Small System for Pop UP RV

Re: Small System for Pop UP RV

That's an interesting idea. Specs for the Elixir ELX-25 Power Converter/Charger show the output of the DC supply is 13.5V under no load and 13.1 under full load (25A). Battery specs float at 13.6V to 13.8V. Bulk and absorption charge voltages are higher. I wonder if the XW MPPT can properly charge AGMs with this lower input voltage.

Re: Small System for Pop UP RV

I have decided to change some things. I have done a few (not enough) more measurements and have determined that I will need about 900kWh/day as opposed to the 800 previously estimated. That is 1800 per weekend with no sun as happened this last weekend. Still 450AH bank. 195W PV. This is a system plan and has not been implemented. The evaluation is currently supported by two 100AH AGM batts (dissimilar and used on separate circuits.) They are charged during the week by "BatteryMinders" in a distant garage. When I arrive at the site I pull the 65AH flooded batt intended to be charged by the tow vehicle which, in the evaluation, is charged during the "away time" by two Brunton 15W amorphous panels with Brunton controller. These were purchased last year at a sporting goods store while shopping for a new fishing rod. BEFORE I found this forum. They put out about 1A in good sun. Anyway, the flooded batt is brought to the distant (1/2 mile away) garage and put on a BatteryTender. The two AGMs are, in turn, transported to the campsite where one is dropped into where the flooded batt sat and the other is connected to a 750W MSW inverter which is connected to the camper's 120VAC hookup. And I get by.

Tony pointed me to the Iota transfer switch and dwf suggests charging the AGMs from the already present Elixir-35 DC Supply Charger or a replacement Iota unit (to accommodate the AGMs required ~ 14.2V absorption.)

Now to the changes. I plan to use three Kyocera 64W panels (probably in series) as the PV array. They will all fit, low, on the roof and will weigh less than 50 lbs. This minimizes the potential of roof raising issues. It also allows the use of Morningstar's MPPt-15 controller. Mounting of PV panels is planned to be removable.

So far so good. But what about the inverter. The camper came with a 1000W (input, not cooking power) microwave oven. It was not an option. I could pull the oven and increase inherent lacking stowage in the camper, but as my buddy Tûr exclaimed this weekend, "If ya got it, use it." So I'm looking at the Xantrex PROSine 2.0. inverter. 2000W, 100A highly configurable charger AND transfer switch. But the price is steep. It seems to me that as I have prowled this forum ,Xantrex is reputable. The batts I am considering can take 45A in bulk. In a series/parallel configuration, that 90A.

The MSW I have been using blocks AM reception on not just my on-board radio but also on C dry cell radios in the vicinity. I have not tested the range of this effect. It occurs to me that using a TSW may not eliminate this problem. It may be caused by the "power switching" circuits in the Elixir-25 DC Supply or EVEN in the planned PROSine.

I have found a "factory" refurbished PROSine 2.0 (I love the features and the detachable panel and remote shutdown) for about half the price of a new unit. Is refurbished O.K.?

Ohhh... I had such great hopes... I became unemployed last January which gave me a great opportunity to complete two lingering projects (unrelated to PV, which have since been completed) and I looked forward to having the time to work on this camper/PV project. Alas or alack, I received a call from an employer (I'm in trucking) that, in the current economic environment/outlook I could not turn my back on.

So, having restored income, cost is less of a factor. And time becomes consumed. Present estimates place the cost at just under 4K. Saving energy or the Earth is not my goal. My goal is to be able to use my camper,as much and in as anywhere as possible, without worrying about where the *last* WH is going to come from.

New block diagram attached.

Re: Small System for Pop UP RV

Greetings! Yesterday, I completed the installation of my PV system into my camper. The PV panels are not mounted on the roof yet. They are temporarily ground "mounted."

It was a little difficult working in cramped quarters, but I started and finished in one day. And the system works great! At least for one day.:roll:

Thanks to everyone here for the help. Without it, I'd probably be wrestling with a bad design and spending more dollars trying to patch it up. And getting discouraged.

Here's what I have:

3 Kyocera KC85TS panels (85W in series)
Morningstar SS-MPPT-15 charge controller w/BTS
4 East Penn 8AGC2 batteries (6V 200AH @ C100 in series-parallel)
Trimetric TM 2020 Battery Monitor w/500A shunt
Xantrex ProSine 2.0 Inverter/Transfer Switch/Charger

The ProSine is connected to the battery bank with 7 feet (round trip) of #4 marine grade cable with a 300A fuse.

The SS-MPPT-15 is connected with 5 feet (round trip) of #10 stranded wire with a 25A fuse.

My largest weekend usage (680WH) was going to be the vent fan for those 85 degree 80% humidity summer nights. But last night I had to run the furnace! It got down to 47F. :roll: Looks like we got Marc's (Cariboocoot) weather and he has ours. Okay with me. :cool:

I'll post some pics when the panels are on the roof.

Happily,
Craig

Re: Small System for Pop UP RV

It was mentioned. But as I understand it the excess power will simply be unused and that it won't damage the controller. The angle of the panels will be a factor. When mounted on the roof it will be about 45 degrees. Voltage drop from the panels to the controller should be negligible. About 30 feet (RT) of #10.

I don't have room for additional panels.

I look forward to the new Morningstar MPPT.

Craig

Re: Small System for Pop UP RV

I am working on an album which will document my journey. This post has been very productive.

