Need Power

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To Mike & Karen
Please check your PM.
Cheers:wave

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"Why does my old amp thunderbiird 1 gig dvd burner soundblaster 5.1 200 gig external had dual 20 gig internal hard drives . survive running off a 1500 watt inverter for the last 3 years ?"

What language is this, exactly?:conf

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You have a 1000 MHZ (1.0 gig) AMD (not Intel, think Ford and Chevy!) Athlon, with ability to copy DVD's, you have 5.1 surround sound for theatre experience ( 200 bucks of computer speakers is equal to 1500 bucks of stereo speakers), you have 200 gigs of external hard drive strorage (I think you may mean 2 gig), and a 20 gig internal hard drive.

Your PC is 3 years old................. :o

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Orginally posted by Eric C

"Why does my old amp thunderbiird 1 gig dvd burner soundblaster 5.1 200 gig external had dual 20 gig internal hard drives . survive running off a 1500 watt inverter for the last 3 years ?"

What language is this, exactly?:conf

Good question. I think it's from a tribe in Acirema. or maybe Adanac.
Another question would be does Mike and Karen know where their PM is?

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Morning Jana:wave
I'm not sure, but being that it is a hot clear weekend, they might be out for the weekend. Time will tell. Cheers

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A "Thunderbird" is a low end AMD brand processor simular to the Intel Celeron CPU. The processor speed is 1GHz

A DVD burner is a drive that can play and record DVDs

Soundblaster 5.1 is a mid range sound card that will provide surround sound.

"200 gig external" should read 200GB external Hard drive. It is a Hard disk drive in a portable housing. In this case it is a large 200GB drive.

Al is telling us he used to have two 20GB Hard disks in the case.

He is also stating that he has powered this computer with a 1500 watt inverter for the last 3 years.

From the spelling I am guessing Al had a glass of wine or two before his post -

Is that pretty much it Al :cheers

Rick is right - this system would not have been available 3 years ago - but that is another story.

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I'm not a EE, or even play one on the web, but here's a little of what I've read concerning inverters.

Some devices are sensitive to the power they receive. Modified sine waves, also sometimes referred to as modifed square waves can have different peak to peak voltages and different 'areas under the curve'. To which characteristic and why these devices are sensitive I defer to others.

<img src=http://www.fiberglassrv.com/board/uploads/3f1bce81e7f05i_sinewaves.gif/>

I suspect that the modified sine wave inverters are getting better because they parse the sine wave into finer rectangles, but I'm guessing here. I also suspect they filter their circuits better to reduce noise.

A second item is that less expensive inverters and generators suffer from a poor 'power factor'. (HUH?) We know that watts are equal to amps times voltage. Volts vary along a sine wave. Current also varies along the same 60 cycles per second sine wave. It turns out that if both sine waves are exactly overlayed, then the watts available is equal to amps time volts. (120 volts times 10 amps yields 1200 watts) But in poorer designed inverters/generators the voltage lags (or leads) the current. Thus, when the amps are at their peak the voltage is something less (120 volts times 7 amps yields 840 watts). Similarly, when amps are at their peak, the volts are lower (84 volts times 10 amps yields 840 watts). The math geeks tell me that the cosine of the phase angle difference is the power factor. A power factor of 0.7 is typical. I'm told that better sine waves usually, but don't always, have higher power factors.

The power factor loss is part of the reason why RV magazines recommend much larger generators than a simple summing of wattages would suggest and also why the Honda 2000 (sine wave) will operate our A/C's while so close to the generator capacity.

Oh man, even MY eyes rolled back on that explanation. :r What am I, a glutton for punishment?

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That's pretty good. It's further complicated by the fact that even the expensive sine-wave inverters often have little notches or ticks on the trailing edge of the peak or valley. These are readily apparent when you look at the output with a scope; but those minor imperfections aren't critical on the equipment we'll be using in our environments... So the more money you pay, the more perfect the sine wave. I have two 1000watt UPSes by different manufacturers. They both advertise sine-wave output. The one has unclean output with a fairly significant notch on the wave, and it weighs about 100 pounds with batteries. The other has almost perfect output with a barely visible notch, and it weighs 260 pounds with batteries. Same wattage, same capacity, but slightly cleaner output, and it costs 160 pounds. Open it up and there's a transformer in there the size of a goose.

Generators don't have this problem because they're motor driven. Of course the challenge with a generator is to regulate the RPM's so that you get as close to 60hz output as possible. This is difficult because, as we know when our cars are idling and the air-conditioning compressor turns on, the RPM's drop. The same happens with a generator when you turn on some heavy draw device, it puts a strain on the motor, the RPM's drop, and now your 60hz is down to 50 or 45 or 30 until the motor can get more gas fed into it.

Ok. I'm probably boring everyone now. I'm not an engineer, but I did sleep in a holiday-inn express last night.

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I think, but I don't know, that small generators that use inverter technology, like the Honda and Yamaha, to generate their AC are less prone to engine rpm induced frequency variation. That being because everything's being artifically, if you will, created.

