Help understanding electricty/leisure batteries and inverters

Welcome to UKHIppy2764@2x.png

UKHippy is a long running online community and of likeminded people exploring all interpretations on what it means to be living an alternative lifestyle -- we welcome discussions on everything related to sustainability, the environment, alternative spirituality, music, festivals, politics and more -- membership of this website is free but supported by the community.

  • Currently I am trying to work out what electric set up we are going to need. What size and how many batteries? And how long we can use them for.


    Now I understand how to change things into amps but what I don't understand is...does that have a time limit?


    Say a telly draws 3 amps and I have a 110ah battery....does that tv use 3amps per hour?


    Does an inverter change this? will I be using more power?


    Basically my son aint worried if he lives on a bus as long as he can uses his xbox now and again (lol priorities) so am trying to figure, lighting, fridge, telly, xbox, laptop.


    We are thinking of having a couple/few batteries with a soalr panel set up, so any advice on this part would be of great help. :)

  • I think if you have a 110ah battery that means you can draw 1amp for 110hrs when its fully charged. So divide 110 by 3 and that should tell you how long you can use your 3amp telly for. I think an inverter makes it a bit more complicated though, hopefully someone else knows more on that... By the way, should make sure you dont let your battery(s) get too discharged. We learnt the hard way and just had to replace ours cause it wouldnt re charge any more.

  • Ah ok, that makes it a bit easier to work out thankyou.


    Yeah have read a few threads here about not discharging them, was maybe thinking of getting a deep cycle battery because I know I'd do something like that too.

  • basically even with deep discharge (leisure) batteries you dont really want to discharge them much more than 50%, so work out what you will be using as a total Amp hours then multiply by 2 - so in reality your 110Ah battery will give about 55Ah usage. if you use an inverter your 3A tv will use more as the inverter is only about 85% efficient, now is the tv 3A at 12V or 3A at 240V (3A at 12V will use about 3 1/2 A max per hour - 3A at 240V works out at about 60A per hour via an inverter) the best bet is to avoid an inverter as much as possible (if you do get one get a pure sine wave version) and get a TV that can run on 12V (some have a 12v mains adaptor).
    This of course assumes that you will be using the engine and charging your batteries on a daily basis. in most cases people have several 110V batteries connected up in parallel. its worth noting here that the leisure batteries shouldnt be connected in with the starter battery (they are different types of battery plus you dont want to flatten your starting battery).
    Grendel

  • hi
    im new on here but i think i can help abit


    "We are thinking of having a couple/few batteries with a solarr panel set up, so any advice on this part would be of great help. :)"


    panels are a good way to go but they need afew other bits


    1. a charge controller...

    these monitor yr battery bank & switch the charging on & off as your batterys need it,
    s/panels always produce something in daylight, hopefully, so when the power would overcharge the batts
    it protects them


    2. a split charger


    this attaches to yr alternator,
    u will have a battery bank in the back & the main battery which starts your vehicle
    if you are in the back using the tv etc off your bank & you flatten them, without a split charger you
    would then start to use the power in the main battery (bummer when u want to move n its flat too )
    a split charger prevents this so u can always start your truck.
    it will also monitor the two batterys, main & back & send the charge from the alternator when driving to
    which ever needs it most


    3. make sure you have a VERY VERY good seal where the panel cables come into the truck
    water will track down them given half a chance


    inverters are useful if you have to have 240 volts but just remember that converting from 12v to 240v is
    never 100% efficient so you will loose some of yr stored power doing it
    most things tvs, laptops etc dont run on 240 even though its plugged into the mains so you will loose more
    of your battery power converting it again


    example
    this laptop im using runs at 19v so with an inverter it would be 12v.....240v....19v
    2 changes & 2 inefficient conversions
    go to somewhere like "maplins" & get a 12v multi adaptor these are cheapish & have a multi position dial which
    u set to the power output u need & come supplied with loads of different fittings so you can use it for lots of diff things tv laptop gameboy etc
    this means only 1 conversion 12v to 19v in this case so saves power


    same with tv,s
    i have a 15 inch flat screen colour tv here in my caravan runs on 12volts & draws 3.1A so no major drain but through an inverter & a mains lead it would be alot more due to the inefficiancies.


    LED lighting instead of bulbs will also save alot of power over time


    with a bit of thought you can reduce your power needs & consumption to a minimium
    do your research & hunt around for the best bits


    BUT above all have fun & enjoy your new life.:panic:

  • Hi Grendel, thanks for the reply - with the telly, was just going to take the one from the house, which because it's plugged in atm, so at 240v. If I can avoid an inverter we will, I just assumed we would need one.


