Charging Habitation Battery's

Discussion in 'Tech/Mech General' started by DAVWOD, Apr 15, 2014.

  1. DAVWOD

    DAVWOD Funster

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    Hi ,after two days up Harrogate with no hook -up just wondered how long does it take to recharge my two habitation batteries (recently installed ones) :Doh:
     
  2. tonyidle

    tonyidle Funster

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    It rather depends on the Ah capacity of the batteries and how you intend to charge them. If using EHU and assuming 200Ah total it will take at least two days. Three to be certain.
     
  3. Chockswahay

    Chockswahay Funster

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    No way :Eek!::Eeek:
     
  4. tonyidle

    tonyidle Funster

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    :Smile: 'Fraid so. You need to put around 240Ah back (allowing for battery inefficiencies and losses). Unless the charger is smart enough to provide a boost at an appropriate point during the charge cycle the batteries will only accept an average of around 4A. 240/4 = 60 hours. And that assumes the van isn't in use whilst charging.
     
  5. Chockswahay

    Chockswahay Funster

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    Well, you are correct. I was thinking that the OP could surely not have used that much and if he did then the batteries would now be shot to pieces :Eek!:

    But…………….the alternator will charge at a MUCH higher rate than mains charger :Smile:
     
  6. Terry

    Terry Funster

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    It all depends on the size of the charger --some charge at 20 plus amps per hour so in theory 5 hrs will see your batts topped back up -Alternators can whack out 100/150 amp so depending on your wiring etc a couple of hours running (theory)It's all in the detail of your set up but overnight charge should see it close to full charge :Wink:
    edit it also depends on how low your batts got -after two days without HU MY ONE BATT IS STILL GOOD FOR ANOTHER 2 DAYS :Wink:
    terry
     
    Last edited: Apr 15, 2014
  7. JeanLuc

    JeanLuc Funster

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    Also depends on whether you have gel, AGM or standard lead-acid batteries. The former two take much longer to charge than lead-acid.
    Making some assumptions, if you have 2 x 110 Ah batteries or similar, and have used about half the charge in two days, then mains charging will take about 24 hours or a bit more if you have lead-acid. For gel, I would double that. These are only 'best guesses'.
     
  8. tonyidle

    tonyidle Funster

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    No it won't. The alternator output is pegged at 14 to 14.5 volts. The batteries will start at, say, 12v - a difference of at best 2.5v. The internal resistance of a lead acid battery is around 0.2 ohms. The maximum charge current that can flow is 2.5 / 0.2 = 12A. As soon as the battery voltage starts to rise that will reduce. At 12.5v it's 10A, at 13v it's 7A and so on. This all assumes no wiring resistance (doesn't happen) and perfect batteries. The 4A I mentioned earlier is a good average on which to base the time for a full charge.

    It is why Sterling (and others) design smart battery-to-battery chargers that effectively boost the source (alternator) voltage to achieve a rapid leisure battery charge. Great care is required in the design of such devices to prevent damage to the battery being charged.
     
    Last edited: Apr 15, 2014
  9. tonyidle

    tonyidle Funster

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    .......... but very close to accurate :Smile:. My post assumed a fully discharged (but not over-discharged) pair of 100 Ah batteries.
     
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  10. JeanLuc

    JeanLuc Funster

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    The OP might do well to read the pages on the A&N Caravan Services website regarding the Reich E-box charging system; I believe these are fitted to Burstners. They suggest that the Reich unit is not very tolerant of overloading and that two leisure batteries can easily do that.
    http://www.aandncaravanservices.co.uk/reich-e-box.php

    The Schaudt Electrobloc pages on the same website are also very helpful for Hymer (and other EBL-equipped) owners. It points out that things like B2B chargers may not be a good idea for these vans and that the EBL already contains some circuitry to boost alternator charge against voltage drop.
    http://www.aandncaravanservices.co.uk/schaudt-elektroblock.php
     
    Last edited: Apr 15, 2014
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  11. Aethelric

    Aethelric Read Only Funster

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    It's nothing to do with the size of the batteries. It's all to do with how much power you used over the weekend. Its not too hard to make an estimate. See here for an example.
     
  12. DAVWOD

    DAVWOD Funster

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    Re Charging Habitation batteries

    Many thanks for the replys .. very technical posts to say the least

    basically I had two new Lion 110amp gel batteries fitted used them for the 1st time for a two night stay running the usual interior lights at night fridge, toilet , ( wild camping :Eeek:) as no facilities ) then as I'm off to Belgium this coming weekend so :Doh: best I hooked upto the mains to top up and after at least 12 hours of charging the panel inside the MH is showing half charged.. so confusing.. but thanks to all your replys
     
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