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Hi my question is is it possible to wire a 75 and a 110 battery together in parallel ??

Thanks s
 

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Yes, cant see why not, pos to neg on the batteries then using the pos from one & neg from other would give u a 185 a/h batt.
I have a cradle I made with 8x 13a/h sealed cell batteries I was given in thus giving a spare 104 a/h that I just hook up with some jump leads.
 

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Nope, that would give you a 24V battery as Glynn has suggested. :eek:

You need to wire them in parallel and not in series. You therefore need to connect the two positive terminals together and the two negative terminals together. The ideal way of doing this is to take a wire from each positive terminal of the same length and take these to a common point and from there go off as a single continuous feed i.e. a bit like a Y shape where the top two stalks of the Y are each connected to a battery positive terminal and the lower stalk goes off to your circuit. For your earth path, you can take both battery negatives down to a common chasis point in a V shape with each cable being the same length ideally.

Also bear in mind that the two battery sets will have slightly different impedances and therefore you should only really consider your battery autonomy / life to be that of twice the lower rated battery as they will discharge at slightly different rates but that's just a general rule of thumb as they will also charge at slightly different rates too.
 

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batts would be better of same capacity..
two 85ah together would work better than one 85ah and one 110ah (if both always connected together in use and when charging)..
alternator cant top up both to 85ah and then keep adding charge until the 110ah is full.
loads of info on here.
 

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HORACE
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Yes, cant see why not, pos to neg on the batteries then using the pos from one & neg from other would give u a 185 a/h batt.
I have a cradle I made with 8x 13a/h sealed cell batteries I was given in thus giving a spare 104 a/h that I just hook up with some jump leads.
NO NO NO This wil fry your whole 12v system mate, thats hows lorries are wired (in series) to give 24 volts :bhd:bhd:bhd the other question you asked about using an 85 and 110 amp together is also no because they are different amp-age and the 85a one will just get hot (bit like if you use one flat battery and one new one in a flashlight)
Its not very successful using 2 batteries together ( parallel) but if you do want to do this then you will have to find 2 evenly matched batteries and this usually means buying 2 new ones, but even then they wont be identical and one will always be slightly under powered than the other and suck a little power from the good one. Your best bet if you want to use 2 is to have then interdependent from one another and just switch over from one to the other as they run flat. T:
 

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Yes sorry everyone a moment of madness! :bhd
in fact if I wired all mine like that I would have about 104v..a few more & I wouldnt need a hook up. T:
Just to prove I am not a conplete mupet u can see my tray of 8 sealed cells here which work fine!]
 

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NO NO NO This wil fry your whole 12v system mate, thats hows lorries are wired (in series) to give 24 volts :bhd:bhd:bhd the other question you asked about using an 85 and 110 amp together is also no because they are different amp-age and the 85a one will just get hot (bit like if you use one flat battery and one new one in a flashlight)
Its not very successful using 2 batteries together ( parallel) but if you do want to do this then you will have to find 2 evenly matched batteries and this usually means buying 2 new ones, but even then they wont be identical and one will always be slightly under powered than the other and suck a little power from the good one. Your best bet if you want to use 2 is to have then interdependent from one another and just switch over from one to the other as they run flat. T:
How does our split charge systems work ok?
Surley the alternator is just charging 2 different amperage batteries or am I missing something:confused:
 

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HORACE
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you can charge 2 different batteries of the same volts (12v) like your 95amp crank battery and your 110 amp leisure battery via your alternator ok because you are putting power into them, its a whole different thing when you want to run appliances from batteries (this is when amps, watts etc come to play tricks with us) and the more you want out of them the harder it is to get right, its not an easy subject this one and best to stick to one 110 battery unless you have some money to invest in big expensive regulators etc your set up looks good T:
 

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Amp hours dude not amps. Technically amount of juice stored.
Its very confusing!
So the set up I have above "should" be ok as they r all the same amp hours, but they may all charge/ drain at different rates as they r old batts & some may be better than others!
Is it therefore possible that one can overheat?
 

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You can use two different AH (capacity) batteries in parallel - you will just get the capacity of the lowest one x 2.

So if you use an 85 and a 110 battery, you will get 85 x 2 = 170Ah equivalent - this is because they will drain at the same rate.

You will however work the lower battery a little harder than the higher one, and shorted it's life - the 85 ah battery will be taking more charge because it will be "more empty as a % of it's capacity" more of the time. Still - no different from using the 85Ah on it's own, in terms of life span....

If you can, you wan't two batteries of the same AH and model, but what you suggest will do.
 

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Its very confusing!
So the set up I have above "should" be ok as they r all the same amp hours, but they may all charge/ drain at different rates as they r old batts & some may be better than others!
Is it therefore possible that one can overheat?
What will happen if you run your system(bank of parallel batteries) flat, is that the weakest performers will run flat a bit before the stronger ones, and the while the stronger ones are giving their last bit of power , the weaker ones are being over-flattened and thus damaged. They may get a little warm.

You'd have to have big battery differences to get overheating.

None of this will happen if you don't let your system drop too low.
 

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Excellent thanks!
They were free anywas so I guess it dosent matter!
Incidentally my mate has just given away over 20 of these but double the size of mine, but unfortunatelly these are strictly not for sale & he will only give em to mates!
 
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