# Battery Size



## mlynnf50 (Oct 2, 2009)

Hello all.  We have a Hymer B524 (A Class) and our leisure battery will not hold a charge.. so thought I had better invest in a new one, can anyone tell me what size I will need and where I can get one from please, and should I buy an invertor at the same time.  Also i would like a fan to fit in the roof in the bedroom has anyone ever fitted one and is it easy, my hubby is generally good at diy so would he be able to fit it for me and if so which one would you suggest.... Oh am on a roll here...lol thank you.


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## uglybob23 (Oct 2, 2009)

Hi,

Might be an idea to see what set-up you already have and replace like for like. I would have thought it largely depends on what you run off it and how long you want to stay in one place. 

With an inverter you might be better off with a larger battery or two joined together (I think it needs to be in parallel?). Again the size of the inverter depends on what you will use it for and how long you need it. A silent generator might be an option instead?

I've been thinking of changing my battery recently and this is the cheapest and most accessible I've found near me:

Quest Leisure Battery 85AH - from GO Outdoors.co.uk

I've seen them at Halfords for double that. I also saw someone on here mention that chandlers were a good source as boater use them too.

Not sure about fans but I'm sure someone will be along shortly who knows more about that and battery/inverter set-ups.

Happy travels.


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## Firefox (Oct 2, 2009)

The system I'm building in my van at the moment consists of two 110 AH leisure batteries wired in parallel and a 1000W inverter. If you are using an inverter I'd go for two batteries. 

Inverters will cane your battery. 240v at 4 amps  (=960w) equals 12v at 80 amps, so run a 1000W inverter for an hour and it will near enough flatten a 85 Ah battery. Inverters are best used for things like microwaves or hair dryers where you are only going to run for 5 or 10 mins max.

Even if you are not using an inverter I'd go for a 110 AH battery not an 85 AH as the discharge will be a smaller percentage of its capacity for any given usage, and thus means the battery will last longer. Unless you spend most of your time on a hook up in which case the smaller one will be fine


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## guerdeval (Oct 2, 2009)

we had a fiamma roof light and fan fitted last year, biggest pile of crap ever,its now stuck closed so I don't have to listed to the fan hitting the casing or replace the sliver of plastic which stopped it catching,to rub salt in the wounds it cost over 600 euros as it was an emergency repair carried out by french highwaymen to replace the old one that cracked, glad I got that off my chest


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## Deleted member 207 (Oct 2, 2009)

Have a look back in the archives on this forum - lots of posts about this topic.

Do a few calculations first so that you can get an appropriate sized battery(ies) for your needs. Add up all the watts @ 12V that each appliance uses and then estimate the number of hours you will use them for each day. You can then use the formula (Watts / Volts) = Amps x Hours = Amps Hours - which is the usual method for rating a battery. Or goto Electric power calculations voltage current and resistance - electricity calculation - electrical power general formula ohms law physics formula wheel power formulas amps watts volts ohms cosine equation audio engineering pie chart - sengpielaudio Se to do it for you. 

Next step is to understand that not all batteries are made equal - cranking batteries are designed to start a vehicle, draw a large amount of Amps for a very short period, and then be recharged by the vehicle alternator. Cranking batteries are not good at being discharged and then recharged and will fail within a few months when used as a power source for appliances/lights.

Leisure batteries are a compromise between a cranking battery and a full on storage battery. They are capable of being discharged lower than a cranking battery but will not recover if they are fully discharged continually. Leisure batteries come in all sorts of different internal configurations - lead acid, gel, glass mat, etc. 

Lead acid require the battery to placed upright with the vent at the top.
Gel and glass mat can often (not always) be fitted in any position you like, which often means you can fit a much larger battery into the space available.

Forget about storage batteries as you need a truck to carry them.

Inverters - unless you have an over riding need for 240V appliances then why bother. Again do the sums and have a look at the watts drawn by 240V appliances and what the startup Amps is for the appliances you want to run - some friends wasted a lot of money on an inverter to find out that it could not provide sufficient Amps to start a 240V water pump - pump drew about 3Amps when running but needed about 15Amps to start it.


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## lebesset (Oct 3, 2009)

interesting that , the quest leisure battery

you will note it says ...semi traction battery ....not absolutely certain what that means but for those of you who don't know a traction battery is , it's a battery used for vehicles that run on battery only , milk floats , fork lifts , that sort of thing 

so obviously designed to be charged up overnight and the run down seriously during the day ...so a lot in common with our RV batteries


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## ian81 (Oct 4, 2009)

mlynnf50 said:


> Hello all.  We have a Hymer B524 (A Class) and our leisure battery will not hold a charge.. so thought I had better invest in a new one, can anyone tell me what size I will need and where I can get one from please, and should I buy an invertor at the same time.  Also i would like a fan to fit in the roof in the bedroom has anyone ever fitted one and is it easy, my hubby is generally good at diy so would he be able to fit it for me and if so which one would you suggest.... Oh am on a roll here...lol thank you.



Easiest way is to remove the old battery and see if the capacity is marked on it and then buy a similar size. Talk to Tayna Contact Tayna Batteries
we had good service when we bough an ELECSOL 110 Carbon Fibre Battery earlier this year.

