From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: Re: AC/DC Power in an RV Date: Wed, 09 Nov 2005 14:26:56 -0500 Message-ID: <3th4n11po97b81qh54m3r1sggac3u7dasp@4ax.com> On Tue, 08 Nov 2005 20:56:33 -0800, altar wrote: >On Tue, 08 Nov 2005 19:22:19 -0600, William Boyd ><williamboyd@cableone.net> wrote: > >>I have been studying the power requirements in my RV and know I do >>not have adequate DC battery bank for boon docking. I have only one >>group 24 deep cycle and the standard converter that came with the >>rig. Would rather have at least two group 27s and add a couple of >>soler panels top side or on stands. With a three stage charger to >>help keep them charged. Am considering putting in the battery >>compartment an APS1000 Power Inverter by Powerbright. with a 30 amp >>adapter to plug in the RV power cord. >> >>http://www.dcacpowerinverters.com/customkititems.asp?kc=APS100012V-4AWG >> >>AC Power requirements are >>Electric blanket = 150watts >>10" ac fan = 66watts >>20" LCD-TV = 180watts >>VCR = 25watts >>Printer = 120watts >>19" LCD monitor = 84watts >>DT Computer = 70watts >> >>Of course all of these will not be running at the same time. >> >>Any more power requirements would have the gen set 2000watt or >>paralleled at 2000watts (actually rated @ 1600watts each) >> >>Any body have any ideas about my proposal? > >I had a similar setup in my last fiver. Several here suggested an >eu2000 and a Vector 1093. That's exactly what I did. And loved it. >In the mornings I would measure the voltage, and hook the charger to >the battery if necessary. Only took about 40 minutes, and voila! Back >in business. I'd go with the Vector 1500 watt inverter that Sam's Club has for $79. I have a couple and can say that they're the best I've ever had. One major feature to look for is auto-reset on fault. A manual reset unit requires that one at least turn the switch off and sometimes disconnect power. If you have a refrigerator or other important load running on the thing, disaster is in the wind. I had my older Vector trip more than once from overvoltage during charge and a couple of fridges' worth of rotten food was the result. I have several inverters in my rig. A 1500 watt one with a transfer relay to feed the house 120vac power, a 500 watt one (modified to auto-reset) just for the electric 'fridge and an old 250 watt one for the electric blanket. This provides redundancy and fault isolation against losing power to the 'fridge. The 1500 watt one will run the microwave or the coffee pot or the electric chainsaw, impact wrench or tire pump. I use multiple 12 volt Group 29 batteries in parallel - lower resistance and therefore lower voltage drop under load than golf cart batteries. As much as I like my Vector charger, I got really tired of having to manually turn it on - and having to have it accessible. I installed a 60 amp Intellipower/Charge Wizard on my rig and never looked back. The next addition is going to be a 12 volt voltage regulator for the house power. This device will hold the house power to precisely 13.8 volts regardless of the battery voltage. This will eliminate flickering lights when the pump runs and the waking up to the furnace fan just barely running from a dead battery. Jacobs Electronics makes a commercially available regulator but I've designed my own. I think the Jacobs unit is rated at 30 amps. These high power regulators have become popular for the boom-boom stereo types to keep the lights from dimming on big bass notes. >The only question mark would be the electric blanket. One battery >wouldn't cut it for the night. I've run everything else you mentioned >plus the furnace from one battery with the recharge regimen mentioned >above. Power to spare. The electric blanket load as far less than indicated. I use mine with another blanket on top. Even with the rig down in the 40s inside, the duty cycle rarely goes over 40%. Overnight with an occasional furnace run, I typically use from 40 to 60 amp-hours from the pack. Which reminds me, don't forget the E-meter/Link 10. While on the subject, I should mention that I've changed the charging architecture of my system while underway. Instead of simply paralleling the house battery with the rig battery while underway, I run the inverter from the rig electrical system and let that feed the Intellipower. This has several advantages. One, the house system always gets the proper multi-stage charge. Two, closely related, the battery is charged as rapidly as possible while underway. Three, the wiring between the rig and house is 120 volts at low amperage and so can be lightweight. An advantage on a MH. A huge advantage for a towable. The connection is simple. Separate the house and vehicle systems. Install a DPDT contactor similar to the one used in the generator auto-switches. These are rated 30 amps per contact continuous duty. Two contacts in parallel easily handle the 1500 watt inverter. Hook the moveable contact to the inverter, the normally closed contact to the house battery and the normally open contact to the alternator directly. Hook the coil to the ignition switch or even better, to an oil pressure switch. This can also be