Battery Cable Parallel Sizing

[a64pilot]

Originally Posted by sailorboy1

the question is the cable SIZE BETWEEN each 12V battery. Not the positive on one end of the bank and the negative on the other.

If I understand that question, I don’t think it would work. Again if I understand, it will work at only one precise load, vary the load any and it’s not balanced anymore and of course our loads do vary quite a bit.

Do you have an example of what your asking? I’m not sure I understand.

On edit, I don’t think what your asking is possible due to the slightly different resistance of an individual battery, batteries in parallel connections will over time drift in SOC due to the lower resistance battery will be drawn down more than a higher resistance one, it’s just the way things are.
I believe and this is just my opinion, but the name equalization charge comes from an overcharge bringing each individual battery in a parallel connection back to being equal.
Just we most often use it for desulphation, but I think that may not have been the original intent.

[kmacdonald]

Originally Posted by Statistical

Common misconception. Gold has higher resistance than copper. It is more corrosion resistant than bare copper but so is tin plated copper at 1/100th the cost.

Yes. But gold plated contacts come with a bottle of snake oil.

[a64pilot]

Originally Posted by Statistical

Common misconception. Gold has higher resistance than copper. It is more corrosion resistant than bare copper but so is tin plated copper at 1/100th the cost.

Sarcastic comment, meant to explain that often times “better” is so insignificant that it’s not really even measurable in reality, more of a theoretical discussion.

[Statistical]

Originally Posted by kmacdonald

Yes. But gold plated contacts come with a bottle of snake oil.

True that is a bonus. Not sure what the resistance of snake oil is though. I guess it depends on the snake.

[Bycrick]

Gold plating is usually used in very low current, low voltage or small signal application to reduce corrosion. Silver is used when the idea is to reduce corrosion when carrying "high" current.

[sailorboy1]

gold and silver plated lugs on my boat, now I have heard enough

[Bycrick]

Oh, my. I really wasn’t talking about gold/silver plated lugs. But for RF connectors, the few cents for silver-plated can be a plus. For RJ- 45 connectors, they come with various gold plating thicknesses, from zero to about 50 micro inches. The good ones last longer and often work better. Most of your small signal connectors, like N2K will have gold plated terminals.

But terminal lugs? Nah, even though in a couple of cases, they were priced like they were solid gold.

[kmacdonald]

Originally Posted by sailorboy1

gold and silver plated lugs on my boat, now I have heard enough

Marine grade.

[sailorboy1]

Originally Posted by kmacdonald

Marine grade.

4 times normal $$$$$

[a64pilot]

Where are you going to get your jumpers?
I usually make my own, but this time I think I will get Genuinedealz in Brunswick to do so. Price seems reasonable, they use adhesive lined head shrink and their crimpers are better than mine, my crimpers are cheap Chinese hydraulic ones.

[Thumbs Up]

Just rotate your batteries

[sailorboy1]

Originally Posted by a64pilot

Where are you going to get your jumpers?
I usually make my own, but this time I think I will get Genuinedealz in Brunswick to do so. Price seems reasonable, they use adhesive lined head shrink and their crimpers are better than mine, my crimpers are cheap Chinese hydraulic ones.

Undecided. But I think i am going to go all 4/0 cables and i dont have a crimper for that and don't want to buy one. I did see a Customboatcables.com online store and the pricing looked fair.

[Frankly]

Don't know exactly what you have in mind, but the only legit reason I can imagine for 4/0 cable is a bow thruster or big inverter a long way from the batteries. I like robust 12V distribution design but not crazy. 660 AH in Cbreeze but nothing bigger than #1 except I did use 1/0 for the bow thruster and inverter.

Get you a piece of 4/0 and try bending it in a medium loop.


Frankly

I am a big fan of collective bus arrangement (+ & -) and an isolation switch on each battery.

[a64pilot]

I’m leaning toward 0000 myself, as it’s going to about 4 ft to the inverter, and you can’t be too big, just too small.
Regardless of distance the Manual for my MS2812 recommends 4/0
It can pull 250 amps after all, I don’t but I have occasionally left the water heater on and not realized it when I turned on the inverter and tripped the 200 amp breaker I have it on.

[sailorboy1]

Saving $60 by using 2/0 cables over the 4/0 just seems silly to me concerning the $2k battery cost. My cable to my the battery switch is 4/0 and fused for that.