Voltmeter install in Roo 19

[oldtool2]

Originally Posted by Jim Schings

They also use several hundred volts (200-1000) to overcome the resistance of the epidermis. 12V or 50V would do nothing at all.

BTW the actual current used is limited to MICROamps anywhere near the heart. OH, AND, a defrib is not used to START the heart. It is used to regulate the heart after fibrillations have started. It does not RE-START the heart.



No argument there.



As I directed him to.



A 80 ampere battery charger. AND the open DC output voltage was actually closer to 30 volts. Felt nothing. Do this same thing with AC at that voltage and you will typically feel some tingling.



Almost always. Actually clean water is a poor conductor of current. In most cases won't blow a normal fuse or circuit breaker. However a GFI will open very quickly since it trips in the milliamp range.



I don't understand this statement a bit. Since the hair dryer has both L1 and N attached to it and in the water, it makes no difference whether you grab it with one, two, or 3 hands. This would make SOME sense if the hair dryer only had L1 connected to it. Then, the potential current flow would be from the hairdryer to the tub or your hand. In actuality the path would be from L1 right to N internal in the hairdryer. That is why death or even shock is unlikely. Maybe you could explain your logic?

Jim,

I think we are getting into more detail than anyone here cares about. Bottom line is we could try things and see if we can walk away, and I don't think either one of us is that stupid. As for the defibrillation, I may have used the wrong terms. BTW, it is defibr, not defrib.

You are right. As a general rule it won't restart the heart, just bring it back in normal sinus rhythm. This is getting far to technical for my blood sense I am not a doctor and have no medical degree.

As for the bath tub and hair dryer, I was keeping it simple. A sever shock thru your heart and or chest area to ground can be deadly. Can we agree on that without getting technical? Not many here even understand what we mean by L1.

The worst shock I ever got came because of a careless apprentice. He wired a metal cased 15 amp hessel (sp) plug wrong. I took 110 VAC from my right hand thru my chest to my left shoulder. I passed out and fell to the ground breaking the circuit. Ten years later I still got cramps in my shoulder. You never know what life s going to bring. They transferred that apprentice the next morning. Something about the general Forman didn't want me brought up on murder charges??

Jim

[Jim Schings]

Originally Posted by oldtool2

I think we are getting into more detail than anyone here cares about.

Yes and way off thread.

But since we are comparing war wounds..... My worst was from a 480V DC supply. I had a pair of needle nose pliers in my hand near a power strip. A pilot light suddenly came on with no lens on it and I tried to shield my eyes from the lamp with my right hand. My left hand (and pliers) moved enough to trough the 480V line. 480 from hand to hand Several hundred MA were available at the supply. Luckily I felt a board hit me right across the chest and I went unconscious for a few seconds. When I awoke
I was not even sure where I was. No long term damage. Lost 10 or 20 IQ points, but I had plenty to spare...

[acadianbob]

Back to the thread. I've used a Voltminder for years; plugged right into the buss on the converter. It is very useful for general state of battery charge; certainly way more useful than the monitor that typically comes with the trailer. By the time it comes off of "full", it is already at the edge of damaging the battery. Are there way better technical solutions? Sure! But the digital voltmeters are useful.

[Jim Schings]

Bob, Agreed. But tell us about your worst electrical shock....

[oldtool2]

Originally Posted by Jim Schings

Yes and way off thread.

But since we are comparing war wounds..... My worst was from a 480V DC supply. I had a pair of needle nose pliers in my hand near a power strip. A pilot light suddenly came on with no lens on it and I tried to shield my eyes from the lamp with my right hand. My left hand (and pliers) moved enough to trough the 480V line. 480 from hand to hand Several hundred MA were available at the supply. Luckily I felt a board hit me right across the chest and I went unconscious for a few seconds. When I awoke
I was not even sure where I was. No long term damage. Lost 10 or 20 IQ points, but I had plenty to spare...

Dc can be nasty and mean! Worked with 250 VDC almost every day for 20 years and got "bit" more times than I care to think about. If I had a dollar for every IQ point I lost I could have retired 30 years earlier! To this day I hate the taste of copper!

Back to the topic. There are other ways to monitor your batteries but a cheap digital volt meter can' be beat. You can get them from Harbor Freight for $5.99 and it will tell you what you need to know for the most part.

Digital Multimeter - Save on this 7 Function Digital Multimeter

Jim

[Jim Schings]

.. a cheap digital volt meter can' be beat. You can get them from Harbor Freight for $5.99 and it will tell you what you need to know for the most part.

Yep and everyone with an RV should have one with them. In regards to Harbor Freight: I have to pay more for my DVM's since I made a pledge to myself and God that I would never buy anything from Harbor Freight that I would ever need.

[oldtool2]

Originally Posted by Jim Schings

Yep and everyone with an RV should have one with them. In regards to Harbor Freight: I have to pay more for my DVM's since I made a pledge to myself and God that I would never buy anything from Harbor Freight that I would ever need.

