DIY copper bus bar

[Muddydogs]

Alright after my last post about messy battery cables http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28283107.cfm and seeing Westend's pic for his DIY wire box I figure I will do the same. Like Westend said finding copper bar stock locally is not easy so I'm thinking about taking a 3/4" piece of copper water pipe and making it flat. Final size should be about 1/4 inch thick by what ever 3/4" round flattens out to be. I'll then use 1/4 x 20 stainless bolts as posts for the battery cables lugs.

What do you guys think? Good idea?

[CA_Traveler]

bka0721,

I wondered where you had all of those batteries. Nice setup.

[bka0721]

CA Traveler wrote:
3/4" copper pipe buss bar and battery monitor shunt. Note: These are AGM batteries and locating a shunt near flooded batteries should be avoided due to the corrosive battery fumes.

CA Traveler makes a really good point in how you decide where and when you place your battery bank. One more important point is to remove points of ignition from close proximity to off gassing batteries. Many place their invertors within close proximity to their FWC battery banks. Often in the storage cabinets under their Motorhomes.

In my case, I have my battery bank completely isolated physically enclosing (all 4 sides) and providing distance. Being a fulltimer I build everything on the road, as shown in the below picture of building my coffin (batter bank enclosure) One thing I learned, the off gassing of the FWC dissolved the wood glue and corroded the finishing nails I used in assembling my cabinet. Coming back and using screws was the solution I should have done at the onset.

[CA_Traveler]

3/4" copper pipe buss bar and battery monitor shunt. Note: These are AGM batteries and locating a shunt near flooded batteries should be avoided due to the corrosive battery fumes.

[bka0721]

Growing up in Kansas, we learned early how to wire simple things while working on cattle ranches and farms. One of the things that was common to use, was copper pipes for buss bars. I learned to do it differently than what has been previously described. So when I was building one of my 2 battery banks (2 AGM 6v & 10 FWC 6v) I used this method here, too.

What is different, is that I took 3 different sized Copper pipes. (1”, 3/4” & ½”) polished them up with a wire wheel and inserted them into a succeeding pipe (nesting). Thus providing even a larger area of copper. Then flattened them with a sledge hammer (I fulltime so I don’t have a garage or work shop to work in) out in the desert on a rock. Bent the appropriate angles with a pair of Vice Grips. Measured for proper locations for the mounting holes. Then I wrapped the entire homemade Buss Bar with black electrical tape. Then cut and removed the tape in the areas where I needed total connection with the adjacent surface I was attaching. So far, this system has been in use, for 5 years now. Below are pictures of this work.

b

[MEXICOWANDERER]

Oops gotta go...

Lots of lead battery posts to change!

[MM49]

MEXICOWANDERER wrote:
Heat copper with a propane torch. Then plunge it into cool water. This is called annealing. Makes the copper softer and highly crack and fracture resistant.

If you have a steel container you can melt enough 100% pure lead to dunk the finished terminal in. Slop on the plumbing paste flux. S-l-o-w-l-y lower the terminal or bus bar into the molten lead. Examine your finished piece for holidays, and re-flux and re-dip if necessary.

Electroplated terminals and lugs, suck. The plating is too thin, and tin is used only because lead is tough to electroplate.

A pure lead hot dip battery terminal is a dozen times more resistant to sulfuric acid attack than a tin/lead electroplate.

WATCH THE FUMES!

Use a painters mask and this is not optional. Do not hot lead dip around children and clean every bit up when you're finished.

If you're after acid resistant and oxide resistant terminations this is the way to do it. TIN is not an optimal metal for this, Gold is the best but, you know...

You might want to re-think the lead coating at 7% conductivity? The article “The Tin Commandments" by AMP might change your mind on tin plating.
MM49

[pianotuna]

Hi Muddy,

Fuse to the wire size on the inverter line. I'd be tempted to use a breaker on the solar panel line as it is a bit easier to disconnect that way.

[Muddydogs]

I need to look at my wire size, trailer is in storage so I just can't walk out back and take a look. Its a pain but I don't have room at home to park it.

Wednesday my DC clamp on meter should be here so I should be able to measure the AMP draw. Kind of interested to find out how much power things use in my trailer so I can better plan my power use. I usually dry camp for 2 weeks in the late fall while hunting so I wanted to get an idea of what i'm using.

