8 volts, and this will only re-charge your caravan battery to around 80% of its true capacity,

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>>>"The maximum output voltage of a combined PSU/Charger is restricted (by EU Regulations) to 13. 8 volts"<<<

 

I have often wondered about this when I have seen in on the forum. When I put my battery charger on in the van it shows 14. 4v on the control panel and the same if I meter it.

 

My van is s Swift group 2008 and the manual states . ...

 

--------------

The battery charger uses an algorithm which

makes it possible to significantly reduce

charging time and avoid permanent damage

to batteries. It starts charging at maximum

current until the battery reaches a voltage of

14. 4V, then charging takes place at a

constant voltage of 13. 8V. In this state the

recharge current gradually decreases and

the battery can be left permanently

connected to the charger without causing it

 

 

any damage.

-----------------------------

 

So I thought perhaps this has changed since 2008. Looking on the Swift website the current manual states . .....

 

-----------------

During stage 1 the battery voltage is increased

gradually while the current is limited to start the

charging process and protect the battery. At

stage 2 the voltage rises to 14. 4V to deliver the

bulk charge to the battery. When the battery

is charged, the voltage is decreased at stage

3 to 13. 6V to deliver a float charge to maintain

the battery in the fully charged state. The

charger can be left switched on continuously

 

 

as required.

-----------------------

 

My interpretation of this is that the charger in my Van will fully charge my battery to 100% not 80%

 

Is this correct?

 

My question is aside from the question of if 13. 8v would fully charge anyway.

Edited by Alansl

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>>>"The maximum output voltage of a combined PSU/Charger is restricted (by EU Regulations) to 13. 8 volts"<<<

 

I have often wondered about this when I have seen in on the forum. When I put my battery charger on in the van it shows 14. 4v on the control panel and the same if I meter it.

 

My van is s Swift group 2008 and the manual states . ...

 

--------------

The battery charger uses an algorithm which

makes it possible to significantly reduce

charging time and avoid permanent damage

to batteries. It starts charging at maximum

current until the battery reaches a voltage of

14. 4V, then charging takes place at a

constant voltage of 13. 8V. In this state the

recharge current gradually decreases and

the battery can be left permanently

connected to the charger without causing it

 

any damage.

-----------------------------

 

So I thought perhaps this has changed since 2008. Looking on the Swift website the current manual states . .....

 

-----------------

During stage 1 the battery voltage is increased

gradually while the current is limited to start the

charging process and protect the battery. At

stage 2 the voltage rises to 14. 4V to deliver the

bulk charge to the battery. When the battery

is charged, the voltage is decreased at stage

3 to 13. 6V to deliver a float charge to maintain

the battery in the fully charged state. The

charger can be left switched on continuously

 

as required.

-----------------------

 

My interpretation of this is that the charger in my Van will fully charge my battery to 100% not 80%

 

Is this correct?

 

Yes that is a proper charger and not merely a power supply i. E at 14. 4 v as opposed to 13. 8 v it will also keep the plates from sulphating

 

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The standard unit that many vans are fitted with and which outputs 13. 8V is a proper charger.

 

It will charge your caravan battery.

 

Now that the good old lead acid battery has become a hi-tech science, everybody is talking about multistage chargers.

 

It sounds like this is what you have.

 

It charges the battery at a constant current during the bulk charge phase, until the voltage rises to 14. 4V.

It then maintains a constant voltage until the charging current drops right down (absorption phase) and at this point, it goes to

the third stage which is float - a constant 13. 8V or less to keep the battery charged.

 

It won't do any harm. The only potential for damage is if you have sensitive electronics that aren't designed to take 14. 4V.

 

Generally speaking, 14. 4V is the maximum voltage that can be applied without the battery gassing and boiling all the electrolyte away.

 

On its own, this isn't enough to completely prevent sulphation and many battery chargers have extra stages for equalisation (a higher voltage) or pulsing and other clever ideas to stir the battery up a bit.

 

I saw a CTEK one recently which had 7-stages I think it was.

 

In my experience, both chargers will charge to 100%.

