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Old 04-24-2014, 10:21 PM   #1
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My Solar Installation

Part 1 - Planning

Last year, after some thought and planning of future trips in our RV, we decided to install solar power on our 29í Holiday Rambler Traveler class A RV. This document is going to cover my experience with my DIY installation and the decisions I made in the process.

About me: I have no professional training, but I have been messing about with electrical stuff most of my life. Mostly this seems to have amounted to fixing some hooptie vehicle I own, but itís been its own reward. I also have a little experience with solar power. For a few years in the 90ís, when I lived in Key West, I owned an electric car that had 240W of panels on a tilting mount on the roof that could slowly charge the car. I also installed a 60W panel and a 7A charge controller in our first camper.

Still, I did a lot of reading, mostly of sources on the Internet. Here are some of the informational resources I used:

RV Electrical - Lots of good info.

Where RV Now? Solar Power - My brotherís site. Handy solar calculator there, too.

http://h andybobsolar.wordpress.com/2011/01/19/welcome-to-handybob-solar/ - Bobís kind of a curmudgeon, but a knowledgeable one.

http://roadslesstraveled.us/solar-po...-installation/ - Includes tutorials.

AM Solar's Educational Pages for RV Solar Systems - I bought a lot of my solar components from these guys, but they have some good information, too.

Additionally, almost every manufacturer has a website with technical documents that will be invaluable in planning your installation and in operating it afterwards.

About the RV: Our 2003 29í Holiday Rambler Traveler came from the factory pretty well equipped for power independence, with a fairly large battery bank of four 6V batteries, a 5.5kW generator and a Xantrex 1500W modified sine wave inverter/charger. The Xantrex works well as a charger, putting out a maximum of 75A back into the batteries, so just a couple of hours of generator operation will bring us back close to full. Our house battery system charges fast from the chassis alternator as well, so if we have a driving day moving from one site to another, it will mean that weíll arrive with full batteries. Weíve got a lot of roof space, so large panels are fairly easy to place. Finally, itís got a fair amount of basement storage, so finding a spot for a controller isnít a big deal.

Inside the RV, Iíve changed over to LEDís in many of the spots where we had incandescent light bulbs that saw frequent use. Iíve also removed the old 24Ē tube TV and replaced it with a low power consumption 26Ē LED 12V TV. All of our device charging needs are met with 12V chargers, so we donít need to turn on the inverter to charge a phone or a laptop.

I started by looking over our energy consumption, watching my 12v battery monitor on several trips. In my opinion, the first thing anyone whoís boondocking or concerned about understanding their 12V power situation should do is install some sort of power monitoring system. This will tell you how many Ah youíve pulled from your battery system. Simple voltage monitoring is not the same. Do this BEFORE you buy anything else.

Iíd suggest either:
LinkPRO or LinkLite from Xantrex ( I have the linkPRO and like it a lot )

Trimetric from Bogart Engineering ( Iíve used it and thought it was pretty good )

Clipper BM-1 from NASA Marine ( limited to 100 Amps, but they make it in a small surface mount version )

All of these will work like a gas gauge for your battery bank, telling you how much power remains in the batteries. They do this by measuring all the current going into and out of your battery pack and comparing it to the known capacity that you program into the unit.

After a few trips doing some dry camping, Iíve come to the conclusion that we can manage pretty happily on about 80Ah per day, as long as cold weather doesnít force us to run the furnace a lot.

Our battery bank is four 6V batteries, each rated for 235 Ah, wired in series for 12V, with the two 12 sets in parallel for a total of 470Ah @ 12V. If we discharge our batteries to 50% discharged, we have 235Ah of usable capacity.

235Ah ( usable capacity ) divided by 80Ah ( daily usage ) is 2.94 days of power out of the batteries before weíre at 50% discharged. Colder ( requiring the furnace ) or hotter ( requiring the fan-tastic vent fans ) days will require more power and we will get less time out of our batteries.

I expect that as we learn more about our usage patterns weíll get better at conservation, but weíll probably be using our computers more and thatíll increase the need for power. Iím hoping itíll balance out somewhat.

In the end, I settled for a goal of being able to put back 100Ah per day or better. If it doesnít meet its goal every day, thatís OK. More power daily would be better, of course. I figured that a 500 Watts solar installation would work for me.

