Dual Battery System Novice

Thanks Bill, Very interesting.

This is a bit theoretical, but do you reckon the current from the second battery finds it way back to the second battery only or both batteries. Totally irrelevant I know, but interesting.

I will have a closer look at my system and nut it out. That's probably in my interest.

Cheers Ian

Ian,

Current doesn't flow back to a battery. It is "energy" drawn from the battery by the load connected to it. (fridge, spot lights, winch. etc.) It is a one way flow from the battery to the hungry little bugger wanting a feed:-)).


Bill.

Don't listen to him Ian, he's fooling with you.

Electrical current does flow back to its source which I guess is why we call it a "circuit". There has to be a return path and a complete circuit or current will not flow at all and there would be no energy transfer.

Your two batteries sharing the same "earth" (vehicle body) is somewhat like two adjacent racetracks....... they both share the same ground (earth) but each is a circuit and the horses complete their circuits and return to their starting point.

That's interesting Allan.

This would mean that even though a load is applied to the battery and draws say 10 amps, this current is returned to the battery?

Gee, that would mean the battery would never become flat.

Thanks Allan and Bill,

I get it now I think: The Earth is SHARED so each battery can do its own thing and the current flowing in each battery's circuits can find its way home to that battery using the common earth.

Thanks for clarifying that.

Cheers Ian

It doesn't matter if an Electron starting from Battery A ends up at Battery A or Battery B.

What WILL happen is that the current (number of electrons) leaving Battery A will be the same as the current (number of electrons) returning to Battery A.

Hey Sandman, "Gee, that would mean the battery would never become flat."

You ARE kidding, aren't you? Or do you seek an explanation?

Yes Allan,

I am definitely kidding.

Sandman, Thank God you told me that before I made a prat of myself going into a long-winded explanation !!!
I have trouble remembering who knows their stuff on this site. Maybe I had better keep a record to remind me

Anyway, Happy Fara Day to you mate.

Sparks: I was removing the canopy from my tray back - first time. There is a heavy wire running from the aux (2nd) battery to the interior of the canopy to a box with plugged outlets - to run accessories, fridge etc.

Now, when I undid the heavy wire it hit the body of the tray and welded itself there for a second. I think it is a 'proper' aux batt system (not b/dodgy) and it has circuit protection. Nonetheless, it was the SPARKS that made me pose this question . I thought the heavy wire/cable had a return wire to the aux battery (its own earth wire) but it doesn't.

"I didn't think that was possible":
I was wondering how the two batteries could interact. But as you say, the electrons will go to Battery A or B. Electrons are electrons. I get it thanks.

Cheers Ian