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  • #76
    @ Wrybread and Sunking

    Will both of you stop arguing and posting crap at each other. I am getting tired of it.

    While both of you have a point to make you can do it without trashing up the threads you both like to attack each other in.

    My vacation was nice and peaceful and I don't want to come back to this forum with a lot of trash talk going on. So both of you STOP IT right now or I will give you both a long vacation.

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    • #77
      Originally posted by Wrybread View Post

      Solar (especially for RVs) is dead simple no matter how much you want to be the high priest interpreting the obscure texts for people. And you're living proof that professional experience gets in the way, since I've built *far* better RV solar installs than you. Charging your batteries, before your trip, hilarious!!
      It is no different than any other off-grid application, same laws of physics apply. The real challenge for an RV is panels that have to be mounted on a roof with poor orientation and tilt angles. All that means is a lot more panels are required.One advantage an RV has and should be used is the engine alternator to make up for the short comings of an RV which is why they come from the factory already equipped on new models.

      MSEE, PE

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      • #78
        Ha good point SunEagle and will do.

        All that means is a lot more panels are required
        With respect, that's a simple need to fill. Two 250 or 300 watt panels instead of one isn't a big increase. I routinely pin my 40 amp charge controller at its max output with my 600 watts of panels, and those panels only cost $160 each. So you're right that the 15% decrease in efficiency from flat mounted panels requires more panels, but luckily panels are dirt cheap so it's no biggie.
        Last edited by Wrybread; 05-30-2017, 07:29 PM.

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        • #79
          The only time we have plugged 34' fifth wheel in during last three years is when we left it at an RV park for a week. We only go to RV parks every two or three weeks to dump and wash clothes and do not plug in since we do not trust US power lines. We do have 1400 W of panels and 9+ kW-hrs of LFP (set at 48 V nominal). We have only run generator for half an hour every month as Onan manual suggests. We spent 14 weeks in Labrador/Newfoundland in summer and 14 weeks in Mexico in winter in 19' Roadtrek (and we are still on speaking terms). We did plug in while in an RV park near Boston and then San Cristobal de las Casas (Chiapas) since we were under trees and it rained a lot. Turned it off at night and ran fridge on propane. Electricity in Mexico can be "dirty" with voltage swinging from 60 to 180 V. So we only run power through battery chargers to LFP battery banks with both systems. Chargers willsupposedly handle 60 to 180 V . There are a lot of ungrounded recepticles in Mexico and some friends plugged into a supposed 120 V which turned out to be 220 V and fried all electrical devices on at the time.

          The Roadtrek has a 315 W and a 100 W panel (real estate is limited) and this required two controllers to as 12 V nominal battery suite (4.5+ kW-hrs).

          Agree heartily with SunEagle's post #76

          Reed and elaine

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          • #80
            Nice on San Cristobal, one of my favorite cities in Mexico.

            Similar experience for me with solar this summer. Have yet to go below 12.2 volts, probably more like 12.4 volts. No generator, no external charging, no plug ins, never think twice about power consumption. 620 watts of panels (two 310 watt panels) into 4 Trojan T105's.

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            • #81
              Originally posted by reed cundiff View Post
              We do have 1400 W of panels and 9+ kW-hrs of LFP (set at 48 V nominal).
              If I may ask... where did you source your LFP?
              CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

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              • #82
                Wrybread - there is only one RV park in San Cristobal, Rancho San Nicholas. Bonampak closed a few years ago (may reopen). Churchs' book notes that do not try getting there with anything longer than 21'. They are correct. The topes are incredibly high. There is a back way in that our birding guide told us to use to get out and it was far better.

                Sensij - we used Manzanita Micro for both the 5th wheel and Roadtrek. The 9+ kW-hrs in 5th wheel have been in use for four years. Our son has been in solar since 1991 (spent time at NMSU Alternative Energy Labs before that) and he designed and fabricated our systems. He is putting in a 20 kW or so residential at this time that has requested LFP and I think this will be around 30 to 50 kW-hrs of LFP. Apparently Korean companies are becoming major players. I googled this last night and a Chinese-Korean consortium will be fabricating LFP in Chile. Turns out that 50% of the easily "mined" lithium is in Chile and the Chilean government wants the lithium batteries produced in-country and do not want to remain a material exploitation nation. Son has utilized Manzanita for a few residences; however, Manzanita are designed for electric vehicles. Their batteries are CALB cells

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                • #83
                  Originally posted by sensij View Post

                  If I may ask... where did you source your LFP?
                  looks like current price for 100Ah CALB is $120 which would result in 10 kWh cost: (10,000 / 100 / 3.2) x 120 = $3,750 just for the batteries. Are you pricing out TOU 'shifter' solution?

                  I'd need about that much capacity to move completely to super off peak rate. If everything is AC coupled this would work: during mid day PV inverter feeds the loads and CC charges the batteries while later battery inverter picks up the loads. On a cloudy day CC would take energy from the grid at highest rate but then it will be returned back during the same rates anyway so it looks like no additional controller would be required at the loss caused by double conversion + battery charge/discharge efficiency: 0.98 x 0.98 x 0.8 = 0.76.

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                  • #84
                    Originally posted by max2k View Post

                    looks like current price for 100Ah CALB is $120 which would result in 10 kWh cost: (10,000 / 100 / 3.2) x 120 = $3,750 just for the batteries. Are you pricing out TOU 'shifter' solution?

                    I'd need about that much capacity to move completely to super off peak rate. If everything is AC coupled this would work: during mid day PV inverter feeds the loads and CC charges the batteries while later battery inverter picks up the loads. On a cloudy day CC would take energy from the grid at highest rate but then it will be returned back during the same rates anyway so it looks like no additional controller would be required at the loss caused by double conversion + battery charge/discharge efficiency: 0.98 x 0.98 x 0.8 = 0.76.
                    reed cundiff thanks for the info, and sharing your stories.

                    max2k .. nah, I over built enough that I'm not going to mess with storage for my house. We've been talking about adding a small camper, so I'm starting to look a little more closely at LFP... overkill, maybe, but a good excuse to learn.
                    CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

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