| |
Subject |
Author |
Date Posted |
Forum
|
 |
RE: Charged a DC-27 battery at 16.7 volts for a couple weeks.
I could put 20v at .01A on for a while and not do serious damage to a flooded battery, even If the battery terminal measured voltage crept up to 20v?
Jim
You will never be able to create that condition with a good battery that is partially discharged. When you apply 20Vdc, then either the current will far exceed .01A or the voltage will drop or both. For any given load, you can control the voltage and the current will go where it will or you can control the current and watch the voltage change but you can't do both at the same time. This is a simple application of Ohm's Law.
|
Cedarhill
|
12/08/12 08:43am |
Tech Issues
|
|
RE: CHINA And Deep Cycle Batteries
It seems to me that the true wealth of a nation is measured in its ability to manufacture products and services that its population and the populations of other countries want. If that is true, then we are slowly transferring our wealth to China. At some point, our money will become worthless to them and they will stop making loans to us. At that time, our economy will collapse and we will all be be truly destitute. That appears to be the trajectory we are on and nobody seems to want to do anything about it. Merry Christmas!
|
Cedarhill
|
12/07/12 01:02pm |
Tech Issues
|
|
RE: Newb
I used to tow a 4400 pound fully loaded (measured weight) Forest River Flagstaff with a 2011 Frontier rated to tow 6500 pounds. There was absolutely no safety issue using a correctly adjusted weight distributing hitch and friction type anti-sway bar. I pulled it all over steep and curvy roads in the Blue Ridge Mountains without difficulty (but some amount of patience). I think the safety issue raised by some people has more to do with a lack of experience rather than lack of towing capacity. On the other hand, I now tow the same trailer with a RAM 1500 with the 5.7L Hemi. It is overkill but I really like the quietness and acceleration of the combination. The Frontier V-6 needs to be wound up to 3500+ RPM to make enough power going up hills and accelerating from a stop. This won't hurt the engine but the noise was very annoying to me. The Hemi just loafs along at 1800-2500 RPM or less most of the time.
|
Cedarhill
|
12/07/12 09:22am |
Beginning RVing
|
|
RE: Low voltage problem ?
Sitting with your truck at idle speeds will do very little but at highway speeds my TT batts will charge up in 30 minutes or so . When measuring amps do so at a FAST idle ! Works for me .
The behavior you describe is not universal. The voltage regulator output on my 2012 Ram truck is independent of engine RPM.
|
Cedarhill
|
12/05/12 02:27pm |
General RVing Issues
|
|
RE: Low voltage problem ?
I don't speculate, I have measured the amperage the battery receives from the TV. I wired it myself with 10 gauge wire. The most I have ever measured was a little over 5 amps going into the trailer batteries. It takes a long time to charge from the tow vehicle.
Plus as the battery voltage increases, the amperage will drop drastically. Measure it for yourself.
I used 10 gauge wire, some TVs don't have that. They could have 12, 14, or even thinner.
In summary, the TV is a terrible way to charge the trailer battery. If you must in a pinch, use a heavy set of jumper cables.
My real life experience is similar but I know of at least one situation where the tow vehicle serves as an excellent charger. I tow with a late model Ram pickup and the original equipment wire between the power management module under the hood and the 7-pin connector on the rear bumper is 10 AWG. I inserted a Turnigy amp-hour meter between the truck and the trailer on a recent trip and measured the current while traveling. The trailer batteries were at 12.1 Vdc when I left under no load conditions. The open circuit truck voltage was bouncing around 14.2 to 14.6 Vdc. The maximum current I measured was 6.1 A which is not much different than what you observed. Over about 8 hours travel time, the batteries received about 36 A-H of charge and were at 13.4 Vdc upon arrival. After bleeding off the surface charge, the voltage dropped to 12.6 Vdc. That state of charge was good enough to get me through the night. In this particular situation, the tow vehicle was an effective and effortless way to charge the trailer batteries. More generally, I have found that 6 to 8 hours of driving is typically enough to get me through the next night. I have also been known to charge a battery sitting in the floorboard of my truck using an adapter made from a cigarette lighter plug and alligator clips. In this case, the charging rate for a partially discharged battery (don't know how much) started at 6A and trailed off to 2A over a few hours. That may not sound like much but every bit helps when there are no hookups and generator usage is limited or not permitted.
|
Cedarhill
|
12/05/12 02:22pm |
General RVing Issues
|
|
RE: inverter genertators
I thought that was something special that the hondas and yamahas did.The article I posted has more to do with running a MW from an inverter (from batteries) and not necessarily an inverter generator.
