RV Solar Power Set-up Advice Needed

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  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    I am pleased to announce that I am the proud father of 4 new MK AGM 8A4D's ($243.27 each), and two Group 27 AGM's ($119.65 each). (Jim, you saved me a small fortune with your recommendation to look for an MK retailer nearby the MK warehouse in Anaheim). Thanks to you guys I have a good headstart in providing them the best care and nourishment available via 6 KC130's, the MX60, the Magnum MS2012 and a TM500A. I would be remiss if I didn't mention Dave at NAW and Robin Gudgel of Midnite Solar (Father of the MX60) who took the time to draw a wiring schematic, plus, Penn Martin of Wholesale Solar - all very generous with their time and advice.

    Jim,

    Re: My question, above, whether or not I can combine and use/charge these two different size banks... I knew I had read about these issues somewhere... and it was in your thread:

    http://www.outbackpower.com/forum/viewtopic.php?t=848&postdays=0&postorder=asc&start=75

    I guess there is a Law of Batteries which states that any bank's performance will degrade to the level of it's least powerful/efficient component.

    I think that the Xantrex Echo Charger is the perfect solution for keeping my Group 27 AGM topped off with use of only the excess charge current (13.5vdc) for my 8A4D's. I will call Dave Monday and get one. Do you guys see any harm to either my bank of 8A4D's or Group 27's (both AGM type) by using the Xantrex Echo charger?

    http://store.solar-electric.com/echo-charger.html

    Finally, would it hurt if I did combine both banks under load for a total of 1KW Amps Hours? Should I get a "1-Both-All" battery switch to combine them once in awhile as needed, or, just keep them isolated; One bank for the House Batteries and one for the chassis (hydraulic slide-out and leveling and emergency brake)?

    http://bluesea.com/products/7650

    BTW I got approval from the RV Manufacturer for my solar power instal with the assistance of the dealer.  Won't have to worry about voiding the warranty. I will take delivery in April.  I won't feel too guilty enjoying the luxury of some more power out in the woods after all of those years roughing it - specially nice clean/quiet solar power.  It's almost scandulous to think of using a microwave at Yosemite.
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    Congratulations on you new toys! I’m glad that so many of our suggestions were useful to you, and it sounds like you had plenty of expert help from others. One small correction: I think dear ol’ Robin is more like the “uncle” of the MX60, as it’s his bother “boB” who’s considered its “father”. I’ve met both of ‘em, and they’re great guys!

    So, I saved you some $$ on the batteries, eh? We may have to get together during one of my HB trips to settle up over an adult malted beverage or two.

    OK… back the batteries. Conventional wisdom says that batteries of different sizes (i.e., 4D’s vs. Group 27’s) shouldn’t be connected to the same charger or loads. Frankly, this logics baffles me, as I would think that each battery would only accept or deliver enough current to maintain a common voltage.

    On the surface, the Echo~Charge looks intriguing. However, its output spec is 15 A, and that’s too small for your system. I’m also not sure that I like its “voltage limiting” feature, as I could see that overriding temperature compensation adjustments. Accordingly, I recommend against it for your installation.

    So, what to do? Well, one possibility (I think) is the Xantrex Pathmaker 250 for two battery banks. This li’l doo-dad may preclude your need for the Blue Seas switch (which is a perfectly good switch, BTW).

    See: http://www.xantrex.com/web/id/104/p/docs/pt/8/product.asp
    and: http://www.xantrex.com/web/id/104/p/1/pt/8/product.asp

    Also, check the terminals on the new 4D batteries. You may need some terminal adapter like these to facilitate installation and wiring: http://www.solarseller.com/battery_post_extension__marine_terminal_by_quick_cable_.htm#marine_conversions_for_batteries_
    Note the different sizes for (+) and (-) automotive posts.

    Finally, I have to admit that this statement has caused me some concern:
    I won't feel too guilty enjoying the luxury of some more power out in the woods after all of those years roughing it - specially nice clean/quiet solar power.

    PV systems typically don’t generate much power “out in the woods”. You’ll need to park with the PV modules in the Sun in order for them to do any good, as shading – even partial shading – will significantly reduce the modules' output. This doesn't mean that you can't ever park in the shade. However, you might have to pull the trailer out into the Sun every two or three days to charge up the batteries.

    Regards,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    That Pathmaker fits the need very well. And with all the money I saved I can sneak it in under the wife's radar!  She loves it when I "save" money when buying all this stuff. Kind of like taking out a 2nd mortgage to invest in a savings account...

    I'll probably get the 3 bank model. With all this talk about trolling motors, it would be nice to have an extra set of leads for swapping/charging trolling batteries.

    I got the large 'L" terminal on the 4D's.

    We use the rv's as a base. My wife and my friends wives and younger kids stay behind in the campgrounds while we go backpacking. Usually only 2-3 days in the backcountry. We have been staying 3-4 days before moving and charging. This set-up will enable us to stay comfortably much longer.

