RV Equipment Help

sweetchucksweetchuck Registered Users Posts: 13
Hello all,

Another noob here with a few questions. My situation is a 5th wheel RV I'm
trying to outfit for living in full time while I travel the country. I'll be hitting
the road in April. I want to be fully self sufficient, though I may connect to
the grid occasionally in an RV park.

Here's what I have:

8 Sharp ND-167U1 - Total 1336W
Cell Poly-crystalline silicon
No. of Cells and Connections 48 in series
Open Circuit Voltage 29.04V (Voc)
Maximum Power Voltage 22.97V (Vpm)
Short Circuit Current 8.02A (Isc)
Maximum Power Current 7.27A (Ipm)
Rated Power 167W (Pmax) (+10% / -5%)
Module Efficiency 12.7% (hm)
Maximum System Voltage 600VDC
Series Fuse Rating 15A
Type of Output Terminal Lead Wire with MC Connector

6 Trojan T-105
Capacity Minutes @25 Amps - 447
Capacity Minutes @75 Amps - 115
5 Hr Rate AH - 185
20 Hr Rate AH - 225
Voltage - 6V

My head hurts trying to put these numbers together to decide which charge
controller and inverter/charger would suit my needs and my budget of $2800.
I was considering the Apollo T80 or Xantrex XW60-150 MPPT. And I've read
about the Apollo inverters, but can't find any prices posted online for those. I
was thinking I would like to get products from the same manufacturer so
they can be connected and work together. Is that important? What should I
be considering? I'm lost.

Thanks
Sweetchuck
«1

Comments

  • RWBRWB Solar Expert Posts: 168 ✭✭✭✭✭
    Re: RV Equipment Help

    Can't wait to see what they work out for ya :)

    How do you plan on attaching all them panels to the roof?
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: RV Equipment Help

    What size RV are you getting? 8 panels needs a lot of roof space. Plus why such a large system? Your adding 700+ pounds. Unless your getting a toy hauler, you maybe going to be over weight on the trailer.
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Equipment Help

    Sweetchuck,

    You may need to rethink your plan a bit. The 1,336 W STC array power spec exceeds the output current ratings for the Xantrex XW charge controller and the Apollo T-80 for 12 V battery system applications. Same issue with the Morningstar Tristar 60 and the OutBack FM60 and FM80. I’ve not yet seen the “fine print” on the Apollo T-100 ratings.

    For 12 V systems, figure on ~800 W STC max for a 60 A charge controller, and ~1,000 W STC max for an 80 A charge controller. Accordingly, you may well need to consider two charge controllers operating in parallel. For example, you could operate 668 W STC (4 modules) on each of two 60 A controllers and they’d be pretty happy, even in very warm weather.

    This might be a good reason for staying with a single manufacturer for the charge controllers, inverter/charger, and their control network. For example, OutBack’s latest Mate firmware synchronizes the float transition of parallel charge controllers on a shared battery bank.

    All of this $2800 looks like it'll be a tall order, especially when you figure in a system controller and network, mounting hardware, cabling, DC-rated circuit breakers, etc. One option might be to consider an inverter only instead of a combined inverter/charger.

    HTH,
    Jim / crewzer
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    crewzer
    Thanks for the info. I think this is where I'm confused. I was thinking that I could wire my 6 Trojans for 36V (1336W/36V=37A) or add two more and wire them for 24V (1336W/24V=56A) or 48V (1336W/48V=28A). Is this feasible? My $2800 budget is just for the charge controller and inverter/charger.

    n3qik
    My rig is 38' long and has 3 axles, so it is about the size of the toy haulers you've seen. I originally planned a 1kw system consisting of 6 panels, but affordable-solar sold me the last 8 they had at a discount ($643 each). My budget was $5000 for panels, so I'm happy. More watts is better, right? I have plenty of space on the roof for more if I ever need them. Campgrounds with electricity and other amenities run $30+/night. There are free or very cheap campgrounds without those amenities all over the US. Unlike someone just offsetting their electric bill with solar, mine will pay my rent. It will pay for itself easily in the first year.

