Adding a second battery

D4Dazz

Active Member
Dec 31, 2011
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Rowville, VIC
How hard is it to add a second battery to the Outback battery system? I want to be able to charge both batteries using the standard on board charger when at home or in caravan parks. The main reason for this is to double the amount of 12v power available so I can stay in the bush
Onager and not have to end to caravan parks every coud of 5 or so day to recharge the battery. Any tps or "how toos" would be most welcome....


Darren.
 

Bmhdg76

Well-Known Member
Oct 6, 2012
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North Lakes, Qld.
Easy as to do...
Get same size battery is best eg 100ah get another 100ah. Negative to negative. Positive to positive. Other than that the only other thing is to get good cables to interconnect the batteries. The more technical guys here will give you the correct guage etc.

BJ
 
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Kenshi123

Well-Known Member
Jun 24, 2012
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Ballarat
Hi mate. As above, very easy to do. (I did it and I'm homeless and being a Handyman). Try and get the batteries as close together as possible I used 6 b&s cable to wire them together. Also try and get the same battery type and size if possible. At least the same type. (Ie don't mix Gel and Agm etc) there are some really good tech minds on the forum that may add some more info. All te best mate.
 

brotys

Well-Known Member
Jun 15, 2013
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leongatha
Go 8 b&s to be on the safe side and put them close together as well
pos to pos and neg to neg
easy job have fun can not have to much power
 

twscoot

Well-Known Member
Jun 9, 2013
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Brisbane
Another easy alternative is (if you can't match the battery) is to buy one of these dual battery switches and simply run one battery at a time.
The setec will not let you completely drain the battery if you run one at a time. If the lights go out.... Switch over to your second battery. You also have the option of running both in parallel per the previous posts.
This is what I did and keep each charged by just switching over from time to time. A very easy option
Cheers
Andrew
image.jpg
 

ROnEM

Well-Known Member
Mar 13, 2012
650
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Macedon Ranges, Vic
@D4Dazz, as pointed out above...
  • Get the same make and size battery
  • +ve to +ve & -ve to -ve
  • Use the biggest cables you can get between the batteries - most Auto stores will make/crimp cables for you
  • Put in a fuse between the batteries - just to be sure!
  • If you can, make sure your batteries are as close as possible to being just forward of your axle - towards the drawer bar - has an impact on ball weight and stability of the van when towing.
  • If you go solar - put the regulator as close to the batteries and possible (reduces voltage drop and maximises charge)
Ask plenty more questions if you're not sure…

Cheers,

Rohan
 

D4Dazz

Active Member
Dec 31, 2011
118
28
28
Rowville, VIC
Thanks heaps for the responses guys.... A couple of questions though;

By connecting these in series does this effectively create a 200ahr battery that is charged as "one" by the setec?

Also does both batteries discharge at the same rate and are they both protects by the setec in that it will not allow them both to "fully" discharge?

Apologies if these seem like silly questions...o_O:biggrin1::humble:
 

Capt. Gadget

Obsessive & Compulsive Gadget Man
Dec 1, 2011
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bbmwa.com.au
Thanks heaps for the responses guys.... A couple of questions though;

By connecting these in series does this effectively create a 200ahr battery that is charged as "one" by the setec?

Also does both batteries discharge at the same rate and are they both protects by the setec in that it will not allow them both to "fully" discharge?

Apologies if these seem like silly questions...o_O:biggrin1::humble:
Connecting batteries in series which is joining one of the negatives and one of the positives then connecting what you want to run to the other negative and positive like a torch when you join AA batteries together actually gives you the same Ah but increases the voltage and is not what you want to do in your van what you want to do is join in parallel which is join the negative to negative and the positive to positive then connect what you want to run off the batteries to the positive of one battery and the negative of the other battery which keeps the voltage the same but doubles the AH if your batteries are the same type and Ah they should discharge at the same rate if connected this way
http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel
 

ROnEM

Well-Known Member
Mar 13, 2012
650
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Macedon Ranges, Vic
Thanks heaps for the responses guys.... A couple of questions though;
By connecting these in series does this effectively create a 200ahr battery that is charged as "one" by the setec?
Also does both batteries discharge at the same rate and are they both protects by the setec in that it will not allow them both to "fully" discharge?
Apologies if these seem like silly questions...o_O:biggrin1::humble:

Connecting in SERIES, you add the voltage - 12V/100AH + 12V/100AH = 24V @ 100AH (Not good and will damage electrical items in your van :( )

Connecting in PARALLEL, you add the amperage - 12V/100AH + 12V/100AH = 12V @ 200AH (What you want in your van :D )

The SETEK will see the two batteries in PARALLEL as one and will think it is charging a 12V 200AH battery.

The batteries will discharge together as the same rate.
 
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