 

The higher voltage of the multistage will get it there slightly faster. On the average 80-110AH battery, there is not a lot in it. If you are talking about a 400-800AH bank which I am more familiar with, it will make a respectful time difference.

 

 

 

>>>"The maximum output voltage of a combined PSU/Charger is restricted (by EU Regulations) to 13. 8 volts"<<<

 

I have often wondered about this when I have seen in on the forum. When I put my battery charger on in the van it shows 14. 4v on the control panel and the same if I meter it.

 

My van is s Swift group 2008 and the manual states . ...

 

--------------

The battery charger uses an algorithm which

makes it possible to significantly reduce

charging time and avoid permanent damage

to batteries. It starts charging at maximum

current until the battery reaches a voltage of

14. 4V, then charging takes place at a

constant voltage of 13. 8V. In this state the

recharge current gradually decreases and

the battery can be left permanently

connected to the charger without causing it

 

 

 

 

any damage.

-----------------------------

 

So I thought perhaps this has changed since 2008. Looking on the Swift website the current manual states . .....

 

-----------------

During stage 1 the battery voltage is increased

gradually while the current is limited to start the

charging process and protect the battery. At

stage 2 the voltage rises to 14. 4V to deliver the

bulk charge to the battery. When the battery

is charged, the voltage is decreased at stage

3 to 13. 6V to deliver a float charge to maintain

the battery in the fully charged state. The

charger can be left switched on continuously

 

 

as required.

-----------------------

 

My interpretation of this is that the charger in my Van will fully charge my battery to 100% not 80%

 

Is this correct?

 

My question is aside from the question of if 13. 8v would fully charge anyway.

Edited by Barry J

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The standard unit that many vans are fitted with and which outputs 13. 8V is a proper charger.

 

It will charge your caravan battery.

 

Now that the good old lead acid battery has become a hi-tech science, everybody is talking about multistage chargers.

 

It sounds like this is what you have.

 

 

Hi Barry,

 

I have the standard Swift configuration. Looking at the manual its generic and applies to Abbey,Sprite,Swift & Sterling (Swift group vans) and judging by the fact that my 2008 manual and the current 2011 state 14. 4v surely this must apply to thousands of Caravans??

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Quite possible. it seems that only older vans have the 13. 8V fixed voltage charger box.

 

 

Hi Barry,

 

I have the standard Swift configuration. Looking at the manual its generic and applies to Abbey,Sprite,Swift & Sterling (Swift group vans) and judging by the fact that my 2008 manual and the current 2011 state 14. 4v surely this must apply to thousands of Caravans??

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Hi Barry J and Alansl.

 

I will try and clear up a number of points in response to your questions: -

  • I referred to a "combined PSU/Charger", which is simply a transformer and rectifier unit that converts 230v. AC to 12v. DC. In most older caravans (and some lower cost new ones) thus unit feeds both the 12v, caravan circuits and also charges the caravan battery. EU Regulations state that any extra low voltage supply "must be maintained within a tolerance of +/-15% of the declared voltage". This means that the maximum voltage that a combined PSU/charger can supply is 12 + 15%. (12v. + 1. 8v. = 13. 8v.).

  • Swift group, among others, have for some years been installing separate Battery Charger and Power Supply Units, thus the charger unit can be a multi-stage charger that can equalise and de-sulphate the battery cells by applying a voltage in excess of 13. 8v. (Usually this voltage is between 14. 3 and 14. 6v. - depending upon the type of battery).

  • A Lead/Acid Battery is merely an electro-chemical storage device that consists of lead and lead dioxide plates in an electrolyte of sulphuric acid and distilled water. The chemical reaction between constituent parts of the electrolyte slowly turns the surface of both plates into lead sulphate, which will have a detrimental effect on the capacity and performance of the battery. This lead sulphate coating can be removed once the battery has been 'bulk charged' by applying a slightly higher charging voltage (usually around 14. 4 volts for a 12 volt battery), which will also equalise the cells of the battery and ensure that it is charged to its full capacity. See http://www. dry-it-ou. ..Battery-Charger for a full explanation.

Sorry if its a bit 'long-winded', but I hope that it helps.

