To busbar or not to busbar

[Sunking]

Why would you parallel 2 12 volt batteries? No excuse for doing that. 24 volt is less expensive and more efficient.

[PNjunction]

I live off the grid and my power needs are in the neighborhood of 2 amps for about 4 hrs a day. I am going to stage my solar install for cost and seasonal reasons. I live in Alaska so solar in the spring. For now I will charge the batts using an AC charger (Iota DLS 45) via my gene.

This is one of the rare instances of too much battery and not enough load! Forget the busbar to a parallel battery!

Ideally if you are cycling them, don't go much shallower than a 10% daily discharge, otherwise you are shallow-cycling them, and that's not good. And that is just for *ONE* 104ah battery. So that solves the busbar question - none is needed with only one battery.

For your power draw, use ONE 1040t battery, and treat yourself to an extra hour of load. Or brighter lights, what have you to get to the 10% DOD mark. Even at this small level, it is more likely your batteries will age faster than you'll ever see a payback in cycle life - especially in a cold clime like Alaska!

If you run at least the 10% DOD (aka 90% SOC), with only one battery, you'll still have 5 days of autonomy, so no problem there.

And, at very shallow depths of discharge, charging that up with a genny is very inefficient, as a light load for the genny just to do a quick top off is going to cost you in fuel. Save the genny charging for when you are down to your 4th day or so when it will run more efficiently with a real charging load placed on it.

The Concorde is a good choice, since you can easily hit them with 0.2C or more of panel current to get them charged quickly - so if you do it right, and with your small loads, you should be able to recover even under somewhat adverse conditions.

Moral - instead of using two batteries, spend the money going to the redundant battery on more panels instead for those days when it IS lights out for 2-3 days straight!

Of course if you change your load requirements significantly, then a rethink is in order. Fortunately for now you can really KISS the project.

[inetdog]

If you end up agreeing that for this number of batteries wire is better than busbar, be sure to look at the interconnection details found at http://smartgauge.co.uk/batt_con.html.

[Mike90250]

Wire will serve you fine, bus bars are a real pain to work with, you need insulated stand offs, and many things get in the way.

[Gpearston]

Laying out the wiring for my pending system on paper and would appreciate some input.

My battery bank will be two Concorde PVX1040T 12V 104ah in parallel. Some day I will go with 6v golf carts that have higher amp hour but I have the Concordes now and do not cherish the idea of going with 24v down the road due to costs. I live off the grid and my power needs are in the neighborhood of 2 amps for about 4 hrs a day. I am going to stage my solar install for cost and seasonal reasons. I live in Alaska so solar in the spring. For now I will charge the batts using an AC charger (Iota DLS 45) via my gene.

Now my question, I would like to bring the batts to a busbar each (1" x 1/4" × 7 copper) for negative and positive. The positive fused at the batt. The bus bars would be about 3.5' from the batts and I would make the run using 2/0, equal lengths for both pos/neg. I am thinking of putting the chargers (ac, solar) on the busbars and not directly on the batts. Appropriate fusing of course. Any reason not to do this? If/when I add an inverter can I add it to the busbar or am I better served going to the batts?

Thanks and have a good one