Increasing battery capacity. Does connection method matter?

[Airassmith]

I'm planning to increase my 'house' battery capacity by adding another battery in parallel. Due to space constraints the new battery will be some distance away from the existing battery. Is there any reason why I cannot connect them with the positive cables meeting at the house battery on switch and negative at the neg earthing point, as these points are approximately half way between the two battery's? Or should they be connected terminal to terminal first, as all the diagrams show? That way my cable length will be much longer.

 

[pvb]

From the description you've given, it sounds fine.

 

[PetiteFleur]

Look at these:- http://perflei.mdproject.co.uk/battery_linking/ and :- http://www.smartgauge.co.uk/batt_con.html which should help.

 

[JerryHawkins]

Looking at the SmartGauge reference, it sounds like what you propose would give a situation as per "Method 3". The positive "node-point" being your switch and the negative "node-point" being your "earth point". This is actually better than connecting the batts in the "traditional" way. In practice, at relatively low currents, you would likely never notice any issues at all in any of the connectivity scenarios.

 

[matelot]

The diagram is an idealaised way of making sure that each battery sees the same circuit resistance and so in theory takes the same proportional current draw. I wouldnt worry about it given that your new battery and the old one will have different internal resistances anyway.

You can bu**er up a new battery by connecting it in parallel with an old dying battery so make sure the old one is in good nick.

 

[Airassmith]

Many thanks, seems clear and I will do it as proposed.