I'm looking for a charge controller for my RV, high voltage.

jackbombayjackbombay Solar Expert Posts: 46
So I'm not totally new to solar panels and batteries, I've set-up a couple of camper vans with solar panels over the years, the first system works fine, and the second (my current system) has been a bit of a disappointment seemingly because of the charge controller.

The first system was a 130 watt panel on the roof of my Vanagon Westfalia with a simple ~$40 morningstar controller, the van had 2 optima redtops (yea, not deep cycle batteries) with no isolator, I rarely ever checked the voltage and the batteries always seemed to have plenty of charge, never had a no start issue and I was pretty stoked on the system. It also had a tilt mechanism that worked decently, here is a vid of how that worked, http://www.youtube.com/watch?v=IRrnawsFyAU

Fast forward to my new bigger better vanagon, a 2003 sprinter, I have 2 Kaneka 60W 48v Thinfilm Solar Panels (they're supposed to be good with low angle light and since I can't easily tilt the panels on the roof of the sprinter I though they would be a good match) on the roof wired in series and a BZ products MPPT250HV charge controller with one fairly large wet cell deep cycle battery from sears.

What is wrong with the current set-up? Well the charge controller seemingly quit on me, its 6 months old and started acting a bit weird 3 months ago, it would hit float voltage, then stop charging the batteries and only start charging the batteries again wen the voltage dropped to ~12.5 volts or so.

Fast forward to a couple weeks ago, the van has been sitting for a while and I notice the voltage was down to 12.2 because the panels had been covered with snow for a couple months, so I swept them off expecting the battery to charge right up and I forgot about it. Yesterday the voltage was down to 11.9 and the panel was in full sun, middle of the day, and the battery was not charging at all.

I do have voltage from the panel, 75V in late afternoon sun, but I may not have amperage coming from the panel, I'm not sure how to check that without letting the smoke out of something.

Besides the current dilemma where the BZ controller seems to be not working it also makes a lot of noise, for about 15 min around dawn and dusk it connects and disconnects the charge current to the battery every few seconds with a click that is easily audible in a smallish van, its enough to wake you up when its 8 feet away, it also did this initially in the middle of the day when the battery hit float voltage.

The controller has a 5 year warranty, but having it seemingly fail inside of 6months in addition to the frequent clicking it makes when it is seemingly working properly has me looking for something different, but I've looked around with google somewhat and I don't know what to look for particularly, I've tried "12v solar high voltage charge controller" and combinations along those lines, but haven't found anything that will work for me :-/ I figure there has to be another option out there besides the BZ product that will work for my needs. Anybody know of anything that will work with the rest of my current set-up?

Right now my panels are putting out a max of just below 96 V, but I could also wire them in parallel and get it down to 48 V, and I have one 12V battery, but would like to add another this spring/summer...

FWIW, all my wring is at or above recommended gauge.


THanks for reading!
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Comments

  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    If you do a search on these boards for BZ Controllers you will find a huge number of posts that suggest that the BZ should have been named BS! It is a POS controller. I actually have one that I ran on a test set up and it performed worse than no controller at all!

    Consider another controller but you have to consider on with a VMP large enough for your Panel voltage. Flexmate 60 out back comes to mind.

    http://www.solar-electric.com/oupofl60mpso.html

    The Morningstar :

    http://www.solar-electric.com/motr45ampmps.html

    comes in a bit cheaper. The problem with you HV panels is that they are not too well suited for 12vdc systems because even though you only have 120 watts of PV (~ 12 amps into 12vdc) you are forced to use such a big controller, and probably not too efficiently.

    Just don't "repair" and reinstall the BZ,, it will only lead to heartache.

    You might consider trying to "trade in" your panels for some lower voltage (17-20vdc) panels and a simple PWM controller. You don't get a lot of advantage of mppt on such a small system.