done with battery isolator solenoid contactors but two are required and a smaller relay to operate them. In this configuration, the inverter takes power from the house when parked and from the alternator when the engine is running. This is especially nice when you need to charge the batteries after an overnight park. I now frequently just crank the vehicle engine and run it at a slightly fast idle rather than cranking the genny. Similar fuel efficiencies, much less noise and with the emission system intact, none of the fumes. >I didn't have the luxury of the room for more batteries, or I would >have considered it. I've stashed three batteries around my rig in three different places. I've spotted a place where I can stick a 4th by fabricating a mounting bracket. All three are currently accessible. The forth will have to be dropped by a spare tire winch from a pickup. >After you check out the solar panel's price, the eu2000/charger combo >begins to look pretty good. It sure made me an energy waster. At least here in the East, solar just doesn't cut it. The sun doesn't shine for weeks at a time and when it does shine, trees and mountains do a good job of shading the good camping spots. John From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: Re: Help with selecting an Inverter Date: Sat, 30 Sep 2006 20:35:59 -0400 Message-ID: <e92uh2tskv73n9vf2alcg42ck821ge6sre@4ax.com> On Sat, 30 Sep 2006 10:34:39 -0700, Owlman <owlman@cox.net> wrote: >I'm the original poster, and I didn't give you the whole background on >my situation (didn't want to provide too much info). > >What is really happening here is that I already have a 2500W Xantrex >inverter on my unit (a 34' Sea Breeze). Ever since we got it, we have >never had enough lasting power while dry camping (once we got beyond our >first day with a really full charge). We have 4-6V batteries. We will >charge the batteries for, say, one hour in the evening, which gives both >our battery indicators a "full" charge (obviously not full, full!). If >we watch TV at all (not usually), go to bed and have everything off >except our 2 tiny nightlights and the projection clock, by morning our >battery level is either already in a "red" condition or it's marginally >"yellow"/good, such that if we have to run our microwave for a couple of >minutes, it totally depletes the charge. > >I have had 3 different RV or electric folks look at our arrangement and >can find nothing else that is drawing on our batteries during the night >and cannot understand how we can run out of juice so quickly. My >batteries (4 Trojan marine/golf batteries) are now 4 years old, so I >thought they might be running out of steam, but they still test well. >And this problem has gone on ever since we bought our new MH in 2002. This is the kind of detail that we need! There are several things going on here. First, your batteries are probably nearing the end of life. The only "test" that matters is that they're running down too quick. There isn't any test available other than discharging them and measuring the energy supplied that will accurately report the battery condition. Having them run down too quickly is a rough version of that test. Second, using that large inverter to run two night lights and the clock is like using a Hemi to run a fan. It works but not very efficiently. The Xantrex will go into a low power standby mode when all load is removed. In this mode the inverter comes to life every so often to see if anything draws any power. If it does then it comes out of standby and operates continuously. Those tiny little loads that you are operating are keeping it out of standby mode. Especially if yours is a sine wave inverter it will draw considerable power from the batteries at this low load. Several things you need to do. First is to get rid of those 120 volt night lights. If you really do need night lights then get or make some 12 volt ones. Single white LEDs would work nicely and consume less than a watt. If you must have a 120 vac clock then get the smallest inverter you can find to power only it. One of those 70 watt inverters built into an oversized cig lighter plug will do. Be aware, though, that it probably won't keep good time. I'm fairly sure that the Xantrex inverter's frequency is crystal controlled. None of the small inverters will be. You'll be much better off with a battery operated clock. If you need a light emitting clock then take a look at the ones sold for truckers. The big Barjan one that I mention in another post doesn't work very well but there are several other brands available at the large chain truck stops. Next, you must make sure that all load is off the Xantrex when you're sleeping or away. Either remove all the load or turn it off. That inverter is not really designed for boondocking. It's designed to let you pretend that you have shore power while traveling. For boondocking, the most efficient configuration is an inverter-per-load arrangement with the power switch for each load turning the inverter on and off. Each inverter is sized for the load. With this architecture when a load is off there is no inverter sitting there idling, consuming battery