vector 1000W inverter?

[Steve L.]

Flooded lead acid. That was the phrase I was looking for.

I had heard that AGM batteries were originally developed for the miltary and jet fighters. The acid didn't spill out while the plane was inverted. Perhaps urban legend, none the less, keeping my trailer upright is a price I'm willing to pay to use the flooded lead acid technology.

Only when I buy a fully aerobatic trailer will I consider Optimas!

[Brian B-P]

...Only when I buy a fully aerobatic trailer will I consider Optimas!

Good plan. When you do, please post action photos! My own aerobatic trailer plans are even further behind than my amphibious trailer plans...

But seriously, Optimas and other AGMs are popular among off-road enthusiasts, who don't usually go inverted but do get to some extreme angles. At least a couple of our members have taken their eggs off-road, and that might be a example of a good trailer application.

I was trying to figure out how to pack batteries under the floor of my Boler, and laying sets of Optima 3-cell 6V AGM modules on their side was a possibility (which I have not pursued).

This still doesn't help Drew power his heater, but I think that's a lost cause regardless of the battery construction.

[Pete Dumbleton]

The guy with the big inverter in the glove box of his Wrangler had it strictly for his coffee pot; he was a part-timer, traveling to Colorado from Florida for half the year, writing books and articles about mining in Colorado.

Bigger inverters cost more in overhead energy used, indeed.

There's no particular advantage to the Optima battery in this application, in fact it's likely less -- The Optima usually has fewer amp-hours available than the equivalent flooded-cell and is a dual purpose (starting and deep-cycle), rather than a true deep-cycle.

[Bob Cupp]

The advantages of the older "convection" heaters. My Love Bug has the original convection heater in it and I love it. I have camped in the LB at 0 degrees F and it stays at about 55F inside. As long has I have propane in the tank, I have heat. During deer season this year my LP tank was used 7 nights and it still has gas in it. The heater is only 9000BTU's so it is not very big. We used our old pop-up camper for 17 years in all types of weatheer, it has a convection heater in it also. These heaters have an outside air intake, direct vent to the outside and use no electricity. The ultimate answer for boondocking. I even picked up an extra heater for the day when my old one bites the dust.

I am a safety freak though, I ALWAYS have a CO/smoke detector on board.

[Steve L.]

Bob,

What brand heater is it? I've not gone the Olympia catalytic route because I don't have a good spot to mount it. If your unit could be made to fit the space where my Suburban forced air unit is, I'd be on it in a minute.

[Bob Cupp]

Sorry, My heater is not for sale. Just explaining the type for anyone not familiar with them.

[Steve L.]

Sorry, My heater is not for sale. Just explaining the type for anyone not familiar with them.

No, I'm not asking to buy YOUR personal heater. I wondered what brand it was so that if it were still manufactured I could research it as a possible purchase/mod to my trailer.

[Brian B-P]

...I've not gone the Olympia catalytic route because I don't have a good spot to mount it. If your unit could be made to fit the space where my Suburban forced air unit is, I'd be on it in a minute.

If the current Suburban is (like mine) the typical fan-forced units in the format current sold as the NT series, I think the search for a fanless unit to fit the space is hopeless. A radiant design would have insufficient radiating area, and likely be facing the wrong way anyway. A natural convection design would need more height for the convective effect (a.k.a. "hot air rises") to work well. I believe that the natural convection furnaces which were sold in some Bolers (not mine, but Chester's I think) are substantially taller.

[Pete Dumbleton]

Steve, I recall seeing a clever Casita owner's mounting of the Olympian on the INSIDE of one of the kitchen cabinet doors, a relatively unused space -- Open door and the heater is deployed!

[Chester Taje]

(I believe that the natural convection furnaces which were sold in some Bolers (not mine, but Chester's I think) are substantially taller)

Yup mine is taller and works like a charm.No fan and heats the unit real well.

[Steve L.]

One member mounted the Olympian to the bathroom door with a quick release gas fitting. However, as I grow older, a midnight trip to the "head" are a regular occurance and I like to keep the door open to let heat into that area.

I considered the optional legs so that I could set it on the floor but I worry about tripping over it in the dark.

Setting it on/in a cabinet door would seem to pose a similar problem with brushing it in the dark and, at best, singeing the hairs on my legs.

Must be time to dust off the ol' "circulating the hot water for baseboard heat" threads again.

Oh well, a brief flicker of hope for the perfect, low-to-no amp consuming cabin heater.

[Per Walthinsen]

Perhaps I should chime in here, because I use a Xantrex Link 10 battery meter which tells me exactly what is happening when you add a load to the batteries.

Over our dinette there is a conventional light fixture with a 14w compact fluorescent bulb in it (60w equivalent), driven with an old inverter, hardwired (150w, no fan, and no noise).