So it sounds like a good idea to put a MIDI / AMI fuse right off the battery post on the line to the bus bar and then another fuse the same size off the bus bar to the disconnect switch? I'll also add a 40 amp fuse off the bus bar to the solar panel line and a 80 amp fuse for the 750 / 1500 watt inverter line.

[GordonThree]

mlts22 wrote:
Would a $50 125A Blue Sea power distribution bus work? It supports up to twelve circuits, each with its own fuse. Blue Sea also has an unfused 150A, 10 screw busbar as well. That can be used with a 150 amp ANL fuse to keep boom from happening if leads get shorted.

I know squashing a copper pipe is just fine for the job, but with electrical stuff, it is something that is best just done once, so might as well pay for the right items. Of course, If I needed something for clamping jumper cables onto, the flattened copper pipes are the best thing for that.

I like the bluesea stuff, it's pricey but seems well made. I put in a Blue Sea ST 5026 fuse box for extra circuits - works well and the screw terminals haven't loosened a bit. Only draw back, it has no "main" fuse. I used a 40 amp maxi-fuse in one of those under-hood weather resistant type sockets.

[westend]

muddydogs wrote:
I was planning on using the fuses but not quite sure what to use for the main line fuse?

Drew pretty much nailed it for advice. Best practices are to have a fuse within 18" of a battery (closer is better and easier to replace) and a fuse should protect the wire between the bus and any device. I used a 150 amp on the 2 X 6V bank that has 1/0 cable.

[mlts22]

Would a $50 125A Blue Sea power distribution bus work? It supports up to twelve circuits, each with its own fuse. Blue Sea also has an unfused 150A, 10 screw busbar as well. That can be used with a 150 amp ANL fuse to keep boom from happening if leads get shorted.

I know squashing a copper pipe is just fine for the job, but with electrical stuff, it is something that is best just done once, so might as well pay for the right items. Of course, If I needed something for clamping jumper cables onto, the flattened copper pipes are the best thing for that.

[DrewE]

What size wire is connected to the fuse?

The main purpose of a fuse is to protect the wiring from overheating in the event of a short or other overcurrent problem. Maximum fuse size should generally be based on the wire it's protecting; in this case, I assume that's the line from the battery to the bus bar. If the wire can safely carry much more than your expected current, choose something with a reasonable cushion over worst-case expected current; maybe 200A if your expected maximum draw is 150A....

If the wire is undersized for your draw, that's obviously a different kind of problem that needs correction.

If it were me, I would have a fuse as close to the battery (electrically) as practical, and certainly before the bus bar. It seems rather too likely for some ham-fisted person (such as me) to accidentally drop a wrench or something on a bus bar and short it to ground, with ensuing excitement.

[Muddydogs]

westend wrote:
Ampacity of copper bus bars. Your 3/4" pipe should be fine as the load from your batteries is probably never going to be above 100-150 Amps. I used a bolt on fuse at the bus and that is probably a good idea for your project. Midi fuses

Tip: Drill slow when drilling copper.

For those wishing to make there own buses with copper bar stock, I bought my bars at Discount Steel. They have a yard close to me but they will also ship.

When I was a kid, we made our own lead soldiers. We heated lead on the kitchen stove and poured it into molds. I think I still have the molds. We also played with mercury out of thermometers, poured gas into water buckets and lit it, and I even had a Chemistry Set. It's amazing that I'm still here, lol.

I was planning on using the fuses but not quite sure what to use for the main line fuse? I will have a main line coming into the box off the battery then heading out to my disconnect switch. What size fuse should I use here? The draw could be anything from 0 to 150 amps depending on the load at the time. Not sure if it even needs a fuse as its not fused right now and the line ends up in the converter fuse box?

I am adding fuses for the solar and inverter.

[westend]

Ampacity of copper bus bars. Your 3/4" pipe should be fine as the load from your batteries is probably never going to be above 100-150 Amps. I used a bolt on fuse at the bus and that is probably a good idea for your project. Midi fuses

Tip: Drill slow when drilling copper.

For those wishing to make there own buses with copper bar stock, I bought my bars at Discount Steel. They have a yard close to me but they will also ship.

When I was a kid, we made our own lead soldiers. We heated lead on the kitchen stove and poured it into molds. I think I still have the molds. We also played with mercury out of thermometers, poured gas into water buckets and lit it, and I even had a Chemistry Set. It's amazing that I'm still here, lol.