Ditching the Generator for the Alternator

The  generator. It’s big, heavy, noisy, smelly, it annoys neighbors, requires maintenance, and is expensive. Why buy one when there are so many negatives? Because we need more energy than our battery, inverter, or solar capacity can provide. We don’t “want” all of the negatives that go with having a generator, but we accept it because it has historically been the only way to power our high amperage loads. Is there a better alternative? I think so. The ability of lithium batteries to store a lot of energy and charge quickly has re-opened an opportunity that always existed, but seldom worked—the engine alternator. I believe “self-sufficiency” is the direction the serious RV community is going and a strong alternator charging system is key to achieving it.

To be electrically self-sufficient, an RV must have a good balance between storage, generation and conversion to meet all demands. In the last decade, low-cost inverters have solved the conversion problem. Solar has come a long way with increased generation efficiency at lower cost, but still leaves a gap because it’s not always powerful or reliable enough. In the last few years, high-capacity lithium batteries have solved the storage problem and make it possible to operate an air conditioner for the peak heat of the day or longer without a generator. Summer camping in the South is never going to be in reach, but if you keep your objectives modest, have a good solar array, an inverter and lithium batteries, it’s time to rethink the generator.

Running all my systems—including my air conditioner—on solar and a second alternator was planned from the beginning, but it’s clear to me, the average truck camper has unfulfilled potential. Developing the alternator system started with an old Lance 1130 (with a propane 3,500 watt generator, removed after the first trip) and continues with my chassis mounted DIY camper, both on the same F-350. My goals and accomplishments were as follows:

  • Eliminate 100+ pounds of generator weight
  • Free up about 8 cubic feet of storage bay in a prime spot.
  • When I got rid of the Lance’s generator and relied on the alternator, propane lasted twice as long.
  • A dedicated alternator is as powerful as (my very capable) generator-based charging.*
  • In my new camper, I only use diesel.
  • Charging on-the-go is “silent” and effortless with no noise while camping.
  • I can run all my appliances, at any time, even all at once, without starting a generator.

* My Lance’s 3,500 watt generator is almost fully loaded running my battery charger in my 4,000 watt inverter-charger (at 105 amps = about 3,100 watts) ……and my battery can charge at that rate. Most who charge from their generator don’t have “enough charger” to load their generator, causing longer and less efficient operation. The original 120 amp alternator put out around 75 amps (2,200 watts) continuously. The new 220 amp alternator will put out about 110 amps (3,200 watts) continuously at about 29.2 volts charging voltage.

Below is a brief explanation of what I did with a second alternator powering a 24 volt system.  Presuming most of you are running a 12 volt system with a single alternator, I have also included thoughts about that as well as newer vehicles with “smart” alternators. This whole system works because of the high capacity and high charge rates of lithium batteries. Getting a lot of charging in a short drive is possible. Not so with lead-acid batteries. They just charge too slowly.  Let me take you through my system and my design process and see if any of this can work for you.

I have a very large lithium battery (24 volt/17.5kwh or 2,132 amp hours at 12 volts); a 24 volt, 4,000 watt inverter;  and a large 24 volt, 950 watt solar array. They meet my (ab)normal operating needs exceedingly well and for a considerable duration. I’m usually boondocking. My solar usually supplies all I need. There are times it doesn’t such as when I’ve been camping in the shade, in stormy weather or running my air conditioner. Periodically, I need a major recharge by something else. I move frequently so having the capability to recharge on-the-move with an engine alternator is super convenient for me, so I have invested significant effort in optimizing it.

This system can be just as easily implemented on a 12 volt system as my 24 volt system, but at a significantly lower capacity. There are a couple of ways to do it;

  • With only one alternator, replace it with a high capacity one and get a large DC-DC charger. You need to have a DC-DC charger if you expect to get a reasonable charge on any camper battery from your smart alternator.
  • Add a second alternator and operate it separately from your vehicle system (even if both are 12 volt). Dedicate it to directly charging the camper’s battery system at an appropriate voltage. Use a thermostat to protect the alternator.