 

 

Regards,

David

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how do they seperate the 12v feed to the caravan from the higher voltages used to charge the battery, if 13. 8v is the EU limit, 14. 4v could damage other components? We have a simple 20a PSU in our van, and that provides 13. 8v which also charges the battery, the battery obviously smooths out the voltages. Presumably the newer vans can disconnect the battery from the rest of the system for charging, but then you lose the smoothing effect of the battery? Is it possible to modify older systems at resaonable cost, and does anyone have a wiring diagram showing how they have achieved the split system?

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Hi David,

 

Many thanks for the detaied information. I think it needed to be clarified as its often posted on Caravan Talk that the Caravan will only charge the battery to 80% when it appears this is only in some (possibly very small number of) cases.

 

There is even a sticky "Batteries" in the accessory forum which states . ....

 

-------------

Although the caravan charger system is sufficient, the technical disadvantage is it never fully charges the battery to its full capacity. The charge voltage is cut off prematurely at 13. 85 volts. Whichever type of battery you use, the in built charger will give a maximum charge to within 80% of the batteries original capacity. Over a period of time, this can cause sulphation of the plates in leisure batteries, due to under charging.

-------------

 

Which I think would benefit from some of the detail you have provided.

Edited by Alansl

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Actually Davids post, which is valid in other respects, doesn't address the 80% question.

I have also read the same 80% statement in the sticky.

 

With respect to the posters, I don't believe it based on my practical experience.

 

I have seen with my own eyes, batteries charge up to 100% using a 13. 8V charger.

 

I believe that that where the confusion is coming about is from a series of misunderstood half-truths.

 

Batteries charge up relatively quickly to about 80% and then it takes an age to get them up to 100% as the charge/time curve

is not a straight line.

 

If a 13. 8V charger gets the battery to 80%, it carries on charging at 13. 8V.

 

A multistage is probably putting out 14. 4V at this point, so the time between 80 and 100% will be quicker.

 

On a single leisure battery, this must only be a matter of hours not days.

 

This is a guess at the 80% rule we keep seeing bandied about, so not conclusive.

 

I only bring the 80% matter up because I think it is misinforming people who then tell others that their 13. 8V charger is only good for 80%.

 

I'm happy to be corrected if anybody can prove otherwise.

 

Hi David,

 

Many thanks for the detaied information. I think it needed to be clarified as its often posted on Caravan Talk that the Caravan will only charge the battery to 80% when it appears this is only in some (possibly very small number of) cases.

 

There is even a sticky "Batteries" in the accessory forum which states . ....

 

-------------

Although the caravan charger system is sufficient, the technical disadvantage is it never fully charges the battery to its full capacity. The charge voltage is cut off prematurely at 13. 85 volts. Whichever type of battery you use, the in built charger will give a maximum charge to within 80% of the batteries original capacity. Over a period of time, this can cause sulphation of the plates in leisure batteries, due to under charging.

-------------

 

Which I think would benefit from some of the detail you have provided.

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I believe the 13. 8V charger/power supply is regulated, so it will put out the same voltage whether the battery is there or not.

 

There are some exceptions depending on the unit, like the Dometic unit used on TEC caravans which came up the other day and is said to have an unregulated output. .

 

Normally the charger charges the battery, which then supplies the appliances through fusing and a battery isolation switch. The battery sits at whatever voltage it achieved when discharged and when the charger is switched on, the voltage rises slowly up to 13. 8V where it stays. The charging current is automatically shared between the battery and the appliances that are switched on.

 

how do they seperate the 12v feed to the caravan from the higher voltages used to charge the battery, if 13. 8v is the EU limit, 14. 4v could damage other components? We have a simple 20a PSU in our van, and that provides 13. 8v which also charges the battery, the battery obviously smooths out the voltages. Presumably the newer vans can disconnect the battery from the rest of the system for charging, but then you lose the smoothing effect of the battery? Is it possible to modify older systems at resaonable cost, and does anyone have a wiring diagram showing how they have achieved the split system?