Last week I purchased a Honda EU1000I genny because I ran the battery bank down to 55% SOC over a cloudy weekend and there was no sun in the forecast. When I arrived at the camper last Friday, the Tri-Metric indicated 80% SOC. It took 5 days of non-use to recover this much. Once I was reasonably confident that the ProSine charger was properly configured, I fired up the genny and connected it to my shore power receptacle. Tri-Metric indicated ~+25A even as we watched TV and ran exhaust and furnace fans (our largest WH loads.)

During the summer I told my wife to watch voltage. That is, >12.7=go. If you see 12.3 slow down. If you see 12.0 or less... STOP. So now, while we're charging off the genny, I switch the Tri-Metric to indicate amps (I'm looking for them to start dropping which should be indicative of absorption.)

She looks over at the Tri-Metric, sees 25.0, and eyes go wide and jaw drops. I explain that we're not looking at volts anymore. LSS she starts to get it and says so.

Coupla hrs go by and amps aren't falling. Switch to volts to see that they aren't fluctuating. They're not. Back to amps and soon we see them decrease over the next 2 hrs. Down to 1~2A and I shut off the genny. Tri-Metric now shows AH=FUL and V is 12.7. Total genny time ~4hr (=.25 gal). Sunny the next 2 days. Cloudy so far this week. Might have to run genny again when we arrive coming Friday. So?

So now the system is robust and nearly complete.

How to mount the panels on the roof safely is the task at hand. Next year.

:-):-):-)

Craig

Re: Small System for Pop UP RV

Start of the album.

http://forum.solar-electric.com/album.php?albumid=12

OOPS! It's backwards.

Re: Small System for Pop UP RV

UPDATE!

In a few weeks, my system will have been operational for a year. It was installed on August 1, 2009. It was "off line" from Dec to Mar.

Now I offer some off the cuff observations and and solicit comments on the changes I intend to make.

First observation: 2009 operation was on the wanning side of the solstice. 2010 was on both wax and wane. And it appears that I have harvested more energy prior to the summer solstice this year than I did after it last year. Something I haven't done before now.

Second: Even with regular loads the battery bank rarely goes below 20% DOD. Two weeks ago, at the river, the air temp was reasonably low but the dewpoint was high enough to make sleeping difficult. We ran the Xantrex ProSine 2.0 all night to power a 120VAC fan, along with the 12VDC exhaust in the roof. This was the first time this year that the battery bank (according to Hobart's Trimetric) went to 80% capacity.

Third: I might halve the battery bank. Meaning that I'll just use two 6V 187AH in series. My PV will then charge at 8% of C20 and the weight load in the trailer (after rear axle) will have been reduced by ~ 200lbs.

I still have to find a way to mount the panels to the trailer.

It's been a great year, so far!

Craig

Re: Small System for Pop UP RV

icarus wrote: »

... As always, I could use a few more watts of PV for bulk charging, but since I am at float nearly every day, it seems unneeded.

My 255W of PV rarely float the 374AH battery bank if the previous night's draw was much more than slight.

BilljustBill wrote: »

... Instead of cutting down your battery bank to "Half", since you already have them, and maybe even add a few more...

Certainly won't be adding more batteries. If I remove two, trust me, I'll find a use for them.8)

BilljustBill wrote: »

... charge another set or two of batteries as you are traveling to and from your camping spots...

The camper is parked for the season (its second such) on land that we own and love. It is one hour away from our working week residence. Once the panels are mounted on the roof of the camper, we will probably make a few short excursions. First to "wet" campgrounds and later (preferred, hence the design) to "dry camps.

BilljustBill wrote: »

... use your panel system to extend your days or add more conveniences to improve the quality of your stay.

The Honda eu1000i can extend our stay to any length we desire. As for adding more conveniences. We already have more than we want. (I more than she.) But we both agree that adding more "conveniences" is not possible because we would view them as burdens, annoyances, loads or, ultimately, inconveniences.

We are both 30 year veterans of wilderness canoe camping. Standard eight night excursions. (Tony understands.)

dwh wrote: »

... it's big enough that he should have a couple of PVs on top to give it some extra juice while it's parked.

DWH, if you're talking about my setup, I do have three 85W panels. I just haven't decided how to mount them securely and safely to the roof in a way that would protect my investment and, more importantly, the road traveling public.

The point of my OP was to illustrate that I have learned much since the inception of this system. Tony is the only one that picked up on this point. My battery is/was too big for my PV.

My "predicted" loads required a battery of xAH. The roof of my camper limits me to <300W. Consequently, I over estimated my loads. (I might go for one more year just to be sure.)

But the results this year show that I have to try hard to deplete the bank below 70% charged. I've not done it yet this year.

With AGMs, if I take them to 50% a few times a year (EVEN! DoD or SoC) I would expect a maximum of 500 cycles. At 30 weekends a year this must still be 10 years or more and probably beyond the lifetime of the batteries.

So, fire, aim, ready. Take two batts out and the rest will do better.



Waht a wh0rhled.

Craig

Re: Small System for Pop UP RV

UPDATE: This summer we had a 30' X 80' pole shed built on our riverside camping property. We have set our camper up inside of it and continue to camp through the winter. Well, not this weekend. It has been snowing and blowing for almost 24 hours. Must be more than a foot on the ground; drifting MUCH deeper.

I'll be able to work on the camper this winter as well.

Anyway, I have added an album that documents the construction of the shed. It is only loosely related to solar energy discussions. I hope that it is found to be informative and entertaining regardless. Here is a link to my new album:

Upgrade to Four Season Camper

Please let me know what you think of it. 8)

Kamala