    Tony

    More on BZ:

    http://www.google.com/search?client=safari&rls=en&q=bz+controller&ie=UTF-8&oe=UTF-8#hl=en&sugexp=nsp7&xhr=t&q=BZ+controller&cp=10&qe=QlogY29udHJvbA&qesig=rtfAMfVsXmVlxLc0lYHfHQ&pkc=AFgZ2tlBLv8hOplyAjkAIGandxWHZaksmODPAdrwNoU9vZ5oaY_VzX16coopKQaeD_gLDSFlLscQjYOuDVSOvPDOXGRuPQBJFg&pf=p&sclient=psy&client=safari&rls=en&aq=0&aqi=&aql=t&oq=BZ+control&pbx=1&bav=on.1,or.&fp=6310ac461fb3c07d
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    Welcome to the forum

    What's wrong with the set-up? "BZ charge controller". That pretty much explains it. You won't find many fans of their products around here.

    A couple of 60 Watt panels aren't going to supply much charge current anyway. On a 12 Volt system you get about 6 Amps, maybe 7? And then here's the thing; to downconvert the higher Voltage panels to a 12 VDC system you need an MPPT type controller. Kind of expensive way to supply less than 10 Amps to a battery. We're talking about $500 here for something that will handle far more panel than you've got. http://www.solar-electric.com/motr45ampmps.html Overkill. :roll: Under the circumstances those thin film panels may not be the best choice.
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    The High Voltage panels you have may have damaged the BZ controller which probably has a maximum solar panel input voltage of 60-75 volts.

    To find a solar charge controller that can manage that high of input voltage is probably in the $500 range or so...

    Best bet--forget the BZ controller, try to Ebay the amorphous panels to somebody else who can use them.

    Get a couple of crystalline solar panels and a matching PWM or MPPT controller (MorningStar or Rogue would be a good start). The Crystalline panels are almost 2x the efficiency per sq.ft. of vs most thin film panels--so you will can get quite a bit more solar power in the same area on your roof.

    If the panels will be permanently mounted to your roof (not removed and put on a 50' cable in the sun while the camper in shade)--Then sticking with PWM is probably a good choice.

    The MorningStar Dual Battery charger might a good one for you... You can separate your house batteries from the vehicle battery and still charge with one set of panels and charge controller.

    If you still have a few dollars left--I really like Battery Monitors (Trimetic is a good cost effective unit from a few reviews here). About as close as you can get to installing a "fuel gauge" on your battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.
    icarus wrote: »
    If you do a search on these boards for BZ Controllers you will find a huge number of posts that suggest that the BZ should have been named BS! It is a POS controller.
    Welcome to the forum

    What's wrong with the set-up? "BZ charge controller". That pretty much explains it. You won't find many fans of their products around here.
    BB. wrote: »
    Best bet--forget the BZ controller,


    But but bit, it has that nifty switch that changes the display from charge current to battery volatge!

    squint.gif

    Yea, I know its junk...



    A couple of 60 Watt panels aren't going to supply much charge current anyway. On a 12 Volt system you get about 6 Amps, maybe 7?

    According to the charge current function of the BZ charge controller I got as much as 9.4 amps in the middle of the day in august, but I have a hunch that isn't all that accurate .


    BB. wrote: »
    The High Voltage panels you have may have damaged the BZ controller which probably has a maximum solar panel input voltage of 60-75 volts.

    The owners manual says it can take a max of 100 volts, but...

    BB. wrote: »
    try to Ebay the amorphous panels to somebody else who can use them.

    icarus wrote: »
    The problem with you HV panels is that they are not too well suited for 12vdc systems because even though you only have 120 watts of PV (~ 12 amps into 12vdc) you are forced to use such a big controller, and probably not too efficiently.


    I live in a small town in eastern Idaho so the panels would have to be shipped to sell on ebay, :-/ I could try to sell them on craigs list when I'm down in southern california, of course CL can have its own share of hassles...

    BB. wrote: »
    If the panels will be permanently mounted to your roof (not removed and put on a 50' cable in the sun while the camper in shade)--Then sticking with PWM is probably a good choice.

