# Second leisure battery?



## Guest (May 12, 2008)

Ok guys let's have your thoughts on these ideas. Having just acquired our first motorhome and having come from narrowboating, where (at least) two leisure batteries are the norm, I find there is ample space to install a second under floor battery box (if I can find one!) adjacent to the original.

We intend to camp mostly on sites where there are no EHU's and are concerned that a two/three day stay may exhaust the current single battery. So I am thinking of installing a second one, wired in parallel to supplement the original. I have checked and I do have payload capacity.

Does anyone know where I can get such a battery box?

One other thing, Is there any reason why I cannot buy an £80 flat screen freeview 240v TV from Tesco's and run it off an inverter, rather than pay £300 for one with a 12v input.

Regards

Tco


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## clodhopper2006 (Aug 13, 2006)

Personaly I've never heard of an underfloor battery box. Would it be accessable for maintenance? You could maybe get one fabricated for you but cant you get another battery alongside the one you have now or uprate to a higher Ah rating?
No reason at all why you cant run a TV throuhg an inverter. They are power eaters though but a lot of folk find most TV's are powered from a black box supply that outputs 12V to the telly. Many have said they just bypass the box and plug into the van 12V. If you do this you will need to ignore all those who will tell you you will fry your telly doing this.

Bob


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## Guest (May 12, 2008)

Thank you for your reply Clodhopper. How can I describe the battery box? Let's see.

It is a rectangular plastic box, about the depth of a normal battery, with a rim flange around the top edge. this flange supports the box which hangs down through a similare sized rectangular hole in the floor of the 'van. 

Thanks for the tip about the 12v supply to mains TV's I guess the next question is how to identify the correct supply point. 

Tco


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## silverlocks (Jun 28, 2007)

Go for the tesco option, I have telly and sat box working thru 300 watt inverter connected direct to 2nd hab bat but not in parallel. keep inverter close to batt and you will find it lasts for about 24 hours continuous use, just depends how long you want telly on each day how long it lasts, we get 4 days no prob and 8 days if we carefull, just OH soaps and my news and weather


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## some-where-in-oxford (Apr 18, 2006)

You should be able to get a plastic battery box from any caravan or motorhome dealers accessory shop.

I've seen them for about six quid at the motorhome shows. They often come with a strap to hold the top on.

http://tinyurl.com/6lfaso

google - motorhome battery box

Lots of links.


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## Rapide561 (Oct 1, 2005)

*12v television*

Hi

I agree re the television - I use a cheapish telly - and if needed, run through an invertor. I will add, however, that when watching SKY TV and the TV is connected to the invertor, the signal sometimes breaks up. Not sure if the invertor is causing some form of interference.

As for the battery box - no idea - but agree having two batteries is a good idea.

R


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## TheFoxes (Oct 9, 2007)

Hi, try www.marinestore.co.uk. I haven't used them personally, but I have been looking for battery boxes for when I relocate my leisure batteries and these are the only ones I have seen so far.
(sorry I haven't sussed out how to insert a direct link to the page yet)
Regards Paul

or have I??


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## Guest (May 12, 2008)

It looks like it!

Tco


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## 107558 (Oct 10, 2007)

I got a cheap 15" LCD from Curries which has the usual 240v to 12v power brick so the TV is basically a 12v model. I bought a 12v regulated power supply from RoadPro and plugged it into a cigarette socket wired directly to one of the leisure batteries (through a 20amp fuse).


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## Vennwood (Feb 4, 2007)

Hi tco,

Another tip to eek out the battery amps when off EHU - you can buy replacement LED bulbs for your internal lighting - makes one heck of a difference on battery usage - it can reduce your amps to a fraction of the current H4 usage. We bought a 17 inch LCD screen for £99 and found it used a 240 volt transformer to supply 12 volts to the TV - we have used it both ways with no ill effect

Pete


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## 109334 (Jan 20, 2008)

we just use a 10ins 12v tv with its own transformer plugged into a 12v socket we had fitted near our table ..its got freeview and we use this tv when we have no ehu ..


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## dcummin (Jan 21, 2008)

I has the same problem with adding additional batteries to my motorhome as mine also hangs beneath in a box.

The lads at RVtex in newark near nottingham fitted two additional batteries for me into the floor of the garage and linked them in. they are self contained in their own little boxes and I havent lost any space - ingenious idea. They lay completely flat and have a secure plastice cover over them - its like they have always been there.

I'm sure these could be fitted under a bed or into the walkway or anywhere really - doesnt have to be in a garage if you dont have one.


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## 104208 (Apr 30, 2007)

Yes two bateries in parallel as close together as possible. But i would recommend they are the same type and age of battery. otherwise one will discharge the other. the older battery will always have slightly less capacity even it it states 80ah. Electricity will always flow between them to compensate for the differnt capacties. So get two batteries the same.

On the TV front. no problem with an inverter and a normal tv. but its all a question of how many watts the TV needs. if u look around and compare tvs, look at the watts rating at 12v. quite often a 12v 15inc lcd tv which uses a transformer will need say 65 watts. another 12v tv may only need 45 wattts (thats just 3.7Amps) so get one with the lowest watts ratting you can get. there is a slight overhead in using an inverter and it maynot give you proper AC, some 240v tvs and their internal switch mode power supplies dont like this. so get a pure sine wave or at least a trapezoid inverter. Cheaper ones can just be a rectangualer wave which are ok for things without built in transformers.

and, a battery under the floor sounds like a good idea, u dont need access to it very often.

