110ah v 135ah batteries

Discussion in 'The Beginner' started by themountaintiger, Jan 8, 2012.

  1. themountaintiger

    themountaintiger Read Only Funster

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    Trying to find ways of lasting more than 3 days without EHU. Been discussing on other posts re extra bank of batteries or solar power etc.

    One thing I have just thought about is replacing current batteries 2 x 110ah with 2 x 135ah. Is there any way 'generally' to know how much better would these batteries be comparative to my current 110ah batteries?

    Would they be 1.5x better or 2 x better 3x etc, or would they last me 4/5/6 days whilst my current batteries last me 3 days..

    Any thoughts gladly appreciated ...












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  2. steveclecy

    steveclecy Read Only Funster

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    There are plenty of electrical experts here (and I'm not one) but simply put, 270 amp/hours as opposed to 220 amp/hours would give 50 more hours at 1 amp, or 1 more hour at 50 amps (theoretical only), but more likely somewhere between the two. You will have just over 20% more capacity, so on the same usage, 20% more time.

    Would the extra cost/weight be worth it?

    Steve
     
  3. themountaintiger

    themountaintiger Read Only Funster

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    Depends on cost of alternatives, which so far has involved addition of solar power, and the one I thought of was extra bank of batteries, but thinking then of adding another 2 x 110ah, or addition of third battery. In terms of weight I have enough payload....

    I was looking at RalphNBevs posts about having Trojan batteries which appear to be better (although not 135ah ones) but need proper venting..


    Just trying to weigh up alternatives
     
  4. Techno

    Techno Funster Life Member

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    I'm curious to know at what voltage you think your batteries are close to being flat?
    I'm sure some people are confused by the state of charge voltages quoted elsewhere as these are off load voltages.
    Sargent EC units don't disconnect the loads until the battery drops to 9.0 volts

    "This is an emergency cut off level to protect the
    battery from severe damage. You should not rely
    on this cut off level during normal operation, but
    manage your power consumption to a discharge
    level of 10v.
    This cut off only applies to power drawn from the
    battery by the leisure equipment that is controlled
    by the control panel power switch; it will not protect
    the battery from discharge by the radio or other
    permanently connected equipment"
     
  5. themountaintiger

    themountaintiger Read Only Funster

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    From memory I think the cut off is 11.9v. I seem to remember someone on here had a table showing that when leisure battery reached this figure then it was close to being discharged. I think my cab battery is set at same figure also...I havent checked exactly...its just from what i remember.

    I didnt think it was as low as 10v though....


    Just reading this web page which was linked on another post within motorhome fun...giving me some great advice re ralph n bevs Trojan batteries are so good...

    http://www.sterling-power.com/support-faq-2.htm









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  6. hilldweller

    hilldweller Funster Life Member

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    12V for long battery life.

    Our Electrobloc trips out at 10.5V.
     
  7. Techno

    Techno Funster Life Member

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    The Sargent disconnects the cab battery at 10.9 volts to ensure the engine will start.

    12 volts under load is nowhere near discharged
     
  8. pappajohn

    pappajohn Funster Life Member

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    to give an idea of load and no-load voltages....

    an engine battery may show as low as 9v when cranking but will almost instantly return to 12.6v when you release the key, depending how long you were cranking (engine not running)
     
  9. themountaintiger

    themountaintiger Read Only Funster

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    Ah found this by Pappajohn in another post


    you should never discharge below 50%/12.1v....which seems to be your indicated start point.

    Here is a table to help you determine the state of charge of a 12-volt battery:

    battery volts......Percent of Charge

    12.73v.............. 100%
    12.62v.............. 90%
    12.50v.............. 80%
    12.37v.............. 70%
    12.24v.............. 60%
    12.10v.............. 50%
    11.96v.............. 40%
    11.81v.............. 30%
    11.66v.............. 20%
    11.51v.............. 10%








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  10. Techno

    Techno Funster Life Member

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    To be honest I think some folk either expect too much or dont use their batteries to full potential.
    If you budget for a pair of these to replace every 3 to 4yrs you cant go wrong
    http://www.ebay.co.uk/itm/250874820...X:IT&_trksid=p3984.m1438.l2649#ht_2297wt_1392

    550 cycles so if you discharged them every outing then that's 550 outings!. Considering most are often on hook up then this is never going to happen. What really causes damage is OVER DISCHARGING and failing to fully recharge them as a matter of urgency
     
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  11. Techno

    Techno Funster Life Member

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    Yes they are with no load on the battery. If your batteries are under load those voltages mean nothing
     
  12. haganap

    haganap Funster Life Member

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    like he says ^^^^^^^^^^^^^^^^^^^^^^^^^
     
  13. Techno

    Techno Funster Life Member

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  14. robnchris

    robnchris Funster

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    batteries

    Adding more batteries to a system isn`t really the answer, I`m thinking best to go to the beginning of the problem rather than the end.
    ie rather than just add extra batteries, identify and control the usage, do you have LED lighting, do you watch your tele for extended periods on 12v, run a laptop etc etc.

    We have found that fitting a solar panel keeps our system topped up for our needs during the summer months, without the need to connect to an EHU.
     
  15. themountaintiger

    themountaintiger Read Only Funster

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    Well im lasting 3 days on the 2 x 110ah batteries, however when I say 3 days the control panel is saying that there is 12.1/12.2v left on the batteries. Ill probably have tv on sometimes with dvd on for 2-3 hrs per day, I have led lighting, the heater fan is only on sparingly, might charge my netbook up once.., to be honest I feel im using power sparingly when just on leisure batteries.

    I think what techno is saying is that I could probably discharge the batteries further. Techno can go down to 10.9v, so perhaps I shouldnt be too worried if I go down to 11.5v??












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  16. hilldweller

    hilldweller Funster Life Member

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    Do they seal them to sell at that price ???
     
  17. Techno

    Techno Funster Life Member

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    Yes that's what I'm saying. If you drop to 11 volts with the TV on etc then I'd consider calling it a day but still OK for some LED ltg and the water pump as it is occasional. Must recharge at earliest opportunity. If you turn everything off you'll see a true battery reading after 5 to 10 minutes reflecting the charge state as per pappajohn's chart
     
  18. themountaintiger

    themountaintiger Read Only Funster

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    Techno, Im almost fainting if the TV is on and its at 12.1v. Im not sure where this fear has come from, perhaps Ive read that if my batteries get to under 12v my motorhome will spontaneously combust!!!!


    Ill try that for now for extended trips off EHU and see how I get on

    thanks :thumb:
     
  19. Techno

    Techno Funster Life Member

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    seal or steal?

    They are sealed units and same as those sold as NUMAX
     
  20. aba

    aba

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    only 3 days on 220 amp thats heavy consumption or your just not discharging them far enough.

    we used to get 2 nights and a day out of our 80ah battery which just wasn't enough so i got 2 x 155ah batteries and so far haven't tried to see how long we can get out of those although i have had on 1 occasion the 80ah one down to 10.2volt heading into the later half of day 2 but we still had a small load on it so i feel the low cut off will only work under a load situation.

    although i have found it seems better to travel with the fridge turned off as it will take around 20amp off the batteries whilst driving thus reducing the charge they are getting.
     
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