    No wasn't going to connect anything to the engine battery really, want to be able to drive away when needs be. But I guess for the engine to charge the batteries will have to connect in some way.


    Hi Revel, wow you've giving me a lot more to think about lol - I didn't realise about the multiple conversions, like I said just assumed most household electrical appliances needed 240v


    So if we've got a few things running at once, would I need a multi adaptor on each one?


    Gonna have to get hubby to read through this aswell because most goes over my head! Lots to think about and research, electrics isn't our strong point.

  • in our caravan we bought a cheap 20" flat screen TV, but we generaly only use it when we are on a hookup for electricity. as I said some run off of a plug in mains adaptor that converts the mains to 12v so you can wire a suitable connector to the battery and plug it straight in instead of the mains adaptor. whereas a standard non flat tv will generally burn through your batteries via invertor in a matter of hours.
    Remember also that any wiring should be rated to the current its liable to be carrying (link wires between batteries need to have a very high rating as they have to withstand not only the maximum discharge current , but also the highest possible chargeing current too.
    Grendel

  • Got alternator/inverter issues meself. Damned Sammy Bus. Sorry I can't help, I've not the info yet.

  • hi cuckoo,
    no that ones no good the imput power is 240v
    you need something like this link


    http://www.maplin.co.uk/120w-laptop-car-adaptor-44736


    this is 12v in & DC 15,16,18,19,20,22 and 24V outputs, loads of uses with 6 amps max
    & only a tenner


    put " laptop car power supply " into their search engine loads come up, & find the best for your needs
    n what u connect to them is up to u


    hope this helps
    revel

  • Bonjour tout le monde (hello everyone).


    I use a 130 AH battery and charge it by running a set of jump leads from my van battery whilst I am driving.I have a small flat screen tele,a music system,computer,dvd etc etc and have only twice run out of power.Strangley enough,both times were with an extended evening of repetitive beats !!!
    I did buy myself a small top up solar panel,but found this not to be too effective,so would recommend that if you are going to go for solar,then go big and expensive (if you can).
    I quite like the idea of a small windmill on top of the van which will not only charge (as well as the jump leads),but also in the wind when I am parked up,but must do some more research into this so to find out if it is efficacious or not.


    I have never realy had any probs with the system that I use,but I shall watch this post with interest,so that I can better my current situation.


    Love and light


    Fly

  • Should of said also that I use a 500 WATT converter,which cost about 40 quid. Sometimes at night,I forget to unplug this,but it rarely seems to effect my battery charge,so I guess it uses very little power !!

  • Very helpful thread, I was wondering about simple battery/charging too. I'm pretty handy with the spanners but when it comes to electrics my brain goes all squidgy.

  • Windmills aren't really worthwhile at the moment fly, they look pretty spinning away but don't actually generate any power unless you have really strong wind and they cost way too much. Better off spending your money on decent panels for the roof.
    Incidentally, your inverter won't use much power just by being plugged in, but absorbs a lot extra when you power things through it. You're always better off running 12 volt direct.
    Hope you're well fly, good to see you again.

  • Wind turbines are great on windy days. In extreme wind they have to be isolated/taken down. If you have the turbine attached to the vehicle. You get a great deal of vibration and noise inside the vehicle, that really gets on your nerves after a while. Especially if your trying to sleep. Pegged out, away from the vehicle is much better.


  • I did buy myself a small top up solar panel,but found this not to be too effective,so would recommend that if you are going to go for solar,then go big and expensive (if you can).


    Hi there, am looking at panels now and wow doesn't the price change alot! what would you consider big? was thinking about 200w panel, is that enough?

    Very helpful thread, I was wondering about simple battery/charging too. I'm pretty handy with the spanners but when it comes to electrics my brain goes all squidgy.


    Sounds like my husband too, very hands on but this electric lark is new ground

    Windmills aren't really worthwhile at the moment fly, they look pretty spinning away but don't actually generate any power unless you have really strong wind and they cost way too much.


    Thanks for that, yeah it seems wind might not be the way to go, it did cross our mind as a source but solar is sounding better and better

    If you have the turbine attached to the vehicle. You get a great deal of vibration and noise inside the vehicle, that really gets on your nerves after a while.


    Noise is not something that crossed my mind but a good point, would drive you up the wall after a while.

