• Anyone any experience of this make of battery? http://www.ebay.co.uk/ulk/itm/121768126886

    Also will my 80amp split charger keep. Them topped up?

    The reason i ask is i will be parking up for maybe a week at a time. Over winter and dont. Want to run out of power.

    They will be running lights, stereo, laptop on alll the time, and a few other things.

    I wont have solar panels as im not sure there's any point if there covered in snow or with. Our 6 hours daylight.

    Another thing. How. Do i measure the power. Ive got in the battery and how do i know what im using?

  • When you say 'split charge relay' are you specifying the simple circuit that will likely overcharge battery and never achieve full capacity and kill batteries quicksmart unless rectified periodically with a smart charger? Or are you talking about a DC to DC smart charger (aka battery to battery charger)?

  • Imnot wired for a hook up, so it would be an extension cable and a battery charger if i use a genny, no sure how a genny would cope at -15.

    Light weight battery's cost Way to much for my pockets. The actual weight isnt a concern, maybe the difference in fuel economy might be.


    How d i work out how much power im draining from my battery? I know i do it with a multimeter but do I measure amps or volts?

  • When you say 'split charge relay' are you specifying the simple circuit that will likely overcharge battery and never achieve full capacity and kill batteries quicksmart unless rectified periodically with a smart charger? Or are you talking about a DC to DC smart charger (aka battery to battery charger)?

    im talking about the thing under the bnnet that was used t power the wheelchair lift battery. Its a black box that splits where the charge from the alternator goes. Sorry dont know more abut it it was there when i got the bus, even although the previous owners never worked it out as they charged the battery in the house then used it in the bus

  • What are the rough dimensions of the thing under the bonnet??


    I'm asking because you are a full timer who won't be conditioned by battery with an AC smart charger and may fair better to splash out on a DC to DC 3phase charger rather than big batteries.

  • What are the rough dimensions of the thing under the bonnet??


    I'm asking because you are a full timer who won't be conditioned by battery with an AC smart charger and may fair better to splash out on a DC to DC 3phase charger rather than big batteries.

    Sorry to appear ignorant here, but where do 3 phases come into DC to DC charging????


    Surely a simple buck/boost converter with microprocessor control is all that is needed to cover step down and step up conditions?

  • your battery will die much quicker through being charged in a single phase. It will never reach maximum capacity and may undermine the efficacy of buying large capacity batteries.


    A DC DC charger will recharge your battery regardless of whether the vehicle is in motion or not and will deliver a 'smart' charge.


    It's worth researching because batteries are expensive and perhaps running your engine/making a journey might be more efficient and cost effective than trashing batteries that are damaged by the voltage and single phase supplied by a split charge relay.


    As far as I know there is no effective method of measuring the charge state of a battery that is in constant use.

  • Sorry to appear ignorant here, but where do 3 phases come into DC to DC charging????


    Surely a simple buck/boost converter with microprocessor control is all that is needed to cover step down and step up conditions?

    I assume that it means 3 phases or stages of charging rather than the generally accepted use of three phase when talking about electricity.


    Any multi stage charger is going to be better than a straight battery to battery connection charged with an alternator but one thing that has to be considered is the op's budget. Split charge is cheap and easy, better chargers cost more money.

  • Sorry to appear ignorant here, but where do 3 phases come into DC to DC charging????


    Surely a simple buck/boost converter with microprocessor control is all that is needed to cover step down and step up conditions?

    that sounds like something I should be learning if you have the time to explain what it means?


    Hmmmmm....perhaps I meant 'stages'?

  • that sounds like something I should be learning if you have the time to explain what it means?


    Hmmmmm....perhaps I meant 'stages'?

    something I wouldn't mind knowing a bit more about.

    Ive looked at the fancy chargers and there probably more than the price off the batterys

    Im planning on selling this van on in may or june and was planning on taking the new batterys out n putting the original one back in. How hard are the fancy chargers to add and remove??

  • Ah.. 3 stage charging makes more sense!!! Most DC-DC converters do go through an AC stage, I just couldn't understand why that AC would be 3 phase!!!


    Straight split charge relays aren't ideal, as the two batteries can often be in different states of charge, ie the leisure battery can be flat as a pancake after a week's park up, but the engine battery is pretty full, having had no load for that week apart from the recent engine start... The alternator will see some kind of average voltage for the two, and adjust its output accordingly, leading to improper charging of one or both batteries...


    That said, I lived on a narrow boat for 7 years with a simple split charge system, and only changed the domestic battery once...

  • Thats the one i had looked at before, simply because its in deep red motorhome.

    What would you recommend?


    If i remember correctly sterling make a fancy one thahas a built in solar controller but im guessing its a bit more expensive ;(;(

  • Wow that would have to save a lot of batteries...


    My solar controller does multi stage charging and battery monitoring for £100 ish. I would suggest that a decent battery to battery charger should be about the same.

    If you are going to be investing in solar maybe connecting the vehicle battery to the solar input terminals would be a short term solution (after all its still only a dc voltage input), although you would have to contact the manufacturer for guidance.

  • It might not treat your domestic batteries perfectly, and might take a smidgen off their life, but the money you save will pay for the difference....

    The money he saves will buy a couple of replacement batteries when they fail, with a lot of change in his pocket for solar or something else more important.

  • I think we need a discussion of basic electrics here. I will jump in and make a start, and I am going to oversimplify at the risk of annoying the experts - if you can explain it better for the OP then let's hear from you, and I will shut up.


    OP, It is difficult to advise without knowing all the equipment you have, and what you will be doing, and, as usual, how much money you want to spend. I have the impression that you will be static for long periods. In that case it will almost certainly be preferable and more efficient to have a separate petrol or diesel generator rather than to run the vehicle engine just to charge the leisure batteries. If you are doing a lot of travelling the situation is different.


    The basic electrical sums you need are


    VOLTS MULTIPLIED BY AMPS EQUAL WATTS


    WATTS DIVIDED BY VOLTS EQUAL AMPS.


    So if you have a 60 watt, 240 volt mains bulb in your house it will draw a current of 0.25 amps. If you have a 60 watt bulb, or a number of appliances totalling 60 watts, in your van on a 12 volt system it will draw 5 amps. Now, how long will the battery supply this for?


    If you are running this on a 60 amp/hour battery, 5 divided by 60 equals 12 so in theory you would run the battery down in 12 hours. In practice the battery is only good for about 50 percent of its rated capacity so you would get 6 hours out of it.


    You need to add up the power in watts of all the electrical things you will be using - assume they will all be on together - divide by 12 if that is your vehicle voltage - and that will be your current in amps. Decide how many hours you will be static and using this current, and that will give you amp/hours. Multiply that by 2 as you can only use 50 percent of the battery capacity, and that will be the leisure battery amp/hours that you need. It will probably be more than you think, so use a generator if you can.


    Incidentally, an inverter will not help you - it may be convenient to use 240v equipment, but you cannot get something for nothing, the above rules still apply and going back to the beginning, if the inverter was running the 60 watt mains bulb from a 12 volt battery it would draw at least 5 amps - more in practice as it is not 100 percent efficient.


    I know the original question was about battery charging but you need to understand this bit first.