Automotive alternators have some mystery surrounding them so some basic understanding is needed for the design:

  1. Alternator “rated capacity” (in amps) is what one can put out at 6,000 alternator rpm (alternators are usually driven at about three times engine speed) into a low resistance load such as a load bank. Notice, I did not say into a lead-acid battery, which is a relatively high resistance load. A lithium battery is a low resistance load and uncontrolled, direct alternator charging will overload the alternator.
  2. “Rated capacity” (amperage) of an alternator is not their “continuous duty” capacity. Continuous duty capacities for alternators are not specified and are greatly affected by under-hood temperatures and availability of cooling air. Assume the continuous duty capacity is about half of the rated capacity and you won’t be disappointed. Automotive alternators are only intended to provide continuous operating power of 20 to 50 amps plus a short recharge to replace the starting debt from one or two lead-acid starting batteries. Extended operation of an alternator above its continuous duty capacity (such as uncontrolled charging of lithium batteries) will burn it out.
  3. An alternator is a dumb device where heat and amperage are concerned (even “smart” alternators). They do not measure either and have no way to control either. Directly attaching a low resistance load, such as a lithium battery, will overheat and burn it out (I hope you note I have said this several times).
  4. The only safe way to reduce the load on a direct charging alternator is to reduce the voltage its regulator is attempting to maintain (which will in turn, reduces the amperage into a fixed resistance load).  If you were to just disconnect the main output lead with a switch, the instant “unloading” of the alternator will instantly spike voltage (faster than the voltage regulator can compensate) and destroy the alternator. This is why alternator outputs are directly connected to the lead-acid battery (a damping load) and are not fused. Overheat/current might burn out the alternator over a short period of time, but removing the whole load at once will destroy it instantly.
  5. “Old style” (dumb) alternators have an internal voltage regulator which attempts to put out a stable, fixed voltage of around 14.2 to 14.4 volts. They cannot be adjusted. They are designed to run a vehicles operating system at a stable 13.6 to 14.2 volts. Directly charging a battery requires changing the output voltage to control the charge rate. These different needs require charging and operating power systems be separate. This is why camper batteries don’t receive a good charge from the “operating” power system.
  6. “Smart” alternator voltage regulators have their output voltage set by the engine controller (ECU) almost second by second. They normally run at 12.4 volts, purposely drawing little engine power and deliberately undercharging the lead-acid starting battery. With this low operating voltage, the vehicle will also draw power from your camper battery if it is connected in the normal fashion, by an isolation relay. A voltage sensing isolation relay will prevent it because it only closes when the charging system is at a higher voltage than the camper battery. The sole purpose of this strategy is to increasing fuel mileage, by operating the vehicle systems off the battery, not the alternator. When the vehicle is braking, the engine controller raises the output to 15.5 volts, drawing power from the drive train through the engine, to push “braking energy” into the undercharged battery. System voltage jumps up to over 15 volts. As soon as the braking event is over, the regulator goes back to 12.4 volts. You hopefully now see how system voltages can range from 12.3 to 15 volts and change constantly. Only a DC-DC charger can keep up with these changes, maintain isolation between operating and camper systems and charge effectively.
  7. Automotive alternators are capable of operating over a large output voltage range, depending on the regulator. Increasing the output voltage increases the output power of the alternator as well as the input power. A 100 amp “rated” alternator is capable of putting out 100 amps at any voltage produced. The rated “test” voltage is 13.5 volts. “Rated” power is 100 amps x 13.5 volts = 1,350 watts. The same alternator running at 28.4 volts (automotive 24 volts) puts out 100 amps x 28.4 volts = 2,840 watts. Keep in mind, increased input power, increases belt tension and thereby, the load on the bearings.

With all this in mind, I set about designing a 24 volt alternator and control system. My 2004 Ford F-350 has a factory option for a second alternator. I was able to buy a “take-off” kit from a junkyard for the second alternator for $175. I initially used the original 120 amp alternator, but recently installed a 220 amp model. Most of my experience is with the 120 amp unit.

F-350 Dual Alternators in author’s truck. 12 volts/135 amps (top), 24 volts/220 amps (bottom)

Since I wanted a “24 volt” adjustable alternator, I just disabled and bypassed the internal “12 volt” regulator to bring the rotor positive lead out to an external “24 volt” adjustable regulator. Even if you are staying with a 12 volt system, you will still need to convert to an external regulator if you want to be able to alter the output voltage to work with lithium charging.

24 volt external adjustable regulator modified for remote adjustment.

I created a control system that includes a monitoring system on my center console, for voltage, amperage and temperature of the alternator; a remote manual voltage/current adjustment; and a safety system that cuts off the 24 volt power that operates the regulator if the battery is full (BMS controlled), the alternator is hot or I don’t want to charge. Note: The Transpo V2400 (24 volt) regulator I use is not available with a remote voltage adjustment. Transpo 911-02R is a 14 to 20 volt regulator with a remote adjustment that sells for around $100.

