12V charging through 7-way connector

[jvbuttex]

BossHogg has it right - when you disconnect from GROUND first then you won't short TO ground if you accidentally touch something while unhooking the hot side first. The ONLY time you should disconnect the 'hot' or positive lead first is if you simply don't have a choice but to get it out of the way to reach the 'ground' or negative side. But if that's the case, I would ALSO be looking into how to make that negative side accessible.

being in the auto industry for years... Positive on first, and off last.

 

[GTyankee]

this site writes that :

Half of the RV community says it's okay to run an absorption fridge while traveling (except through tunnels, and when refueling).

Ask Dave: Is it OK to drive with the propane refrigerator on?

Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the "RV Handbook" and the managing editor of the RV Repair Club. Thi

www.rvtravel.com

as part of his answer

Propane may not be transported through the Lincoln or Holland tunnels or across the Lower Level of the George Washington Bridge.

 

[jvbuttex]

tunnel, sure I can see that, your a bomb in confined space. In Portland, there is a tunnel, NO hazardous materials can be transported through it...

A bridge?????? its open air

 

[18CrewDually]

tunnel, sure I can see that, your a bomb in confined space. In Portland, there is a tunnel, NO hazardous materials can be transported through it...

A bridge?????? its open air

Lower level has lows in the road surface that a gas heavier than air like propane could settle and be explosive. Plus there are portions of the lower level that are more Tunnel than bridge.

George Washington Bridge (Lower Level) south/westbound

One of America's most iconic structures, the George Washington Bridge (Interstate 95) opened in 1931 and connects Fort Lee, NJ with Upper Manhattan across th...

youtu.be

 

[RamDiver]

Probably for the same reason it is advised to pull the negative battery post first, no spark, also prevents a battery from short to the ground by wrench when working with the positive battery cable. The negative terminal is attached to the vehicle's chassis so no spark. Despite popular belief, current, in a DC circuit, flows from negative to positive.

BossHogg has it right - when you disconnect from GROUND first then you won't short TO ground if you accidentally touch something while unhooking the hot side first. The ONLY time you should disconnect the 'hot' or positive lead first is if you simply don't have a choice but to get it out of the way to reach the 'ground' or negative side. But if that's the case, I would ALSO be looking into how to make that negative side accessible.

Besides the other reasons posted, also its simply easier because many times from the battery there is one ground lead. It is easiest to remove the one and go to the switch then from the switch to the battery ground. The hotside alot of times has a few wires attached to the terminal so you would have a bunch of wires to contend with.

I believe I misinterpreted the original comment by 18CrewDually.

The discussion revolved around disconnecting the fridge power, I was focused on only the fridge and couldn't grasp why one would choose to remove only the ground from the fridge,
my mistake.

The more experienced user of a travel trailer, (not me) likely knew the reference was to disconnecting the DC supply to the entire trailer.

I trust that the trailer has its own battery or set of batteries, yes?

Do modern travel trailers not include a proper DC power distribution center that includes an input supply disconnect? I've seen them on fancy yachts.

.

 

[18CrewDually]

I believe I misinterpreted the original comment by 18CrewDually.

The discussion revolved around disconnecting the fridge power, I was focused on only the fridge and couldn't grasp why one would choose to remove only the ground from the fridge,
my mistake.

The more experienced user of a travel trailer, (not me) likely knew the reference was to disconnecting the DC supply to the entire trailer.

I trust that the trailer has its own battery or set of batteries, yes?

Do modern travel trailers not include a proper DC power distribution center that includes an input supply disconnect? I've seen them on fancy yachts.

.

Plumbing manifolds and wire distribution blocks are not common practice in RV construction but is available in a few brands.
If you saw the behind the scenes Rats Nest of wiring in most RVs you would not believe it. I tidy up as much as I can but the way they're built is all about saving time and material. Nothing like building codes in a house.

 

[chopperdog45]

what model of fridge do you use?
Also what type and how big are your batteries?
looking to upgrade.
thx

I have a Furrion Arctic 12V fridge - https://furrion.com/collections/ref...0-cu-ft-furrion-arctic™-dc-refrigerator-black. I have one deep cycle marine battery. I have not upgraded the battery because I have not had the need to yet. It works fine for me - I don't do any boondocking, so the one battery and my solar panel has worked very well for me.

 

[jvbuttex]

I have a Furrion Arctic 12V fridge - https://furrion.com/collections/ref...0-cu-ft-furrion-arctic™-dc-refrigerator-black. I have one deep cycle marine battery. I have not upgraded the battery because I have not had the need to yet. It works fine for me - I don't do any boondocking, so the one battery and my solar panel has worked very well for me.

thanks for the link

 

[chopperdog45]

thanks for the link

You're welcome

 

[RamDiver]

I have a Furrion Arctic 12V fridge - https://furrion.com/collections/refrigerators/products/10-cu-ft-furrion-arctic™-dc-refrigerator-black. I have one deep cycle marine battery. I have not upgraded the battery because I have not had the need to yet. It works fine for me - I don't do any boondocking, so the one battery and my solar panel has worked very well for me.