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how do they seperate the 12v feed to the caravan from the higher voltages used to charge the battery, if 13. 8v is the EU limit, 14. 4v could damage other components? We have a simple 20a PSU in our van, and that provides 13. 8v which also charges the battery, the battery obviously smooths out the voltages. Presumably the newer vans can disconnect the battery from the rest of the system for charging, but then you lose the smoothing effect of the battery? Is it possible to modify older systems at resaonable cost, and does anyone have a wiring diagram showing how they have achieved the split system?

In a combined PSU/charger unit the fixed 13. 8v output is used to feed the 12v. sockets and 12v. appliances in the caravan and charge the battery (as with your “simple 20A. PSU”).

 

Where a caravan is fitted with separate PSU and charger units fed from the 230v. AC mains supply, the output from each unit is entirely separate; the PSU feeding the 12v. caravan appliances and 12v. sockets with 13. 8V, and the charger unit charging and conditioning the battery with a variable voltage of up to 14. 4volts.

 

Hope that this has explained it OK?

 

Regards,

David

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Actually Davids post, which is valid in other respects, doesn't address the 80% question.

I have also read the same 80% statement in the sticky.

 

 

HI Barry, from my point of view I had tried to prevent the two questions being rolled into one as is it unclear enough already.

 

Its clear that a very large number of vans have multi stage chargers which can output 14. 4v and will without question fully charge the battery.

 

Some vans have chargers which only output 13. 8v, whether 13. 8v is sufficient to fully charge the battery is another discussion.

 

pedantic ? me ? . .....noooooo

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whether 13. 8v is sufficient to fully charge the battery is another discussion.

 

pedantic ? me ? . .....noooooo

 

I cant find a trustworthy definitive reference to answer that but my understanding gleaned over the years is that the voltage has to rise above 13. 8 for a full 100% charge, then to hold a 100% it can be reduced to 13. 8 without associated gassing.

I would also welcome info on this.

I suppose a way to check is to take a somewhat depleted charge but sound battery and put it on a charger which does not feature the voltage lift, then after removing for two days check the OCV open circuit voltage. If you get 12. 7 to 12. 8 then with most wet batteries its a reasonable assumption it is charged to 100%, if its below this at 12. 4 12. 5 then its nearer 80% charged.

I unfortunately have not got such a rudimentary charger to enable me to do this test.

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I cant find a trustworthy definitive reference to answer that but my understanding gleaned over the years is that the voltage has to rise above 13. 8 for a full 100% charge, then to hold a 100% it can be reduced to 13. 8 without associated gassing.

I would also welcome info on this.

I suppose a way to check is to take a somewhat depleted charge but sound battery and put it on a charger which does not feature the voltage lift, then after removing for two days check the OCV open circuit voltage. If you get 12. 7 to 12. 8 then with most wet batteries its a reasonable assumption it is charged to 100%, if its below this at 12. 4 12. 5 then its nearer 80% charged.

I unfortunately have not got such a rudimentary charger to enable me to do this test.

 

Sounds like a good idea. Although thinking about it there must some owners on here with the aforementioned 13. 8v max output chargers in their vans.

 

I'm sure many of these people don't use any other type of charger, ever . ...... therefore if they meter their batteries or if they have gauge/readout in the van, will they never see a reading of >= 12. 6v ????? ***when the charger is off or EHU is disconnected.

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Whether or not the battery is full charged from the on board charger is debatable, but when towing, the caravan battery will get up to 14. 4v from the car alternator, depending on demand elsewhere.

Brian

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Whether or not the battery is full charged from the on board charger is debatable, but when towing, the caravan battery will get up to 14. 4v from the car alternator, depending on demand elsewhere.

Brian

 

Good point Brian. I think though, if someone with an integral 13. 8v charger has their van on the drive, doesn't use it over winter (or for a sufficient period) and the battery is allowed to fall to 12 - 12. 2 volts (or wharever), then with only using the charger in the van, can they get their battery to show a reading of >=12. 6v. Surely there are owners out there how can tell us? . .. you could imagine such a scenario as someones first trip of the season.

 

Or is purely looking at the voltage not a true indication of % charge anyway?

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