Sometimes small systems are plenty

[HiTech]

Friday my wife suddenly got the urge to camp. Immediately.

All the TT has is the original Group 24 battery, 5w solar to maintain it and a 700w/1500w inverter I've never even run under significant load. I didn't really need the system to do a lot since at 103 degrees in full sun we will be absolutely doing full hook ups.

Fired up the fridge at 8 am on propane. Pupmed the over chlorainated full water tank almost dry to be ready for use. Ran the compressor from home on the inverter to air up all 4 tires and headed to work.

At noon the freezer and fridge were cold so she loaded but did not even run the fan as the camper still held the cool from overnight.

1:05 PM we headed out for Fredericksburg and wine country.

The current set up is barely above factory, but the battery was brimming with charge and the inverter did everything we would have wanted except for the AC.

I actually think it is the ability to use the microwave that will finally push me to get the Deka AGMs put in the TT. Putting them in will mean i pit in the solar charger to maintain them without cooking the, dry or leaving the discharged. Other than the microwave though, there is just no burning need for us at the moment.

Now if I went crazy and got enough batteries and inverter to run the AC for an hour 15 times a year, that would he a horse of a different color.

😉

Jim (sipping a nice glass of 2010 Brennan Dark Horse)

[Almot]

Mena, some people live in their RVs. Talk about "necessary".

Yes, 120V rig without a generator is a dream, meaning - fiction. Can be used with shore power though.

Expensive 12V pump? Slow, yes. I think paid $12 for it in "Crappy Tire" back in 1999 or 2000. Probably expensive, considering inflation. I think it still costs under $15 in the same store. Don't need more than 40 psi in my tires.

Yes, Mr Wiz is fulltiming offgrid with 120V frig, - with a generator.

BFL, I wouldn't make anybody drink kool-aid, this is inhumane.

[mena661]

I don't consider a RV a necessary item LOL!!! You're killing me Almot! :B HiTech, 120V only would be a dream rig thing for sure. O&S, I think those electric-only rigs still have 12V just no propane. Not sure though.

[HiTech]

In the Class C forum we used to get discussions about 12v compressors. When you have enough amps of 120v to run a real compressor and compare it to the expensive slow 12v units side by side, you will never go back.

Jim

[BFL13]

There will be no movies until morale improves!

Mr Wiz is full-timing off grid with a 120v res type fridge. It has to do with the cost of a replacement RV fridge, vs the cost of a similar cu ft size res fridge, and not having to go get propane so often when there is no supply nearby.

I used the 120v air compressor last week when we took the trailer away from our seasonal site for a weekend trip. I had to boost the back tires on the truck up to towing weight pressure from non-towing pressure. I tried one of those 12v kind that was in an emergency kit we got somewhere--what a farce! It just handled the trailer tire pressure (50lbs) before it ate itself. Good luck with the truck back tires at 80lbs 🙂 Ran the air compressor off my oversized inverter.

Hope Mr Almot won't make me drink that Kool-Aid for doing that! 😞

[Old___Slow]

"Sometimes small systems are plenty",

Honda, Bring back the 'QUIET' small gen. the 650!! Please.

The big new rigs, from what I see are 120v only.

O&S

[Almot]

12V TV - yes, a problem.
Mostly, my rant was aimed at oversized 120V inverter systems that so many campers consider crucial. Small 200W inverter will take care of 120V TV. Again... I don't consider TV a "necessary" item. Not something that you must have or would suffer enormously without it, like without AC in 105 weather. A short break from a week of watching news and stupid shows won't hurt.

120V fridges have made their way into hookup-only campers. Relying on it in offgrid situation would be a disaster. In theory, there shouldn't be that much difference in efficiency between 12V and 120V fridges, given same size and insulation, but in reality 120V frig is too much burden on battery. Partly because they are big (usually), partly because compressors made differently than in 12VDC. Plus, inverter losses. 12V or 48V bank - doesn't matter, you still have to invert from DC to AC.

Air compressor? Don't remember when I topped up my tires the last time, definitely not something to do every day, and small noisy 12V pump works well enough.

[Old___Slow]

Jim,


Yes, yes & yes.

[HiTech]

No it was a great test.

I'm talking about essentially no 12v systems (probably would have to keep brakes and exterior vehicle lights). Use 120v interior lights, 120v fridge, 120v control boards for electronics, 120v furnace fan...etc. so no need for a converter. Just a way to charge the battery bank that runs the electric brakes and the inverter.

This would even allow for a 24v or 48v battery bank. For emergency brake use just tap a single 12v, since hopefully use would be infrequent to 0.

