Are there any RELIABLE, low, light, Roof, electric AC's/heaters on the market

[breeze]

Camping World

Feedback on Camping World was 2 - 1 of 5 reviews, and their phone help was even less information (they will say anything - ??)

It may just be an unreliable design compared to standard car or house ac units; but it sounds like a space saver if it goes significantly longer than 1 year (which was 2 out of 2 of their only feedback responses!)
:-/

I guess I'll ask my Commercial Nissan dealer, but if anyone has any leads on the subject, ... I'm running out of floor space

 

[highdesertranger]

mounting a heater on the roof is the most inefficient place to put a heater. notice how it says for 40 degrees or above, heat pumps don't work good below 40 very inefficient. highdesertranger

 

[Almost There]

What type of camping lifestyle are you envisioning for yourself.

That unit is a 120V unit that will only be functional if you're either plugged in to the grid or running a fair sized generator whenever you're using the unit.

Keep in mind that that item is the outside parts only AFAIK, you also need to order the inside section separately.

Most of us who boondock do without a/c and use a heater like the Mr. Buddy for the occasional times that heat is needed. We move with the weather wherever possible. That said, I'm sure glad I have my Mr. Buddy for these cools evenings and mornings here in the desert....  

If that's what you really want, then shop around, CW is known for their high pricing structure, you might find a much better deal at another RV dealer. The unit is made by Dometic, a very major manufacturer in the RV industry so I wouldn't worry too much about quality.

You'll probably be able to find better technical specs on it directly from Dometic on their website.

 

[tx2sturgis]

Google:

"Coleman Polar Cub"

and/or

"Coleman Mach 8"

They are for smaller campers, trailers, vans, etc. 

The cooling capacity is a bit less than the bigger units, the upside is they pull fewer amps. 

I have never used one, so read all the reviews before pushing a 'buy' button.

And FYI: there are two kinds of RV roof ac-heater combination units:

Heat pump style and heat strip style. 

They BOTH use a considerable amount of power when outside temps drop below 50, and especially below freezing, and will only be economical IF you are hooked up to shore power at a campground or RV park. You do NOT want to try to heat with them on generator power all night, every night, all winter long...but maybe for the occasional cool night when traveling or boondocking.

 

[Stargazer]

Highdesertranger is right.  My Class B has a heat pump (different brand).  In the owner's manual, it states when the temp gets to 40 degrees, it shuts off and will not come back on until the temp gets back up to 45.  I can say from experience that this is exactly what happens.  When it's below 40, one needs to use a different heat source.

if you are in an RV with a propane furnace, the battery will most likely not provide enough power for the furnace blower.  The generator will but it seems the time when you want to use the furnace is late evening and early morning when it would be most disturbing to others.  Therefore, I carry the Mr Heater Buddy.

 

[breeze]

I was mainly looking for AC by using dual alternators to charge li-ion batteries; which 2nd high output alternator (Nation's) is almost 10 fold more efficient than solar charging (under perfect conditions). I'd still have maybe 3 solar panels, but would not rely on them for the bulk of charging when alternators are so much more efficient.

https://www.thefitrv.com/rv-tips/how-much-solar-do-i-need-on-my-rv/

 

[tx2sturgis]

Alternators are certainly productive, but it takes power from the engine to run them, and that power comes from fuel. 

Alternators are about 50-80% efficient, on average, but the engine that provides power for this is about 20% to maybe 40% efficient.

It all depends on what you are trying to measure, and what result you expect to see. 

Also, you have efficiency losses during battery charging, then losses when re-using the stored power thru an inverter to run the AC/heater.

It's all going to be expensive, complex, and failure prone. The least expensive and most efficient way to provide cabin heat when off-grid is burning fuel like propane, and the best way (without large solar arrays) that we have now to provide AC when boondocking is to run a generator to power an AC unit. 

Of course if you super-size the solar array, with plenty of surplus power available, and plan to do this for years, then solar powered heating and cooling can be a usable, and 'efficient', option. ('efficient' meaning lower on-going costs).

