Home made bus bars

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cold
Posts: 4
Joined: Fri Apr 18, 2014 10:15 pm

Home made bus bars

Post by cold » Sun May 04, 2014 12:50 am

I was looking over some older videos(yes, I still find them entertaining), and liked how you built your battery box and the metal strips you used as bus bars. I was wondering how well they conducted, what they were made of, and what kind of losses were realized in the system. I was thinking something along the lines of making some strips out of scrounged copper pipe by running it thru a vise.
I am thinking of removing the non-running Onan generator from the rear compartment of my RV and expanding my battery bank into that compartment, since it is right beside the original cabin battery compartment. Maybe one day I'll get some pictures of what I'm working with and show them. Thanks.

techman
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Re: Home made bus bars

Post by techman » Sun May 11, 2014 6:50 pm

Taking out the dead generator and putting batteries back there is a great idea.

I used galvanized steel strip for my bus bars but I am sure there are some losses. Due to the large size though I am sure the losses are minimal.

Copper is way better and your idea is preferred.

mr bugsier5
Posts: 63
Joined: Sat Jun 15, 2013 12:36 pm
Location: Brielle , west coast of holland(europe)

Re: Home made bus bars

Post by mr bugsier5 » Thu May 15, 2014 1:04 pm

The strips Troy uses are good enough, copper is a better conductor, but in this case it doesent matter that mutch, the most inportant thing is that you connect your battery's in sutch way that the are totally equal in use and charge , it is most inportant for the life of your batterys that any battery in the bank is exactly the same, so in case off using 4 6 volt battery's connected sery parralel is to connect the pos and neg wires oposit of each other , and also (most people , even proffesionals forget!!) conect the couplings from the 6 volt battey's also together (so make two banks of 2 6 volt battery's in parralel, en conect tese in serie's, not as commonly both six volts in serie's and than the second bank parralel, always conect the 6 volts also parralel, to keep al 4 battery's the same!, your battery bank doesent only work better this way , it also lives mutch longer! ;)

this is my proffeseional advice!, the battery banks I install are living twice as long , as the ones other people sell, connecting it wrong!. :mrgreen:
dont be afraid to ask!, a stupid question does not exist!
forgive me my bad English!, as long as you know what i mean it,s fine for me!
(you thry dutch, wont be easy to! HA HA!)

techman
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Re: Home made bus bars

Post by techman » Wed Jun 04, 2014 10:16 am

Actually yesterday I discovered a problem with my setup. It has performed nicely all this time. I never noticed a real problem at all until yesterday afternoon.

I was running my air conditioner with 92 degrees outside and mid 80s inside. The battery temperature was around 80 degrees. I was using pure solar power to run my AC, which uses about 500 watts of power. I was also working on my computer and using my large 32 inch monitor.

My MPPT charge controller was pulling in 792 watts with 59 amps. This is near the maximum power that the controller can handle so it was limiting the total 1,600 watts of solar panels down to the charge controllers max. I never saw it running this high before but then again I never used my AC in full sunlight with this many solar panels.

Everything was running well but I decided on impulse to feel the bus bar. I am happy that I did. It was hot to touch. Too hot to hold my hand on the negative side. The positive side was cool to touch.

Now the bad part is that only the part of the bus bar near my inverter was hot. The negative wire of the closest set of batteries was also warm to the touch.

This means that only the first set of my three sets of batteries was being used. The other two sets of batteries were not being used as much. Most of the current was flowing in the first foot of the length of my bus bar. Not good at all.

I am going to look for something better to improve my system.

I am embarrassed to say this but it may be why I have been having so much trouble all this time with my total usable energy out of my battery bank. But honesty is what I try to keep going so I am admitting my mistakes and learning as I go.

I will do a video showing this next time the sun is shining and I get a chance to repeat the problem.

I am also going to find a better bus bar.

I wonder if I can just cut up some 0 gauge wire to use for the job.

mr bugsier5
Posts: 63
Joined: Sat Jun 15, 2013 12:36 pm
Location: Brielle , west coast of holland(europe)

Re: Home made bus bars

Post by mr bugsier5 » Wed Jun 25, 2014 4:42 am

the bars are conducting serieois power, but iff the positive is cold, and the negative hot there is another problem, i think one off the connections is loose or not torqued hard enough, the resistance tus created will make the bar hot to, remember when you use the inverter at max power it will draww lots off amps!
the amps flow equal trough the positive and negative, iff one off them is hot and the other not its a loose connection. ;)
dont be afraid to ask!, a stupid question does not exist!
forgive me my bad English!, as long as you know what i mean it,s fine for me!
(you thry dutch, wont be easy to! HA HA!)

techman
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Joined: Thu Dec 22, 2011 11:49 am

Re: Home made bus bars

Post by techman » Mon Jun 30, 2014 3:11 pm

Thank you. I will check all the connectors. But I am also looking for some more wire to run them properly to my bus bars. I know you are supposed to have the plus and the minus terminals on opposite sides of the battery bank. I need to get this set up properly and see how it works then. Should be better.