But you need, you need!!!

[Jim Schings]

I have a couple Flukes and a Simpson 260. Don't need any more...

[RJHuser]

Lets clarify one thing. Yes, if I were working on a heavy cable connected to the battery, I would disconnect the negative cable from the battery. That cable has the ability to cause damage - to the battery - with the possibility of secondary damage to me, electrical or chemical burns.

However, the OP was discussing a very small size conductor (on the meter) to a FUSED small sized conductor in the trailer. Being IN the trailer, it is highly unlikely to find a grounded piece of metal for a accidental short to occur - we all have had problems with grounding in trailers. If a short to neutral did occur, the worse that would happen is the fuse would blow.

I will restate what I said - 12 VDC won't hurt you. The analogy used for electricity is water flowing in a pipe. Voltage is analogous to pressure and amperage is analogous to volume. If the water pressure (voltage) is low, no mater what the volume (amperage) is, the water flow can be stopped easily, for example, the water flow in a garden hose connected to a low pressure source (say 10 psig) can be easily stopped with kinking the hose or putting your thumb over the end of the hose. Increase the pressure to 10,000 psig, and it not so easy. In fact, a micro volume of flow can cut right through skin, bone, even metal!

As stated by others, until you get above 30 or 40 volts, you can't even feel it if you grasp a conductor in both hands. There is not enough "pressure" to overcome the electrical resistance of the body.

With everything said, I will and do make a conductor "dead" before working on it.

And by the way, in my job I work on electric systems upto 2300 volts with ampacity of thousands of amps, and have been involved with electrical system abov 14k volts.

(By the way, the so called "electric chair" that was used to execute death row prisoners generally used 2300 VAC, anything less and it didn't kill the person or actually ended up "cooking" the prisoner to death. Even at that voltage, there are many accounts of failure to kill the prisoner, or prolonged time to do the deed. Generally, the used three short "shots" to do the deed as it was more effective than one long shot.)

Rick
(Still alive and kicking after working on my trailer 12 volt electrical system)

PS: I was successful in my post, to get people thinking and to dispel many of the myths and incorrect ideas concerning low voltage electrical systems.

[MarsMan]

I see 12V discussions of any kind are interesting and varied

[oldtool2]

Originally Posted by RJHuser

Lets clarify one thing. Yes, if I were working on a heavy cable connected to the battery, I would disconnect the negative cable from the battery. That cable has the ability to cause damage - to the battery - with the possibility of secondary damage to me, electrical or chemical burns.

However, the OP was discussing a very small size conductor (on the meter) to a FUSED small sized conductor in the trailer. Being IN the trailer, it is highly unlikely to find a grounded piece of metal for a accidental short to occur - we all have had problems with grounding in trailers. If a short to neutral did occur, the worse that would happen is the fuse would blow.

I will restate what I said - 12 VDC won't hurt you. The analogy used for electricity is water flowing in a pipe. Voltage is analogous to pressure and amperage is analogous to volume. If the water pressure (voltage) is low, no mater what the volume (amperage) is, the water flow can be stopped easily, for example, the water flow in a garden hose connected to a low pressure source (say 10 psig) can be easily stopped with kinking the hose or putting your thumb over the end of the hose. Increase the pressure to 10,000 psig, and it not so easy. In fact, a micro volume of flow can cut right through skin, bone, even metal!

As stated by others, until you get above 30 or 40 volts, you can't even feel it if you grasp a conductor in both hands. There is not enough "pressure" to overcome the electrical resistance of the body.

With everything said, I will and do make a conductor "dead" before working on it.

And by the way, in my job I work on electric systems upto 2300 volts with ampacity of thousands of amps, and have been involved with electrical system abov 14k volts.

(By the way, the so called "electric chair" that was used to execute death row prisoners generally used 2300 VAC, anything less and it didn't kill the person or actually ended up "cooking" the prisoner to death. Even at that voltage, there are many accounts of failure to kill the prisoner, or prolonged time to do the deed. Generally, the used three short "shots" to do the deed as it was more effective than one long shot.)

Rick
(Still alive and kicking after working on my trailer 12 volt electrical system)

PS: I was successful in my post, to get people thinking and to dispel many of the myths and incorrect ideas concerning low voltage electrical systems.

Rick,

I won't dispute most of what you have written. My bottom line is this. I don't want to see anyone get hurt, and am sure you don't either. Those of us that have worked with electric all our lives know what it can do under the right conditions. I will go back to what I said earlier, for a couple of minutes work why take chances.

An old saying comes to mind, do as I say don't do as I do. We need to remember that many of us have experience with electric but many here do not. I would rather see them safe than sorry. I am sure all of us involved in this discussion feel the same.

Jim

[redwolfpei]

Wow this has been a busy thread...

Ok, so I was out camping for the weekend and installed the voltmeter. The wiring in the control center was too confusing for me so I aborted my initial plan. I decided to tap into the propane detector and install on the rear bench seat. Looks good and provided me with a general idea on my battery state each day.