Leisure battery question - mixing Ah?

Discussion in 'Tech/Mech General' started by Xan, Oct 1, 2012.

  1. Xan

    Xan Read Only Funster

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    Our MH has two leisure batteries. The handbook says to use 85Ah batteries, and both batteries are 85Ah.

    I'm testing them at the moment, but if one needs replacing is there any reason why I shouldn't use a higher Ah type?
     
  2. chatter

    chatter Read Only Funster

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    Idearly you would replace as a matched pair, if one battery is not as good as the other, the worse of the two would pull the good battery down, the same as if you put two different amperage batteries on you would only get to 'fully charge' in situ as high as the lower rate of the two batteries
     
  3. scotjimland

    scotjimland Funster Life Member

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  4. rainbow chasers

    rainbow chasers Read Only Funster

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    It is one of those grey areas - the reason being, that many 80ah batteries are actually relabelled 110ah. It has become common practice to relabel the larger batteries as they are cheaper to manufacture in bulk.
     
  5. scotjimland

    scotjimland Funster Life Member

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    Really . .how do you know this.. ?

    if this is happening surely a case of fraud .. also.. how can it be a 'grey area' , fraud yes but grey ?
     
  6. Gooney

    Gooney Funster

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    That's what I was thinking, in actual fact I thought the punch line was going to be the 110's were relabelled as 85's:RollEyes:
     
  7. Terry

    Terry Funster

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    I think RC has read the same advertising blurb as me a few months back- I am not sure if they have changed how they label amp hrs on battery's but he has got the jest of it right.:thumb:Some are labeling batts at say 110 amp hrs when on the new system they are only 100 amphrs -not sure how it works as I was not that bothered at the time :BigGrin:Still not :Wink:
    terry
     
  8. Terry

    Terry Funster

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    Sorry but both battery's would keep on charging until they both reached there peak IE 85 and 110 amp hrs your charger will only see the pair as one 195 amp hrs battery :thumb: Not arguing that it would be better to fit a matching pair :BigGrin:
    terry
     
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  9. Xan

    Xan Read Only Funster

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    Well, the 85Ah Numax's that are installed are showed 12.8v and 12.7v respectively after about 10 hours on the hook up yesterday.

    I've checked them again, some 24hrs later and both are showing 11.9v.

    They're not sealed, so I'd like to check the fluid levels and do a hydrometer test before deciding to replace. Which brings me to my next question / challenge.

    How on earth do you remove under cab seat batteries? Do I have to remove the seats from their mounting plinths?
     
  10. Terry

    Terry Funster

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    after only 24 hrs,At 11.9v both are creamcrackered:BigGrin:
    Terry
    Edit yes remove seat
     
    Last edited: Oct 1, 2012
  11. Minxy Girl

    Minxy Girl Funster Life Member

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    Yup - but be warned they are HEAVY!!!
     
  12. pappajohn

    pappajohn Funster Life Member

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    Taken from a previous post by me...


    Quote:
    Originally Posted by loubsterlouise
    Well for a start I was led to believe that batteries only charged to the lesser or weaker one so why connect all 3 if 2 have larger capacities.I wouldn't know where 2get bits from or what bits required.Finally not very confident with electrics and with 2small kids wouldn't want to get it wrong.




    then you were lead to believe wrongly.....a myth.

    you can connect any sized battery to any other sized battery without problem. (parallel connection in this case)

    the only time it really matters is if one battery is beyond help.....or is a different type...gel, AGM etc.

    a simple example.

    take a sink basin, a washing up bowl and a large jug.

    basin = 125ah battery, bowl = 100ah battery and jug = 75ah battery.

    now stand the jug in the bowl and the bowl in the sink and start to fill the jug.

    once the jug is full the water will overflow into the bowl and in turn the bowl will overflow into the sink.

    all three are now full.

    same applies to batteries.

    once the 75ah is full it wont take any more charge but the charger will continue to charge the 100ah until that is full, then it will continue to charge the 125ah until that too is full.

    you will then have one large battery of 200ah capacity.

    the charger doesn't 'see' 3 batteries...only one 200ah battery.

    if one battery is faulty or old it will then impact on the total capacity...it wont take/hold a full charge but the two good ones will still be fully charged but will show an overall reduced capacity due to the duff battery..
     
  13. pappajohn

    pappajohn Funster Life Member

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    dont know about the newer Fiats/peugeots etc but the older ones have two bolts at the front of the runner, on the front face of the seat plinth, and a further two torqs bolts inside the runners at the very rear of the runner...seat needs to be right forward to access the rear bolts.

    and the seats are very heavy for what they are.
     
  14. Pigwam

    Pigwam Read Only Funster

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    I have assumed I have read this wrong, it used to be common practice to relabel batteries at different hourly rates eg 28ah @ c5 hour rate would be relabeled 36ah @ c20 hour rate depending what use it was going to be sold for, but not the other way round just look at the price of lead.

    the first thing you always do if you suspect a battery has been labelled a higher capacity than it should be is to weigh the battery and I can assure you that different capacity's even 5ah will weigh in at different weights. and check the battery spec from the manufacturer.

    If batteries are over 12 months old always change them as a pair.

    its not good practice to use batteries in parallel or of different capacity's for al-sorts of reasons, but we are limited for space normally so its an easy option.
     
  15. Xan

    Xan Read Only Funster

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    Well, the seats have been removed and the two batteries taken out until their replacements arrive tomorrow.

    Only 4 bolts per seat to remove, but of course front and rear are different types and sizes.
    Rear 6mm allen no nut, front 5mm allen with nut. To get at the nuts on the front bolts, the plinth sides have to be removed. :RollEyes:

    A right kerfuffle........
    [​IMG]
    ................I don't like it.
     
  16. Xan

    Xan Read Only Funster

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    ...oh, and I got a matched pair.
     
  17. rainbow chasers

    rainbow chasers Read Only Funster

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    No It was me! I typed the wrong way around - 110 relabelled as 85's it should have read!:Doh:

    Battery supplier informed me of this a couple of years ago, as it was cheaper to manufacture the 110 in greater bulk than the 85 and 110 separately - so in effect, those buying 85's MAY get a better battery depending on source.
     
  18. Xan

    Xan Read Only Funster

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    Is that really likely? Given that 110's are generally bigger due to having more plates?
     
  19. rainbow chasers

    rainbow chasers Read Only Funster

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    That was what I was told when ordering leisure batteries, that it was best to go by physical size (there are lots of different dimensions) rather than capacity. Indeed when replacing the last one, with a labelled 85ah, it was a good three inches longer and maybe half inch taller than the original, and did look more like the size of a 110 - which it probably is in reality. Fitted in though - just!

    We now always take dimensions rather than capacity to size like the old days, when it was uniform unless it was an import vehicle.
     
  20. Pigwam

    Pigwam Read Only Funster

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    While not wanting to cause an argument i think its very unlikely that a manufacturer would do this and after 20+ years of independently testing batteries I've not come across this, read my previous reply which was the only thing i could think of is hourly rates which can make a difference.

    more plates doesn't mean a bigger battery, its normally fewer plates that make a better battery for leisure use, eg 11 plates more lead good for traction while auto batteries have more plates less lead but very good at cold start, again as i said before always look at the weight of the battery.
     
    Last edited: Oct 2, 2012
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