My most challenging issue was how to get the power from the roof to the controller without a long wire run that wastes power, or where Iíd go through the interior of the coach. My refrigerator vent is on the side of the coach, so that wasnít an option, and everywhere else that had a space I could drill through the roof and run the cable didnít have a good path to the basement compartments. In the end, I decided to run it down alongside the tank vent and use heavy 4 gauge wire to limit voltage drop as much as I could, despite the long cable run.

I found a good deal on a MPPT controller from a company in Canada, so I ordered a Blue Sky Energy Solar Boost 3024iL and the battery temperature sensor so the controller could temperature compensate the charge voltage to the batteries. I chose this controller for several reasons.

It was in the wattage range I needed, though buying bigger always gives you the option to add more panels, a bigger MPPT seemed to be a jump of about $300.
It would fit well in the compartment I planned for it.
It had an additional 2A charge port for the chassis battery on the RV, assuring that it would always remain charged when the RV was parked, without any additional circuitry.
Good quality and track record, from what I could find on the Internet.

I liked the idea of being able to tilt my panels and liked the quality of the stainless steel panel mounts from AMSolar, so I ordered three of their 160 watt panel kits with mounts and 10/2 ( 10 gauge, two conductors ) wire. I also ordered a combiner box for the roof, and some 4 gauge wire to go from the combiner to the controller and then on to the battery bank from AMSolar as well.

The folks at AMSolar were very helpful before my purchase, answering questions and helping me understand exactly what I needed for my installation. One of the panels was damaged in shipping ( it looks like UPS punched a bolt-sized hole in it ) and AMSolar was quick to replace it. Also, while I bought three panels, each with 15í of 10/2 wire, three 15í segments would have been inconvenient, being too short where I planned to put one panel, and too long for another location. So they let me buy another 10í of 10/2 cable and sent me a single uncut 55í length, which I could cut to length as I needed. Very nice.

To max out the capacity of my controller, I decided to add one more panel, so I got a 60 Watt panel from Amazon and some inexpensive aluminum mounts. I knew that I couldnít tilt it like the other ones, but I couldnít find a 60W panel that would fit the other mounts. I also ordered some of the other assorted items I would need from Amazon as well, like the panel disconnect switch and the circuit breaker/battery disconnect. I also got cable ends, Dicor roof sealant and 3M VHB ( Very High Bond ) double sided tape for attaching the 60W panel and the junction box to the roof.

This would bring the panel wattage up to 540 watts, the maximum the controller would allow at 12V. Actual wattage will be lower in normal conditions, but I figured this would get me to my 100Ah/day goal.

Using my brotherís solar calculator, I should be able to get 100Ah or more per day ( in sunny conditions ) in any part of the US Iím likely to go in my RV, in any of the seasons that Iím likely to go there. So, while I canít get 100Ah in Wisconsin in December, Iím unlikely to visit then. In the south, in the summer, I could get as much as 250 Ah per day. Thatíll do.

The calculations donít take into account the possibility of tilting my panels, so if Iím somewhere for a while during marginal sunlight times, I may be able to adjust my panels to get additional power.

Next: Assembling all the bits and installing the wiring under the RV.

Photos here - https://plus.google.com/photos/10153...NKhpNigsd_DpgE
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Old 04-24-2014, 10:22 PM   #2
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Part 2- Installation

Part 2 - Installation

As mentioned earlier, UPS damaged one of the panels, so there was a delay while AMSolar shipped another one.

In the meantime, I laid out all of the other components on a table like a big schematic and walked through all of the steps I had ahead of me and checked to see if I thought I had all of the parts Iíd need. Of course, there were the inevitable couple of trips to the hardware store, but after going over it a couple of times I was pretty sure I had all the specialized components Iíd need. This also gave me a chance to prep some items, like the wire seals and holes that needed to be installed in the combiner box, or the cable clamps in the knockouts on the controller.

When my replacement panel arrived, I was ready to start.

I began by mounting the controller in a compartment close to the batteries and pulling a pair of 4 gauge wires from there to the battery box. I mounted the 50A marine circuit breaker in the battery compartment inline with the positive. I went ahead and connected it to the batteries, but I left the breaker open so the rest of the cable was disconnected. I also ran the temperature sensor into the battery box and the chassis charge wire to the chassis battery disconnect switch in one of the front compartments, connecting to the battery side of the switch with a 5A fuse.

All of these connections, with the exception of the controller ( which had large screw terminals for bare wire ) required crimped on lug ends of one size or another.