Console controls for 24v system on top (-R), manual voltage adjust, volt/amp display, Thermostat with current temp/cutoff temp display, system enable switch.
200 amp Hall effect current sensor on 2 gauge alternator lead.
Temperature sensor on the alternator case.

The alternator is connected to the battery main bus with 2 AWG welding cables (about 140 amp capacity to support a 220 amp alternator). When deciding to charge, I check the battery voltage, and knowing my drive time, manually adjust the output voltage to charge up to the continuous duty rating of the alternator, depending on my drive time and charging goals. I rarely plan to achieve a full charge and usually target 80 to 90 percent SOC. Not fully charging lithium batteries is not harmful. As the battery charges, resistance increases and amperage tapers off, so I periodically tweak the output voltage upward if I want to maintain the charge rate to max of 29.2 volts. This is actually just how the first stage of “bulk/constant current” charging works. With the 120 amp alternator, I could charge at 75 amps continuously. The 220 amp alternator can charge continuously at around 110 amps without exceeding 120C, but I’m still experimenting with that.

If you are only able to have one alternator, the best solution will always be a DC-DC (aka “battery-to-battery”) charger. A normally operating vehicle will draw 20 to 50 amps depending on how much equipment you have operating. A 50 amp charger will add to that, likely driving a standard (100 to 150 amps rated) alternator over the max continuous duty capacity (50 to 75 amps). I would replace a standard capacity alternator with a high capacity one (about 200 to 250 amps….don’t go crazy) and upgrade the gauge of the output cable between the alternator and battery. Even though you will connect your battery charger directly to the alternator output, upgrading the cable when you upsize the charger will prevent melting the lead if some unknown demand happens. Most smart alternators are already rated “high capacity.”

Connect your positive and negative leads of the charger directly to the alternator with an appropriate gauge cable. Attach a ground lead to the back of the alternator case (installation instructions should also direct you to do this). Many alternators have an 8mm tapped hole in the back case for that purpose.

FYI, most smart alternator systems also have current shunts to measure current in-out of the starting battery, located right at the battery negative cable. Don’t connect your DC-DC charger leads to the battery, so that the charger current flows through the shunt. You’ll make the ECU think all that power is going into the starting battery. Remember, you only have one alternator and if you cook it, your vehicle will no longer operate.

There is a similar system in the sailing community that may be superior to my system (does the same thing but more automated). These are called “charging regulator” systems, which are designed to operate on a large, second alternator on a sailboat engine to maximize battery charging. They provide superior battery charging without affecting the engine operating system. Temperature sensors are also available (optionally) to lower (not turn on and off like mine) charge rates to reduce alternator temperatures. Charging regulators are not appropriate for single alternator systems. Cost of these regulators alone is about $350 to $400 for the regulator plus $60 for the temperature sensor. Balmar and Mastervolt are two manufacturers. They also recommend their own high-capacity alternators which cost $1,800 or so, but I suspect it is impossible to find brackets to mount them on an automobile.

If your vehicle can mount a second alternator and you don’t want to pay the “dealer premium,” I would look on eBay for a scrap dealer parting out a wrecked truck similar to yours that has a factory second alternator installed. They may only be advertising the “second alternator,” but I’d bet they can remove and sell you a whole take-off kit if you asked. If you set up the second alternator to not be connected to the vehicle electrical system, but directly to the camper charging system, there should be no warranty issues (a guess).

As an engineer, I’m always tweaking my system to perform better, but am pretty happy with the way it works now. There is more information on my whole power system on my you-tube channel (workingonexploring) or blog at workingonexploring.com. If those don’t answer your questions, you can reach me by commenting on a post/video. As we head into the summer “air conditioning season,” I’ll be testing my 9k BTU mini-split with this system and will be posting the results.

About Steve Hericks 1 Article
Steve holds a mechanical engineering degree from MIT, was a US Army combat engineer officer for nine years, and is now retired from engineering and program management in high-tech manufacturing. He currently works on and travels half-time with his wife, Cheryl, in a custom truck camper they built called Maximus.

