Power Inverter Question

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  #1  
Old 05-21-05, 03:21 PM
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Power Inverter Question

I have an Old Fan travel trailer that I am restoring, and I just installed a new deep cycle battery for the inside 12 volt lights etc, The lites all work, but I cant get any power to the receptacles. Do I have to turn the inverter on somehow? could the inverter be bad? the inverter did have some fuses on it, that I checked and they all looked good. how would I test it? The inverter converts 12 volt to 120 volts, right? Any info would be greatly appreciated. RH
 
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Old 05-21-05, 08:31 PM
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If it is an older trailer what you will likely have is a 120 volt ac to 12 volt dc transformer.
They are set up usually with a switch that will allow you to plug in the camper to 120 volts ac to power up the 120 volt receptacles and the transformer to power the 12 volt lighting.
There should be a switch to be able to run the 12 volt accessories when away from power.
Some transformers would also charge up the battery but you will need to check the label on it to know what you have.

Post all the numbers on the transformer if you are unsure.
 
  #3  
Old 05-22-05, 06:27 AM
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Hey Greg, thanks for the reply, I just found the owners manual for this 1971 camper trailer, so it tells me that it has a converter, not an inverter, so when you plug it into 120 volts it converts it into 12 volts, and yes it also automatically charges the battery, whenever it is plugged in.
I plan on installing a 100 amp solar panel on the roof to help keep the battery charged up,and also couple of 12 volt cig lighter plug ins to run 12 volt stuff. I am looking at installing a 12 volt fridge, but I dont know if that would be to much for my deep cycle battery or not?? I am trying to set this up to be completely self contained, so when our power goes out again ( our power was knocked out for about 5 weeks) from the storms we are supposed to be getting, we will be able to use this as our "hurricane shelter". also trying to figure out a way to run some kind of AC and or fan for cooling this thing. It did not come with an AC unit installed. RH
 
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Old 05-22-05, 10:28 AM
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RH,

I know what you are trying to do and depending on a deep cycle battery is not going to work out too well.

The capacity of a deep cycle battery is rated in reserve capacity. This is the amount of time a battery can provide 25 amps at 80 deg F.
A typical deep cycle battery might have a reserve capacity of 100 minutes.
You can then take this number and use it to figure out how long your devices will run off a single battery.
If you have then say a single 100 watt at 12 volt bulb it would draw about 8 amps. 25 amps reserve capacity divided by eight amps to get the multiplier of 8 times the 100 minutes reserve, would tell you the 100 watt bulb would burn for 800 minutes which is about 13 hours.
A refrigerator draws more power than a 100 watt bulb so you can see that it may not be practical to use batteries.
Also, I'm sure you meant 100 watt solar charger.
A solar charger like this is only good for preventing a fully charged battery from self discharging.
This is not enough capacity to recharge a discharged battery.

What you really need is a generator that is sized to run all your devices with a deep cycle battery or two so that you could shut off the generator at night for sleeping and still have lights.
A propane camper fridge will keep your food cool and a deep freeze would likely maintain already frozen food if you were to only run it for 12 hours/day.

I would also suggest you forget about trying to run an a/c because even if you had a gen large enough to run it, you will be limited in how much fuel you can legally store.

It would be a shame to run out of fuel half way through the crisis.
 
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Old 05-22-05, 06:50 PM
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Yes, I did mean 100 watt solar charger, but you say that is not enuff for a small 12 volt fridge? how may watts would it take? I could get several 100 watt panels and , well maybe not, they are about 5 or 6 hundred bucks each!
Better to go with a small LP gas fridge. But I do have a 5500 watt gas generator, so I could do like you say, and run that in the day time to conserve battery power.
During the last storm, and power outtage, we used a borrowed generator for 2 circuits in the house, one for the fridge, and another for a window AC, a few lites, computer, tv etc. this worked ok, but the generator makes a lotta noise! And your right about storing fuel, and fuel might also be hard to come by around here, I could store maybe 20 or 30 gallons I guess. I was thinking about getting one of those big enclosed diesel generators that automaticly comes on when the power goes out, because they are much quieter, and fuel effecient, but very expensive! The had one at Home Depot, I think it was like a 30 K watts, it was about 6 grand.
So here we are at hurricane season again, at least I am trying to be more prepared this time around. Hopefully, we will be ready next time. I dont think I could take to many more storms like we had last year. might have to move back to West Virginia, 4 big storms one right after the other, and to think we almost moved to Nova Scotia, back in 1972.
 