    Sweetchuck

    This guy is my hero!!! He11 Yeah!!!
    a1.jpg 61.7K
  • MoeMoe Solar Expert Posts: 60 ✭✭
    Re: RV Equipment Help
    sweetchuck wrote: »
    I was thinking that I could wire my 6 Trojans for 36V (1336W/36V=37A) or add two more and wire them for 24V (1336W/24V=56A) or 48V (1336W/48V=28A). Is this feasible?

    Not usually. Everything possible in a RV usually runs on 12VDC power. That typically includes the slide(s) extend/retract motor(s), all the lights, the vent fans including the range hood, the stereo, an active television antenna, the water pump, the tank gauges, the LP furnace control and fan, the LP water heater control, and the LP/120VAC refrigerator control, gas solenoid, and anti-condensation heater around the door. If that's the case with yours, you need your Trojan T-105s wired as 12VDC (three parallel strings of two in series).

    About the only built-in things that typcially run on 120VAC from an inverter in an RV are the microwave oven, satellite receiver(s), notebook computer(s) and LCD monitors/TVs, possibly the central vacuum and washer/dryer but the latter two are usually best generator/campground powered unless you have a large system. The air-conditioner(s) are strictly generator/campground powered. In fact, the first component of my RV solar system would be a 3600W minimum Onan LP generator.
    sweetchuck wrote: »
    My $2800 budget is just for the charge controller and inverter/charger.

    As Jim explained, if you're going to use the additional two panels, you'll probably need two charge controllers and the control box that integrates them, leaving less for the inverter/charger.
    sweetchuck wrote: »
    More watts is better, right?

    If you need them, and if you have all the additional equipment to handle them and large enough battery bank to store them.

    Personally, I would've put the $1300+ for the extra two panels toward a larger bank of AGM batteries. YMMV.
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    I applaud your going out and exploring the US... Something that I have always wanted to do--and did a little bit back 30 years ago (when I was much poorer).

    Generally, your better deal is to look at how much (and what type/voltage) of power you will need... And trim those requirements to the bone through energy efficient appliances and conservation.

    Once you figured how much power you will need--then you can look at how much power you will need to store--for long battery life, a good starting rule of thumb is 6x your daily electrical needs (3 days of no sun, 50% maximum discharge).

    In your case, since you are hauling around batteries--you might modifiy your need to 1-2 days of no sun and count more on a good backup generator to recharge when needed--also, your "daily needs" may be flexible--you may only do a wash when the sun is shining, for example.

    Then you get back into what you need for solar panels... Depending on where you go---your available sun may be highly variable. A good place to look would be these two links.... The first is a series of PDF files by state--so you can see how location, season, mounting options will affect your yield. The second is a very easy to use solar calculator (for off grid with AC inverter, recommend that you use a derating factor of ~0.52 to account for battery and inverter losses--makes it useful for off grid systems too--note that the PV array is rated in KWatts, not Watts).

    Solar Radiation Data Manual
    Solar Performance Calculator

    And, when looking at your array--look at how you will mount them too--if you can slant them, you will be able to collect a bunch more power in the winter and high latitude areas.

    Lastly, assuming you will still need a backup generator--look very closely at fuel flow vs kWatt*hours generated....

    Even the cheapest $500 5kW genset looks efficient when outputting 5kWatts of power (I have seen some work out to ~6 kWhrs per gallon of fuel)... However, when the power usage gets down to below ~1/2 rated power--the fuel flow typically does not drop.... So, for example, if you are using 1kW of your 5kW genset, you may be using 2-4x as much fuel as if you sized your load/genset appropriately.

