Need advice on ...

[themexicandoctor]

It's Labour Day & I posted late last night but I was hoping for some advice on this thread;

https://www.classbforum.com/forums/f...ing-11122.html

It might be that I am splitting hairs with putting the batteries 36 or 42 inches away from the shunt?

Or maybe I didn't ask for advice which I am now because Wednesday they are going to do the work as to my wishes.

If I lose a little efficiency, I didnt want to further compromise by using cables that were not big enough for the extra distance.

Here are my questions but it might be easier to answer with the photos on the otiginal thread.


Which is more efficient in terms of connection, next to the battery box or 36 - 42 inches away?

I presume the answer is the closer the better.

But considering the previous configuration up to 7-9 feet away not wired in such a way ro compensate for the 3 foot difference & therefore an imbalance, is this considerably better?

Am I achieving a reasonable enough advantage, to go through the trouble & cost of moving the inverter back, and, getting them right up against The Box?

At what length, does 1 foot, 3 foot, etc does cabling distance begin to have a sizable difference to the efficiency?

And what size cables should I use at 1 foot or less, 3 feet or 3.5 feet?

Do I also need to increase the size of the inverter cables if I move it back 14-17 inches?


The other benefits of the configuration;

Any & all runs will be closer than it is now.

The batteries will be balanced.

There will no longer be a battery sitting above the exhaust with a record high of 52° Celsius/ 124° Fahrenheit.

Everything will be more accessible on top of the chasis rather than below.

[GeorgeRa]

Without a layout drawing it is difficult to follow your question. What are the layout tradeoffs? To calculate cable size use a wire gauge calculator like for example this one Circuit Wizard - Blue Sea Systems Some of your question are related to shunt location, I would think that a shunt would be easier to relocated than find a good place for 2 x 6V batteries.

[themexicandoctor]

Originally Posted by GeorgeRa

Without a layout drawing it is difficult to follow your question. What are the layout tradeoffs? To calculate cable size use a wire gauge calculator like for example this one Circuit Wizard - Blue Sea Systems Some of your question are related to shunt location, I would think that a shunt would be easier to relocated than find a good place for 2 x 6V batteries.

Thank you George,

Here is couple of diagrams, diagram #1 first & then diagram #2 second;

[themexicandoctor]

Here is diagram #3

Showing option A, next to the battery box

Option B, about 36 inches away by the rear door

Option C, about 42 inches away, by the rear door, center rear of dinette

[themexicandoctor]

The considerations of #1 is that I already have my Inverter mounted upside down, to the ther side of the bed frame, close to the battery box.

I could move it back 12 inches but that would require making the inverter cables longer.

A secondary consideration would be difficulty accessing the batteries to check clamp tightness, etc.

[themexicandoctor]

Originally Posted by GeorgeRa

Without a layout drawing it is difficult to follow your question. What are the layout tradeoffs? To calculate cable size use a wire gauge calculator like for example this one Circuit Wizard - Blue Sea Systems Some of your question are related to shunt location, I would think that a shunt would be easier to relocated than find a good place for 2 x 6V batteries.

Great chart - I do not know the wire they are going to use, I am certain this guy won't cut corners as we have worked together for 9 years & he knows that I would always err on the side of caution.

I do see the magic inefficiency # is 3%

[jakegw2]

Have you looked at a power loss to distance run table like this one?
101 Wire Loss Chart

Without knowing your wire gauge and maximum current draw we can't give you an exact number. With the small distance difference you mentioned, unless you are using something smaller than a #6 wire, the difference is not going to be significant.

[themexicandoctor]

Originally Posted by jakegw2

Have you looked at a power loss to distance run table like this one?
101 Wire Loss Chart

Without knowing your wire gauge and maximum current draw we can't give you an exact number. With the small distance difference you mentioned, unless you are using something smaller than a #6 wire, the difference is not going to be significant.

Thank you Gentlemen,

This Friday is the day of execution, at most the batteries will be 42 inches away / 3 1/2 feet which is a lot closer than they are now.

I have no doubt the wire gauge will be sufficient, this guy knows his stuff & I never cut corners on this stuff.

[GeorgeRa]

Originally Posted by themexicandoctor

...................this guy knows his stuff & I never cut corners on this stuff.

While you at no cutting corners check if these crimps are OK, I am not sure if they are done correctly, they look like oversize lugs for the cable size and questionable crimping technique. A good test is to try to pull wires from lugs and/or test for temperature rise under a decent load.

Bad battery crimps can cause fire or a month-long refrigerator saga in Los Angeles.

[Bud]

"or a month-long refrigerator saga in Los Angeles"

I'm wondering if that is a Class B Forum record of some kind. I've having not been here long enough to comment.

[themexicandoctor]

Originally Posted by Bud

"or a month-long refrigerator saga in Los Angeles"

I'm wondering if that is a Class B Forum record of some kind. I've having not been here long enough to comment.

The issue was another RV Guy who added something underneath, by the shunt, which connected my batteries, to the negative side & it was loose.

Here are a couple of photos of the Repair, at the time i didn't crawl underneath because I had Patients & was in my Scrubs.

Instantly everything performed better electrically including the fridge thst was able to cycle on & off & solar performance improved.

LOOSE NEGATIVE CONNECTION

It was exactly what the Hrad Engineer at Novakool asked me to check.