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Old 05-27-05, 07:53 AM
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something off the course of the converter/inverter question.. you mentioned it was going to be your "huricane" shelter?... what kind of straps are you using to fasten it to the ground?.... fortunately I don't live with the threat of huricanes (knock on wood), but my thought would be to go underground...
 
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Old 05-31-05, 01:43 AM
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My two cents in the "for what it's worth" department... Solar panels are quite unreliable. I'm not an electrician nor am I an electrical engineer, but I have had my experience with batteries, engines and electrical systems. I am sure you can find it on the web, but there is an efficiency curve chart avaliable that shows how solar panel efficiency declines rapidly as the temperature increases. Most sales literature will present glowing stats at 72 degrees F, but here in Florida face it, a solar panel is going to be hot! And as such, they are quite inefficient.
 
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Old 06-04-05, 07:36 PM
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I didnt know that solar panels lose their effeciency from heat? My sister has a solar powered house on the desert in calif, and I know it gets hot there! They have had this thing for as long as I can remember, and it has served them well, as they have no other source of power.
As far as the hurricane shelter goes, what I am talking about is after the storm, that is, we will hopefully stay in our house during the storm, but after we lose our power, we will then move into the camper trailer until regular power is restored.
 
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Old 06-05-05, 12:58 AM
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Different type of solar panel I suspect. A solar panel that heats water for a swimming pool, for example, works quite well the hotter it gets. But it's still solar energy.

I used to manage a Marine Supply Store, and we sold solar panels designed to charge 12 volt batteries, on the 100amp area. Being the entirely too honest guy and not the typical salesman, I told the truth. The performance stated on the product literature was at optimum temperature, but the hotter the things got, the lower the amperage and wattage potential. It was quite the curve, producing signifigantly less electricity above 90-100degreesF. As I said, I'm only going from memory, and the fact remains that it was a good ten years ago that I ran this store and looked into it. For all I know, the technology has improved greatly since then...
 
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Old 06-14-05, 11:39 AM
FRANK C
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frankc

I surely would move from there I DID
 
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Old 07-08-05, 09:27 PM
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I see that this thread is almost a month old but with hurricane dennis bearing down on florida this might come in handy.. RH, Greg is right on about the battery thing.. BUT as I read your post this was one battery? What kind? group 24? 27? Only one? Irregardless of inefficency you will want a solar charger if you expect to loose power for any length of time.. I personally would want two batteries, group 27 if possible.
A propane fridge will keep your food and a propane stove in your trailer will allow you to cook, BUT the fridge will not work without battery power to run the circut boards! some old pilot light models are still be out there that would keep on chuggin without power but not the non pilot light models. Your lights are going to draw more or less about an amp per bulb so be sparing with them if you are going to be without power for a long time and relying on your batteries. Remember your solar panels will have to replace what your take out of the batteries so keep that in mind. Amps X volts = watts. So 100watt solar charger is just over 8amps max charge (minus any load) under optimal conditions.
It is possible in a pinch to use jumper cables and your car or tuck to charge the batteries. Hooking up to the car or truck as if for a jump. KNOW This if you try this!! The alternator is not designed to run a vehicle and charge dead batteries at the same time! It may do it but it could cause it to fail. A dead battery is a very large amp draw for any alternator. Many a alternator has died under the load of a dead battery. So This is a "must charge" last resort.
A 20 or 30# cylinder of propane will last you a long time if you only run a refer and a stove with it. Remember as well that a propane refer is an absorbsion refer. it has no fan to move air about inside. it has no compressor. it absorbs heat from the ice and refer boxes through convection currents to its cooling surfaces, it takes longer to cool down and longer to cool back down after you open the door and or place items inside. this may seem trivial with how well many of these refers work, but if you are going to be relying on this as your only shelter and you have no A/C you might be getting into it too often and cause the temp inside the box to get higher than you would like.
I hope this all makes sense. If not let me know.
Eric
 
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