12 V Parallel hookup

[aatauses]

Hi everyone,
I thought I understood this, but now heard another version (from workamper.com). They stated when connecting 12V in parallel, on battery # 1 it goes out to +, then battery # 2 goes to neg. and connect these in parallel
I had heard that one battery could go both to pos and neg--and then just add cables to the second battery.
Meaning leave my current battery connected as it is now and just add a second battery and connect pos to pos and neg to neg.
Does it make any difference?--I'm asking because my second battery will be in the front storage and a relatively easy connect to my original battery, however if I should connect my second battery to the ground then I will need to run some added cables.
thanks
al
currently in Kenai, AK

 

[BigJim45]

Check out this link.

http://www.rvdoctor.com/2011/05/rv-battery-wiring.html

 

[Silverado23]

if your simply adding a 2nd 12V battery to another 12 V battery in parallel. Neg. to neg and pos to pos is correct.


The pos to neg is used to hookup batteries in series such as two 6V batteries to add up to 12 V You would then hook the pos to the 1st 6v battery the neg of the 1st 6v battery to the pos of the 2nd 6v battery and then the neg of the 2nd 6v would go to the trailer neg.

 

[BigJim45]

Check out this pic.


http://1.bp.blogspot.com/-vlFswiqwORc/TdRLxKWjhtI/AAAAAAAAA-g/R7KvOytK0_o/s1600/2-12-Best.jpg

 

[brianharrison]

To put it into words, When adding a second 12V battery in parallel, the positive feed to coach should come off one battery and the negative ground to coach should come off the other battery, as noted in the pic links above. The two batteries have their positive to positive and negative to negative.

In this way the electrical curcuit is required to flow through both batteries; simply connecting the second battery in parallel with the coach positive and negative leads connected to the same battery will only draw from the one battery (circuit of least resistance), until the first battery is dead, then the second battery. You want to correctly wire them up to draw equally from both batteries.

Hope this helps.
Brian

 

[aatauses]

Thanks,
appreciate the pictures and links---I now understand what I need to do and the amount of cable I will need.
Have a good day,
al
currently in Kenai, AK

 

[evolvingpowercat]

When tying second battery to first one in parallel, plus to plus and minus to minus with two jumpers, personally I put an 80 Amp fuse in one of the two jumpers, so that if by accident you tie plus to minus and minus to plus you just blow the fuse vs. having this amazing and scary event happen to you where worst case you can fuse the cable end on to the battery post and destroy battery post, and or cables, and or cable ends.

 

[Willym]

A little exaggeration here - the first battery won't die before the second one takes over. The voltage drop across decent size connecting cables securely connected will be minimal. If you feed the system from just one battery, with the other connected to it, then one battery will be just a smidgen ahead of the other in voltage decline during discharge. Not worth worrying about in my judgement. Ideally they should be connected as above, but it's not critical. Ample size connecting cable and good solid connections are the most important thing.

la

To put it into words, When adding a second 12V battery in parallel, the positive feed to coach should come off one battery and the negative ground to coach should come off the other battery, as noted in the pic links above. The two batteries have their positive to positive and negative to negative.

In this way the electrical curcuit is required to flow through both batteries; simply connecting the second battery in parallel with the coach positive and negative leads connected to the same battery will only draw from the one battery (circuit of least resistance), until the first battery is dead, then the second battery. You want to correctly wire them up to draw equally from both batteries.

Hope this helps.
Brian