13 Comments

  1. I’m following your articles with interest. And I absolutely agree with your comments about insulation. The industry seems caught in a 1950’s time warp. I had thought of installing a second Nations alternator on an F350 dedicated to charging 600a/h of lithium in a Bundutec Roadrunner. But I get stuck on two things. First, how to limit the alternator output to an appropriate duty level? A Wakespeed regulator might allow that. Second, how to disconnect the camper? The alternator needs a load, right? It seems like I need a standard battery in the circuit anyway. But without fully understanding how the Ford dual alternator 397 amp system actually works, I don’t know if it could reliably produce, say, 60amps for a dc/dc charger. That would certainly be the least expensive option.

    • Christin,
      We’ve been conversing on our blog (workingonexploring.com) but for posterity, thought it might be helpful to others to add some bit of that here. (if you are reading this and want to follow our in-depth discussion, please go to the comments for the blog article on ‘alternator charging’.)
      1) I’m advocating a trend in camper design and independence I see desired and coming. Much of what I have done, can’t be done economically achieved by modifying an existing camper with simplistic systems. The biggest change needed is to move to a higher DC voltage. There are several class B’s that option high power 24 and 48V systems.
      2) People who want significantly more capable campers can make significant improvements to get them part way there. DC-DC chargers, larger alternators, larger lithium battery banks and more available controls are on the market.
      Some specific answers to your questions;
      3A)Limiting alternator output; Lithium will draw everything an alternator can provide and burn it out if allowed. For direct alternator charging, there needs to be both current control and temperature control. Current control is achieved by voltage control through an adjustable regulator. It can be done manually but is best done automatically with a ‘charging regulator’ such as a Balmar MC612/MC624 or probably the Wakespeed (I’m not informed enough to say for sure). Temperature control can similarly be done separately (external thermostat interrupting the alternator excitation) but can be done by the same charging regulator with an optional temperature sensor. Temperature control is mandatory to reach high, continuous duty charging rates without burn out out the alternator.
      3B) Disconnecting the camper from a vehicle with a dedicated charging alternator(external regulator); No the alternator does not need a load even if its rotor is spinning if the winding is not powered. It is as simple as either providing excitation from the camper battery (once the camper is detached, excitation and load are both disconnected) or adding a manual switch to cut excitation power to the regulator. FYI, Many alternators with internal regulators cannot be shut off once energized so simple external regulators may be needed.
      3C) A second alternator, dedicated to a DC-DC charger, would need a separate LA battery as part of its connection to the charger so there is a ‘load’ to absorb alternator fluctuations.
      3D) DC-DC chargers are no were near as powerful as direct charging. Most DC-DC chargers are 40A or less with one or two at 60A. Charging 600Ah of batteries will take a long time at even 60A. If you ‘go for’ a large battery, you need to plan for a similarly large charger if you want to keep it supplied. If your limited by a 60A charger, you should dial back both your battery size AND planned consumption to meet that limitation.

  2. The new hot new system in the marine world is the Wake speed system. Similar to the Balmar but more features and adjust ability.
    http://wakespeed.com/
    As mentioned in the article the simplest way to use your existing system more effectively is a DC to DC charger, Just make sure you keep it at a reasonable level to your alternator rating. Something like a 20Amp DC to DC charger can help quite a bit with minimal effect on the car system. <y expeince you won't see more then 5-10 amps on the 7 pin without something like a DC to DC charger, Chargers made by Redarc and Renology are very popular for this purpose in Europe and Australia..

    • I was unaware of Wakespeed so was interested to check them out. They have an interesting product.

      Current measurement IS the key to improving automated charging. One thing that ‘other’ charging regulators omit but since they (can optionally) sense, alternator temperature, they can still tell when they are pushing maximum amperage.

      I recently purchased a Balmar MC624 used ($50) and it is what I wished I had when I started. It has completely programmable ramp time/voltage settings but it is not easy to program. Now that I am through all of my development and testing, I prefer my semi-automated system because I can charge at less than maximum to reduce my engine load which I find myself doing frequently. Pushing maximums are only a good thing when you need them and understand what they do to your other systems. I concur with your ‘just get a small DC-DC charger’ comment.

  3. It is pretty difficult to replace the amount of energy in a liquid fuel like propane, especially in terms of the space it occupies and for heating purposes. There are also 6 phase alternators from Mechman all the way to 370 amps. That system of charging from an engine mounted unit is only good if you drive enough and not for sitting and producing power which a generator will do. I have solar also but don’t like parking in the sun on going on summer trips. Why be in with the crowds?