    For example, you probably don't need much power to run your whole RV (excluding Air Conditioning). I really like the small Honda eu2000i (1,600 watt rated continuous) as it is still pretty fuel efficient down to 1/4 load (400 watts). Runs 1,600 watts for 4 hours on 1.1 gallons of fuel (5.81 kWhrs per gallon)... And 400 watts for 15 hours on 1.1 gallons of fuel (5.45 kWhours per gallon). Example calculation:

    0.400 kWatts * 15 hours / 1.1 gallons of fuel = 5.45 kWhrs per gallon

    If you choose to use the genset to recharge your battery bank, using too small of a charger may cost you a bunch of money in fuel usage on the typical large internal genset in a large RV.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,877 ✭✭✭✭✭
    Re: RV Equipment Help

    Depending on how you PV panels are mounted, (flat on roof, with 6" air gap) or aimed at sun, you are not too likely to be getting full power out of them. If I recall correctly, the charge controllers just throttle back if they get too hot, or reach their limit, so unless you had perfect solar conditions, you may not max out the charge controllers. Converting 48V(36, 24) battery bank to 12V house power, there are DC - DC conveters out there, but they are rated around 200-300 W, not even close to what you will need.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    Thanks again everyone for your patience. I want to address a few of the concerns.

    The panels will be mounted in a way that they can be tilted towards the front or rear and of course the RV can be parked in a way that gets the most sun on them. I haven't ruled out some kind of single axis tracking motor to follow the sun, but I can look into that later.

    I have 2 Honda EU2000i generators that can be paralleled for backup. These things are great and very quiet. I used them for my home when the last hurricane killed power for 3 days.

    The solar panels are bought and paid for, so there's no turning back now. I will probably go with the Apollo T100. It's about $130 more expensive than the Apollo T80. So that will leave me $2000 for the inverter/charger. I haven't found any pricing for the Apollo units. Does anyone know who sells them?

    Thanks
    Sweetchuck
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    Our host, NAWS, sells Apollos... Their web-store does not yet list the 100 amp version--either Apollo is late, or the web-store needs updating.

    I like that the Apollos have a Trimetric Battery Monitor built in--I highly recommend a battery monitor of some sort for any solar system that has expensive battery sets and/or will be a primary source of power... And may be operated by other people than the installer/owner (wives, friends borrowing a cabin, etc.).

    Outback's newer solar charge controllers may also have a battery monitor function built in too... Don't know the specifics and capabilities.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Equipment Help

    OutBack's FLERXnet DC system monitor includes a batetry monitoring feature. The FN-DC is an option for OutBack based systems; it plugs into the Hub and uses the Mate as its display.

    HTH,
    Jim / crewzer
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    I've been talking to Marco at affordable-solar. He says I can do 2 strings of 4 panels at 29V per panel gives me 116V. And 8A x 2 = 16A x 1.56 = 25A. He says I can easily get by with a 60A charge controller with this configuration for a 12V battery bank. Is this correct?

    The specs for the panels are in my first post.

    Thanks
    Sweetchuck
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    No--The confusion is over how MPPT controllers work...

    Basically, a 60 amp MPPT controller can pass a maximum of 60 amps on the input and the output...

    So, the input is fine...

    However, there is POWER or P=I*V...

    P = 16 amps * 116 volts = 1,856 watts--input power from your 8 panels

    P = 60 amps * 15 volts = 900 watts--output power charging a 12 volt battery bank at ~15 volts maximum (near equalization voltage)...

    While the controller will not smoke--you are "wasting" about 50% of yoru panels' output because of the limitations of the charge controller's output...

    A MPPT type solar charge controller is the "DC equivalant of variable AC transformer"... The controller can figure out the maximum power available from the solar panels by playing with the P=I*V of the input current--and will dump as much power as it can (or needed) by the batteries based on their P=I*V of the battery bank...

    You can see, if you set your battery bank to 24 volts--you could double the "power" through the controller to the batteries because while the input power (I*V) remains the same, the output voltage has doubled:

    P = 16 amps * 116 volts = 1,856 watts--input power from your 8 panels

    P = 60 amps * 30 volts = 1,800 watts into a "24 volt" battery bank.

