Batteries

  • Cheers but I already have a good understanding of the mathematics behind energy usage.

    All i really want to know is, are they A decent brand of battery and do i measure my battery in amps or volts so i can work out how much power it has.

    Ive got everything else sussed, i kinda think

  • My plan is to measure the battery power when i get back withthe dog after work, this way the battery is aT its maximum charge for the day and had at least a hours rest. Then to measure again in the morning before leaving for work.

    By my thinking that should tell me the previous nights power usage. If im wrong with this please explain where im going wrong

  • You're lucky, in that lead acid batteries have a pretty linear voltage / state of charge relationship... ie the current voltage is a reasonable indicator of current % capacity...


    This document may help you work it all out..


    https://pssurvival.com/PS/Batt…harge_Vs_Voltage_1993.pdf



    Other battery types keep their voltage really constant until they're pretty much exhausted, and this method is useless for them... Lead acid might be big and heavy, but it's pretty good really!

  • Cheers but I already have a good understanding of the mathematics behind energy usage.

    All i really want to know is, are they A decent brand of battery and do i measure my battery in amps or volts so i can work out how much power it has.

    Ive got everything else sussed, i kinda think

    Well if you understand it already why did you ask?

  • Well if you understand it already why did you ask?

    i didnt ask, i asked if anyone had experience with that make off battery and If i should measure the amps or volts to find out if they need charged. I know i hardly use any power for the size of batterys im looking at but i want them to last a decent time between charges, thats my reason for going for a large battery bank not my power usage

  • Post by Snowypanda ().

    This post was deleted by the author themselves ().
  • 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 i didnt have hookup I was totally reliant on solar/wind setup and that coped for most of the year but on occasions in winter had to run a petrol genny to top up batteries and if you dont have a decent output genny that can run a high output battery charger youll just be wasting petrol.


    My old 1000w genny has hopeless running my 11+amp charger id be lucky to squeeze 6 amps out of it so after running it all day id only have topped up the batteries by 50ah and have to do that at least 4 times a week.I got a 3kva genny in the end which easily runs my charger to full capacity.

    The other option you could use is stop on a hookup site once or twice a week and charge overnight.Theyve all got 16amp hookup.

    If youre not wired for hookup you can get a camping hookup cable set which gives you hookup plug, 10metre cable 3 x 3pin sockets and safety cut-off theyre usually about 35 squid from most caravan and camping outlets.

  • You cannot "measure the amps" of a battery in isolation. Amps are what goes in or out of it when it is connected to something. If you put a meter across the terminals you are measuring the voltage.


    If you know your electrical load, generator output, and the time between recharges you should be able to work out roughly the battery capacity you require.


    I think you will find that to keep the battery charged you will have to put in about the same amount, in amp-hours, as you took out. Surprising, really.

  • I have a digital ammeter in the circuit so i know whats going in or out and the charger load was creating a resistance drag on the genny alternator slowing it so I rarely got enough current to charge the batteries more than maintenance topup until i bought a bigger output genny.I agree its an in/out balance and for me charging 50ah all day at a cost of a fiver in petrol was not balancing my useage out of the battery because of using an inverter which drain batteries quickly and not good for my wallet being drained quickly either.

    In the summer with solar and wind I always had a surplus of power.

  • Well i woke up with no power. This morning, Fell asleep with my laptop On charge and drained the leisure battery to the point it could barely power led lights. Van started ok so thats a boost. Will be going for a drive tonight before parking up

  • I have a digital ammeter in the circuit so i know whats going in or out and the charger load was creating a resistance drag on the genny alternator slowing it so I rarely got enough current to charge the batteries more than maintenance topup until i bought a bigger output genny.I agree its an in/out balance and for me charging 50ah all day at a cost of a fiver in petrol was not balancing my useage out of the battery because of using an inverter which drain batteries quickly and not good for my wallet being drained quickly either.

    In the summer with solar and wind I always had a surplus of power.

    There will always be a power loss converting voltages and ac to dc however you do it.


    It may not always be convenient, but if If you need to charge 12 volt batteries with a generator, the most efficient method is to use a 12 volt dc generator designed for the job. If you need to use 240 volt ac then the most efficient method is to take it straight from a 240 volt ac generator, and forget the batteries and inverter.


    Efficient = uses less fuel.

  • There will always be a power loss converting voltages and ac to dc however you do it.


    It may not always be convenient, but if If you need to charge 12 volt batteries with a generator, the most efficient method is to use a 12 volt dc generator designed for the job.


    Efficient = uses less fuel.

    There is more to efficiency than fuel use. Charging a 12v battery from the 12v output of a generator is far less efficient than using the 240v output and using that to power a multistage battery charger which will not only charge the battery to its full capacity but will also extend its life. Sure you have no conversion losses using 12v but you will get more charge in the battery using a proper charger which equals better efficiency.


    Plus efficiency has a cost. A cheap generator driving a battery charger may cost a bit more in fuel than a properly designed and premium priced system but the saving in purchase price will pay for a lot of extra fuel.

  • Again I agree but the 12v supply on my genny was an absolute max 8amps (insufficient) and I couldnt run the genny at night when i needed the 240v because doing so would have got me attention of nosey village snoopers and evicted.During the day the genny noise blended in with the daily farm noise.

    Ideally its better to not use 240v power units for laptops at all but use a DC voltage converter/transformer but since I was normally running a huge excess of power for 3/4 of the year I wasnt really bothered about wasting power through inefficient adapters.Having a dozen different adapters for all the gear ive got just gets a pain finding storage space for it all.

    Obviously if its critical to conserve power all year then you pick the most efficient method when its free im not so bothered.

  • I wasnt brave enough to measure the volts in mine this morning, disconnected everything today so its only had about 20 miles to chaRge it up. Everythings charged n it will get a decent run tomorrow evening. Tonight we have led lanterns for lighting