    The panels will always stay on the roof of the van, the van is insulated and it is white so parking in the sun isn't too much of an issue, and where we live its cold enough most of the year that we typically try to not park in the shade, and when we do travel farther from home we do our best to avoid hot weather nod.gif


    BB. wrote: »
    Get a couple of crystalline solar panels and a matching PWM or MPPT controller (MorningStar or Rogue would be a good start). The Crystalline panels are almost 2x the efficiency per sq.ft. of vs most thin film panels--so you will can get quite a bit more solar power in the same area on your roof.

    I had initially though that 120 watts of panel would be plenty for us, but while camping in the van this last fall (early nov) our usage was identical to our harvest so through the winter we would certainly be consuming more than we would be harvesting so it would be nice to get some more incoming wattage. We do plan on living out of the van for a few years starting in 2013 or so.

    BB. wrote: »
    If you still have a few dollars left--I really like Battery Monitors (Trimetic is a good cost effective unit from a few reviews here). About as close as you can get to installing a "fuel gauge" on your battery bank.

    -Bill

    I like that, the $140 trimetric looks like it should do the trick!




    I did find this morningstar MPPT controller for $245 which will work with up to 75 volts of panel voltage so I could wire my panels in parallel (48 volts) and use my existing panels, which would do ok through most of the year, but we should really get some more wattage on the roof anyway...

    I'll put together a list of parts for a whole new system and see where I'm looking at $$ wise, I'll of course post the parts list here so you guys can warm me away from another "BZ quality" product...


    Thanks for all your feedback guys! :D
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    This 135W panel for $360

    This battery gauge for $140

    I'd like to leave the possibility of adding a second 135 W panel down the road if we need the power so I would need a controller that can handle 22.5 Amps, correct? My math, 135 watts X 2 = 270 watts 270/12 = 22.5 amps, or do you divide the watts by the max panel voltage 270 W/17.7V = 15.25 amps?

    Pro star 30 amp Charge controller for $145. Is anyone familiar with this charge controller? How much noise does it make at dusk/dawn/low light situations? They also have that same controller but with a digital meter, here but the description doesn't state what is displayed on the meter, could that potentially replace the "battery gauge" I linked earlier? Or is this just voltage and charge current?


    So for one new panel, the charge controller, and the "battery gauge" I'd be out $645, and maybe as much as $1005 down the road if we added another panel.

    Or I could get the $245 morningstar MPPT controller and use my existing panels, but I wouldn't have the option of adding another panel in the future with that set-up.

    I am leaning towards keeping my exiting panels and getting the $245 MPPT morning star controller. I'll have a couple years of road tripping around occasionally and working out of the van to determine if we'll need more panel or if 120 watts is enough. I'll also get the trimetric battery monitor.
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    The 48 volt Vmp panels may be a bit "too high" of voltage for the MorningStar 15 amp MPPT controller (75 volt Voc maximum for this controller). You need to figure out the Voc-cold output voltage for your panels.

    The PS 30 amp controller is a fine PWM charge controller. I don't believe they will make any audible noise... However, if you are into AM DX'ing or Ham, many solar charge controllers are fairly noisy. Perhaps some others here with HAM experience can tell you more about the PS 30.

    As I understand (I am not in the solar biz), MorningStar makes their money with options (like the digital meter option). Normally, I recommend the remote battery temperature sensor option for any charge controller. Battery charging voltage is pretty sensitive to battery temperature. A RBTS can really help ensure the battery is quickly and properly charged.

    The Meter on a charge controller is pretty nice--but, in my humble opinion, it does not replace the usefulness of a battery monitor.

    The charge controller meter only tells you what the controller is doing. Helpful--but not enough.

