Wiring in parallel - both leads from same battery or from different ones?

[George_SD]

So there are two ways to wire leads from batteries in parallel - one is to have the positive and negative leads going to load and ground from the same battery OR having positive going from one and negative from the other.

Does it make any difference?

[smac999]

yes the first one is better from different batteries.

first one has bad typo though...

[Tillsbury]

Yes, always the first way

[Nicholson58]

If the wires are sufficiently large, oversized, the difference is negligible.

The greatest current on Roxy occurs during charging. Pick the cable gauge accordingly. Remember that as batteries approach full charge the current drops so the large wires tend to equalize the treatment of all batteries. If your primary daily charging is solar and wind (lower amps than the generator) then wiring layout is even less of an issue.

There are far worse things we do to our batteries.

I could have made all wires the same length and other considerations but the result would have increased the total length of all wires combined - worse by far and a spaghetti of cables. 24 volts. Max generator and other sources 60 amps. Normal max output 6 amps. Max solar alone 24 amps.

[BillKny]

It does make a difference, and it is important.

https://fetchinketch.net/boat_though...y-connections/

The problem is that most people mistreat their batteries in so many other ways, their batteries do not live long enough for this to matter. As a general rule, if the answer to this question is not already known to you, it is very likely the connections aren’t your biggest battery issue.

[George_SD]

Ok, that helps. Thanks.

[Pete7]

Originally Posted by BillKny

As a general rule, if the answer to this question is not already known to you, it is very likely the connections aren’t your biggest battery issue.

What happened to "be nice"? We all have to start somewhere.

Pete

[Franziska]

Originally Posted by Pete7

What happened to "be nice"? We all have to start somewhere.



Pete

Thanks Pete, very true.

[goboatingnow]

Originally Posted by Tillsbury

Yes, always the first way

It doesn’t really matter that much in reality. The life cycle of batteries is complex

[Stewie12]

The difference is very negligible and of no real importance. More important is the gauge of the cable alway go up and never down in size. This is one occasion where bigger is better.

[Clivevon]

This assumes you have only 2 batteries in your battery bank. Get up to 4 & things get different.

[Cadence]

Electrically they are the same thing. Drawn differently.

[Clivevon]

Take a look at this. SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

[goboatingnow]

Originally Posted by Clivevon

Take a look at this. SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

That analysis is fatally flawed as he takes the steady state soley as a comparison

In reality the SOCs are changing and the batteries that get worked harder discharge so that the lazy batteries shoulder the load

The result is therefore far less dramatic then his calculations suggest.

[cal40john]

Originally Posted by Cadence

Electrically they are the same thing. Drawn differently.

I agree completely, assuming perfect zero ohm wiring.