Advise needed wiring twin batteries in parrallel!

[TUFFTEE]

I have 2 Brand new Heavy Duty Batteries Which i want to Wire in Parrallel so that i get 12volts and both batteries are working together? as well as being able to run the winch when required?

[muddymart]

Hi, there is a topic on this somewhere,but i'm having trouble finding it,use one battery as usual,and use a split charge relay to charge the second one up, use the second one to operate winch/cb's/lights etc.. i think thats the best way round it

here it is.

http://forums.mud-club.com/viewtopic.php?t=13538&highlight=charge+diagram

http://www.maplin.co.uk/Module.aspx?ModuleNo=37767&doy=12m12D

[TUFFTEE]

Thanks for your help Buddy! :lol:

[PUX]

oi oi nev u can have a look at mine on the 28th dude and see wot ya think  

[petergalileo]

If both batteries are identical in every way there should be no need for a split charge system.  If you are just connecting the batteries in parrallel both will charge together and drain together.  I would act just like a bigger battery with more cells in it.

You only really need a split charge system if you are having 2 different batteries like a standard and a leisure one.  If you connect 2 different ones in parallel the larger powered one will try and charge the smaller one and will succeed in making it overcharge and over heat.

Peter

[TUFFTEE]

If both batteries are identical in every way there should be no need for a split charge system.  If you are just connecting the batteries in parrallel both will charge together and drain together.  I would act just like a bigger battery with more cells in it.

You only really need a split charge system if you are having 2 different batteries like a standard and a leisure one.  If you connect 2 different ones in parallel the larger powered one will try and charge the smaller one and will succeed in making it overcharge and over heat.

Peter

I have just Bought (TWO) Lucas 4 Supremes Calcium powered HD Batteries Running at 75 Ahr

And i need them in Parrallel?

[petergalileo]

yes, you need to connect negative to negative, positive to positive then you will get a battery twice the capacity but still at 12 volts.

[TUFFTEE]

So! It's the other way to get 24volts then?
ie pos to neg i think? :lol:

[petergalileo]

if you disconected your earth strap, connected it to the positive of the new battery then connected the negative of your new battery to earth you would get 24 volts.  

DONT DO IT !

I reckon you would blow all of your electrics.  I dont even think the cigar lighter could handle 24 volts !

[karloss]

So! It's the other way to get 24volts then?
ie pos to neg i think? :lol:

No. That's how you get a fire. :lol:
For 24v use the pos and neg off two seperate batteries as feed and connect the other two together. Which is most likely what you meant, just not how it sounded!! :lol:
Think about stacking batteries in a torch, same difference.

[TUFFTEE]

if you disconected your earth strap, connected it to the positive of the new battery then connected the negative of your new battery to earth you would get 24 volts.  

DONT DO IT !

I reckon you would blow all of your electrics.  I dont even think the cigar lighter could handle 24 volts !

I don't Intend too! Don't Worry? I used to have to sort out the Batts on ffr landies in the army and Truck batts later on? but you tend to forget! :lol:
Many Thanks Peter!

[TUFFTEE]

So! It's the other way to get 24volts then?
ie pos to neg i think? :lol:

No. That's how you get a fire. :lol:
For 24v use the pos and neg off two seperate batteries as feed and connect the other two together. Which is most likely what you meant, just not how it sounded!! :lol:
Think about stacking batteries in a torch, same difference.

use the pos and neg off two seperate batteries as feed and connect the other two together.That is what i meant! :shock:  

[Wanderer]

Series to up the volts
Parallel to up the amps.

24v on a Disco won't do it a lot of good. The starter won't half turn fast until it goes bang!

[muddymart]

have a look here

http://batterytender.com/connecting.php/?osCsid=26a337728da30f95fd66b74f6e55d63f#1

and you need it like this: not that ive done it, helped a friend do his though. :roll:

[colintandy]

got mine wired in parrellel dude easy  pos to pos neg to neg run warn xp 6hp no problems run loads lights no problem done 2 winch challenges no problems i use a heavy duty isolator switch for winch and uprated waterproof solinoide mounted behind front bulkhead and i wire every think of the main battery just remember to cycle batteries every couple months boyh monitored by national lunar twin battery monitor both batteries go down together and come up together keep it simple dude no relays required no split charge thingy just battery power i use twin exide deep cycle 950 cca do it it makes so much sense  :lol:  :D

[TUFFTEE]

Colin! Mine are X2 760cca's 75 amps each! Should be Ok i would have thought? :lol:

Thanks for all the Answers Lads!

[muddymart]

colintandy, do you connect everything to one battery,or spread it over the two?

[muddyweb]

colintandy, do you connect everything to one battery,or spread it over the two?

