Help with RV Solar Charging

ClaybeClaybe Registered Users Posts: 5
Hello,

I am new to this forum and was wondering if anyone could help me with letting me know what I will need in the way of a solar system for my RV. I will need to be replacing between 20 and 50 amps a day depending on winter/summer conditions as I camp year around. I have 2 12v deep cycle 110 amp hour batteries and it will be going on the top of my truck camper (which is a pop up so it can't be too heavy as I still have to lift the top up). Please include links to specifics. Thanks!

claybe

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    that may be a problem for that much pv power especially in the winter. you may be able to supplement another charging source with a few pvs, but to reliably have only pv power may not be happening except possibly in some summer periods. note that all time-periods are prone to cloudyness and bad aiming angles from your camper further reducing the output. maybe a good inverter generator and a good 3 stage charger is in order for a primary charge source. i say fit as much in pv as you can on the camper and allow that to be secondary to the generator. the pvs would at least quicken the bulk charge and should easily handle the acceptance and float stages so you won't have to run the generator quite as long. be sure to allow the batteries to go to 100% fully charged as much as possible to avoid sulphation occurring in the batteries.
    to fit more pvs might involve remote ground mounting. this is a real and good possibility to gain more or all of it from the sun. this makes it easier to aim too as ground mounts are easier to work with, but make theft a higher possibility too. you can also park out of the sun with remotely mounted pvs.
  • ClaybeClaybe Registered Users Posts: 5
    Re: Help with RV Solar Charging

    I am trying to avoid using the generator. I have one but really don't like to use it. I have "re-worked" the worksheet and taken out the forced air furnace and now would need to be replacing around 10 amps a day (as long as I get the Olympian Heater). Is there a list of what these solar panels can put out in optimal conditions?

    Also, what kind of package do I need to do this? Thanks for the help.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    packages are not always a good deal as nearly everyone's needs are special and do not fit a package.
    that said, if you are only in need of 10ah a day this could easily be accomplished with pv. normally at 5 full sun hours a day that would be 10ah/5hrs=2a from pv. being the pv will most likely be flat or not at the sun i would double the 2a required to 4a. because of clouds and winter(big problem with snow on flat pvs) i would at least double the amps again to 8a. this is a minimum of 8a and you can look over the pvs sold by this forum's host northern arizona wind & sun here as to which provide the necessaary 8a for 12v. http://store.solar-electric.com/hiposopa.html btw, the 12v pvs are pvs have a vmp in the neighborhood of 17-18v. the other pvs with higher vmp ratings like 26v for example could be used with an mppt type controller like morningstar's sunsaver mppt as this will downconvert the voltage to a more optimum voltage so the higher voltages will not go to waste. http://store.solar-electric.com/mosumpsochco.html if you use a standard 12v pv the need for mppt is eliminated so a standard pwm controller can be used in that case. you can find the pwm controllers from xantrex or morningstar. http://store.solar-electric.com/chco.html in all cases a battery temperature sensor should be used to allow the controller to adjust the charge to the battery with battery temperature changes.
    edit to add:
    you will need a battery that is deep cycle and not a starting battery like a car battery. the pv amp rating should be within 5-13% of the current amp hour rating for the battery. (example-5a pv = 5% of 100ah battery) mppt controllers may up that current from the pv so if you are considering that route it may be easier to ask our opinions on the stuff you select as to how well it'll work for you.
    hope this helps.
  • mike95490mike95490 Solar Expert Posts: 9,363 ✭✭✭✭✭
    Re: Help with RV Solar Charging
    Claybe wrote: »
    I will need to be replacing between 20 and 50 amps a day

    Say a 200W panel puts out 15V @ 13A. That's only when at OPTIMUM sun angle. Flat RV roof is not optimum, so you are going to be lucky to get 50% power from the panels.