So you'd have a native 120v RV instead of a mixed 12v/120v RV.

Jim

[mena661]

BFL13 wrote:

Did you miss the test I posted the other day on inverter powering converter no loop? (sorry can't link it right now due to shortage of internet data time at the moment)

Here you go BFL.

Inverter Powering Converter No Loop Test Results

[BFL13]

HiTech wrote:
.............

I could actually see an RV that just bit the bullet and ran non-regulation-mandated systems via an inverter and 120v only. I wonder how bad the inverter and other losses would be if designed specifically for this service...

Jim

Did you miss the test I posted the other day on inverter powering converter no loop? (sorry can't link it right now due to shortage of internet data time at the moment)

[mena661]

X2 12V TV's suck and I have yet to see any outdo my 26" Vizio at 20W (yes that's 20 watts). It's MUCH easier to run 120V in my rig as my entertainment systems run on 120V. Converting those items to crappy 12V versions is an unnecessary expense with no gain whatsoever. Simpler and cheaper just to wire in a 300W inverter and use what's already there. A bit off topic, RV's are toys and everything about them is unnecessary. What difference does it make how you camp? One is not better than the other. I mean, I can waste a few hours telling you how "wrong" you are (I LOVE to argue!!) but why should I. Neither way is right and everyone can use their rigs however they damn well please. Almot STOP telling me how to use my rig!! Get off of it already!

[HiTech]

Yes it did everything we wanted to prep for the trip in the unpowered storage lot except the AC. The principle does apply to short trips with small systems too, or long trips with really good conservation.

I do prefer 120v. For example I have never ever found a portable air compressor in 12v that i really like. I have had quite a few bad ones, and a few fair ones. None I have had could keep up with just your average portable tank compressor. So much faster topping off the tires.

12v TVs stink for the most part. Love 120v entertainment systems better as a rule though you can get great 12v audio systems. 120v residential fridges have really made inroads into RVs.

I could actually see an RV that just bit the bullet and ran non-regulation-mandated systems via an inverter and 120v only. I wonder how bad the inverter and other losses would be if designed specifically for this service...

Jim

[Almot]

HiTech wrote:
O&S it is 106 degrees out. Seriously no interest in not having the AC on. Spent most of our time outside, but once you feel hot and want some AC, nothing else will do.

I can say this again - AC is the only necessary item that you can't have without genny/shorepower. Everything else can either be removed without physical suffering, or run on 12V. Dry foods have now more to offer than just dry fish, and LED lights run forever. Though, there isn't much need in dryfoods when you have either propane fridge or 12V fridge + more solar. In the initial post - long forgotten since 🙂 - somebody wrote about a small 5W system that could run inverter (on a short trip with batteries pre-charged) for "everything we would have wanted except for the AC".

HiTech wrote:

If I had been able to order appliances that could run efficiently from propane for hot water, fridge and heat, I would have gladly paid the energy loss of an efficient small inverter to not run any 12v.

It's easier to not run any 120V, because AC is the only.... etc etc. If you don't need AC on some short trip, then you don't need 120V. People fulltiming in their rigs is a different story, they need power tools or small appliances like vacuum that you can leave home for a day or two, but not for several months. Weekend warriors can live without 120V (unless they need to run AC), the problem is - they don't know how and are not too willing to learn.

[BFL13]

I have limited internet access right now so can't waste data time looking up stuff. But ISTR we did all this last winter with extensive low voltage tests and excellent comparative data and the AGMs won by a mile on the low voltage issue.

IAW the AGM stayed above inverter alarm 11v for way bigger loads per batt capacity than my 6s, and ISTR any 12s too.

4-6s do give you the ability to handle your high loads when down near 50% SOC, where ISTR from previous tests 3-12s would do the same (but you can't have three 6s) so kind of "not proven" (as in Scotch law)

I would rather have 6s than 12s and I would rather have batts I can use an hydrometer on, so that solves that for me. There are all sorts of good reasons for an RV to have AGMs (side mounting, tongue weight, etc) but not my concern, thank goodness.

Point is we already did those tests.

[full_mosey]

HiTech wrote:
You can get the info from the discharge curves for the battery. My East Penn Batteries match the factory curves well (even outperfom them a bit). No idea if there is a BCI standard for this. Seems like many tests end at 10.5v


Jim

The CCA test ends at 7.2V. That is useless in evaluating how long a constant Wattage inverter might run until LVD. The RC tests use 10.5V, but then again, that is a constant current not a constant Watts test. Same problem, but at least the Volts are closer to LVD.

We need to run our own tests.

HTH;
John