any reason why i can't? battery bank question.

[minimotos95]

i have noticed with most battery banks the positive is switched off while leaving the ground hooked up 24/7. why is this? it would seem more logical to me to have all the positives hooked to each other, including the starting battery and the entire electrical system then switches on each ground instead so you can run anything off any battery.

yes? no? the only downsides i see are more switches and ring terminals.

 

[peacetara]

Electricity flows the opposite way you think it does. You ALWAYS want a ground.

There are 2 ways to hook up battery banks (aka more than 1 battery), Serial and Parallel , more information here: http://www.batterystuff.com/kb/articles/battery-articles/battery-bank-tutorial.html

 

[minimotos95]

yes DC current flows + to - but if the - of a battery is disconnected it can't output power and it's a cleaner break then the positive, that's why when working on a car you disconnect the ground first. here's is what i had in my head.

which would make it so you can use any or all of the batteries for anything in the electrical system, like starting the motor with just one of the house batteries while leaving all the other batteries disconnected from the circuit.
of course my head has been known to come up with ideas it thinks should work but don't work at all

 

[WheelEstate USA]

Much easier to set up a Perko switch and most likely cheaper in the longrun.

 

[peacetara]

DC current flows from the Negative terminal to the Positive terminal (so from - to +), hence totally backwards than what humans think. A negative charge has an excess amount of electrons, and it desperately wants to get rid of them, by shoving them to the + point (where electrons are missing, and are happily wanting more).

In your example, you have 4 batteries wired in Series. If they were all 12V batteries (I assume), then you could potentially be putting 48V thru your electronics, and that's a really bad way to treat your electronic goodies.

What exactly are you trying to accomplish? It sounds like you want to involve your starter/engine battery somehow in your house electronics. Why and for what purpose?

 

[Willy]

Actually, to me, it looks like a parallel connected battery bank in the example. To be in series, the + of one battery would have to be hooked up to the - of the other. ..Willy.

 

[peacetara]

DOH! sorry I am sleepy today. Willy is right.

 

[minimotos95]

Bindi, i really like those marine style selectors but usually one switch will only support up to 3 power sources and the most practical way to set them up that you can kill all power is to direct all the power to a distribution block. and i don't want to use a distribution block, they are expensive, bulky, and have to be bolted down

(edit/delete: willy already got that)

i found this, i guess you're right, http://www.allaboutcircuits.com/vol_1/chpt_1/7.html. pretty interesting they didn't teach that in public school.

why i want to do it this way, i could type them all out but those reasons are just control without using tools to disconnect. it seems more practical being able to shut down each battery individually. i know on tractors and other equipment they use disconnect switches on - instead of + but those don't have anywhere near the fire concern or frequent use of a RV/van/boat/offgrid house installation.

i suppose the same functionality could be accomplished using individual switches on each of the positives but then you still need a distribution block.

 

[Zil]

Oh, you are talking about isolating batteries in a house bank. If you are using more than one 12 volt battery, then yes you can disconnect (switch) the negative to select what ever battery you wish to not use or not charge. Hooking the start battery permanently into the house circuits is a bad idea, many a sailor was marooned when the engine would not start after making pop corn and playing electronics all night long. Also, house loads generally don't rely on the chassis for a good ground.