power. Since you have the Xantrex, you can use it for the microwave and other heavy loads. Simply get some smaller inverters for the smaller loads such as the TV, stereo, etc., and leave the Xantrex off except when you're actively using an attached load. Lastly, look at your batteries. Four year old batteries that haven't been actively managed are probably near the end of their lives. I've written several times before on load testing batteries so you might want to look at Google. Or if you don't want the hassle, just replace 'em. Only a couple hundred bux. John From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: Re: Is there a 2-way 'manual' switch to go between inverter and shore power for the TV ? Date: Sat, 16 Feb 2008 14:44:54 -0500 Message-ID: <1ncer3lroer1qgi54ldf9arbnvug0mv02l@4ax.com> On Sat, 16 Feb 2008 09:35:56 -0800, "Jepp_23" <Jepp_23@hotmail.com> wrote: >Lone, > >This sounds like a great solution. Where did you find the inverter? What >model is it? > >Jepp Trace Engineering was bought out by Xantrex quite a few years ago. Xantrex offers pretty much the same line of RV inverters under the Freedom brand name. http://www.xantrex.com/web/id/8/inter.asp Understand that we're talking apples and oranges. This type of inverter/charger is very nice but very expensive. Nearly a thousand bux for 1500 watts. http://www.oasismontana.com/Trace-DR.html (first google hit, not necessarily recommending) If you already have a good smart charger/converter in your rig then it makes little sense to spend that kind of money. 2000 watts of modified sine wave power can be had for (sometimes far) under $150. For example http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95596 I use this one http://www.samsclub.com/shopping/navigate.do?dest=5&item=179459 In fact, I use a bunch of 'em. I have one in my RV, another in my cube van, another in my car and finally, one in my house as part of my whole-house UPS (vital here where day-long power outages are routine affairs.) Sam's sold it for $49 for a long time. Then they raised the price to $79. In the Chattanooga store they finally remaindered the last few for $59 and quit carrying it. I cleaned off the remainder table :-) This is a sweet inverter. Maybe the most important feature is its auto reset feature. If it trips off because of a momentary under- or over-voltage on the 12 volt side or an overload, when the voltage returns to normal, it automatically resets and comes back on line. Many inverters stay tripped until manually reset. If you run a refrigerator on the inverter like I do, the result is spoiled food if you don't catch the trip in time. Let me chat a little more about auto vs manual transfer. Auto transfer is nice under ordinary conditions. You pull shore power and the inverter kicks in automatically. No muss, no fuss. However, that doesn't allow you to address some other situations. Consider, for example, you're sitting in an RV park when you detect an abnormal power situation approaching. Say, big dark clouds blowing up and thunder in the distance. Or the heat of the afternoon has set in and the park's inadequate wiring is letting the voltage sag too much. Or whatever. You're watching da big game and don't want to miss the end. You're in the RV park so you probably shouldn't fire off the generator. Inverter to the rescue. With auto transfer, in most cases, you're going to have to make a trip outside to either unplug from shore power or flip the pedestal breaker. With manual transfer, you simply reach over and flip on the inverter. If you unplug or flip the breaker to make the auto transfer work then you have no idea when the power is OK again. With the manual transfer and a voltmeter to monitor the shore power connection, you simply occasionally glance at the meter and when the voltage is normal, manually transfer back to shore power. Another example. In rural/mountaineous areas such as where I live and camp a lot, the power lines are long and frequently have poorly cleared right-of-ways. The result is that tree limbs across the lines is a frequent event. Many times the linemen will try to blow away the fault by manually restoring power. If the limb doesn't blow clear, this generates many very heavy surges. Even if the limb does blow clear, at least one big surge will occur. I've learned through the painful experience of many blown light bulbs, surge supressors and some electronics that the first thing to do when the power goes out is to hit the main breaker and run on standby power until the utility power comes on and is stable. I do the same thing in my RV. Manual transfer lets me flip over to inverter power when shore power goes out and then stay there until the shore power is back on and stable. Auto transfer, depending on whether there is a delay built in or not, may just connect back to shore power in the middle of a big surge. Both manual and automatic transfer have their happy users so if you go the auto route you'll probably not be unhappy. But with my utility background and very conservative nature, I like to have control over even rare events so mine is strictly manual. John |
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