Charging leisure batteries (episode 201)

Discussion in 'The Beginner' started by oldun, Mar 24, 2009.

  1. oldun

    oldun Read Only Funster

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    I have a bog standard 12V/240 setup in my Devon Monaco campervan with the one exception, I have added a second 110 Ah battery.

    At present the two leisure batteries (and the engine battery if necessary) can be charged from the charger power supply fitted by Devon.

    I understand that due to the limitations of the 12V system the batteries will not receive the full voltage necessary to fully charge them.

    I would like to add a multistage battery charger to the system.

    My questions are these.

    1. Am I right in thinking that I just cannot replace the built in charger by the new one due to (a) the higher voltage of the latter and (b) the heavy demand the 12V system may place on the charger?

    2. Can anyone offer me a schematic diagram the the wiring diagram need so that I can have both in place but only use one at a time?

    3. Am I unduly complicating the situation?

    4. Are there any good links you cab direct me to?
     
  2. Losos

    Losos Read Only Funster

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    I'll leave it to others to answer your other points but the 'demand' I think you are refering to is the current used by all the things running from the battery (Inverter, lights, kettle etc) if your battery is in good condition and at least 50% charged then it will not effect your charger because the current needed will be supplied by the battery (and the charger will just put a small charge into the battery), of course it won't stop the battery from running down if you keep all your appliances running 24 hours a day, but normally people switch off when they go to bed and leave the charger to bring the battery up overnight.

    If you imagine the battery is a big bucket of water, one (big) pipe out feeds all the appliances and one (small) pipe feeds water in. If no water is flowing in the big pipe (Everything switched off) the little pipe will (eventually) fill the bucket up.
     
  3. pappajohn

    pappajohn Funster Life Member

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    yes your right about the voltage limitations on your onboard charger.
    the battery wont mind 14.4v but some of the electronic equipment might so the onboard is limited to around 13v.

    to give your batteries a proper boost you could use something like the ctek chargers which will double as a power supply for anything not voltage critical.

    C-tek charger

    not a cheap option but it should last for many years.
     
  4. oldun

    oldun Read Only Funster

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    Thanks for that but how do I wire it to the battery?

    Do I just connect it to the positive and negative, switch off the original power supply, switch off all the 12V electrical equipment that may get damage by the over voltage and then just switch the Ctek charger on and ...... or what?

    Is there any fool proof method of connecting it? I do not want to cause any serious (expensive) damage to the 12V electrics.

    I imagine that fridges, heaters and lights will not be affected by over voltage.

    I also think that TVs, DVD players, telephones, computers etc powered via a stabilized circuit will be OK.

    So what 12V equipment is at risk, will the power supply be damaged if left switched on?
     
  5. scotjimland

    scotjimland Funster Life Member

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    Hi

    Budget permitting, I would replace the old unit with a Sterling Multi Stage Battery Charger/Power supply unit .. around £250 .. these are just about the best on the market .. A 30A unit should be man enough for your needs, you won't find better.

    Sterling 12v 30 amp, 40 amp and 50 amp Digital Battery Chargers
     
  6. oldun

    oldun Read Only Funster

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    Some very useful info here, I must take some time to red about then and see what suits me best.

    At first sight they both seem excellent products.
     
  7. scotjimland

    scotjimland Funster Life Member

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    Hi

    There is a review of the Sterling by Olley here:

    Sterling Pro-digital Battery Charger
     
  8. Terry

    Terry Funster

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    Hi you can always use a (Lidl)Tronic or Aldi x5 battery charger (both around £10) to top up / help your on-board charger--- simply plug in and switch on :thumb: or a cheaper version of the CTEC at around £50-- no need to mess with wiring just clip on and charge or if leaving permanent wire direct instead of clips.:thumb:
    terry
     
    Last edited: Mar 26, 2009
  9. Terry

    Terry Funster

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    Further to the above reply if you want to cut off one of the battery's get a battery isolator switch about £6--WHY ? you may be going too complicated :Rofl1::Rofl1: keep it simple :thumb: also cheap :Rofl1::Rofl1:
    terry
     
  10. oldun

    oldun Read Only Funster

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    But these chargers produce a higher voltage at certain stages of the charging and this voltage may damage the more delicate electronic equipment such as TVs.

    Its the high voltage I am trying to guard against.
     
  11. pappajohn

    pappajohn Funster Life Member

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    i think these chargers only put out a high voltage when in 'recovery' mode.

    ie: when the battery is seriously flat.....it charges at a high (14.4)voltage to break down the sulphated coating on the plates so allowing a better charge.

    once that stage is over then it reverts to a smart charger...altering voltage and current so the battery recieves a full charge without the higher volts but a constant current all the way through the charge and then reverts to a trickle charge to keep 'em topped up..

    normal chargers have a tapering effect...as the battery charges, the amps drop.

    these dont. they are constantly adjusting to give the best possible charge rate.

    us lesser mortals call it witchcraft/black magic !!! :BigGrin:
     
    Last edited: Mar 30, 2009
  12. Terry

    Terry Funster

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    Hi tvs are a lot more tolerant than people would have you believe :thumb::Rofl1:
    My mate does everything electrical for me --- he mends tvs videos etc, and understands a lot more teccy stuff than I care to understand--
    My own van is wired up by him and the tv direct to the battery via tv Ariel power plug / in-line fuse and has been in all my vans over the last 7 yrs without problems.When I asked him about voltage stabilisers - years ago -- his reply was that the battery works as a very good one :thumb::thumb::BigGrin: not to worry it will not harm the tv etc, I am looking for problems before they happen -stop reading all the shit that I do and nattering.This or that works so why look for the probably non existent problem :Rofl1::thumb:
    He has proved this lots of times over the years so now I trust him when he says it works :Rofl1: Another example was my boiler refusing to stay lit,I messed, rang Truma - got very good advise to do all sorts of tests etc, Paul came along did all the tests that took about half an hour (me probably 4 if I could have done them :Rofl1:) Stuck an hair dryer on the PCB -took it out changed 5 capacitors,again half hour and hey presto all is well
    terry
     
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