    • John,
      Thanks for the feedback.
      A couple thoughts on Propane as a fuel; Its main features are it’s convenience and inexpensive to use (equipment is cheap to build) which is one of the factors that lead to its widespread use. IMHO, in RV’s it is relatively inefficiently implemented which is one reason i decided to used diesel and electricity only. I consider cost efficiency, space efficiency and weight efficiency in all my considerations of ‘efficiency’.

      My thinking based on my experience with my Lance evolved like this;

      If you use your camper infrequently, propane probably makes sense, having a single fuel for cooking, heating space and water and running a generator. With a longer duration use, propane becomes expensive (due mostly to the inefficiency of an absorption refrigerator and generator) and adds to burdens to source a separate fuel.
      1) Absorption refrigerators consume 8 times as much energy as compressor refrigerators (and don’t achieve similar results), whether that energy comes from propane or electricity. The main reason they remain a mainstay of RV construction is it is easy enough to pack enough propane into an RV to operate it for some time, cost effectively (but not efficiently) where an electrical system would be much more expensive. I did some calculations of use of propane with Lance (on a summer trip with no furnace). I only used propane for the refrigerator and water heater (electricity for induction and microwave cooking). I figured that I used 86% of my propane for refrigeration and 14% for water heating.
      2) Storage space efficiency of propane is poor, largely due to the shape of pressurized gas cylinders when compared to liquid fuels. My Lance had 2 – 30lb horizontal tanks so I’ll use that for my comparison. A 30lb tank is 12″ dia x 24″ high. The compartment to store 2 was therefore ~30″ wide x 28″ deep x 14″ high = 6.8 cubic feet. Being energy equivalent, 60lbs of propane = 64.4lbs of diesel (9.3 gallons). That much diesel occupies 1.2 cubic feet and needs none of the ‘airspace’ or ventilation demanded by propane cylinders.
      3) Diesel is an ‘inherently safe’ fuel where propane is readily ignited by spark or flame, requires monitoring in enclosed spaces, cannot be readily transferred to tanks, tanks require inspection and certification, etc.
      4) I can easily get a diesel fired air heater to replace my propane furnace and did, fare less expensively than a new propane furnace). It is less than 1/4 the size of my propane furnace although lower capacity. My propane furnace was 20kBTU vs. my diesel heater which is 5kW (17kBTU).
      5) It is significantly more difficult/expensive to get a diesel fired water heater. This is where propane shines. I currently use 120V electric element in the tank and a vehicle coolant heat exchanger with the engine coolant….granted, this is more complex, expensive and not truck camper friendly.
      6) Generator conversion efficiency (propane to electricity) is on the order of 30%. The truck engine is likely only a little better.

      Enough on that..

      I agree with the move frequency ‘problem’ working with the alternator. It works for me because i move usually every 2-3 days and have battery for a week.

      However, one benefit of ‘parking in the sun’ and using solar is that having the panels cover my whole roof, turns them into something of a sun shade and gives me the benefit of being able to run the A/C as much as I want. When in a desert environment, shade is usually not an option anyway. I am also considering mounting (2) solar on my tow (Jeep) so I can park it in the sun and the camper in the shade. Most commercial truck campers have extra ordinally poor insulation (~R3-5) which will drive you to shade. My camper as R-14 walls which not only allows me to tolerate being in the sun but being in the cold and operating smaller heating and cooling equipment.

      Putting ‘too much alternator’ (more than 2x and existing IMHO) on an engine is most likely going to result in problems. Alternators just convert mechanical energy to electricity. That mechanical energy is transferred through the serpentine accessory drive belt. Usually there is only one and it drives the alternator, air conditioning compressor, power steering, water pump and radiator fan. All of these systems demand energy from the belt and tripling the demand share for the alternator is likely to overload the belt and cause it or bearings in the system to fail prematurely. The highly driven alternator increases belt tension over every device between it and the crankshaft. If ANY of those device or idler bearings are in that path, and they almost certainly will be, the large alternator may cause them to fail, leaving you on the side of the road. My second alternator (and all factory options) is on a drive belt all by itself (with the primary belt being an 8-groove and the secondary being a 6 groove).

      Wow I ramble on….hope you made it this far and found it worthwhile….