    A battery monitor tells you want is happening with the battery (charging current, stat of charge, discharge current, etc.)... Pretty much, proper off-grid operation should focus around keeping the battery bank happy.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.
    BB. wrote: »
    The 48 volt Vmp panels may be a bit "too high" of voltage for the MorningStar 15 amp MPPT controller (75 volt Voc maximum for this controller). You need to figure out the Voc-cold output voltage for your panels.

    How would I go about figuring this out? Through this next week we have lows down to 10*F (-12*C) and highs in the upper 20s F. Do I just face a panel directly at the sun in the middle of the day and check the voltage with my multi meter?
    BB. wrote: »
    The PS 30 amp controller is a fine PWM charge controller. I don't believe they will make any audible noise... However, if you are into AM DX'ing or Ham, many solar charge controllers are fairly noisy. Perhaps some others here with HAM experience can tell you more about the PS 30.

    Cool, I'm just interested in audible noise.
    BB. wrote: »
    Normally, I recommend the remote battery temperature sensor option for any charge controller. Battery charging voltage is pretty sensitive to battery temperature. A RBTS can really help ensure the battery is quickly and properly charged.

    Good to know, the remote temp sensor is only $30 so I'll pick one up when I figure out which route I'm going to go :-)
    BB. wrote: »
    The Meter on a charge controller is pretty nice--but, in my humble opinion, it does not replace the usefulness of a battery monitor.

    The charge controller meter only tells you what the controller is doing. Helpful--but not enough.

    A battery monitor tells you want is happening with the battery (charging current, stat of charge, discharge current, etc.)... Pretty much, proper off-grid operation should focus around keeping the battery bank happy.

    Battery monitor it is. I have ruined a few batteries over the years in various RVs and I always feel like such a clod when it has happened in the past. Now I monitor battery voltage pretty frequently and don't let them drop below 12.2V which from what I gather is a big part of battery life, to not discharge them below 12.2V, roughly %50.
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    Yep, keeping batteries above 75% state of charge for the long term, avoiding cycling too often below 50% state of charge, and never below 20% state of charge are all important.

    What is the exact brand/model number of thin film panels do you have?

    We are looking for the open circuit voltage when the panels are very cold (sun rise).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    Kaneka is the manufacturer, this panel \/

    http://www.affordable-solar.com/kaneka-60-watt.solar.panel.ika-gsa.htm
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    Your panel's ratings:

    Pmax @ STC 60 W
    Pmax @ PTC 56 W
    Vmp at Pmax 67 V
    Imp at Pmax 0.9 A
    Voc @ STC 92 V
    Voltage change -280 mV/C

    Using 0F, the Voc-cold for your panel would be around 104 VDC... Too high for the MS MPPT 15 amp controller.

    The high end controllers (Outback, Xantrex, MS TS MPPT, Midnite Classic) are 150 VDC input controllers (Midnite has other higher voltage options too). But they are way overkill for your application.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    I don't think the Pro star will take the input voltage of the Kanaka ~48 vdc and down convert it to 12vdc. For that you need a MPPT controller.

    Remember, only an MPPT type controller can take higher voltage inputs and convert them effectively to lower voltage outputs.

    T.

    Like was suggested, surplus the Kanaka, they probably have some value (or trade them in to some reputable retailer) for some 12 v (nom) panels, and go with the Prostar. Might be the cheapest/best alternative in the long run. You really are trying to round hole a square peg.

    T
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    So that wold mean the BZ controller died because of too high voltage :-/

    Its looking like the $645 option of all new everything is the best way to go, dropping ~$450 on a charge controller that can handle 45 amps when I'll only be putting ~7 through it is a waste, not to mention that its larger than I would like...


    As far as the $645 system I proposed, which way do you figure the amps for charge controller sizing? Using the input voltage or the output voltage?


    Thanks a bunch for all your help with this :D
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.
    icarus wrote: »
    Like was suggested, surplus the Kanaka, they probably have some value (or trade them in to some reputable retailer) for some 12 v (nom) panels, and go with the Prostar. Might be the cheapest/best alternative in the long run. You really are trying to round hole a square peg.