    There is some discussion here on whether or not the 1.25 or 1.56 (1.25*1.25=1.56) safety factors apply to the solar charge controller--the 1.25*rated current (60 amp * 1.25 = 75 amp wiring safety factor) certainly applies to the wiring under NEC.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: RV Equipment Help

    what bill is trying to say is that when an mppt cc is downconverting the current is upped by roughly the same ratio. i believe the current based only on the ratios will look very close to 40a for 1 string to downconvert to 12v. this is about 8a under the controller's 48a input limit to meet nec requirements for a 60a output. adding another string will exceed even what the output rating of the controller would be and will thusly be limited to 60a. technically the guy is right that it can handle those 2 strings, but 1> it violates the nec and 2> it wastes much of the power that it was fed.
  • MoeMoe Solar Expert Posts: 60 ✭✭
    Re: RV Equipment Help

    If you are adamant about using all those panels, and possibly more, that can be done by adding a couple more T-105 batteries for a 450 ah, 24 volt bank, running nothing but a 24 volt input inverter/charger off the 24 volt battery bank, and wiring the RV's 120VAC system into the inverter/charger. This will power the RV's 120 VAC-12 VDC converter/charger to in turn power 12VDC items in the RV and charge its 12 VDC battery bank. You'll need to move the air-conditioner(s) and water heater's 120VAC electric element (if you have one) to a separate breaker panel between the RV power cord for generator and campground power and the 120VAC "In" of inverter/charger transfer switch. The 120VAC "Out" of the inverter/charger transfer switch would connect to the input of the original 120VAC breaker panel.

    This is inefficient "bubba" engineering (I'm pretty good at that) because the 12VDC appliances are powered by, and the 12VDC batteries are charged by, DC that's converted to AC and then back to DC. Lots of wasted energy, but it lets you do what you want and is possibly the solution Marco had in mind when he was referring to a 60 amp controller.
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    OK. Just so you know, I haven't given up. I've decided to go with a 24v battery bank to avoid having to buy 2 charge controllers. I will be ordering the Apollo T80 and Apollo TSW3224 tomorrow.

    The original 120vac to 12vdc converter in the RV was a 30 amp unit, so I'm looking for a 30 amp or greater 24vdc to 12vdc converter. I would appreciate your recommendations if anyone with experience with these. I've been looking at the Samlex SDC-30 for around 100 bucks.

    I realize I will also have to make some changes to my battery bank to get it to 24v. I was really planning to replace the bank anyway, as the Trojans I have are second-hand and untested.

    Does this sound like a reasonable solution?

    Thanks
    Sweetchuck
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    Sounds OK...

    I would check with the manufacturer to see if their 24to12 volt converter can really be connected safely to charge a 12 volt battery bank...

    My guess is that this would not be your best option (not a multistage batter charger, no temperature connection, no remote battery temperature sensor).

    I would suggest you look for a DC Input Battery charger--for example, like this one (I know that this is too small for your needs).

    Here is another vendor that may meet your needs.

    The other possibility is to use your 24 vdc to 120 vac inverter to power a good quality 120 vac to 12 vdc charger (the Xantrex TC 20 or TC 40 should be good charger candidates---Hmmm, see that the TC family has been discontinued and replaced with the TC2 family--details to follow -- should have the Remote Battery Temperature sensor and PFC/wide AC voltage input support).

    In the grand scheme of things, if you can run your inverter at 90-95% efficiency--you probably will not loose much extra in the conversion from 24 vdc to 120 vac to 12 vdc... Plus the 120 vac to 12 vdc battery charger can be used on shore power too (one less piece of equipment to buy, maintain, haul around... You will have the inverter and probably want a 12 volt AC battery charger --- just plug the two together).

    Or, if you are satisfied with your original 120 vac to 12 vdc converter (batteries charged OK, good life, etc.) and it runs off your new 24 VDC input inverter--perhaps just keep the old one for now.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    This is for an RV. It has 120vac loads and also 12vdc loads.
    Here's what I want to do.

    The Apollo T80 charge controller will charge a 24vdc battery bank.
    The Apollo TSW3224 inverter/charger will run the AC loads in the RV.
    I will get a 24vdc to 12vdc converter like the Samlex SDC-30 to run the DC loads in the RV.
    The original 120vac to 12vdc converter in the RV will not be used, but possibly kept as a backup.

    Thanks
    Sweetchuck
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    I understand--my previous post just asked if the Samlex was OK to connect to a battery and use as a battery charger (as well as supplying your 12 VDC loads)...