      • The extra load the larger alternator puts on all the bearings only does that when it is charging. 2 one doesn’t know the failure rate of the other bearings until one does comparison testing. 3 Not all vehicles have room for a second alternator and that in itself is more things to wear out.
        When a camper already has a compartment for the space wasting propane tanks designed into the unit it would be difficult to reuse that space.
        Another consideration for a roof full of solar panels is weight, top heavy weight. The lithium battery system is good but overpriced for now and they will degrade over time then battery system won’t keep up. A generator doesn’t lose much output if any over time.
        You use the desert camping environment to make a point about no shade but not everyone spends all or anytime in that environment. Sorry if you do. The solar has some benefits but it is overstated and overrated since it works best in the worst of camping areas and season.
        The first consideration for all these things is how much time does one stay in the camper? I have a home base on 15 acres in the sierras with a 7700 square foot workshop and a 5300 square foot house where I like to be. I take the camper out for occasional trips. Most people do partial use.
        My brother and I both have truck campers. He is an electrical engineer from Stanford (PHD) and was a researcher for RCA and Bell laboratories. He switched to being an endocrinologist. I have 55 years in the automotive industry while owning and operating a general engineering business.
        We have pondered and implemented many things for the campers we own but in moderation for our usages.

        • John,
          You are absolutely correct on all your points. I think the keys you have highlighted are 1) Everyone uses their camper differently (duration and location) and 2) making sweeping changes to mass produced campers is difficult, expensive and frequently impossible. These mean, everyone has different goals and budgets for their campers.

          Much of what I advocate can only be done, at the level I’ve reached, building a camper from the ground up, with camping objectives and costs, prioritized. I began my design with a clean slate, seeking big improvements in ‘what is possible’ and designed around most of the limitations I encountered with my Lance 1130 test bed.

          For example, My 5 solar panels weigh 154lbs but I don’t have the 100+ pound A/C on the roof to add to the ‘waddle’ I absolutely did have when they were on my Lance. Solar production IS a crap shoot and just not reliable enough for my heavy demand. I felt I first needed lots of battery to get around being forced to move or limit my conveniences due to weather or shade. I set a goal to operate for a week (modestly) in the shade, or 2 days with A/C (which would give me enough time to move to cooler surroundings). When I am able to camp in the shade, solar is never going to ‘catch up’ on the drive which is why I have lots of alternator power. It does all go back to how you want to camp and how long you are out. What I’ve done is not for everybody but I talk to a lot of folks who don’t want to be constrained to short trips or RV parks. I’m trying to offer insight into possibilities expanding resources can provide.

          It sounds like you and your brother also have experience and expertise that would be valuable in some form.

  4. Steve,
    We loved your demonstrations and presentations at the last TCA Rally in Quarzsite.

    Your above article was a creative explanation of 12v or 24v truck/RV electrical system power like I’ve not seen before.
    Thanks for the ride.
    For me it was more than a little intimidating.
    Our new Ford F-350 gasser has the power power control module which includes 397 watts from 2 alternators and 2 storage batteries under the hood with in cab 110v AC and 12v DC outlets plus a built in inverter under the back seat.
    We have 330 watts of solar panels feeding into 2 large AGM batteries to run the Northstar camper.
    The stored energy from the solar panels is plenty to run the 12v DC only compressor fridge, pumps, fans/heater, USB connections, and plenteous lighting. Propane generates heat for the water heater and cooktop. It has never failed us even in the depth of winter.
    The secret is we have no air conditioner or other major amp sucking appliances.
    Why? We don’t do summer; only fall, winter, and spring, so we can get by with the the Fantastic fan and open windows and vents.
    The Northstar runs on the solar panels and storage batteries, and a propane tank without being connected to the truck except to activate the running lights.
    So far, so good.
    jefe

    • Sounds like you have a solution that works well for you….that new Ford truck power system is neat….want to check one of those out….

      I complain that one of the major failings of the truck camper industry is ignoring insulation. It is essential for both summer and winter travel. Its easier to just crank the (propane) furnace in the winter but without options for A/C in the summer, its game over. I also hate the weight and noise it adds. You have evidently been forced to comply…..I really like having my 2.5″ thick, R14 walls and think if the industry could provide something similar, you COULD have small but comfortable A/C running on a small battery bank/solar…..and I think it will happen as the RV demand for more capable vehicles grow….it will still be expensive….OBTW, I have spent in the neighborhood of $32k on my entire truck/camper so far….

  5. Nicely done! Not all of us have advanced engineering / mechanical capabilities, so we will struggle along with the regular truck alternator while driving, lead acid batteries, 200 watts of solar, and a generator!

    • Thanks for the complement. I was ‘making things’ from an early age and the Army was the only way I could addend any college to learn more….I have been making and breaking stuff ever since. If you want advice or help on a project, I’m happy to be a resource.

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