    T

    Yea I am slowly allowing myself to realize that :-/

    I can swing through flagstaff where NAWS in a few weeks when I'm on the road, do you know if they take trade ins?
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    Basically, we try to work backwards from your loads, to your battery bank size, then to the solar panels/charge controller...

    In the case for RV's--Generally we start with how big of panels you can fit on the roof (assuming fixed roof mounting), the go forwards from there.

    PWM charge controllers are sized based on the maximum current from the solar array. MPPT charge controllers are usually based on the maximum sized panel * a derating factor...

    Say you can fit two 135 watt panels on your RV:
    • 2x 135 watts * 1/14.5 volt battery charging * 0.77 derating = 14.3 Amps typical maximum current
    So a 15 amp minimum MPPT charge controller would be a nice fit.

    If you think you will be going larger--the Rogue 30 amp MPPT controller can be a nice choice too. It does include the panel meter in its base price (as I understand).

    -Bill

    PS: Thin film panels are only ~$1.00 per watt when new (in quantity)--So I would not expect much from trying to sell/trade them in.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    If I went with the 12V panels that I linked earlier then I could use a PWM controller though, right? I think one of the 135 W panels would work for us, but I'd like to have everything sized so I could add another panel in the future without having to upgrade anything else. So this Morningstar SS-20L 20 Amp PWM Solar Charge Controller would work for me which is $80 less than the PS 30 amp PWM controller I linked earlier.
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    12 volt panels paralleled into a PWM controller would work fine.

    Selling the Kaneka's on E bay might be a viable option. People pay way more than things are worth for single PV on ebay. I have seen used panels for way more than the price of new ones.

    Tony
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    Ok, so I'll go with a 20 amp MS PMW charge controller, a 135W 12V panel and the battery monitor, I will check that the 20 amp charge controller works with the battery temp sensor, if it doesn't I'll get the 30 amp controller that does work with the battery temp sensor.


    Thanks a bunch of all of your help everybody :-)
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    Ta Da!

    Panel and charge controller have arrived 8)

    2011-04-05131456.jpg


    One question, the run from the panel to the battery via the charge controller will be about 15', what gauge wire should I use for that?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    for a 15ft run (30ft of wire) that would be #10 or better with #10 giving a vdrop % of 2.43%.

    that controller has temp compensation on the controller only and there's no way to put it to the battery remotely.
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.
    niel wrote: »
    for a 15ft run (30ft of wire)

    I might have used the term "run" incorrectly. From the panel to the charge controller (which will be mounted right next to the battery) will require about 14' of wire, and then there would be another 1' length from the charge controller to the battery.
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    Run is fine... Some voltage drop calculators assume one way "run" and others assume 2 way round trip "runs"...

    Also, you are correct, you want the cable from the charge controller to the battery bank to be short.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    as bill said it is fine as you have 2 wires (+ and -) going that distance do you not? that is 30ft of wire total any way you shake it and you do have to consider the wire to the battery in vdrop calculations too.
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    cool, thanks for the clarification guys 8)
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    To make this as future proof as possible I realize I should run wiring large enough for an additional panel if we end up needing more power. I would just run another 135 watt panel like the one I just bought as that width will work well with the ribs on the roof of the van. Same distance from the battery, 15' with the CC mounted right by the battery and with a total of 270 watts of panel. So what gauge wiring will I need? TIA 8)
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    there are 2 ways you can approach the additional pv. one is to have all wires able to handle the current from the 2 pvs ahead of time and the other way is to just upgrade the cc to battery wires now and just run a separate #10 wire run from the 2nd pv to the cc.

    this is a doubling of the current that needs to pass so for that it is 3 gauge numbers lower. x2 current = present gauge # -3. that means #10 then will be #7 which is not a common gauge number. you would need to use #6 or #4 as they are available gauge numbers. this bigger wire would be a definite requirement from the cc to the battery in both cases. if you don't run a separate #10 run then the #6 or #4 would be used throughout.

