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Second Battery


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I`m thinking of installing a second battery.


It will be another Elecsol 100 to match the one i already have.


They will not be running a large inverter, just the Sterling 350W

and the normal 12V habitation equipment.


I just want i a little more ( staying power ) don`t we all !!


I have 2 questions.


( 1 ) How close to the existing battery does the second one have to be,

there isn`t room by the one already in the van.


( 2 ) What size / guage does the cable need to be ?


I`m sure we have some " Techies " that will know





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The length of the van is your max distance! Ideally as close as possible but anywhere within the van is possible.


2. A heavier gauge the further the cable run to mimimise voltage drop.

Ideally you need 4.5mm stranded conducter diameter ( 10 square mm of copper cross section ) if close to existing battery, and lets say from 1 meter up to 3 meters then 6.3mm diameter ( 16 square mm).


Some bright spark will calculate cross section and say above diameters to not match cross section ..Air space between the strands!


Fit extra fuses. You can do this by adding a fuse between the two battey positives of 40 Amps, or join the positives together after individual fuses for each battery but then you will need to drop each fuse to 20 Amps each ( may blow when charging from alternator although unlikely) so better to fit a 40 amp fuse in each positive connection and Y then together then a 3rd 40 Amp fuse in the commoned positive. See Clive's website here..... http://www.motts.org/second%20leisiure%20battery.htm bottom two diagrams. He has shown 25Amp fuses, use whatever your existing fuse value is. Cable sizes I have given will cope with 40 Amps continuous. You can connect the extra battery to the chassis from the negative if you want, but I prefer to run a seperate negative lead back to the 1st battery negatobe or battery ground point if close. You may not find a convenient point to connect to the chassis and it can introduce ground loops so if the battery is going to be a long way away from first run two cables back to area of 1st battery.


Now a note on choice of battery. You do not have to fit a second Elecsol 100. ( HINT!)


You would probably be better to go for a Banner, Bosch or Varta 80Ah or thereabouts which is the same physical size. ( You cannot get 100 litres in a 80 litre container!!!). I would then put the Elecsol furthest away in the circuit. Remember to add a 2nd venting tube.


Do I have to read all I have written for mistakes or can I just post -- I shall just post..and regret later!


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