Not saying your plan won't work, it probably will if done correctly. But it will be expensive and will involve a lot of driving. Your idea is very similar to many anti-idle cab heating and cooling solutions in the transportation industry. 

Them aint cheap either!

 

[John61CT]

Ya forget theoretical efficiency numbers, look at dollars and cents practicality.

Alternators off the propulsion engine are very rarely a significant enough source of energy to justify the cost of beefing them up. Unless you drive for hours every day, and even then it's LFP that really makes sense, will cost thousands.

A little quiet portable genny usually makes a lot more sense, and combined with as many solar watts as you can fit on the roof, maybe a shore power charge overnight once in a while, you don't need to go LFP.

 

[breeze]

OK, the heater idea was half-baked. I knew about the efficiencies before, but I forgot (doah! no need to keep bantering the heater subject.) AC components were the 'main' intent for the inquiry. I'll do what Bob does with the propane oven for heat Thanks for the reminder and suggestions!!

180 a/hr (Nation's 2nd gen) is all the math I need to know: infinitely better efficiency than solar AND lead acid batteries and about 25% the weight with 1% the maintenance hassle and .05% the maintenance risk. ** 1 hour/day generator run for 5 hrs ac? Look at the alternatives, sitting in the Sun for solar at a small fraction of the efficiency (duh!) Please don't suggest all efficiencies are the same: they are not. Sample realistic estimates are multiplied together would be more realistic. In reality, there is an ultimate 1,000 % efficiency difference between the alternatives, and that my friends it the difference between reality and never realizing any goals (except profuse sweating, or living in sticks and bricks, or chasing the end of the rainbow.)

Did anyone read the article? It was the holy script of camping lifestyle, and it took me reading it over and over over weeks time to sink in. My camping lifestyle will have nothing to do with nasty fidgety heavy lead-acid batteries or their time absorbing risky maintenance. As a past value engineer, you have to look at all the probability trails of alternatives (multiplied times EACH other getting smaller and smaller!) The lead acid trail is doable, but not self-sufficient: again read the article. The probability trail of lead acid would end up in single digits if not a fraction of one: that's what happens in sequence probabilities of unreliable systems. Lead acid batteries is just a 'cash-cow' for the rich taking advantage of the public, imo, from studying philosophy and business for the last 2,000 year focused period. I have been an engineer in the battery charger industry for several years, and it's dirty business top to bottom.

Yeah, everyone's different, but I've worked around batteries in high school: no more. If your time is not worth anything at all or carries a negative value, fine: time is my final resource. Again, read the article (3 times is not too much, believe me.) Making the end's all meet is another thing, but knowing your goal from a value engineer's perspective is priceless. Bob is the guru who laid the foundation, but this is the anti-early-nineteenth century lead acid battery solution. Quit being distracted by disjoint minutia ideas spouted by the battery industry (that's all they have left.) Yeah, one time costs for a single component is advantageous, but the battery industry would give batteries away to hook lifetime customers to an obsolete technology (it just keep balooning up requiring unrealistic expertise that is never attainable to make lead acid batteries even work! - $,$$$.) What else do you have but this ONE comparison? All negative value factors that exponentially changes the cost/benefit structure.

And just one more time, please read the article I posted above. That is the ultimate rv lifestyle. Of course I replaced his Winnie with a Nissan NV 3500: it's all I could afford, and rv's cannot be near the quality of the Nissan NV from my surveys. Do what you like, but lead-acid batteries were a feeble idea in 1900 to keep the cash cow fed, along with oil. And ALL-solar to replace ALL-lead-acid battery is only a partial solution, and can NEVER be a total solution by itself: more lead-acid battery-industry sucker-suggestions imo. Drive Safe!

 

[Ballenxj]

The first place to start looking when considering a smaller A/C to draw less power is your insulation, and that includes windows. The better insulated you are, the less power your unit will need to draw.

 

[John61CT]

https://www.thefitrv.com/rv-tips/how-much-solar-do-i-need-on-my-rv/

I see nothing new to me there.

Yes if you are

driving on a very regular basis, and

willing to spend thousands on a good and large LFP system

then a high-output alternator setup

(**if** your vehicle can be so adapted, very much harder with new Euro-style high-mpg designs)

can deliver all the power you need.