mr bugsier5
Posts: 63
Joined: Sat Jun 15, 2013 12:36 pm
Location: Brielle , west coast of holland(europe)

Re: Home made bus bars

Post by mr bugsier5 » Thu Jul 03, 2014 3:44 am

;) dont forget to couple the 6 volt ends also together. ;)
dont be afraid to ask!, a stupid question does not exist!
forgive me my bad English!, as long as you know what i mean it,s fine for me!
(you thry dutch, wont be easy to! HA HA!)

techman
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Re: Home made bus bars

Post by techman » Fri Jul 04, 2014 4:46 pm

I saw what you posted. I will reply there. Thanks

TimeDrawsNigh
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Joined: Thu Jul 03, 2014 8:07 pm

Re: Home made bus bars

Post by TimeDrawsNigh » Sat Jul 05, 2014 8:00 am

Troy asked that I come to the forum and give my thoughts on battery boxes so here goes. I decided not to use a bus bar system in my battery box really for several reasons.
1. I found making interconnects myself was easy and affordable. I oriented the batteries in the box such that the negative and positive post of each L16 string is only 7” apart. One of my strings has an interconnect exactly 7”, another is 9”, and the last is less than 12”. The parallel interconnects combining the three strings into a single bank are short as well. The first parallel pair are 0 gauge made to fit and the second is a slightly too long 4 gauge store bought pair that I plan to replace. I’ve checked them many times in many situations for heat and they have never been hot.
2. There are already exposed battery post in the box and I didn’t see any reason to mount another exposed potential mishap in the box. [ the bus bars ] I dropped a wrench across two 6 Volt post and the resulting spark convinced my to have as little exposure as possible.
3. It seems every successful battery bus bar example I’ve seen (on the internet) has short copper strips with terminals, with the strips being 6 to 9 inches long. Copper will surely corrode in time unless it is treated and I do not know how to “tin copper”. Again, these are short copper strips. Some suggest that the battery interconnects from the post to the bus bar must be “exactly” the same length. Some say it’s not important.
4. I hooked my charge controller on the far left string and my inverters (yes plural) on the far right string. I also put my multi meter on each 6 Volt L16 from time to time and I am confident that each battery, string, and the bank as a whole is charging as one homogeneous unit. No guessing about resistance or where on the bus bar to position my inverter and charge controller.
All in all, the bus bar system seems to introduce several potential “points of failure” and lingering questions with little to no gain. This is not being critical, just an observation. When I first say Troy’s battery bus bars I thought “that looks like potential problems on many levels”. First, the bars each look to be about 6 feet long. Second, they look like galvanized steel, not copper. Third, so much exposure to accidents and mishaps that could zap all the batteries. (one crowbar across the bars and… who knows?) I don’t think any of these points could be considered an asset to the battery bank. Troy has PLENTY of panels and incoming watts/amps but defiantly needs more storage, (amp hours). Ideally, he could isolate his DC loads to only those that he is using by building a new DC bar bus and/or DC Load Center. I’ve seen old RVs / Travel Trailers that have numerous phantom loads and it’s a booger finding them all if there’s a problem. Best to isolate all the new 12 volt goodies and bypass the old RV wiring. (Phantom Loads?) Also, always check battery water levels. I think I remember Troy having an equalization mode on his charge controller. With continued use, he may need to equalize every 4 to 6 weeks. I use my Black & Decker Smart charger with its equalization mode. I know I should check all 18 cells of my RE L16 XC batteries with my hydrometer to confirm the need to equalize but I don’t always do that.

My Portable Solar Panel Array assembly with switched combiner box: https://www.youtube.com/watch?v=dHpqxQV3Nf8" onclick="window.open(this.href);return false;
My Battery Box: https://www.youtube.com/watch?v=_9joBlFLClU" onclick="window.open(this.href);return false;
My Inverter Shelf: https://www.youtube.com/watch?v=kzgThAUO5OA" onclick="window.open(this.href);return false;

Anyhow, those are my thoughts and I hope maybe something here can help,
Roddy… (TimeDrawsNigh)

techman
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Re: Home made bus bars

Post by techman » Tue Jul 15, 2014 11:33 pm

Thank you for sharing this. Now you have me thinking. A bus bar is not necessarily needed but it is simply a convenient place to connect everything up.

I would use only the same length cables in everything throughout the system though. Electricity takes the path of least resistance and a shorter wire will be followed before a longer wire causing in-equal charge, discharge rates between the battery pairs.

I may go with your idea but have a DC bus bar for attaching my loads going out. This can simply be a couple inch strip of metal with screw terminals for attaching various wires and circuits.

I bypassed the entire RV circuitry long ago and removed the AC/DC control box. I only kept the AC breakers and the DC fuses in place and used them with my new wiring.

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