Positive ground?
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Topic: Positive ground?
Posted By: JoeBUtah
Subject: Positive ground?
Date Posted: 23 Aug 2017 at 8:59pm
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First time post (not counting my intro): 2016 178. Just noticed that the battery is connected bass-ackwards. Red cables to negative post, white cable to positive post. I'm not sure what to make of that.
I just contacted the fellow I bought it from and he's puzzled as well so I'm guessing the dealer hooked it up that way. Is this a typical configuration? It seems odd to me. I'm about to wire in a Zamp charge controller so I can utilize a portable solar panel and I'd rather not fry it. Any thoughts? |
Replies:
Posted By: Tars Tarkas
Date Posted: 23 Aug 2017 at 10:44pm
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I can't imagine how that could possibly work, unless you have a positive ground tow vehicle. And even then, the converter/charger would have to be wired backwards too. I would kind of hope you have a blown fuse on the converter and that it's isolated now from the situation. I think someone probably made a serious mistake when they put the battery in. TT ------------- 2010 176 FJ Cruiser |
Posted By: voisj
Date Posted: 23 Aug 2017 at 11:51pm
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Follow the wires from the battery to just underneath the front of the Pod and you will see one going to ground screw and one going to a small Silver Box, I think it's a fusible link that's the positive side. The smaller set of wires coming from the zamp port usually near the back of the Pod one of those is white and one of those is red it could be these that you're seeing. ------------- http://www.rpod-owners.com/forum_posts.asp?TID=9426&title=slopod-180-mods-johnsue - SLOPODMODS John&Sue,SLO,CA 2016 180 HRE, 2013 F150 Eco Boost 
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Posted By: eye95
Date Posted: 24 Aug 2017 at 4:39am
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Don't just judge by the colors. See how the wires are being used, what they are connected to. That being said, folks who did the wiring should have followed conventions to avoid confusion. ------------- <0> 2017 178 The "eye-Pod" 2011 Nissan Titan |
Posted By: GlueGuy
Date Posted: 24 Aug 2017 at 9:30am
If yours are wired that way, then somewhere along the line someone color-blind changed the wires. The electrons don't care about wire color, but it would cause a technician some puzzlement. The point being you should probably trace it out to see what had been done. ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: JoeBUtah
Date Posted: 24 Aug 2017 at 10:21am
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Here' a picture of what I have; I can't really trace the wires back as they go directly into a loom, but you can see they are clearly labled as are the terminals.
https://goo.gl/photos/bGt7FPixEPzf4c549 - Battery Set Up |
Posted By: JoeBUtah
Date Posted: 24 Aug 2017 at 11:01am
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This just keeps getting weirder: disconnecting the battery leads I checked for continuity. The white/negaive labled wire has no resistence (0.00 ohms) to the frame. However, the red/positive wire has about 5.5 ohms.
I attempted to connect the wires back up with the correct (as we know it) polarity, and fastened the red wire to the positive post. Upon connecting the white wire to the negative post, it arced. Big time. Very strange. Inside the fuse box there are two 40 amp fuses; they are toast. Ithink it's time to hook up and head to the dealer and/or give Forest River a call. |
Posted By: JoeBUtah
Date Posted: 24 Aug 2017 at 2:40pm
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Mystery resolved.
Turns out the battery had reversed polarity; I don't know how, when, why, where that could have happened. In talking to a local RV service guy, he mentioned to put a volt meter on the battery itself. Sure enough, it should -11.58 volts. I bought a new battery and as soon as I finish this yummy pb&j sandwich I'll wire it up. Thanks All! |
Posted By: mcarter
Date Posted: 24 Aug 2017 at 4:29pm
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WOW, that is rare and crazy. The only way that could possibly happen is to have a completely discharged battery, then charge it backwards. The battery will charge but it will be ruined and useless. It won't spark when you begin charging because it has to be completely discharged for this to happen. You don't see this very often, but it can happen. ------------- Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability." |
Posted By: GlueGuy
Date Posted: 24 Aug 2017 at 4:33pm
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There are many batteries that come in "normal" and "reverse" polarity. I discovered this years ago when I had to replace the battery in my tractor. The model number was ****R, where the "R" meant reverse polarity. When I ordered the replacement, I omitted the "R" when I picked up the battery, only to discover that the terminals were reversed. Oh my! ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: mcarter
Date Posted: 24 Aug 2017 at 4:41pm
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Familiar with that from being an old tractor guy, but I think someone messed this up badly. I'd be surprised if there wasn't some other stuff effected. ------------- Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability." |
Posted By: spydie
Date Posted: 26 Aug 2017 at 11:16am
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I did some research and it seems that reverse polarity batteries are easy to find in deep cycle marine batteries. I wrote to the company that sold them and they said they were for applications where the battery would only fit in a certain way. I think there is some other reason for it because batteries are the same dimension regardless which way you insert it in the battery box and if the cables don't reach you can get longer cables. I see no reason for a reverse polarity battery and a google search only turns up items about people that charged their batteries backward. There has to be a reason for it but the vendors of the batteries excuse makes no sense. It's one of those imponderables in life I guess. ------------- 2018 R-pod 176 2017 RAM 1500 5.7L Hemi 
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Posted By: furpod
Date Posted: 26 Aug 2017 at 11:46am
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Actually, Black Hot, White Neutral or GND is normal. All the red/black/blue etc etc is just user preference. Go open any piece of 2/1 Romex. Black, White, Bare or Green. There are some "standards" for colored wires, mostly on multi-pin connections, like your 7 pin. While there are still a few positive ground systems in the world, unless you own a vintage British car or motorcycle, and a couple BMW motorcycles, also vintage, you are VERY unlikely to have to deal with it. As long as cable "X" goes from the + on the battery to the "POS" clamp on the 12v distribution panel and Cable "Y" goes to the "NEG" clamp. It's all fine. ------------- |
Posted By: GlueGuy
Date Posted: 26 Aug 2017 at 11:53am
Red/black is common in DC circuits. However, conventions vary according to the "vintage" of the builder. I subscribe to red always being positive. In some telecom installations, they will use red to designate the "hot", because telecom installations are "usually" positive ground. If you're working on a system you're not familiar with it's best to get out your DVM or other test equipment to see what the convention was. OTOH, if you're working on our house, you check everything because the previous owner used whatever color was convenient; convention be damned.
 ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: spydie
Date Posted: 26 Aug 2017 at 11:54am
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In the world of DC that I grew up in, red was always positive and black was always negative. Now they are starting to use black and white like it was AC. That's what confuses a lot of older guys. For instance, the 12 volt DC wires on the LED lights in the Pod are black and white... that's not conventional for DC, that's conventional for AC. ------------- 2018 R-pod 176 2017 RAM 1500 5.7L Hemi
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Posted By: furpod
Date Posted: 26 Aug 2017 at 12:11pm
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I will bow to your "older guy" wisdom, having only been retired 20 years, I am still a youngster.. But, anyways.. having worked on a BUNCH of pods over the years, and a couple Airstreams, and now a Lance, they were all wired Black and White from the batteries. Maybe because on a TT you have both 120v and 12v, so they follow the 120v convention, I don't know.. but I fully agree that a DVM is a MUST have... But also, having been to the Pod birthing grounds a few times.. I know that "Bob" uses "what is at hand" for a lot of things.. LOL So seeing a different or odd color wouldn't surprise me much. ------------- |
Posted By: GlueGuy
Date Posted: 26 Aug 2017 at 1:21pm
------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: Tars Tarkas
Date Posted: 26 Aug 2017 at 6:17pm
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I get the idea of the polarity of a normal battery being reversed. As Mike said, it's very rare and pretty much requires someone isn't paying attention. The positive terminal becomes negative and the negative terminal becomes positive. I don't understand how in the world anyone could even make a reverse polarity battery for sale though. Unless that means having the + on the right front instead of the left front so the cables will reach the appropriate terminal. (Why not just turn the battery around?) On these alleged reverse polarity batteried the positive terminal is positive and the negative terminal is negative. Right? I used to have an old John Deere tractor that had a positive ground. You just had to connect the positive cable to the block and the negative cable wherever it was supposed to go (voltage regulator?). You didn't need some kind of special reverse polarity battery. TT ------------- 2010 176 FJ Cruiser |
Posted By: Tars Tarkas
Date Posted: 26 Aug 2017 at 6:18pm
------------- 2010 176 FJ Cruiser |
Posted By: GlueGuy
Date Posted: 27 Aug 2017 at 1:33am
------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: Tars Tarkas
Date Posted: 27 Aug 2017 at 2:26am
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So the post are reversed, not the polarity. That makes sense, although different cables would be easy and maybe cheaper.
TT ------------- 2010 176 FJ Cruiser |
Posted By: spydie
Date Posted: 27 Aug 2017 at 9:24am
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actually if the + post is really negative and the "-" post is positive, I'd say it's really reversed polarity. ------------- 2018 R-pod 176 2017 RAM 1500 5.7L Hemi
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Posted By: GlueGuy
Date Posted: 27 Aug 2017 at 10:00am
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The battery isn't reverse polarity, they just built the posts on the opposite sides from "regular", whatever that is. If you go through all the batteries on the store shelf, some will have + on the right, some will have the + on the left. I don't think there is any right or wrong here; it's sort of like some cars having the gas fill door on the left side, some have it on the right. I would say it's kind of odd that someone chose to switch the polarity of the battery on an existing installation. It might be that they were out in some out of the way place, and had to use whatever someone happened to have on the shelf. ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: Tars Tarkas
Date Posted: 27 Aug 2017 at 10:29am
My guess is that the original issue in this thread was that someone threw on a screwed up battery just before they sold their pod. They had a battery on which the polarity had been reversed by accident or negligence, but they hooked it so it would work. That is they ran the "positive" terminal to the ground, and negative to the load, which would let it work for a while. It would be a pretty crappy thing to do, and possibly dangerous. That's one issue. The other thing is that no one sells new reverse polarity batteries. That would mean the post labeled + was - and the post marked - was +. Reversing the position of the posts, so the positions of the + & - posts are reversed is fine. That makes perfect sense. But that's not a reversed polarity battery, it a battery with the posts reversed. Apples and oranges. I'd say no one chose to reverse the polarity on the battery. From my very limited understanding, this is a freak thing that can happen. You might be able to encourage it by completely depleting a battery and then hooking it up a charger backwards, but I'm not sure that doing that is guaranteed to cause the polarity to change. Whether such an exercise works or not the battery is pretty much toast. Why would anyone do that on purpose? TT ------------- 2010 176 FJ Cruiser |
Posted By: wthoms2000
Date Posted: 10 Nov 2017 at 6:25am
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Positive is positve, and negative is negative, ask Nikola Tesla. A $15 VOM (volt ohm meter) would confirm the negative cable is actually connected to ground using the continuity beeping setting. The VOM set to 12V would also confirm the pos and neg polarity on the battery, regardless of the markings.
2 cents from robotics engineer. Enjoy! ------------- Porta Poddy Wil and Luz, Orange County, CA 2017.5 179 HRE 2021 Ranger XLT FX4 REDARC Brake Controller |