  • Be wary of just getting a normal tv that runs 12v and wiring it direct to your battery it won't last long as often you battery voltage will be over 12v. You can get one that has built in regulator and has lighter style socket on the end rather than a 3pin plug, these work either 12 or 24v

  • You can get one that has built in regulator and has lighter style socket on the end rather than a 3pin plug, these work either 12 or 24v


    ahhhhhhhhh I didn't even realise you could get these, (having a browse now), sounds like a different tv is the way to go, we've got a plasma and an LCD here, so will look at a LED tv with lighter socket.


    This makes me much more engergy aware of what I am plugging in at home already!


    The xbox is another must have and have just realised that it already has this huge step down box, taking 240v and outputting 12v - so I'm guessing because it actually runs on 12v I can plug that in normally?

  • You will still have to be carefull as the step down box will send out a steady 12v but if you put a meter on a 12v battery it will read nearer 13v when fully charged and over 14v when charging! Also the box will control the amps going into xbox, much better to get an adaptor that you can plug straight into battery and then xbox. Ofcourse all this depends on how often you will charge and how you will charge the battery's. In winter your usage goes up through having lights on and genrally being inside more and this is at the same time that the days are short so solar struggles! If bus is moving every few days then an intelligent split charger is a worth while investment! If not maybe one of julians tinder box's if you have a burner fitted. Hope all this helps Jay

  • All helps Jay, thanks for replying. yes makes sense about the fluctuating voltage actually. Will look into the split charger too, my list is getting longer and longer!


    Woodburner is probably on the list, would love one again tbh

  • At the risk of wandering off topic I would say a wood burner is prob one of the best things you can fit in a van, espcially if your living in it! I'm sure all of the nomads on here would agree with me on that.

  • If going down the solar panel route, think about making up the total wattage you require by using more than one panel. Example if you want 200watts then get a couple of 100 watts, at least then if a panel fails or a yobbo lobs a brick on top of your van, you won't have lost all of your power!!

  • At the risk of wandering off topic I would say a wood burner is prob one of the best things you can fit in a van, espcially if your living in it! I'm sure all of the nomads on here would agree with me on that.


    Yeah and at least I don't need one as big this time compared to our one in the last house, we'd roast! lol

    If going down the solar panel route, think about making up the total wattage you require by using more than one panel. Example if you want 200watts then get a couple of 100 watts, at least then if a panel fails or a yobbo lobs a brick on top of your van, you won't have lost all of your power!!


    That is a really good point and noted, thankyou

  • Great advice Bluemerle :) though I'm not a fan of panals on the roof myself, when I quit work next year I'm planning on a panal I can place leaning on trundle to make best use of the light rather than it just facing upwards

  • Couple more points, just in case your head isn't spinning quite fast enough yet:
    You can buy a 12 volt regulator really cheap. Unregulated supply goes in and constant 12 volt comes out. Probably a tenner or so from evilbay via Hong Kong.
    As far as panels go, look at standard sizes. 80 watt is pretty common so likely to be cheaper. Two or three hooked up in parallel would sort you. You need a regulator on those too, a simple one is about £15 and will work fine but won't tell you your charging/discharge rate, battery condition etc that everyone likes to fuss over. Better ones cost more. This hooks to your battery and may be as high as 14.4 volts depending on your battery type. You still need the little regulator on the output from the battery to give you your 12 volts for the tv. Incidentally, these things are adjustable, and you should adjust it with the tv on as turning the tv on will cause a voltage drop.

  • Ditto to most of the above (I haven't read everything...)


    Batteries. If you can afford it and can find them, go for something better than Leisure batteries. Marine are a small step up and a bit more durable, UPS/backup type batteries are some of the best unless you can afford the new types designed for solar.
    I used to run a 600AH bank of s/hand marine batts and in the winter it just wasn't coping, having to run the genny every night.


    I managed to obtain a load of 6volt 100AH Yuasa gel backup batteries, the are stonkingly good, I have a 1000ah battery bank and it keeps me in power nearly all year with minimal genny input :-)
    (You wire the 6v cells up to make 12v then wire them in parallel to the charge controller)


    Don't forget the fuses! Put a large fuse in the main live feed off your batteries - like this:
    http://www.windandsun.co.uk/Components/Fuses.htm#fuses


    Wind and sun do a useful book on building off grid systems.


    The 12v step up laptop power supplies are great, have been using one for years, its what is powering this post... :-)

  • Couple more points, just in case your head isn't spinning quite fast enough yet:


    lol....hah so much for the simple life :S

    Don't forget the fuses! Put a large fuse in the main live feed off your batteries - like this:
    http://www.windandsun.co.uk/Components/Fuses.htm#fuses


    Wind and sun do a useful book on building off grid systems.


    thanks for input, the website looks to be under maintenance atm but will check back again soon