    However, with this inverter set-up I can see someone getting carried away with a hair blower, Playstation, or other toy.  But like I said we've been doing this and being very conservative for about 10 years so I don't expect any sub-50% DoD's. But just in case, with this isolator/combiner, we'll still have the full chassis batteries. 2 group 27's (200Amp Hours) is a respectable back-up that should get us out of the woods w/o being obliged to keep hitting on the 50% discharged house bank.

    Thanks again! By all means let me know when you are coming out this way again. We'll go out and "save" some more money. HA!

  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Just for the record... I went withth Balmar Digital Duo Charge

    http://balmar.net/
    http://www.go2marine.com/product.do?no=111818F
    http://www.go2marine.com/search.do?q=balmar+sensor

    It is more adjustable. You can use two different types of batteries in each bank, plus, it has an optional battery temp sensor. Both the isolator/charge combiner and the temp sensor are about the same price as the Xantrex Pathmaker alone.

    It does not have an emergency switch to boost the starting battery from the house batteries. I can always hand wire/patch-in the house batteries in if needed.
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    I need to take a look at the Balmar unit... more later today or early tomorrow...

    Jim / crewzer
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    Balmar's Duo Charge looks OK to me. Installed "downstream" from the big 800 Ah house battery bank, its 30 A capability should be fine for your pair of Group 27 AGM's, and I like the temp comp feature. You can wire in the optional solenoid if you need more charging current. Take a look in the Product Guide: http://www.balmar.net/2007-product-guide.pdf

    So many fun toys! 8-)

    Regards,
    Jim / crewzer
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Thanks again Jim.  That Duo Digital Charge should give me a little more flexibility to swap-in dissimilar battery types for charging like trolling batteries from my buddies bass boat - but only when charging at 30 Amps through the Duo Digital Charge which can be set for different types. Using the Duo Digital Charge through activation of the solenoid for full amperage from the main battery bank bypasses the unit's regulator circuitry.

    I hope I won't have anymore questions. You all have been great.

    Phil
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    I just returned from 3 days at an Excel 5th wheel dealer in New Mexico setting up the solar system with 6 ea KC 130 modules, a MX-60 controller (RTS), 1,000 AmpHours of batteries (4 each AGM 4d size batteries, 2 each Group 27 AGM batteries), a Magnum 2012 inverter (RTS).  Still have to hook-up the Xantrex XBM battery monitor with RTS.

    Back on February 5, 2007, Bill had estimated/predicted that this system would produce an aveage of about 239 Amp Hours/day, as follows:
    Based on my numbers (not an optimal array orientation):

    15,000 Whr/day * 6*130watt/3,500 watt = 3,343 watthours per day or 3,343/14 volts = 239 amp*hours per day...

    Today en route from Williams, AZ to Huntington Beach, CA (about 1/3 of theday overcast) the system produced 234 Amp Hours.  About 200 AH's of that was made by noon when the system went into the Absorb mode.

    Congratulations Bill on a very "real world" estimate predicting my system's production! Unbelievable!

    Since we estimate that we will be using about 150 Amp Hours a day, and wanted to have some reserve capacity for low production days, this should take care of our needs just right.

    Now that my system is finally an operational reality, I must thank you all again for such gracious provision of your expertise.

  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed

    GREAT news, Phil... Enjoy!

    8-)
    Jim / crewzer
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    Thank you for the compliments--but of course--luck has something to do with the numbers being so close.

    And, nobody was ever too disappointed if their array produces somewhat more than they expected, rather than less--hence my tendency not to try and be too optimistic on estimates for new systems/users.

    Have fun out there with nature!

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Thanks again Bill! I hope those numbers hold up when we get up your way this winter... Big Sur, Santa Cruz, HMB...
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: RV Solar Power Set-up Advice Needed

    Phil,

    I hope you understand that the those numbers will not hold up for winter (at least up here)...

    The numbers I gave you were a "summer/non-winter" average (of my home) for April through September... The averages for October through March are about (9.6/15=) 64% of April through September's averages... And for January, the numbers are much less and more variable (Last two January's where kWhrs/day 4.3/15=29% and 6.9/15=46% of Ap-Spt averages for my San Mateo CA array)... And, in the foggier areas (like HMB), if you get even a 1/4 of your average "summer" power--you should be happy (although--coastal weather patterns sometime invert wrt the summer patterns of fog on the coast and clear inland--hot summers draw marine layer inland--winter fogs in valleys don't usually form on coast)...

    In the end, you will be at the mercy of mother nature and the amount of sun for the area you are visiting.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 9,361 ✭✭✭✭✭
    Re: RV Solar Power Set-up Advice Needed
    HB Phil wrote:
    specially nice clean/quiet solar power. It's almost scandulous to think of using a microwave at Yosemite.

    Park in a sunny spot ! Enjoy.
    Mount a mirror on a pole, and show others how you can run a microwave w/out generator.
    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 ,

  • System2System2 Posts: 6,290 admin
    Re: RV Solar Power Set-up Advice Needed

    Microwave, coffee maker in the morning, DVD in the evening on the built-in 27" LCD HDTV.

    I'm looking forward to setting up a smaller energy efficient PC computer with 19" LCD Monitor for staying in touch and for daily digital photo review and PS editing while on the road instead of waiting until we get back home.

    All of that should max out the available Amp Hours per day.
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