Wow!

The 12 VDC powered fridges are expensive at $1900.

What are the advantages of using 12 VDC versus using an inverter and having appliances that use regular household AC power?

.

 

[lpennock]

Wow!

The 12 VDC powered fridges are expensive at $1900.

What are the advantages of using 12 VDC versus using an inverter and having appliances that use regular household AC power?

.

When traveling off grid. The DC fridge draws less power than using a AC fridge with an inverter.

 

[Tulecreeper]

I have a Furrion Arctic 12V fridge - https://furrion.com/collections/refrigerators/products/10-cu-ft-furrion-arctic™-dc-refrigerator-black. I have one deep cycle marine battery. I have not upgraded the battery because I have not had the need to yet. It works fine for me - I don't do any boondocking, so the one battery and my solar panel has worked very well for me.

That's pretty good. What is the Ah/Reserve Capacity of that one battery?

 

[chopperdog45]

That's pretty good. What is the Ah/Reserve Capacity of that one battery?

I'll look at it when I go out to the camper.

 

[cdn cj]

Just a couple of my thoughts, I’ve always considered the truck to rv as a maintainer as opposed to a charger.
I make sure the battery is charged on AC before we leave.
I also travel with the fridge running although I will ensure I don’t have to refuel with the trailer connected.
Lastly to cool down the fridge before packing I make sure there’s a bottle of water in the fridge and freezer. They need something to draw heat from and plain air doesn’t work.

 

[RamDiver]

Lastly to cool down the fridge before packing I make sure there’s a bottle of water in the fridge and freezer. They need something to draw heat from and plain air doesn’t work.

That's an interesting idea.

Are you suggesting that placing a bottle of water in the fridge and freezer compartment at startup will reduce the energy required to obtain the setpoint?

And how could cooling water require less energy than cooling air?

Do you have any references to support this concept?

.

 

[cdn cj]

That's an interesting idea.

Are you suggesting that placing a bottle of water in the fridge and freezer compartment at startup will reduce the energy required to obtain the setpoint?

And how could cooling water require less energy than cooling air?

Do you have any references to support this concept?

Nope , sorry no references.
Just passing along misinformation apparently.
I can’t see where I suggested it uses less energy?
Maybe it will cool the air but at least I can tell it’s working if there’s something inside.

 

[RamDiver]

Nope , sorry no references.
Just passing along misinformation apparently.
I can’t see where I suggested it uses less energy?
Maybe it will cool the air but at least I can tell it’s working if there’s something inside.

Thanks for the clarification, that's why I had to ask.

I was intrigued with the last line in your post. "Something to draw the heat from and plain air doesn’t work ".

That sounds a bit technical and my curiosity was piqued.

I was involved with a natural food store a few years ago, and when I bought temperature gauges for the fridges & freezers, I bought several for home too.

I suppose a bottle of water could work in a pinch.

.

 

[chopperdog45]

That's pretty good. What is the Ah/Reserve Capacity of that one battery?

I went out to my RV to winterize it this past weekend, and took a look at the battery. It is 88 AH/160 RC/750 CCA. Just a marine deep cycle Interstate battery. Works for me. So far, at least...

 

[2003F350]

I went out to my RV to winterize it this past weekend, and took a look at the battery. It is 88 AH/160 RC/750 CCA. Just a marine deep cycle Interstate battery. Works for me. So far, at least...

That's pretty much the standard, though going with more CCA doesn't necessarily hurt you, especially if you've got a bigger camper with more circuits. The newer batteries are supposedly better, but frankly I've never had a need to go away from a standard deep cycle marine/rv battery.

 

[Tulecreeper]

I went out to my RV to winterize it this past weekend, and took a look at the battery. It is 88 AH/160 RC/750 CCA. Just a marine deep cycle Interstate battery. Works for me. So far, at least...

I always find it interesting that a battery manufacturer will put both Ah and RC on a label, but when you do the math it doesn't add up. While 88 Ah is not bad, 160 RC computes to 66 Ah.

There are two ways to compute Ah from RC. One is to divide the RC by 60, then multiply that number by 25 - (RC/60)x25. The other, and much simpler, way is to just multiply the RC by .417 - RCx0.417. In your case a 160 RC is about 66 AH - 160/0.417 = 66.7Ah. So I think the manufacturers want to push their Ah as high as physically possible as a sales thing. Still, even if you are only getting 66 AH that's even more impressive and tells me your 10 cu-ft fridge is even more energy efficient.