Many non-inverter generators put out a perfectly good sine wave, and if your MW ran fine, then yours probably did. The problem comes from running a MW from a MSW inverter.
I would go so far as to speculate that most any good synchronous generator will put out a quality sine wave until it is loaded to near the maximum output. I had an occasion to verify this with an oscilloscope after I (unfortunately) destroyed the electronic controller on our house stove. I investigated the failure and observed that my 6.5kW generator put out a beautiful sine wave until the load approached 5kW. As power was increased past that point, the waveform turned into nasty (+) and (-) spikes of 200+ volts.
|
Cedarhill
|
12/04/12 09:16pm |
Tech Issues
|
|
RE: How did they do it!!!!!!!!
The weight listed on the yellow sticker does not include fresh or waste water tank contents. On my trailer, that could be 100 gallons or 830 pounds. Just a full fresh water tank, which is a more likely condition, would weigh over 300 pounds. The weight of dealer installed batteries isn't included either.
|
Cedarhill
|
12/04/12 05:15pm |
Travel Trailers
|
|
RE: Electrical Guru's...Need Help
Sorry I let you down Larry. Given my other projects, my response to Cedar was too hasty. Nothing like placing the cart before the horse. But I am glad you were able to untangle my post to make sense of it. Bottom line, a nonlinear circuit (such as found in the microwave or converter) will create PF less than one and can cause ac voltage measurements to be low when true RMS meters are not used.
Sal
Sal, I'm a bit disappointed. You are usually more careful.
Glad to see the old Salvo back! :B:B
I hate to be the grumpy old man in this thread but the fact that microwaves and converters are basically inductive will have very little effect on a voltmeter reading. These loads will shift the current waveform to lag the voltage waveform and will increase the complex current but unless the entire load is huge - enough to blow a circuit breaker - you are not going to see enough distortion to cause an RMS meter to read differently than an averaging one. You will just see an equivalent amplitude drop in both. Keep in mind that the original poster plugged into the grid and not a generator and the voltage is much less subject to distortion due to reactive loading.
The tolerance of handheld voltmeters is quite large, even with expensive name brands. Furthermore, as someone already pointed out, calibration has to be a periodic exercise if you want consistent accuracy. What are the chances that either the OP or the electrician had their meters calibrated recently?
|
Cedarhill
|
10/17/12 03:09pm |
Tech Issues
|
|
RE: Electrical Guru's...Need Help
My definition of the engineering term "power factor" is absolutely correct to the extent I have explained it. I have worked with power factor as an engineer in an industrial environment for far too many years to need any additional study on the subject. To get into a discussion of the concept on a forum such as this would be neither interesting nor useful. I will simply stand by my statement that power factor is not the reason why the various meters didn't produce the same numbers. In more general terms, I don't think it was either noise or distorted waveforms either.
|
Cedarhill
|
10/16/12 08:00pm |
Tech Issues
|
|
RE: Electrical Guru's...Need Help
Do your meters measure true RMS? Most cheap meters measure average voltage. They then assume it's pure sine and make an average to RMS conversion. If the waveform is not pure sine then there will be a measurement error. If the PF is not one, then it's not pure sine.
Sal
The power factor is an indication of the phase relationship between the voltage and current. It doesn't necessarily imply anything about the shape of the waveform. My opinion is that the discrepancy is unrelated to the shape of either the voltage or current waveform.
|
Cedarhill
|
10/16/12 05:47pm |
Tech Issues
|
|
RE: Why Antifreeze if no water?