    My other suggestion is that, I assume, you are getting a 24 volt DC input to 120 VAC output inverter? If so--then you could think about connecting your battery charger / 12 volt converter directly to the 24 volt power AC Inverter...

    If you are not getting a 24 VDC inverter--then that suggestion will not work for you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    The Apollo TSW3224 is 24vdc to 120/240vac .

    120 / 240 Volt AC Split-Phase Input and Output
    No external transformers are required for step up, step down or balancing, thus, saving added costs, installation time and several points of efficiency.
    The output provides 240 volts for well pumps, appliances, or shop tools while providing 120 volts for standard circuits.
    Either side of the line can supply up to 75% of the total load. The input can accept the line or 240 volt AC generators. The transfer relay is internal.


    And is also a charger.

    Efficient multi-stage battery charging
    Power factor corrected, the high-current battery-charger circuit is designed to optimize the efficient use of energy from generator or line input.
    The 5-stage charging algorithm maximizes both battery life and storage capacity.


    I had assumed the 24vdc to 12vdc converter would connect directly to the battery bank.
    I don't plan to use it to charge anything, just provide power to the 12vdc loads in the RV.

    Thanks
    Sweetchuck
  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: RV Equipment Help

    Just a heads up - we no longer carry the Apollo stuff for the simple reason that far too much was coming back on warranty.
  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    You are planning on "pulling" the house 12 volt battery bank and only running on the converter?

    May work OK if--check if your loads will run on 30 amps 12 volts or not... May be an issue if some of your stuff has microprocessors and such (like clocks) inside that need 24x7 battery voltage present for proper operation. I don't see anything on efficiency/standby losses--so I could not tell how much power it will consume if you want to run it 24.x7.

    The other issue may be if you like to run AM radio--many switching power supplies (inverters, chargers, converters, etc.) generate a fair amount of "hash" on the AM broadcast band--Some people find that they have to turn off all of their inverters/chargers/switching power supplies to get a clean AM signal--If you don't have a 12 volt house battery--you may not be able to run a 12volt AM radio (or have to find a 24 volt version--or look for another converter if this one has problems)...

    I don't know that you will have any issues--just that these have come up before here.

    Good Luck and have fun touring!
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • QuabillionQuabillion Registered Users Posts: 22
    Re: RV Equipment Help

    I dont recommend using a 24V battery bank unless ALL of the 12v RV loads can be changed out to use 24V.
    Using a 120V to 12V converter powered by a 24V to 120V inverter will waste huge amounts of your precious power.

    I do recommend that you stick with the 12V loads already in the rig, and configure the bank for 12V. Yes this means 2 charge controllers in your case. I had this same issue when I installed my own system, and I solved it with 2 charge controllers :)

    In my rig the majority of the loads are 12V. The lights, my LCD TV, water pump, furnace blower motor, sewage pump, tank heaters, and air conditioner thermostats are all 12V. The inverter is used for the fridge , microwave, and sat TV box. My fridge is NOT the normal RV ammonia type, but is a compressor and freon based unit.

    My roof.
    rig-1.jpg

    I say stick with 12V, but hey, when you get this all finished you gotta to my neck of the woods and we can camp and see each others systems;)
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    Quabillion, I never intended to convert 120vac to 12vdc. The original converter in my 5th wheel is long gone. I'll be using a Newmar 32-12-35 DC-DC Converter. It will convert 24vdc from the batteries to 12vdc for the DC fuse panel.

    Roof? I don't see a roof. But I like what I do see. Do you tilt any of those modules, or just keep em flat? I think I saw them on RV.net. 1440w, right?
  • mike95490mike95490 Solar Expert Posts: 8,877 ✭✭✭✭✭
    Re: RV Equipment Help
    sweetchuck wrote: »
    Quabillion, I never intended to convert 120vac to 12vdc. The original converter in my 5th wheel is long gone. I'll be using a Newmar 32-12-35 DC-DC Converter. It will convert 24vdc from the batteries to 12vdc for the DC fuse panel.