With no load on the inverter it wastes <.1 Amp (1.2 w). When the 14w bulb is added the total usage is 1.3 Amps or 16.38 watts which means about 2.4 watts is wasted in the inverter. I'm using an arbitrary 12.6 volts as a ballpark voltage level from the batteries.

I'm happy with the equation since I'm getting a 60w light level from a total of 16.38 watts.

Brian: I tried the 12v compact fluorescent bulb. It burned out in very short order. I'm guessing that my old Newmark converter messed up the 12v so badly that it fried the ballast. If I tried it again with the Intellipower unit now installed it wouldn't surprise me if a similar bulb would soldier on indefinitely. Much more expensive, however.

[Brian B-P]

Per: thanks for the heads up on the 12V CFL. My converter is the original 1979 unit, and the output may be very noisy (I haven't had a chance to put any useful instrumentation on it), which I agree might be hard on the integral power supply in the CFL when on shore power. I guess we'll find out... and maybe I'll make a point of reserving it primarily for use on battery power.

[Brian B-P]

... a conventional light fixture with a 14w compact fluorescent bulb in it (60w equivalent), driven with an old inverter, hardwired (150w, no fan, and no noise).

With no load on the inverter it wastes <.1 Amp (1.2 w). When the 14w bulb is added the total usage is 1.3 Amps or 15.6 watts which means about 1.6 watts is wasted in the inverter. ...

This makes sense to me, as the smaller inverter has smaller idle consumption (compared to a 1000W unit), and a similar loss of about 10% under reasonable load.

I think the lesson is that if we are going to convert power through extra stages, we should at least try to match the inverter to the load. As I recall, other members have come to the same conclusion, using a collection of variously sized inverters for specific purposes. I have yet to use my 1000 watt inverter, and had only planned to use it for high loads of short duration - that's still the plan.

[Per Walthinsen]

Before someone with sharp eyes calls me on it: I copied my notes incorrectly. The correct data are now in my post. Doesn't change the overall picture much.

The little Xantrex inverter may be a little long in the tooth, but I appreciate the lack of fan noise. Since it is hard wired I have a conventional house light switch controlling it which makes it easy to use it only when needed. Watch some of the later units, because I have found some which require a push on the casing to get it started, meaning no remote operation possible.

[Brian B-P]

I've seen some inverters in stores which can be remotely switched, but you need to wire in a switch to remote control terminals, not just turn the supply of 12VDC power on and off. The Xantrex Prowatt 1000, 1750 and 3000 series is an example, although not exactly the one I have seen.

It does make sense to me to be sure that the mounting and wiring method makes it easy to turn the inverter off when it is not needed.

[Pete Dumbleton]

Why use either? I put in one of those small 12VDC fluorescent fixtures that take either a connection to 12VDC or internal AA batteries (last I saw, the lights are $10 at Wally; also seen at home improvement stores as closet lights). I mounted mine right next to the Bargman light fixture and picked up the power lead from inside the overhead cabinet.

I don't know how much they actually draw, but I can go for weeks on my deep cycle battery using that light for my night time eating and reading.

Most expensive thing about it is the replacement bulbs, costing almost as much as a new fixture.

[Brian B-P]

Certainly, an inverter and a AC-to-DC power supply in the appliance (such as a lamp) have losses, so the efficiency of getting power to the end device by this method is less than the efficiency of connecting them with just a wire.

We got here because the comparison was between using 12V-specific fixtures, or making use of 120VAC fixtures... and if the 120VAC stuff is a lot more effective (e.g. fluorescent) than the available 12VDC sutff (e.g. incandescent light bulbs) then maybe all the inverting and converting can still come out ahead.

I think we all realize than in an ideal world we would stop by WalMart and pick up a high-efficiency LED or CCFL lamp designed for 12VDC operation for the same price as a household light bulb... but the world is very far from ideal. It does offer many opportunities for creative thinking!

[Pete Dumbleton]

Umm, I believe the RV manfs use the incandescent bulbs because, in part, they always have and why mess with it, but mostly because they they don't have to mess with supplying an inverter (cost and complexity) -- They really don't care about power efficiency, just bottom-line assembled costs and follow-up repairs -- Helps sell RVs if they are brightly lit inside in the showroom.

I would **guess** that a 120VAC fluorescent lamp powered by a standalone inverter (I can certainly feel the waste heat and hear the waste fan) would use more energy for an equivalent amount of light from a 12VDC incandescent bulb (also lots of waste heat), but I would also **guess** that my 12VDC light uses less energy than either of the two.

Indeed, it does help to replace the original incandescent bulbs with lower wattage, same base, versions -- At one time, one of the Yahoo Scampers had a table of equivalents (like the #93 in place of the #1156, etc.) -- No doubt the RV parts manfs equip the fixture with the brightest bulb, not the most efficient one.

[Rich]

Hmmm, something seems fishy around here...