Note - If youíre going to do this yourself, most of what you need are normal hand tools, but if youíre going to be working with wire heavier than 10 gauge, I suggest getting a good pair of cable cutters ( Amazon.com: Greenlee 727 Cable Cutter, 9-1/4": Home Improvement ) and crimpers ( Amazon.com: Klein J1005 Journeyman Crimping/Cutting Tool, Red and Black: Home Improvement ) .

From the controller compartment, I had to run more 4 gauge cable up to the roof where the panels and the combiner box would be. I chose to run it up along side my black/grey vent pipe at the rear of the RV. This made for a rather long wire run, which is why I chose to use 4 gauge wire for this. If you have a refrigerator vent, I suggest using this route to get the power down from the roof.

I tied the wire along the back frame of the basement storage, going over the suspension on the chassis framem taking care to keep the wire secured with wire ties and up out of any of the points where the suspension would move.

On my RV, thereís a panel on the passenger side of the tank compartment that removes with about a dozen screws, exposing the ends of the tanks and the bottom of the vent pipe that goes up through the roof. With the tank ends exposed, I could see an open spot in the bottom of the compartment to drill a hole to pull the wire up. There was extra space around the floor where the vent went through, so I pulled the wire up through there. I then sealed the floor space around the cable with expanding foam and the bottom of the compartment with silicon sealant and put the cover panel back on.

I tied the wire to the vent pipe with plastic wire ties and ran it up to the ceiling of the RV. On the roof of the RV I removed the vent and cut a large enough hole in the side of the vent for the wire to exit. We replaced the vent ( now with the wire running through the side ) and covered the base and the wire exit liberally with sealant.

With the wire runs done, we took the cardboard that protected the panels during shipping and put them up on the roof to use as templates to figure out where we were going to lay the panels on the roof, as well as how much 10 gauge 2 conductor wire we would need to go from the panels to the combiner box.

With the panel locations penciled on the roof and the wire runs planned, we got back down and prepared the panels. First, we cut the individual runs to length and marked each panel with tape and a sharpie so the right panel ( with the right length of wire ) went into the right position. Then we crimped the wires from the panels to the cable runs and put heat shrink tubing over that to protect them. Finally, we attached the mounts with the included bolts and taped cardboard over the panels so they would not be putting out power while we connected them.

My RV has an aluminum roof, so AMSolar had suggested that the 3M VHB double sided sticky tape was sufficient to hold them in place on the roof without any additional screws and thus additional roof penetration leak points that come with them.

We carefully handed the prepared panels up to the roof and set them in their positions, laying the cables back to the combiner box, with a foot or two to spare. Where the cables ran alongside one another we tied them together with plastic cable ties ties ( use the black ties for UV resistance ) and stuck it to the roof with a cable tie mount. When we were sure we were happy with the position of the panels and the wiring ( make sure to leave enough extra wire to tilt your panels if you have tilting mounts!), we cleaned the roof well with rubbing alcohol and stuck down the mounts.

Next, we used VHB tape to stick the combiner box to the roof. We then ran each wire into the combiner box, cut it to length, stripped the ends and fastened them to the busbars inside the box. We did the same with the 4 gauge wire going down to the controller through the RV and put the cover on the box.

Then we went back and sealed around all the panel mounts, cable mounts and the combiner box. You want to totally cover the VHB tape to keep sun and rain off of it, to prevent degradation to the adhesive.

We removed the cardboard from the panels and we were done! Unfortunately, it was dark out by this time, so we didnít have any idea if it worked.

Details on how it came out, what I think I learned from this, and a mostly full component list with pricing in part 3.

Note - Pictures of many of the components and the installation are at https://plus.google.com/photos/10153...NKhpNigsd_DpgE
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Old 04-25-2014, 09:25 AM   #3
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Great read with photos. I think it should provide inspiration for others. System should be more than adequate for most situations. We did quite nicely for years with 400 or amp-hours at 12 V (5 kW-hours or about 2 kW-hours usable at 60%) and 400 and then 700 W solar.

Alas, my skills are zip and just had older son do design and fabrication for our system
We are going on 74 and son suggested adding more panels rather than going up on roof to tilt panels and so we did (rather he did). Panels are inexpensive and it is just a question of space and wiring. Son Cary ganged the panels in series to provide 90 V from roof. This decreases power loss but is a problem with shading.
Reed and Elaine
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Old 04-25-2014, 11:02 AM   #4
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Excellent write up Eric. Including reference link is very, very helpful!