On a paralleled system, the loads are connected over both batteries.  When you connect them like that, you are effectively just making one bigger battery..   just think of it in those terms.  You can't connect some loads to one and some to the other.

[Range Rover Blues]

Ours is wired in parallel, the only problem is when one battery goes it takes the other with it.  On the plus side it does crank nicely for a very long time.

[muddymart]

so i take it you wire everything to one battery(standard),tyring to get my head round this,at 0120 in the morning,visualising all that wiring for the winch etc.. plus connnecting another battery to it at as well??

so basically your just adding another a battery?

[petergalileo]

it doesn't matter if you connect something to the positive on battery A or the positive on battery B or in between.  You are effectively only increasing the size of the battery.  Its like sticking all the internal parts of the batteries into a bigger box.

I think some are confused by what they do on some lorries with 2 12 volt batteries connected in series.  In that system you can take a 12 volt feed and a 24 volt feed.

On a parallel system it doesnt make any differnce at all where you connect your accessories you will only ever get 12 volts.

I will say it again though, this only works if both batteries are both exactly the same ! If one battery is a higher capacity or one is 5 years old and one is new this will not be an good.  you will only succeed in knackering one or both batteries as the better one of the two will try and overcharge the smaller (or older) battery.

If you have 2 different batteries then you need some sort of split charge system.

[Bulli]

I have a similar set up to Colin. It makes it easier to connect some things to 1 battery and some to the other. Makes for a tidy install as you dont have 10 wires coming off 1 battery. If you are running winch cables through the front of the disco they soon take up a lot of space, the 2 batteries make it a little easier i think.

[colintandy]

:D at the moment i have every think wired to main battery the only thing i would wire to the second battery is going to be comms equipment and very delecate laptop ect..... evry think then has the added bennefit of running direct power from the 100amp alternator /winch /lights starter ect..but like tim says it is just one big battery now and have kept the link between the batt1 and winch isolator as short as poss to prevent any loss in power to the winch ...but im also toying with the idear of dedicatting a 24volt system just for the winch but i think its going to be overkill myself as the winch i got is powerfull enough and has not let me down yet !

[Slimer]

I will say it again though, this only works if both batteries are both exactly the same ! If one battery is a higher capacity or one is 5 years old and one is new this will not be an good.  you will only succeed in knackering one or both batteries as the better one of the two will try and overcharge the smaller (or older) battery.

Asked a mate of mine about this, he used to be an auto sparks (now does far more high-tech stuff) and generally knows what he's talking about, this is his respnse:

"complete b******s, as long as the interconnecting cables are capable of the full CCA of the largest battery, no difference at all. Both batteries will balance out the charge levels, higher capacity batteries give up charge more 'easily' than lower capacity ones, so each battery will always have the same %age of charge, i.e. one battery will not empty before the other. the only thing to watch with any second / third battery installation is the recovery rate. If the alternator is not sufficiently rated, it may well overheat the regulator, rectifier, rotor, stator or all four attempting a prolonged high current recharge. In cases where deep discharge is expected a timed relay is sometimes fitted to allow 'pulse charge' on auxilary batteries to prevent this. Vehicle alternators are designed for 20% recharge, 80% direct consumption (vehicle running, acessories etc.) at revs in excess of tickover, most will only function at full output at approx 2500rpm or above"

Don't shoot the messenger.....

[colintandy]

:D like i said dude i havent had any problems with my set up and i was given the advice and tech expertise by a friend who does know what he is talking about been compertion driving and winch extreem events for about 10 years now and for your mate to say its bolxxxx is very arrogant is he saying that i got it all wrong then whats his advice then dude cos it works well for me and my truck aint let me down yet dude but then i only take advice from people who do know :D

[Slimer]

Woah! I think you missed the bit I quoted  :?

He's just saying that your batteries don't have to be identical to run in parallel. Which is what you're doing I think Colin, don't know if you're batteries are identical or not but it shouldn't matter

[petergalileo]

I won't shoot the messenger.  I would have thought that mixing 2 differing ampage batteries the higher capacity battery would try and charge the lower amperage battery.

It would also make sense that if you had an old battery and added a new battery the new battery would try and charge the old battery.  This is why electrical equipment tell you not to mix old and new batteries.

Connecting 2 batteries together that are different they would try and balance themselves out.

[Bulli]

Peter I think thats the point Slimer was making is they do balance themselves out without the need for a complicated system and the idea that charge travels between them ad infinitum is untrue.Ie they both charge/discharge equally.

[sulley]

When you do this (run two batteries in parallel) do you need to uprate the alternator to a more powerful/capable one??

[petergalileo]

I wouldnt have thought so, you are just adding storage capacity to the system.

It would follow that if you managed to flatten both batteries it would take longer for them to charge up again.