Leisure battery, invertor, generator!!!?????

Discussion in 'The Beginner' started by errpaul, Mar 5, 2009.

  1. errpaul

    errpaul Funster

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    Hi,

    We're just about to take the plunge and get our very first van but still can't figure some things out.
    Now this may all sound very silly, as it's probably all so simple, but I just can't get my head around it at the moment, so any help would be great.....:Doh:

    Firstly, I see a lot about leisure batteries....now are these just the same as a car battery or are they different. Is there anything special about them? Is there a simple way to add addition batteries if required?

    Secondly invertors or generator.......what exactly does an invertor do? I'm guessing it's for wild camping (which we plan to do), and allows you to use normal 3pin plug appliances from leisure batteries???
    Does an inverter need to be wired in or is it just an add on?

    Finally, I see that there are some silent generators (would not want to use anything which is going to disturb others, and would restrict times of use). If you run one of these do you connect it like EHU or is there some other way to connect it?
    Do you then use normal plugs or the 12v ones?
    Does the generator charge the leisure battery?

    Thanks for your help...I understand that until we get out there we won't know exactly what we need, but would be great to know what the options are.

    :Smile:
     
  2. pappajohn

    pappajohn Funster Life Member

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    hi,

    yes leisure batteries are different to car batteries,
    they are constructed in a different way so as to allow longterm slow drain rather than sudden bursts like a car battery.

    an invertor converts 12v to 240v electronicaly and you would use your normal 3 pin plugs.
    they can and do use a lot of battery power so a large battery bank is , in my view, essential.
    they can be free standing but a lot of folks hard wire them direct to the leisure batteries, you should have as short a wires as possible between batteries and invertor.

    generators.....yes. just plug it in as you would a hookup and use normal 240v plugs or 12v plugs, the genny will power both.....the blurb says 'silent' but they aint silent....just quite.
    yes it will charge your leisure batteries just as it would on hookup.
     
    Last edited: Mar 5, 2009
  3. pappajohn

    pappajohn Funster Life Member

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    forgot to metion adding extra batteries.

    not a problem, just try to keep them as close together as possible.
    one train of though is they should all be the same ampage and age....
    if one is an old one and you fit a second, new one will only be as good as the old one......if the old one is not holding a charge as it should then the new one will be pulled down with it.

    my original battery position is under the passengers seat and the new one is under the dinnette seat.....1 mtr away.
    both are new and the same make, size and ampage, (110ah so in total 220ah)
    they are connected together using 50amp cable with a 30 amp fuse at both ends of the wire.

    they are connected + to + and - to - so its still 12v but double the ampage.

    if you buy an invertor buy the largest you can afford.....a 150w may be ok for running the tv but try plugging in a fan heater :Eeek:
    i have a 500w but only use it for shirls hair curlers/tongs 'cos of the battery drain. if i use it at its max power it will take about 45amps from the batteries per hour. her hair stuff is about 150-200watts and its only used for around 10 mins so not too bad.
     
  4. errpaul

    errpaul Funster

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    [

    my original battery position is under the passengers seat and the new one is under the dinnette seat.....1 mtr away.
    both are new and the same make, size and ampage, (110ah so in total 220ah)
    they are connected together using 50amp cable with a 30 amp fuse at both ends of the wire.

    they are connected + to + and - to - so its still 12v but double the ampage.

    if you buy an invertor buy the largest you can afford.....a 150w may be ok for running the tv but try plugging in a fan heater :Eeek:
    i have a 500w but only use it for shirls hair curlers/tongs 'cos of the battery drain. if i use it at its max power it will take about 45amps from the batteries per hour. her hair stuff is about 150-200watts and its only used for around 10 mins so not too bad.[/quote]

    Brilliant, thanks.
    So basically you just 'extend the circuit from the main battery', for want of a better way to put it. There is no need to do anything more complicated with the wiring...just connect to main leisure battery as you've said and add from there depending on the power it turns out we need.

    Do you know anything about TV's? We want a TV DVD combi...is there any one which is best to get or is it a case of anything from currys/comet for example. I've seen some posts which mention TV DVD which run on 12v?
     
  5. pappajohn

    pappajohn Funster Life Member

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    nearly all the smaller (15"ish) and some 19" LCD tvs work on 12v and the power drain is very small...around 2ah for mine using TV only, DVD will use more.

    the thing to check for is the mains power lead....does it have a small transformer box in the lead. if it does then it will run ok on 12v, just do away with the transformer and fit a new power lead. (see link to stabilizers below)
    if it doesnt then its 240v only.

    got mine from Asda, i think its an ONN....probably their own brand name. about £115....Analogue+Digital freeview and DVD player built in.

    i wouldnt bother with the 'made for motorhomes' type (Avtex ect).....they are far too expensive for what they are.

    if you run on 12v then, in my opinion, it worth buying a voltage stabilizer..click <<HERE>>

    not cheap but your TV could be damaged by over voltages without one, ie- if you just got on site, turned off the engine and plug it in i could be the battery may have 14+ volts which will kill you TV.
    some folks say they dont have a problem but i wont risk my TV.
     
  6. errpaul

    errpaul Funster

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    i wouldnt bother with the 'made for motorhomes' type (Avtex ect).....they are far too expensive for what they are.


    I did look at some of these which is what prompted the question as they did just seem to be ridiculous prices! I'm far happier with your idea:thumb:
     
  7. JeanLuc

    JeanLuc Funster

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    On the subject of inverters, they are really useful but there is an inevitable loss of efficiency in making the conversion from 12V DC to 230V AC. If it possible to buy a 12V version of whatever you want to use, that is a more efficient option. However, there are some things you cannot get in 12V format.

    Inverters up to 150W are available with cigar lighter plugs. Above that power, they have to be wired directly to the batteries. Even when using a small inverter, there can be a problem of voltage drop due to the relatively thin nature of the cabling used in many motorhomes to feed the 12v sockets. That loss of voltage can cause malfunctioning of certain devices, including flat screen TVs I am told. I have a 150W pure sine wave inverter that is used to power a laptop and active speaker system. We watch DVDs instead of bothering with a TV. It's also good for recharging camera and phone batteries etc. When I had the inverter plugged into a 12V socket, it suffered voltage drop and failed to work properly, so even with this small unit, I had to remover the cigar lighter plug and wire it directly to the batteries. I have mine powering a stand-alone twin 230V socket that I have fitted. It is possible, with a large inverter to wire it to supply the van's main 230V sockets, but that is quite complex and you should not attempt it unless your are a competent auto-electrician. The two systems have to be capable of isolation otherwise you will get into all sorts of bother if the hook-up and inverter are connected at the same time. In my view, it is much easier to keep the two circuits entirely separate.

    One final thought. As already mentioned, inverters are pretty power-hungry because you need a huge current to drive anything powerful when the input potential is only 12V. You probably know the formula, Watts = Amps x Volts, or to calculate the current drawn, Amps = Watts / Volts. So if you draw 1 kw from an inverter (a small electric kettle) the current drawn from the battery will be 1000/12 = 83 amps. Even my 150W inverter can supply peak power of 300W to allow for the surge that some appliances draw on start-up and that equates to a current draw of 25 amps. So the message is, get plenty of battery power and then use inverters with care. And make sure the wiring from battery to inverter can handle the current, and that it is fused appropriately.

    Here is a link to a downloadable pdf on Sterling Power's web-site showing required cable gauge. Sterling make some very good inverters - and a lot of other good electronic stuff.

    <<What Cable>>

    Philip
     
  8. pappajohn

    pappajohn Funster Life Member

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    very detailed explaination Philip.

    much more in depth than my attempt. :thumb:
     
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