Hope you enjoy the new found power - it is a swell thing!
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Old 04-25-2014, 12:49 PM   #5
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My Solar Installation - Part 3

Part 3 - Results, lessons learned and component list with pricing

I had to work the next day, but when I tested the system the following weekend, I saw a max of 26.2A going into batteries that were just 3% drained by heating a cup of water in the microwave for a few minutes.

Interestingly, this current is a little under what my brotherís solar calculator ( Where RV Now? Solar Power ) comes up with as the theoretical maximum for my panels on the date they were measured. I think that means the system is working pretty well.

If we assume that the calculator is accurate ( now that we have a number that seems to match ) this means that my panels will, on an appropriately sunny day, put out my goal of 100Ah or better until mid November in any latitude Iím likely to visit at that time. Actually, if Iím that far North at that point in the year, Iíll be looking for shore power for a heater.

Mission Accomplished.

As for the lessons learned, well, I didnít cover this much in the planning post, but I had originally seen the 3024iL listed as a 40A controller, which it kind of is under certain conditions. So, I had originally planned on purchasing four 160 Watt panels ( rated at 9.6A Short Circuit each ) for 640 watts, rather than the 540 I ended up with.

However, once I got the controller in hand and read the manual, I discovered that the 40A rating is only the OUTPUT side of the MPPT controller, and only when the input side is using 12V panels going to a 12V system. Under all circumstances, the input side is limited to 30A.

The controller can take 24V input, but then maximum power is limited to 400W.

This meant that I couldnít use the four 160ís I had originally planned, either in series or in parallel. So I cut back to three 160W panels and added a 60 Watt to round my output to the controller maximum wattage at 12V of 540W.

The lesson: If youíre doing the planning and install yourself and you donít have extensive experience with this stuff, you need to hit the internet, download the MANUAL ( not just the spec sheet ) and READ IT. Particularly if youíre operating anywhere near the limits of the equipment.

The good news is that I did eventually read it before I ordered my panels and so the results I got are still within my original goals, even if theyíre 100W down on my first plan.

Issue 2: The installation required something like a dozen trips to the hardware store for little fiddly bits that I didnít realize I needed until I actually tried to assemble the whole deal. 2 tubes more sealant than I had figured, stainless hardware, butt connectors, more cable lugs after I crimped two of them poorly, that sort of thing.

The lesson: unless you live RIGHT NEXT TO hardware store and an auto parts store ( a good place for high power battery connectors and stuff ) get extras of almost anything that you need multiples of, can be thought of as ďsuppliesĒ and isnít very expensive. $30 worth of that kind of stuff before I started would have saved me a weekend of putting the installation off because I didnít have everything and $20 in gas running to the hardware store in the middle of the job.

Issue 3: The job took way longer than it sounds like in my description. Just running the wiring around on the underside of the RV took most of a week of after work labor crawling around by myself under the RV. After that it was most of two days assembling the panels and getting everything installed on the roof, since there were complications with the roof vent installation that I didnít cover here.

The Lesson: Guess how long itíll take and double it.

The complete parts list and costs:

Roof Combiner box $72.00 AM Solar
35' 4/2 cable $175.00 AM Solar
10' 10/2 cable $25.00 AM Solar
3 cable seal $9.00 AM Solar
4 4AWG lugs $4.00 AM Solar
Shipping $58.00 AM Solar
Four tubes sealant $30.00 Amazon
10 tinned copper lugs $10.00 Amazon
3M VHB tape 3/4" $20.00 Amazon
Renogy Z brackets $13.00 Amazon
50A circuit breaker $29.00 Amazon
High current switch $24.00 Amazon
Plumbing vent kit $6.00 Amazon
60W solar panel $105.00 Amazon
3024iL and temp sensor $275.00 WeGo Solar
Cable ties $6.00 Home Depot
Nylon cable holder $2.00 Home Depot
Stainless bolts $6.00 Home Depot
Silicon sealant $4.00 Home Depot
Expanding foam $6.00 Home Depot
5A fuse holder $2.00 NAPA auto
15' 16/2 wire $10.00 NAPA auto
Crimp connectors $4.00 NAPA auto
Self Tapping Screws $2.00 Home Depot

Total $1,977.00



Note: The Solar Panel kit from AM solar included the panel, mounts, 15í of 10/2 wire, cable ties and cable tie mounts, VHB tape.

AMSolar was very helpful, answering a bunch of questions or confirming the decisions I had made. They also helped to make sure I got all of the specialty pieces I would need in one order. I would definitely order from them again.