Mike


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## mechanic (Jan 2, 2006)

My 2004 autotrail apachee 600 has its battery box cut into the floor and accessed via a top cover.


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## bobandjane (Dec 29, 2007)

Hi tco I have a fiat ducato that had one 85ah under the passenger seat, I put some ply wood under it to make it flat, and turned the battery the other way and there is enough room to put another 85ah next to it. If not you could always put one under the drivers seat. Its worth a look. Good Luck. Bob.


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## RussandPenny (May 21, 2008)

*Twin Liesure battery conversion*

Hi TCO,

I've just carried out the exact conversion you're talking about on my 1994 laika Ecovip. 

I also know exactly what you're talking about in terms of a battery box, because I was looking for the same thing!
Unfortunately I was unable to track down what seemed to me to be such an obvious solution for a battery box and finally plumped for installing it under one of the dinette seats, caravan style.

I'm running a 1500w inverter, adjacent to the new battery (both are 110A) and a power-supply/charger that is connected to the liesure batteries ONLY, thus enduring no loss through a split charge sytems.
The split charging is taken care of via an ADVERC ABM SOLONOID when the engine is running (http://www.adverc.co.uk/products/adverc/abmsol.asp) which also allows you to jump-start at the touch of a button should you manage to run the cranking battery down. Hence no need for split charging from the mains. I upgraded to a 95A alternator (70A as standard) to help the batteries keep up with the inverter.

All of this was pretty much aimed at enabling the Mrs to run a small hair-dryer while avoiding the necessity to stay at campsites, and it seems to have worked really well so far, with the simple house rule of running the engine when using the hair-dryer! LOL
Another issue for my vehicle is that the original battery is located under the bonnet at the front, and unwilling to lose more space inside, I was forced to run 35mm² cables between the batteries (200A fuses at either end) to keep up with the potential demand of the inverter and avoid a voltage drop between the batteries.

The inverter is also wired directly into the vehicles 240v mains system via a change-over relay, so that as soon as a mains supply is enabled from an EHU it changes over, disconnecting the inverter.
The battery charger/PSU is powered only when connected to an EHU, so no need to remember to switch it off when running on the inverter

As far as the TV goes, my advice would be to go for the Tesco unit (I certainly intend to) and ditch the power supply as this is the part that uses big current, not the TV itself.
There's no point in inverting 12v up to 240v, just to transfrom it back down to 12v again! remember, there will always be a loss to heat when you change voltage in whichever direction.
If the input voltage for the TV is not 12v, then buy a small transformer from Maplin or similar to deal with the difference with a much smaller loss.

I hope all of this drivel is of some use to somebody! :?

Russ.


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## vardy (Sep 1, 2006)

I have a cunning plan........... :twisted: I've got a powerpack 300W that you can plug a 13Amp appliance into. If I stick a trailing socket in it, can I run a 19 ins telly and freeview box. Need it a couple of nights for a few hours over the weekend.

Yes - I KNOW I won't have it charged up if the van won't start, but I've got AA and would probably electrocute myself using it to jump start the van anyway.

Will this arrangement work - Or will I fry???? nfire:


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## johng1974 (Jan 17, 2007)

yes Russ


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## RussandPenny (May 21, 2008)

It really depends on the power consumption of you TV and FV box.
Why don't you try it before you go?

At the end of the day, it will probably work, but not for very long!

Russ


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## vardy (Sep 1, 2006)

Thank you Russ - just need a late night film so will check consump. Not worried about noise of pack, as I'm using headset. But don't want to get to the end of the 'whodunit' and miss the last 2 mins!


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## RussandPenny (May 21, 2008)

I generally take a laptop and a few DVD's for times like this...

worth noting too that you can buy in-car chargers for laptops rather that using an inverter.
Here's one I found after a quick search just now: http://www.powersuppliesonline.co.u...plane-laptop-power-supply/14129cp/default.htm

Remember, it's best not to invert all the way up to 240v just to bring it back to a lower voltage if you can possibly avoid it.

Russ


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## geraldandannie (Jun 4, 2006)

RussBroom said:


> Remember, it's best not to invert all the way up to 240v just to bring it back to a lower voltage if you can possibly avoid it.


Hi Russ

That's one theory, although in a recent discussion, I'm sure someone with far more knowledge than I showed that it wasn't as bad as you might think.

Also, on the 'not buying a dc-dc converter' side, I use my lowly 150W inverter to not only charge up my laptop (whilst we're eating or reading or something), but it also helps to charge up our mobile phones (using chargers we already have), our cameras (using chargers we already have), my rechargeable razor (using ... you get my drift), batteries for the MP3 speakers, iPods, and something else I've forgotten 

I'm quite happy to forego a few percent of efficiency (if indeed it is less efficient to use an inverter / laptop charger than a dc-dc converter), for the cost and convenience of being able to power and recharge all those devices above on a longish trip away.

Gerald


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## RussandPenny (May 21, 2008)

You're absolutely right geraldandannie,

My point really, is that if you've got one particular appliance that you use a lot (eg TV) then it's better to run that from a dedicated power supply and switching the off inverter.
This will help to sustain battery life.

As far as the phone/camera/etc chargers go, you're better off just running them from your inverter.
That is after all why you went to the trouble of fitting one.

Russ


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