    Those BIG heatsinks mean BIG losses. Efficiency: 85%


    http://www.powerconversion.com/products/cat/26/DC-DC-Converters
    Has some with 95% eff, really nice, but 48 - 12V, not 24V, so you may be stuck with the low efficiency gadgets
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    I appreciate your criticism. If you know of a better converter (gadget), I'm all ears.

    For a 24vdc system, my charge controller and inverter each operate at 92% efficiency. If it were a 12vdc system, I would only get 90%. Looks like a trade off.

    Just out of curiosity, what if I swapped all of my 12vdc lights and appliances for 120vac models. Would the better efficiency rating of my inverter mean I won't be wasting as much power? I wouldn't think so.
  • mike95490mike95490 Solar Expert Posts: 8,877 ✭✭✭✭✭
    Re: RV Equipment Help

    Might improve if you got a 24V 300W suresine, and only powered on the big one as needed. Can't parallel inverter outputs though, must dedicate separate 120V strings. You can also get 24V CFLs
    http://store.solar-electric.com/mosu300wasiw.html
    http://store.solar-electric.com/th224vo8wadc.html
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 30,752 admin
    Re: RV Equipment Help

    To really do a good job at making a very energy efficient setup--you probably have to do some testing yourself...

    CFL's have variable light output and different electronic designs. You should get a couple 120 VAC CFL's and test them with a kill-a-watt meter and see how much light you need vs the wattage they consume.

    You can do the same thing with LED's... AC and DC--some have electronic ballasts (can be very efficient) and others simply use a power resistor to drop the voltage (very wasteful).

    I don't have one (yet?)--but the Watts Up and Doc Watson DC Watt*Hour meters look like a neat thing to have for testing too. (One person here preferred the Watts Up as more accurate for him).

    Lastly, take a look a getting a Battery Monitor--About the best piece of equipment for you to monitor the state of your battery. May even pay for itself if it saves you from killing one battery bank with over discharging/under charging incident.

    Same thing with the inverters--measure their input current and voltage vs the output power you are using. Some inverters will have a graph of efficiency vs output wattage.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • QuabillionQuabillion Registered Users Posts: 22
    Re: RV Equipment Help
    sweetchuck wrote: »
    Quabillion, I never intended to convert 120vac to 12vdc. The original converter in my 5th wheel is long gone. I'll be using a Newmar 32-12-35 DC-DC Converter. It will convert 24vdc from the batteries to 12vdc for the DC fuse panel.

    Roof? I don't see a roof. But I like what I do see. Do you tilt any of those modules, or just keep em flat? I think I saw them on RV.net. 1440w, right?

    Shoot, I thought I had read converter in this thread, my bad.

    ;) Thanks for the roof comment :D
    All of my panels are mounded flat with no tilt mechanism.

    I am in the process of removing the roof mounted A/C units to free up room for 2 more panels, as well as removing the shadow they cast onto the adjacent panels.

    Yeah you did see my roof on RV.net, its my sig pic.

    As far as the lighting, perhaps 24V bulbs/fixtures or LED would be the simplest and easiest IMHO. The fewer "conversions" your power has to go through the better and more efficient your system will be, ie. inverter, transformer, converter, DC-DC converter.

    I think that you will end up needing the DC-DC for a few key items such as the furnace blower and control board, the stereo, the water heater control board, the fridge control board, the air conditioner thermostat and control board, Tank level gauges, and the propane/carbon monoxide detectors.

    So its kind of a draw here. You will need the DC-DC, but you will want to run as few watts as possible through it to limit the losses.
  • jwdukesjwdukes Registered Users Posts: 7
    Re: RV Equipment Help

    Sweetchuck,
    I'm rigging out my RV as well and want to know what you ended up with and how it's working out for you? A 24 to 12V converter may be worth considering in my case too.
  • sweetchucksweetchuck Registered Users Posts: 13
    Re: RV Equipment Help

    Hey JW. Congrats on your choice to become a fulltime RVer. I've been on the road for just over a year and it is a wonderful lifestyle.

