Installing Batteries and Solar

[Cory350]

Time is ticking and I've got to get this done. My first question is about wire sizing for connecting my 2 12v batteries in parallel. genuinedealz.com was recommended in another thread but I'm not sure exactly what I need. 

Here are my parts:

2 12v Batteries:
https://www.samsclub.com/sams/durac...rv-battery-group-size-31dtmagm/prod3590232.ip

Renogy 200w Solar Kit with PWM controller

Dometic CF-18 Fridge

MaxAir Fan

I was pricing out cables and I came up with about $60 just to wire them in parallel. That doesn't seem right.

I believe I have M8 lug connectors based off the specs from another website.

 

[Zizzer_Zazzer_Zuz]

I would run the jumpers between the posts not the bolts.

So, you will have one positive and one negative cable much like the one you pictured.

Your ground cable needs to run from negative to the chassis. I'm thinking you can go with 4awg for the ground cable. If you leave the batteries at the back door longest wire run would be 3 or 4 feet. You might just go as long as 5-6 feet just to have some extra play.

 

[John61CT]

Yes good wiring well terminated is expensive.

 

[Cory350]

I would run the jumpers between the posts not the bolts.

 The posts are the bigger ones right? I measured them at 1/2in diameter but i assume thats a universal size?

 

[Zizzer_Zazzer_Zuz]

 The posts are the bigger ones right? I measured them at 1/2in diameter but i assume thats a universal size?

Yes. And yes, as best I can tell.

I'm not certain how to tell the size.of the bolt (the one with threads). They do seem to be universal though.

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[highdesertranger]

the bolt size is most likely 3/8's but some are 5/16's. take a nut off one and go to a hardware store and ask them what size they are. however mounting to the post with military terminal is a better option IMO. highdesertranger

 

[galladanb]

The bolt size on my batteries are 5/16. You could order that size and if you need bigger, simply drill them out for that individual connection.

I ordered 3/8 mistakenly, and they are slightly sloppy on the 5/16 connection points.
I feel it is better to order smaller and enlarge, but you can't shrink the lugs.

I used what I bought, and it's all ok! Really! Someone will chime in and call me an idiot, unsafe, fire starter, whatever... But I have already proclaimed all of those things for myself first!

Main point is that you will be way better off in the long run to order want you need.
Don't try to DIY the cables, or go cheaply. Neither approach is good in the long haul.
Think of failure avoidance on that long lonely night in the snow in northern Nevada, where the nearest ANYTHING is five hours driving away. Better to not go cheapply, just saying!

I've tried to plan everything around a failure point. It will, but I want it to fail when it's convienant to me. Hope that makes sense?

Good luck!

Such Fun!!!

 

[John61CT]

I ordered 3/8 mistakenly, and they are slightly sloppy on the 5/16 connection points.

Not dangerous, but not ideal, less contact area, depends on the post design.

Don't try to DIY the cables

It's not rocket science to do a proper job, just study up and buy the right tools and supplies.

But the proper crimpers are hundreds, so likely not sensible economics for just one buildout.

 

[Zizzer_Zazzer_Zuz]

Not dangerous, but not ideal, less contact area, depends on the post design.

It's not rocket science to do a proper job, just study up and buy the right tools and supplies.

But the proper crimpers are hundreds, so likely not sensible economics for just one buildout.

I've been watching the arguments on this one for a while now and folks seem to talk in absolutes and this issue is FAR more nuanced than that.

For what it's worth this is the decision I have come to and why.

Starting off learning to crimp 2/0 cable for critical and possibly life ending applications is a MISTAKE! With a little practice and decent tools and consumables just about anyone should be able to assemble and connect just about 4-6awg and smaller.

My intent is to be as self sufficient and usefull to others as I can be. I don't need a professional tool I need a decent tool that will last with occasional use and make a better than "that'll do" quality crimp. This is NOT something I will use every day.

I have practiced with a cheap set with cheap rings and crimps and see some of the pitfalls withe the cheaper tool.

So, when you make your blanket statements please qualify them a little. Big cables may be too much for a novice and the tool to do even a decent job is expensive and will not be used often enough to justify the expense. Smaller crimping tools for eletrical runs, adding or repairing head lights or fog lamps, and hardwiring 12v sockets is something that most people can handle IF THEY PAY ATTENTION AND ARE CAREFUL.



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[Zizzer_Zazzer_Zuz]

the bolt size is most likely 3/8's but some are 5/16's. take a nut off one and go to a hardware store and ask them what size they are. however mounting to the post with military terminal is a better option IMO. highdesertranger

I have a question. The military lug has a 3/8's bolt but no way to attach dirrectly to the 2/0 other than a ring terminal. Isn't crimping the lug directly to the wire an inherently better connection?

My skoolie has these lugs that crimp on the 2/0 (hell it may even be heavier) AND have 3/8 bolts on the same lug. I have not been able to find these commercially.

 

[John61CT]

I've been watching the arguments on this one for a while now and folks seem to talk in absolutes and this issue is FAR more nuanced than that.
...
So, when you make your blanket statements please qualify them a little.
...
IF THEY PAY ATTENTION AND ARE CAREFUL.

Yes of course smaller wire gauges are easier and even the right tools are more affordable.

I was very clear the economics don't make sense for most.

However even a total beginner, IF they can afford the right tools and are willing to put in a few dozen hours researching, CAN create their own wiring infrastructure to a professional level, maybe not aesthetically or maximum efficiency, but certainly with safe crimps to MIL-T-7928G tensile pull tests strength.

Obviously, the "qualifier" missing from the above is based on the fact that someone interested in following this path would respond with a question like "where do you guys recommend I start learning?"

To which I would answer, reading up from people like Maine Sail, practicing with guidance from trusted members of several forums, ordering the basic texts, etc.

https://www.google.com/search?q=Maine-sail+crimp

Note also great deals on tools do come through eBay, which is a whole 'nother skillset.

For example I bought some top-notch crimpers that retail over $3,000 for under $150, and they turned out to be in great shape, probably last for thousands more crimps.

If anyone thinks $150 is a lot to spend on tools, they should definitely use ​genuinedealz.com and powerwerx.

 

[highdesertranger]

Z those do work really well. however they are one shot deals. if you ever need to replace one you need a completely new cable. the bolts that tighten the lugs are 5/16's not 3/8's. actually those auxiliary cables attached to the tightening bolts is not the best practice. that is what make military terminals so nice, easy to connect multiply cables/wires. Genuine Dealz has those battery terminals if you are looking for more,

http://www.genuinedealz.com/marine-electrical-supply/wire-connectors

highdesertranger

 

[John61CT]

The military lug has a 3/8's bolt but no way to attach dirrectly to the 2/0 other than a ring terminal. Isn't crimping the lug directly to the wire an inherently better connection?

Yes, it seems the military style doesn't do direct crimp, just ring lugs.

I'm sure practical reasons, just speculating but:

Inflexibility and weight of that gauge means better to have an adjustable "angle of attack" to the mount point.

The post lugs do wear out, design for easy replacement in the field without having to re-crimp.

Plus, appropriately sized ring terminals are used for some pretty darn high current levels, a solid connection, right sized on both parts gives good surface area, should not have any significant resistance.

 

[John61CT]

Also check out ​http://www.bestboatwire.com

I think same company as genuinedealz, but sometimes better pricing.

Their ​Pacer wire is as good as Ancor.