    2 pvs with various wire gauges-
    #10 throughout 4.86%
    #8 throughout 3.056%
    #7 throughout would equal the same 2.43% as the single pv system with #10
    #6 throughout 1.92%
    #4 throughout 1.21%

    it is also possible to mix and match the wires.
    for example running #4 on the - side and #6 on the + side would be between the above %s at about 1.57%. try the voltage drop calculator in my sig line at 194 degrees f and 12v.
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    While the ~%5 loss with #10 throughout is more than I'd like, we would have plenty of power if we did end up going to 2 panels so losing some efficiency running 2 panels through the #10 isn't too big a concern for me. IF running the 2 panels through #10 is a safety concern at all I'll certainly spend the money for the #6. I'd like to buy one of these and cut it in half and that would be all the wire I'd need to set up my panels and if I added another panel down the road I'd just need a multibranch connectors and I'd be set.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: I'm looking for a charge controller for my RV, high voltage.

    you could do it that way if you wish to live with the higher losses. you could make up for a small amount of those losses by going with a few large gauge wires from the cc to the batteries. keep in mind that originally this was 30ft total and that included the wires to the battery from the cc. if you use the 30ft from the commercially made mc4 wire that this will add 2 more feet of wire and more losses for 30 +2 =32ft now. to stay at the 30ft calculation you'd need to cut off 2 ft of wire from that commercially made wire. i also did not see a gauge # on that wire from the link. be sure it is #10 or i'd suggest a small #10 jumper and splice larger wires to that to run back to the charge controller from the pvs.

    don't forget that the pvs have a length of wire on them too and that has to be figured into these losses too so this throws out the previous calculations as being wrong on the short side of things and i highly recommend not using just a single run of #10 wire for the 2 pvs.
    from this link to the pv specs,
    the - lead is 72.4 inches and
    the + lead is 29.9 inches
    for a total of another 112.3 extra inches (9.36ft) without a mention that i saw of what gauge they are using. this pushes losses way too far imho.
    http://lib.store.yahoo.net/lib/wind-sun/KD135GX-LPU.pdf
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    Ok, I'll probably just run 2 of the #10 mc4 wires (one pair for each panel) as that will be cheaper than any of #6 wire that I have found so far.
  • jackbombayjackbombay Solar Expert Posts: 46
    Re: I'm looking for a charge controller for my RV, high voltage.

    So my solar system was working fine until recently, the batteries would have a full charge but would not make it to morning, so I checked the electrolyte level and I had to add 1/2 gallon of water to each of my 2 batteries, 1 gallon total :-/

    I doubt the batteries will be "ok" after this, is that a correct assumption? They are charging off the panel now and once fully charged I will unhook the panel from the system and run the fridge for 12 hours and see where the voltage is, but I'm not expecting much here...

    So I obviously should have checked the electrolyte levels this spring, but didn't.... I'd really rather not mess with having to check/add distilled water every, 3 (?) months to prevent this in the future so I'm considering some AGM batteries, but I've read that they are not "real deep cycle batteries", is that true? I'd love to have 2 100 AH batteries so I'd have 100 useable AH.

    Thoughts?
  • BB.BB. Super Moderators, Administrators Posts: 30,167 admin
    Re: I'm looking for a charge controller for my RV, high voltage.

    AGM are about the "perfect" deep cycle lead acid battery (clean, low mantenance, huge current surge capabilities). The draw backs include price (around 2x as expensive) and their life may not be quite as long as high quality flooded cell battery bank.

    For a smaller system--it is hard to ignore the Golf Cart size/type batteries. They are not too expensive, lots of options/suppliers, and if there is an "oops"--Not to expensive to replace.

    And yes, batteries ran "dry" are not usually long for this world. :cry: Check your charge controller--it could be over charging/floating too high of voltage if you have to fill the batteries too often or too much (refilling every two months or so seems a good average).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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