Is that what you're on about?

It may even be worth the wear and tear on your propulsion engine to generate while idling, but I would only recommend this approach if you're driving many hours per week.

How do you figure one hour charging per 5 hours of aircon? Please show your work.

And what is special about that Nations alt?

Have a look at Zena, and there are CEN units that put out over 10kW from a single unit, go for $4-500 on eBay NOS.

To me Eco-Tech is the best, 200+A at 1800rpm, they'll tune your charging profile to your specs, excellent post-sale support.

But all said and done, a quiet pair of paralleled eu2000i IMO delivers much better flexibility and value engineering.

 

[jimindenver]

There is a 12v 9000 BTU roof air that pulls 600 watts and runs just under $2000. I use a 5000 BTU window shaker mounted in a cabinet that pulls 410 watts. It can run all day off of my solar system without affecting the batteries. Then again you will have issues getting that kind of wattage on a van. It is possible with the right panels but that does not do anything for you at night.

In the short run a small inverter generator to run a smallish AC can make sense due to the simplicity and limited up front cost if you can do without the very best. A 2000 inverter generator can easily run a 6000 BTU window unit pulling 500 watts or even the 9000 BTU roof A/C mentioned above.

 

[John61CT]

Note that Jim's most excellent advice above is **not** talking about running the aircon off batteries, but from an active power souce that you would also use to charge your batteries, likely not trying to do both at the same time.

LFP lets you get the bank charged up very quickly if those kind of amps are available, but the AH capacity you'd need to feed aircon **without the power source running** overnight would be massive, as in many thousands of dollars, probably a $10+K system done properly.

Also, compressor startup amps is much higher than continuous, so you may want to check out capacitors, "solar maximizers" so you don't need to oversize your power source as much.

 

[John61CT]

On that last note, some kombi style inverter/battery chargers have a "power boost" feature, that will when needed combine the available genny/grid power and supplement with power from the battery bank to handle short-term startup and surge loads.

So switch between charging to the bank or drawing from it dynamically as needed.

Not cheap, but they let quite large aircon or other huge-amp shore-power loads be carried by muge smaller (quieter fuel efficient more portable) gennies, so well worthwhile for some situations, including when you'd otherwise be blowing circuit breakers at an inadequately wired campground.

 

[jimindenver]

I am packing up today and decided to try the Sportsman 800 watt inverter generator running the new 5000 BTU window shaker that replaced the old one that drew 450w. The Sportsman could not start that older A/C possibly due to age but it started and is running the new one just fine. I am thrilled because it gives me the after dark solution for my A/C needs and should run it for 5 or 6 hours on .6 gallon of gas too.

 

[breeze]

whoops!

 

[breeze]

How do you figure one hour charging per 5 hours of aircon? Please show your work.
*180 a/hr/5hrs = 35 a/hr for ac

And what is special about that Nations alt?
* They are the ONLY SECOND alternator ADVERTISED for rv's (and NV3500's too

** In AC's it IS or it Ain't. My  oem 130 A/HR alt. on Nissan is perfect, and since this is the ONLY second alternator (at 180 a/hr) it IS and does support ac breaks when required while parked. That is all the relevant math required. You can probably wash and dry a load of clothes too on that generous estimate of 35 a/hr for ac estimated average for 5 hrs (the all in one wash dry machine for van space), but I have not got that far yet.  :-o

 

[John61CT]

OK, I've gone back a bit, and think I'm understanding more, please correct or clarify.

You have a Nissan NV3500, which comes with a stock alternator rated to in theory produce a maximum 130A.

You want to fit a second alternator as well, and believe the Nations 180A version to be a good choice (it certainly is not the only one, nor the most powerful)

You plan to leave the original factory alt alone, dedicated to the vehicle requirements.

You plan to buy an LFP system, how many AH in size?

> 180 a/hr/5hrs = 35 a/hr for ac

Note a/hr looks like you mean amp-hours (AH), while I assume you just mean amps.