If you are wishing to add an inverter first question is what is the usage?
Are you wishing to use more electricity than previously?

If so you may want to uprate the battery capacity or buy 2 and wire in parallel.


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## andytheplumber (Jan 21, 2010)

my turn now,we were away at the fireballs at new year and the van was parked up at lunchtime-the heating was on all the time(fan assisted) and the tv on for an hour when we got back on newyears day at 10am the 80ah battery had lost half its power...what size batt do mosy of you run,I want to last for three days wilding..I do have a honda suitcase but I agree they are noisy(although mine is 60decibels)I have room for to batteries -do I go for a 110ah or two new 80ah or add a 80 to my existing which is two and a half yrs old.


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## derekfaeberwick (Jan 21, 2010)

I'd go for 2x110 ifyou have the room and the money.   ,


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## PaulC (Jan 21, 2010)

Batteries are a more complex subject then you might think. Go to this link and look further on the site

Sterling Power Products: What is the best battery to use for an auxiliary charging system?


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## NicknClair (Jan 22, 2010)

PaulC said:


> Batteries is a more complex subject then you might think. Go to this link and look further on the site
> 
> Sterling Power Products: What is the best battery to use for an auxiliary charging system?



It is ineed much more to batteries and inverters. My end result was single 220AH Elecsol, coupled with a Sterling pure 1.5kw inverter and advance charging. Have been happy with this set-up for the last 2 yrs now and works a treat for heavy use. we also put on a good battery monitoring system to check our use so we knew when we were close to system switch-off and when to get the battery recoved again. Would be brave to say that 95% was no hook-up last year (5% was free  ).


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## BedfordMJ (Jan 22, 2010)

lebesset said:


> interesting that , the quest leisure battery
> 
> you will note it says ...semi traction battery ....not absolutely certain what that means but for those of you who don't know a traction battery is , it's a battery used for vehicles that run on battery only , milk floats , fork lifts , that sort of thing
> 
> so obviously designed to be charged up overnight and the run down seriously during the day ...so a lot in common with our RV batteries



The words semi-traction no doubt is a gimmick it will be a normal 12v battery and they will charge you more for it.
As has been mentioned before, get the biggest amp/hr battery you can, varta are a good brand.


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## andytheplumber (Jan 22, 2010)

I think the answer I am looking for is will a 110 ah last 3days or do I go for two 80ah


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## bigboack (Jan 22, 2010)

depends on what your running for the 3 days away wilding, Tvs are a big drain, the bigger the tv the more drain on the battery, Inverters are for more like a laptop or something of lower wattage. Sit down and think what leccy you will use while away for 3 days. Have you thought about a solar panel to charge it during the day.

Ask the Question Generator/ solar/ wind power, see what response you get. Good luck.

I have all three. FWIW


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## Kontiki (Jan 22, 2010)

I would personally fit 2 smaller batteries rather than one big one, if one battery does fail you won't be completely stuck. I only have the one 85 amp battery at the moment, I don't have room to fit another one in the locker & if I have to replace it I would have to just buy the biggest I could fit in. At the moment we can manage on the one, it does seem to last really well I don't know if its because its an Exide Gel.


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## NicknClair (Jan 23, 2010)

I'm not sure on that statement, as 2004 seen me loose both batteries as a result of a collapsed cell in one of them, causing damage to both. Secondly power delivery and charge going to one battery would have less wiring and resistance than a battery bank, hence why I fitted one large 220AH (not 2 x 110).
However if space is a premium, then it is sometime unavoidable that 2 x batteries are used. Going back to 'Z' question, if you have the room large single, but if not then 2 x 80's would be better but bear in mind of the risk in battery banks.


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## andytheplumber (Jan 23, 2010)

thanks to all, I was at deevalley caravans today and he advised to just keep the 80ah and take my honda suitcase.


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## barnybg (Jan 23, 2010)

*Battery ??!*

Same as what the prostitute said to the vicar 'the bigger the better' !

When your 80 amp finally gives up,go for a bigger one,and if you have the room  X2...your generator is fine,IF its not raining,you have enough petrol,you can use it without disturbing others......


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## Firefox (Jan 23, 2010)

Go for the biggest capacity 2x80 A, because although the 110A may last 3 days it will be more heavily discharged, and it's not good to deep discharge batteries. Most leisure batteries are little more than starter batteries and do suffer shorter lives if you deep discharge.


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## barnybg (Jan 23, 2010)

Thus the reasoning for  2   ....110's.plenty of life,without draining also less use so longer life..?


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## Firefox (Jan 23, 2010)

I agree with that, but he said his choice was between one two 80's or one 110. I've got 2 x 110, they're not too bad in terms of space, but space is often tight.


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## andytheplumber (Jan 23, 2010)

this is more like it,I agree on the genny but I hate using it because of the noise,although its a honda suitcase I hate it if somebody uses the dam things all the time.so I would rather go down the battery route,I have plenty room for batterys,my local caravan shop has 85ah batterys for 48quid.


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