I never use antifreeze except in the traps and I have done it that way for 35 years in 3 pop ups, 2 motor homes and a travel trailer. I will not advise that anyone else do it that way because you have to thoroughly understand what you are doing and do it correctly in order to be effective. The problem is typically not the pipes, which are PEX these days and will expand to accommodate ice without breaking. The problem is usually valves and fittings which may trap water if you aren't careful and will not expand like PEX pipe - at least that is what my dealer says. By the way, he never uses antifreeze except in the traps in any of his inventory, new or used.
|
Cedarhill
|
10/16/12 09:34am |
Beginning RVing
|
|
RE: Walmart Internet that does not expire
This is an extremely sparse coverage area
http://www.showmycoverage.com/images/TEL986SCDO.gif
compared to the one shown on this web page:
Verizon coverage
|
Cedarhill
|
10/14/12 12:01am |
Technology Corner
|
|
RE: Use an inexpensive DC-to-DC converter to charge from solar?
Hi Cedarhill,
How can a 68 watt panel @ 16.5 volts (4.4 amps) send more than it's output current to the batteries and overload the dc to dc converter?
First of all, the detail about 68 watts was not posted until after my first reply. My clairvoyance skills are a little on the low side.
There is a minimum input voltage required for the DC-to-DC converter to work. If the load presented by the battery causes the converter to pull too much input current and drag the panel voltage below that level, then the converter will shut down. The current overload would be on the input side of the converter rather than the output.
|
Cedarhill
|
10/13/12 11:47pm |
Tech Issues
|
|
RE: James County Island Park
The Hunley is housed in a big warehouse in a big wide open area. You would have no trouble finding parking even if you were in a big motor home.
|
Cedarhill
|
10/13/12 11:21pm |
General RVing Issues
|
|
RE: Use an inexpensive DC-to-DC converter to charge from solar?
MPPT controllers are DC-to-DC converters by definition. However, they have other properties that make them better suited for battery charging. The converter you linked to puts out a continuous 13.8VDC. That isn't a high enough voltage for maximum charging rate but it is too high for float charging. Also, the load presented by very discharged batteries may be too great for the controller and it may shut down at times from an over-current condition. If you keep these limitations in mind and are willing to disconnect and reconnect the converter as needed, then I think it would work just fine. The hassle involved and the risks presented by system inattention would rule it out as a permanent solution for me.
|
Cedarhill
|
10/13/12 10:58am |
Tech Issues
|
|
RE: Walmart Internet that does not expire
"Internet on the Go" sounds like a great alternative under the following conditions:
* You only travel to major metropolitan areas
* You only travel by way of US Interstate highways
* You only use the internet for email and simple web page viewing
The coverage is too poor, the data rate is too slow and the data charge is too high for any other circumstances.
|
Cedarhill
|
10/13/12 10:28am |
Technology Corner
|
|
RE: Surge protection
I mean I guess on one hand spending $300 for the sake of protecting a 5 or 6 figure RV is a no-brainer. But on the other I just hate paying more for whiz-bang type stuff (like maybe the LCD screen in this case) when it offers no additional features, functionality or protection.
Just curious if anyone can speak to any additional protection or features offered that warrant it being $200+ more then the Progressive Industries product?
I don't understand your comment. What surge protection device are you comparing the Progressive unit to. Your comment implies that the alternative is in the $500 range.
The other thing I don't understand is the guy's reference to a "5 or 6 figure RV". All you are protecting with these devices is the items which run on 120VAC, which isn't typically even $1000 worth of stuff. The 12VDC items aren't at risk. I don't think it is a good value to spend $300 or $500 to protect $1000 with such a low probability of occurrence, especially when you can often do just as well with a $10 voltmeter.
|
Cedarhill
|
10/13/12 08:42am |
General RVing Issues
|
|
RE: James County Island Park
A half day tour of Charleston is about like a half day visit to Disney World. You won't even be able to get a good start in that amount of time. James Island is a really nice campground that deserves more than a half day by itself.
|
Cedarhill
|
10/13/12 07:57am |
General RVing Issues
|
|
RE: Using the CAT scales
For those of you who are worried that you were not in the truck when it was weighed, why don't you just add your weight to the truck weight? What is the big deal? :h
|
Cedarhill
|
10/10/12 12:31pm |
Travel Trailers
|
|
RE: Grease EZ lube axles
Do you guys really think Dexter is so incompetent that they would design a grease mechanism that will risk damage to the seals when used and then leave it that way for a decade? If you think they are that stupid, how can you possibly bring yourself to buy a trailer that rides on their axles?
|
Cedarhill
|
10/01/12 08:34pm |
General RVing Issues
|