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hmm.. that could be the case. I hadn't seen anything like that but it makes sense, bringing us back to the inverter output characteristics...

thanks.

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Huh?:m I think my brain just blew a fuse.:wak

I vote screen door.:chased

Dina (& Jim) Schulz

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I think that for what you are trying to do, a 450 CCA sealed car battery would have enough juice to run the lights all night and a 12 volt fan,(available at Wal Mart for $12.00.) Check out the batteries at NTB or Sams Club and get a heavy duty battery for $75 and install it in the jeep. The jeep alternator is designed to keep the spare battery charged which should not be connected to the main battery when the ignition is off. (At least on the old CJ it wasn't.)
There is a hot wire on the 6 and 7 prong plugs for running accessories in the trailer.
Put a 15/20 Amp circuit breaker (4 at Ace)in a protected area near the battery.Hook your hot lead from the plug to the load side of the breaker. Make a battery tap out of some 10 guage braided wire and crimp on ends to put on the battery clamp back to the input side of the breaker... It sounds more complicated than it is.
I just finished 17 days out to Oregon and back and the truck kept the Casita battery charged. We hooked up the fan to a bullet plug in the trailer at night when it was hot in Nebraska and slept well. It ran all night without depleting the battery.
I'm too cheap to buy a generator but the laptop has a plug adapter for the truck and trailer. Sam penny pincher. :o

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Orginally posted by Mark M.

We didn’t put much of a dent in the capacity. It still measured 13.5 volts before I put it on the charger when we got home. It took a full charge in just a few hours. I will know more when I take it on a longer trip, but so far so good.

Mark!

Please tell me that it is just an error and that it should be 12.5 volts instead of 13.5 volts. Otherwise, I give up trying to learn about battery!!:weep

I have never heard of a (non even full) battery at 13.5 volts. :shg

But I could easily be wrong!

Alain

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no, that's about right. I was trying to find a short on my truck last night and while poking around with my meter, discovered my battery was at 13.8 and thought to myself "well, at least it's not draining the battery with the ignition off."

An alternator charges at around 15V and it's not uncommon to see a perfectly healthy battery up around 14V fully charged...

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I have a defective WalMart deep cycle battery that will only charge to 12.4 VDC, but Wally's meter prints out "OK", so they think that's fine. My truck starting battery, also from Wally, charges to almost 14VDC.

Despite the lack of full charge on the deep cycle, I have gone several times for 3-4 weeks on it using only a few lights and running the fantastical fan for short times to exhaust cooking vapors. I use my small 12VDC flourescent light for reading, rather than a filament light.

Pete in the RatHaus

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We just bought a 13' Trillium 1976 and it needs a battery among other things. I wanted to mount the isolator in the battery compartment in the trailer. If I run a 8 or 10 guage cable from the truck battery to the trailer with a plug near the hitch and connect it to the "Alternator" terminal of the isolator and connect the positive of the trailer battery to "Battery 1" of the isolator would that not work? The isolator is basically a big double diode, but in this case I would only be using one diode. Does anyone see any problem with this? One thing that could happen is that the truck battery could be drained if it is connected to the trailer and there is a lot of load on the trailer electrical, like the fridge. Has anybody tried it this way? Appreciate any replies.<img src=http://www.fiberglassrv.com/board/uploads/3f22009088ba6Dscf0238s.jpg/>

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Phil and Dan

If you hook it up that way it seems that the female connector at the rear bumper will always be hot.It also seems that you could drain the battery in the tow vehicle,

I usually use a ignition switch controlled heavy relay at the battery so that I will only supply electricity to the trailer when the ignition is on.

Be sure to install a fuse between the battery and the relay. I use a 20 amp fuse. I am not in favor of a relay here because in the event of a short you will get electric pulses as the relay cycles.

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Not from my own personal experience, but from my readings on other forums, the best way to isolate is with a 12VDC relay under the hood (opinions differ as to whether this should be a relay designed for the purpose or a less expensive starter relay).

Problem with using a diode is that the voltage will drop 1/2 Volt across the diode. Doesn't sound like much, but there is a big difference in capacity between a battery charged to 13.0 VDC and one charged to 13.5 VDC.

Actually, one doesn't really need isolation of the truck battery unless one has something with high amperage, like a 3-way reefer that might be left in 12VDC mode, while the truck and trailer are connected.

Pete in the RatHaus whose isolation comes from disconnecting the umbilical cord

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Rathaus?

Pete - For what city is your trailer the town hall? The town hall in Nogales back in the late 60's was a trailer in the train yard....

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My previous Jayco is the office for a used car lot in the capitol city of Vermont (last I heard), but my RatHaus is NOT really a Rathaus, but rather a Rollin' Haus were I live with rats (a.k.a. Long-Tailed Norwegian Hamsters) as opposed to the kind of Rathaus one finds in Germany, Switzerland and Austria which are staffed with humans of the rodentia persuasion, much like our own various halls of politics.

Hope that clears things up,

Pete in the Rollin' RatHaus, currently not rollin' in Silverton Colorado, home of millions of flies...