    Reconsider the loads you have, or carry a small generator. (honda eu1000 style)
    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 ,

  • homerramirezhomerramirez Solar Expert Posts: 102 ✭✭
    Re: Help with RV Solar Charging

    You should consider the solar panels weight , going on RV roof top it will be good the brand that combines the best amps per sq. ft., also I have seen some threads where RV users try to mount'em flat, can you build a frame were they can be hinged while parked and locked flat when travel? ;).... there some very good of grid solar panels out there, but before you invest any money do some research and weight your best option...good luck. :cool:
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    homerramirez,
    i agree with you that an angle towards the sun is best, but is not easily achieved in an rv as the mount would need to be able to swivel to that point as parking can face any direction. a fixed direction that can adjust upward will work only if you can adjust the direction the rv is parked in so as to face the right direction for the pv(s). ground mounts would be easier to do this for if that would suite the op and would optimize things as to allow a smaller pv to be used, but as i mentioned this can lead to theft or even leaving it behind because you forgot it. angles on the roof can also be forgotten to be readjusted flat if angled causing it to pull off of the rv like a sail. there are pluses and minuses to both ways and will be the op's choice as to which is best. maybe they can come up with ways to lessen the negative points and if so i would ask that they let ys know what they had done.
  • ClaybeClaybe Registered Users Posts: 5
    Re: Help with RV Solar Charging

    Forgive my ignorance, but what is a "pv"?

    As for the panels, my truck camper roof is not really accessible, so they will have to lay flat. I am still trying to decipher the other posts about all of these equations. Thanks for the input.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    pv=photovoltaic=electric solar panel.
    try to follow it through if you can and learn about what we are talking of. we have no problem in answering queries by you such as the one you had just done though. you do have to know what you are dealing with, what it can do, and what it means to have and maintain them. i encourage you to read up on this stuff, but i also understand that you have some kind of purpose or goal in mind for this so maybe you can elaborate on what it is you're trying to do to educate us so we can advise you better?
  • ClaybeClaybe Registered Users Posts: 5
    Re: Help with RV Solar Charging

    So, can I only buy a couple of pv's and a controller and that is all? I have been researching and see that some people don't get a new converter and don't install an inverter. What is the benefit to these?
  • mike95490mike95490 Solar Expert Posts: 9,363 ✭✭✭✭✭
    Re: Help with RV Solar Charging
    Claybe wrote: »
    So, can I only buy a couple of pv's and a controller and that is all? I have been researching and see that some people don't get a new converter and don't install an inverter. What is the benefit to these?

    couple 130W PV's $1,120 Kyocera KC130TM 130W w/J-box http://store.solar-electric.com/kykc130wasop.html

    Charge controller 12V $234 SunSaver 15 Amp MPPT
    http://store.solar-electric.com/mosumpsochco.html
    OR
    Xantrex C35 PWM Charge Controller $114 (non MPPT)

    inline MAXI Fuse holder $7
    20A MAXI Fuse $2 http://store.solar-electric.com/dcblatmma.html

    This would connect to your camper's house battery, and keep it charged, if you don't use too much. You'd need proper wires and such, and you could run many12V LED lights. Maybe a fan for a while. A water pump for the sink. A radio or 12V TV, but the more you run the TV or laptop, the less power you have for lights.
    The benefit of an inverter, is that it can power "normal" 120V appliances. (power tool chargers, oscalating fan, small toaster oven) but you can consume your power much faster.
    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 ,

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    don't forget the battery temp sensor.
  • ClaybeClaybe Registered Users Posts: 5
    Re: Help with RV Solar Charging

    So what are the converters for?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    a converter basically goes from one dc voltage to another like 12v to 24v or visa versa. i don't think you need this.
    an inverter takes the dc voltage (usually 12v, 24v, or 48v, but 12v in your case) and creates an ac voltage from it. this is a possibility if you want to run some things that are 120vac. read up on it before you buy something or run it past the guys for their opinions.
  • QuabillionQuabillion Registered Users Posts: 22
    Re: Help with RV Solar Charging

    A side note on terminology here.

    In the RV world a "converter" is a 120V to 12V power supply.
    Some of the newer and high end models are really 3 stage chargers as well.

    In the non-RV arena, niel's description is the accepted term.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help with RV Solar Charging

    very good on that added info as he won't need those if he runs things off of 12v, but in the event he has or gets an inverter then he may elect to have some of that type of converters. yes, i know them as either power supplies or wall worts.

    i noticed you are using agms and have been off grid since 03. i'd be curious of how long you've had the agms and if there's anything you can add to this thread on life expectancy?
    http://forum.solar-electric.com/showthread.php?p=28727#post28727
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