Also, a normal 180A alt will likely only output 120-140A, and is likely to overheat pretty quickly at that rate even while driving, cutting output drastically. Very few alt can actually put out near their rated output for more than 15-30 minutes, and will do far worse at idle.

Maybe the Nations can, I don't know, but I would make sure before buying one.

In order, to properly charge LFP from an alt, it will need to be converted, to use an external voltage regulator, ideally the Balmar MC-614, so the voltage setpoint and charge profile can be custom adjusted.

I don't know if the Nations alt is suitable for that.

OK, assuming you overcome those issues, and can put 120A into your LFP bank, hypothetically 500AH in size.

You say your aircon unit draws 35A (450W?), let's say you want to use it 10 hours per day, so 350AH per day. There will be some inefficiencies, especially with an inverter involved, so let's say 400-450AH per day to be conservative. You may need a 600AH LFP bank.

So 3-4 hours of driving will supply enough energy for ten hours of aircon.

Parking and idling the engine to try to charge tgat much would be very expensive, foolish IMO.

 

[John61CT]

I'll repeat:

A little quiet portable genny usually makes a lot more sense, and combined with as many solar watts as you can fit on the roof, maybe a shore power charge overnight once in a while, you don't need to go LFP.

 

[breeze]

A 420 a li-ion (dedicated house) battery fully charged should supply more than a couple of man-shift-weeks (or 10 ea, 8 hr shifts) of ac no problem. (3) Solar panels would slow the usage rate of the battery down, and then there may need to have electrical hookups and/or run your 180a alternator (at 8x the max rate of Solar charging, rain or shine) randomly and/or periodically to replenish the fully charged battery. 1 trailer park day per month (or per couple of weeks) to fully recharge, fill water tanks up, and clean the pooter out does not sound too unreasonable with quality battery monitor gages. Monitoring 'one' hi-tech 65 lb. li-ion battery is not going to be anything similar to monitoring 500 lbs. of 50% capacity lead-acid batteries that you can scrap the whole toxic pile of batteries if you do not maintain them 100% correctly (or significantly reduce their life, each and every recharge cycle(!), if not perfectly maintained.) Li-ion batteries conversely are very robust and last 10x longer approximately without the variable lead-acid scrap rate. (Plus if you get lead-acid spills in cuts on your hands, they have a healing problem, and you can constantly get holes in your clothing to boot.)

More importantly, you have to be a highly trained battery technician monitoring lead-acid batteries with not-exact methods (a losing battle for the lower 95% of the population.) And if you do get the 'more' exact measuring devices for lead acid batteries, you could almost have bought li-ion batteries and not work a solid part time job maintaining them: that you could have been part time employed paying for your next 500 lbs of lead acid batteries.

How in the world are you going to keep lead acid batteries charged on a 50% charge level, depending on perfect Sun days, and THEN a few hours of Sun per day charging (based on 50% max level in the Winter) will not do too much good except to require you to spend your 2 week limits in trailer parks just recharging your batteries?? And if you live in AZ in baking Sun days in the Summer, LOOK at the all the heat you now have to deal with. It's a lose-lose proposition with Lead Acid batteries w/o doing any number crunching at all; but I understand the technology has just changed enough for people now to experiment and feel (much) safer with the new battery alternatives.

Li-ion would have the perfect battery characteristics to prolong recharging (almost effortlessly) with a variable mixture of conditions and alternative lifestyles without the impossible task of Lead-acid 50% charging limits ONLY on perfect Sun-days. Because the electrical charging diagram on the Fit RV article (posted earlier) printed out on a page break on the article above (due to advertising), I had to copy and paste the diagram on a full page to better understand it. It is definitely tomorrow's technology TODAY for all intensive purposes. Pareto the high volume 2nd alternator use for charging (at 8 times Solar charging rate minimum) and li-ion batteries for lead acid, and you are done. And it can be more economical too: but I don't have time unfortunately to cost it out with a range of usages. But for my dollars, lead acid just does not get the job done in today's (or last century's) technology. Ymmv. I'm just glad I did not get sucked into the heavy lead acid battery technology sales pitch: I will not have room for them in my floor plan! And no loud, smelly genny either.

See you next year!