How Long Should A 75Ah Battery Last?

Discussion in 'Water Fed Pole Cleaning' started by Belfastcleaning, Feb 28, 2013.

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  1. Belfastcleaning

    Belfastcleaning Grand Master
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    My controller has started flashing batt quite often.. This never happened when I was only using a 20ah... Although i am now using the system alot more, usually parked up for at least an hour before moving on, sometimes 3-4 hours without any driving.. It's all rigged up to a split charge.. I maybe only drive 10-15 miles a day.. Am I not driving enough for the battery to charge up?
     
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  2. rcproperty

    rcproperty Hero
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    would of thought it should last week maybe 2 weeks without any charge.

    if the vans main battery is poor then the charge wont be going to the 2nd battery untill the main van one is fully charged.

    thats why i fitted a solar panel trickle charger onto my system, so even when the van is parked up doing nothing there is always a charge going into the battery.

    i have a 110ah battery in mine, not been out or charged in a year
     
  3. JDMW

    JDMW Guru
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    should last a while, my 9ah battery lasts about a day and a half with a backpack. i used to use a car battery when i had my van system and that was 130ah from a diesel car. that lasted me a week.
     
  4. Smurf

    Smurf Banned
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    I would have thought that is the case as the battery is not being given the proper charge it needs.

    Funny enough my controller started flashing batt at me yesterday while I was just starting an exterior house clean. I have been caught out before so now I always carry the charger that came with my pf trolley 24ah battery. As I was going to be there for approx 4 hours just asked the customer to plug in my extension lead. Problem solved… :)

    If I had been on a job where the customer was not at home without an outside live power socket I would have been stuffed.


     
  5. bluemonkey

    bluemonkey Guru
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    not enough charge going in, your controller should tell you the amp of the battery
     
  6. spruce

    spruce Grand Master
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    Its not the distance you travel, but the time it takes. Your battery would be more charged if you were in stop start traffic than if you just drove down the motorway.

    I have fitted a volt and amp meter to my system to see what actually happens during a normal working day.

    With our Varistreams the higher the pump flow rate the more current (amps) the motor draws. If we assume that your pump is drawing 4 amps per hour and your pump actually pumps water for 4 hours through the day, then the pump will have drawn 16 amps of current from the battery. In theory this means that if you have an 85 amp battery you will only have 69 amps left.

    Even when my battery is half charged my alternator settles down to a charge rate of 8 amps when recharging the leisure battery. In theory this means that my van needs to be charging my battery for 2 hours to replenish what I took out. (Unfortunately it isn't as simple as that as the battery will only accept a smaller and smaller charge as it gets fuller. I once read in an Australian camper van article that someone estimated it would take a road journey of 750 kms to recharge an 85amp leisure battery via the vans alternator.)

    Now it usually takes me 10 minutes to drive to my first house maybe another 10 minutes moving the van etc and 10 minutes driving home. So using the above example, I am taking 16 amps put of the battery and only putting 4 amps back in during the day (30 minutes driving at a recharge of 8 amps). So within a short period of time my battery would be flat if I didn't supplement it's charge with my battery charger.

    If I get stuck in traffic, thats good for my leisure battery as the van still charges my battery at the same rate idling as it does at 3000 rpm on the motorway. So the longer it takes you to get home, ie the slower your drive, the more charge you are putting into your leisure battery and also saving fuel.
     
  7. spruce

    spruce Grand Master
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    The battery's state of charge is determined by its voltage. 12.8 - 12.9 is considered fully charged after the battery has been standing idle for a while and 'settled' down.
     
  8. Bingo

    Bingo Grand Master
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    Hey Spruce, two good posts, I wish I could explain things like that.....I know, I know...... I should've done better at school :D .
     
  9. essex boy

    essex boy Active Member
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    I use 110amp and was always told it is better to get the biggest that you can. If you only do mostly local jobs like I do then the split relay will not be enough on its own. I know most firms recommend charging every night with a good charger to be safe and most good charges have a smart trickle charge so once the auxillary battery is full the charger just maintains it so no electricity waste.

    I bought a decent charger and fixed it to the inside of my van high up on the side above the aux battery. I leave the clips from the charger permanently attached to the auxillary battery as it says this is okay and then every night I just unwind my extension a few metres to the van and plug in the charger that is already sitting there. It just takes any hassle out of the process.

    When your van is running the split relay will not start charging your second battery until your van battery is over 13 volts. This should happen as soon as your van is running because even if the battery isn't any good the alternator will keep the voltage up, unless of course your alternator is shot.

    Y our battery if in good condition is good enough but it just isn't getting adequate charge so you almost certainly need a charger
     
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