Battery re-wiring ???

[Rotzilla]

I have 2 24 series batteries wired parallel (12v), and have a rats nest of wires running out of my battery boxes.

I am considering using a bus bar attached to the frame to lessen the number of wires going directly to the batteries.

I have a solar panel controller, genset, camper main wire, and the parallel cables all attached directly to the battery.
Is there any thing that can be moved to the bus bar, or do charging items like the solar and genset have to be directly wired the batteries?

I am not a electrical engineer, so go easy on me, any help would be appreciated.

Thanks

[westend]

I bought bus bar from Discount steel. Holes are drilled and tapped in the bar. The copper bar is attached to pieces of HDPE I had around and those pieces are epoxied in place. I used standard weatherproof 4" utility boxes.

You need two bus bars if you are organizing both the positive and negative phases of the 12 V DC system. If your negative phase is split off to the frame and organized well, you only need one bus bar. Bus bars are also sold premade or a guy can buy a lug terminal strip to handle the connections.

Good luck with your project!

[Muddydogs]

In my pic the box on the left is positive, the right negative. I can see some confusion since I have red wires running into each box. I used a couple sets of 4ga jumper cables I had to wire my solar controller and inverter. The jumper cables have a ripped cover on one side and a smooth cover on the other, I used the ripped side for positive.

[Muddydogs]

On mine one box is positive and the other is the negative box. Unless you have a ton of stuff a bus bar with spots to hook four or five lugs is about all one needs.
I got my bus bar from an electrical tech friend, he gave me 2 pieces of copper and 2 pieces of aluminum about 4"x 8". I cut one of the bars in half and trimmed the length to fit in the electrical box. 1/4 X 20 holes were then drilled and taped into the copper, spaced appropriately for the fuses I was going to use on the bus.
I had some nylon washers about 1/2" tall from Lowes that I epoxied to the bus bar then to the bottom of the box. The washers may not hold up in the box but all they were needed for is to keep the bar in place while I hooked up the wires. The bar is cut tight to fit in the box so once the wire are hooked up the bar isn't going anyplace even if the epoxied washer fail.
I purchase boxes with threaded holes in them but if I was going to do this again I would get boxes with no holes and just drill my own so I could space the holes out along the box height so I didn't have as much trouble keeping battery lugs from touching each other. Follow westend's link to fuses as the ones I purchased from my local radio install place were longer and made things really tight in my positive box.
For connections to the bus bar I used 1/4" x 20 x 3/4" stainless bolt's, lock washers and flat washers screwed into the taped bus bar holes. The same bolts where used with nuts for fuse to lug attachments.
My next step is to put a little tape around the wire entry holes inside the box then fill each hole from the outside with silicone to seal of these entry points.

[Rotzilla]

Thanks for the pic's, I definitely was not envisioning anything like that. I like the way everything is protected in the electrical boxes.

Where did you get the bus bars from? In all my searching I never seen anything as simple as those.

Did you run a individual battery wire to each bus bar, or are they wired in a series? Power provided to the second junction box from the first box?

[westend]

RJsfishin wrote:
Quote:
You will need one main fuse between the battery and the buss bar
------------------------------------------------------------
What for ? Just to add 2 more connections to where you were trying to make less ??

Because that is the correct way to do it. If there is no circuit protection between the battery and the bus, the cable connecting the two can fail and fail horrendously. In Muddydog's system he has the original circuit breaker to protect that part of the circuit.
Best practices are to have circuit protection within 18" of the battery but for RV's and IMO, having the fuse or circuit breaker either on the positive terminal or close to it, is the most elegant.

[Muddydogs]

Fuse as much as you want. I didn't have a fuse on the old wiring from the battery to disconnect but after the disconnect there's a factory installed fuse on the trailer frame. I didn't see the need to add a fuse from the battery to bus or from the bus to the disconnect switch. I did fuse the inverter and solar controller. The fuses I purchased are not quite as compact as westend's and I had problems getting more then 2 fuses in the box. Any more the 2 fused lines and cable lugs would have been touching.

[MEXICOWANDERER]

Make the battery to buss bar cable impregnable. Wrap with nylon spiral wrap and you can whack the cable with a claw hammer and not hurt it.

Individually fuse branch circuits leading from buss bar. Use toothed Shakeproof lock washers under every nut or screw.

[RJsfishin]

Quote:
You will need one main fuse between the battery and the buss bar
------------------------------------------------------------
What for ? Just to add 2 more connections to where you were trying to make less ??

[Muddydogs]

Here are some before and after pics of my rewire job. I didn't take the cover off the boxes but they look the same as westend's on the inside. I still have a couple long wires that run to the battery disconnect switch which is not working right.My next project is to remove the leveling jack so I can get to the back of the switch and replace the disconnect switch with a better design. I have all the parts for this just haven't got around to the work yet.

[time2roll]

All branch circuits can be moved to a bus. Then a single cable to each battery.

[Muddydogs]

I just did this and out right copied westend's design. I ran my solar, inverter and trailer wires to the bus bar. Going to the battery I have a Pos and Neg off the bus bars as well as I left my genny starter cables attached to the battery. This made for a nice clean wire setup with everything protected by the trailer frame and nothing hanging below the frame.
I ended up cutting and replacing the cable lugs on every wire under the trailer as they were to long to begin with. I purchase 2ga wire to run from my bus to battery but in the end I would have had enough just off the extra cable coming from the genny to make the bus to battery run. Yep there was an extra 4 feet of genny cable zip tied and hanging under the trailer on both the pos and neg side.
I also found that the genny neg cables was grounded to the frame and then attached to the neg battery post. After thinking about it and talking with a RV tech I could come up with no reason the genny needed frame grounding and removed this extra chunk of wire, now the genny neg goes directly to the battery.

I will post a few pic this weekend of my handy work.

[westend]

Install bus bar in utility box and mount to frame. You will need one main fuse between the battery and the buss bar and individual fuses from the buss bar to the devices those wires power.

I used these AMG style fuses because they're cheap and a 1/4" bolt fits the hole. They are not the quickest acting but will do the job. ANL fuses are the quickest to interrupt.

Bus bar with fuses:

[YC_1]

Sounds fine but do take pictures before removing any wires. Do not rely on your memory or color of wires.

[CJW8]

On my last rv I bussed all of my positive cables on to a Blue Seas buss bar and ran size 0000 cable from the bar to the batteries.

All my nagatives either went to the frame or the top of a shunt which was also frame grounded and the same size, 0000 to the batteries.

Motivation was the same, to clean it up.