    Your choices are nearly infinite when choosing the equipment for your rig. Unfortunately, free space and weight are very limiting factors. The best advice I can give you is to read everything you can get your hands on before you buy anything. Download the manuals and read them cover to cover. Join the forums and read the posts. Most are full of useless opinions, but if you can get past the bickering and BS, there are a few very knowledgable contributors. In the end, only you can make the choice.

    My system has worked out perfectly for my needs. The equipment I have is:

    8 Sharp ND-167U1 - 167 watts each for a total of 1336 watts
    8 Energizer EGC2 Golf Cart Batteries (Sam's Club)
    Apollo Solar T80 Charge Controller with remote display
    Magnum Energy MS-4024AE Inverter with remote display
    Midnite Solar MNE250STM E-Panel
    Midnite Solar MNPV6 Combiner Box
    Newmar 32-12-35 DC-DC Voltage Converter

    I was holding out for the Apollo Solar TSW3224 Inverter, but Apollo just took too long to get it certified and available to the public. Apollo's products can communicate with each other via a network cable and can be monitored with one remote display. Looks like they finally got the inverters out now. I've been more than happy with the Magnum, though.

    As for the DC converter, I chose a 30 amp Newmar. These are primarily used on yachts with 24v battery banks. It has an input range of 20 to 50 volts and gives me 13.6 volts for the 12v fuse panel. I removed the original 12v battery and Parallax AC/DC converter that came with the rig, and wired in the Newmar in it's place. It couldn't have been easier.

    If I were to make any changes to my setup, I would like a larger battery bank. Mine currently drain to about 65% by the time they start charging in the morning. I settled for 8 golf cart batteries because I couldn't fit 12 in the compartment. But, I do have plenty of height, so I could replace them with the taller L16 batteries. Of course, that's another 300 - 400 lbs to consider.

    My 50 amp breaker box is divided. I have the air conditioner on one half and everything else is on the other half which is powered by the inverter. I only have one A/C. I can plug it into shore power if I'm in an RV park or I can power it with my 2 Honda 2200 generators paralleled. I've run the A/C from the inverter for a couple hours just to try it, but it drains the batteries pretty fast.

    There are tons of things you can do to conserve that will really help, especially if you plan to boondock alot. I don't really conserve much. If I want to nuke something, I nuke it. If I want to watch TV all day, I do it. Hence the 35% battery usage each night. I don't really subscribe to the "no more than 20% discharge" rule. These batteries are fairly inexpensive and the difference in battery life isn't worth sacrificing my comfort.

    I've done a couple things, I guess, to conserve. I heat my water with gas. I installed a hot tub timer beside the water heater switch, so all I do is turn it on for 15 minutes before I take a shower or wash dishes. This gets the water plenty hot and I don't have to remember to turn the water heater off. This may be my favorite mod. My propane lasts forever. I replaced my gas/electric fridge with a residential unit. The gas option was nice to have, but there is no comparison with the space inside the residential model. And it gets a whole lot colder. That is my second favorite mod. LED lighting is a great energy saver, but I haven't done it yet. I don't use a lot of light and LEDs are still expensive. I have an induction hot plate that I use in the summer so I don't heat up the rig with the gas stove. That saves running the A/C as much. It uses a good bit of electricity, but that's free and gas isn't. I have a convection microwave oven that I can bake in instead of the gas oven for the same reasons just mentioned.

    I'm considering building a small wind turbine, but haven't committed to it, yet. My panels lay flat, 4 on each of the 2 aluminum racks I had made. There are 8 6-inch legs on each rack to allow airflow under the panels. I can remove the racks from the roof if I ever need to without removing the legs that are screwed into the roof. Each rack was made so that I can disconnect one side and tilt the whole rack up at an angle. I had them made this way thinking I would tilt them toward the sun in the winter if necessary. But there is just too much weight on the rack so that it bows when tilted, so I don't do that. It makes it easier if I need to mess with the wiring or wanted to scrub the roof, though.

    I recommend that you buy as many watts of solar as you can afford and have space for. You can't have too much. Not in an RV, anyway. And buy equipment that will allow you to add more in the future.

    Good luck
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