First we tried the Clampmeter which was reading 2.1amps at the fridge, not 2.2.

A few days later he got underneath & saw the issue.

With the new system, the runs will be considerably shorter & everything will be inside the truck, visible & away from the elements.

When i installed the Magnum I also installed a fan in the door that accessess the underbed storage area because akbown problem with the archaic Tripplite RV612ULH was its overheating & failing in thst litte electrical box.

Now my inverter, which I rarely use, is located outside the box & the fan is supposed to exhaudt hot air.

In one of the photos you can see the inverted mounted upside down & just below it, a 5 foot CT Audio Sub Woofer - another thing I barely use but when I do, its required.

[themexicandoctor]

You can see the repair taped up in the latger photo, the second photo shows it is aft of the driver's side rear Bilstein Shock

[GeorgeRa]

Originally Posted by themexicandoctor

The issue was another RV Guy who added something underneath, by the shunt, which connected my batteries, to the negative side & it was loose.
.................................

First we tried the Clampmeter which was reading 2.1amps at the fridge, not 2.2.
...............

You could get to the source of the problem very quickly by measuring voltage at the refrigerator as it was suggested multiple times. Diagnostics of electrical issues often start with measuring voltage; it is the first step. A clamp-meter measures current, not voltage. Low voltage would lead you to troubleshooting of electrical wiring not chasing ghosts of thermal cooling issues.

[GeorgeRa]

Originally Posted by themexicandoctor

You can see the repair taped up in the latger photo, the second photo shows it is aft of the driver's side rear Bilstein Shock

Do you have two shunts? This is one shunt, is the taped one also a shunt?

[themexicandoctor]

Here is the underbed area/U Shaped Dinette, showing;

The Fuse Box to The Electrical Box

The Trap Door to access under the bed next to the driver's side, rear wheel well area.

The Inverter mounted upside down, over the Sub Woofer

The Fan cut into the Trap Door.

And two views from the rear drivers cargo door open, showing the wheel well, the inverter, the sub woofer & the small amount of space where the Two 6 Volt Batteries can go or just behind the center portion of the dinette rear.

My questions were fundamentally do I achieve a worthwhile efficiency advantage by;

Moving the Inverter back 12-14 inches

And placing the batteries next to the rear of the battery box

Doing away with the subwoofer, perhaps putting it ipfromt of my vehicle

OR

Having a 36inch or 42 inch run from the battery box, to the rear of the rig there, without interfering with the inverter or subwoofer or does a run even with thick enough cables, lose more than 3% efficiency at 36 - 42 inches.

Even though its much shorter than whst I presently have.

[themexicandoctor]

Originally Posted by GeorgeRa

You could get to the source of the problem very quickly by measuring voltage at the refrigerator as it was suggested multiple times. Diagnostics of electrical issues often start with measuring voltage; it is the first step. A clamp-meter measures current, not voltage. Low voltage would lead you to troubleshooting of electrical wiring not chasing ghosts of thermal cooling issues.

George,

It has been 2 weeks since I coukd get an apptt but when he did the unscheduled check he said "here is the problem, repaired it, taped it up..." & subsequently evidence proved so.

Its not that I ignored your request, it's that he found the problem & I haven't been back until this Friday & I will then ask him to check the voltage.

[themexicandoctor]

Originally Posted by GeorgeRa

Do you have two shunts? This is one shunt, is the taped one also a shunt?

In reference to that photo, there was a secondary connection underneath that another rv guy put together that failed.

That was what was taped up.

I do see there is a shunt that is connected to my solar and then the Bussman, which is a 50amp fuse I believe.

You have to remember that until he got underneath, the only thing we checked as per the Novakool request was amps with an ampmeter.

Then it was suggsted it was an issue with negative grounding - these are the experts, I just pay the bill.

Are there any questions I should ask further?

By tearing the outer system apart, putting the batteries under the bed, the Theory was that there would be some improvement in performance with the shorter runs & everything would be clear & visible and balanced at the batteries who would be side by side.

Eliminating all these lines & connections running underneath.

As it is, we are again in a Heatwave but the fridge is performing to spec & even though we have a lot of ash in the sky, by 10.30am to noon the SOC is back to 100% so the solsr is performing as it should.

[themexicandoctor]

Originally Posted by GeorgeRa

Do you have two shunts? This is one shunt, is the taped one also a shunt?

Are you saying thst whst is taped up, UNDERNEATH MY RIG TEMPORARILY, is regarded as a second shunt?

[themexicandoctor]

Originally Posted by GeorgeRa

While you at no cutting corners check if these crimps are OK, I am not sure if they are done correctly, they look like oversize lugs for the cable size and questionable crimping technique. A good test is to try to pull wires from lugs and/or test for temperature rise under a decent load.

Bad battery crimps can cause fire or a month-long refrigerator saga in Los Angeles.

I will have him check those crimps also.

[GeorgeRa]

Originally Posted by themexicandoctor

Are you saying thst whst is taped up, UNDERNEATH MY RIG TEMPORARILY, is regarded as a second shunt?

I think you wrote this was shunt. I have no idea as it is covered with tape.

Anyone can gain good lessons from troubleshooting. In retrospect you could get your issue resolved much faster if you would start with measuring voltage not current. Let’s assume you measured voltage and it was 11V at the fridge. Folks from Novakool and from this forum would be telling you FIX the WIRING, instead we all chased a wild-goose.