Amazon is tough to beat for cheap prices and fast, cheap shipping, but you get almost zero support, so it can be tough to put together a package without any missing bits. Still, if you had the right installation, you could put together a 400W MPPT system from Amazon for about half what I paid for my 540W one, though youíd have to make some compromises.

In Conclusion: Over the course of a few months of planning and ordering, followed by a couple weekends of messing about on and under the RV, I successfully installed a high quality 540 MPPT solar system on my RV for just under $2000. Iím pretty happy with that.

Thanks for reading. Feel free to email with questions: airmon at gmail dot com.

Note - Pictures of many of the components and the installation are at https://plus.google.com/photos/10153...NKhpNigsd_DpgE
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Old 04-25-2014, 04:30 PM   #6
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I just noticed, in the copy/paste process from where I wrote this, I lost the price of the panels. Sorry about that...

Three 160W panel kits $1080.00 AM Solar
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Old 04-26-2014, 06:27 AM   #7
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a lot of good info here. thanks
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Old 04-26-2014, 10:15 AM   #8
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You did a fantastic job for a quite moderate price. But your handyman skills are far superior to mine. AM has an excellent reputation (probably the best for RV solar) and is where we would have considered going (all the way to Oregon) if our older son were not in the business of commercial solar work (currently finishing as prime sub-contractor on 1.5 megawatt system for power company). Son is off-grid, daughter has 7 kW on-grid and brother in law has about 3 kW on grid.

We have similarly installed a number of 12 V outlets (aka cigarette lighters) around the 5th wheel: above the lounge chairs, in the rear, two over the bed, two under the “desk” (most Open Range have these as an electric “fireplace which we ordered without fireplace since Elaine used it for beading), and two in the forward baggage compartment (floodlamps as required and water pump). The “fireplace” is used for storage and one outlet is used for the booster antenna for the tire monitor system. The 12 V are used in summer for 12 V fans which make a large difference on warm nights for sleeping.
We had a propane outlet installed next to refrigerator so that we can use a catalytic propane heater for nights when it does not get far below freezing. This saves on electric power and propane. The catalytic heater keeps the living room down to the teens but it does not keep the baggage compartment and thus the plumbing from freezing. This is T’ed to the propane going to the refrigerator.

We primarily boondock but have hooked into power in Mexico (boondocking solo is not advised in Yucatan unless with a few friends – drycamping at all night truck stops is quite safe - even though the Yucatan has the lowest murder rate of anywhere in the world) and it can be spotty (voltages going from 85 to 145 V). Heck, it can be spotty in the US so our son installed battery chargers on previous rig when they flew down for a week to visit on beach in Yucatan. He did his professional job on current rig. Power comes through 15 amp power cord (20 amp cord will cause lower V loss but haven not been able to find one) to battery chargers, to battery, to inverter etc. Batteries are not as fussy as the microwave (burned one out in Baja and another in Yucatan through the 30 amp power cord) and AC (almost lost one at a state park near Denver, CO) and once it goes through a PSW or MSW inverter, the electronics are fairly happy. We have tossed the 50 amp and about to toss the 30 amp power cables. We have a 4 kW PSW inverter so that we can start (takes over 2 to 2.5 kW to start) and then run the AC if we do use line power through this system. You might have problems getting it started in this manner with a 1.5 kW inverter. 1.5 kW inverter will allow MW to be used in this manner.

Hope you write further of your system.

Reed and Elaine Cundiff
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Old 04-27-2014, 10:24 AM   #9
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This article is a gift, thank you!
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Old 04-27-2014, 12:23 PM   #10
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I absolutely agree with Tobias. I should hope that you write further of your experiences and developments with your system. We have only had good experiences with our systems over six years.
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Old 04-28-2014, 04:29 PM   #11
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Reed –
Thanks for the compliments on my handiwork. It sounds like you have very good resources to call on to assist you. IIRC, you have an LFP battery pack, right? Have you done any writing about your experiences with that? I have contemplated installing one, but eventually decided to wait and see how well my current system ends up fitting my needs.
Thanks for the Mexico information. We might make it there some time.
As I learn more about how the system works out, I’ll report back.
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Old 04-28-2014, 06:20 PM   #12
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Eric

I have written on the LFP before and hope I do not bore others in responding.

So far the LFP has lived up to highest expectations. It consisted of 4 battery packs in series. Each battery pack is four 180 amp-hour LFP batteries of nominal 3.3 V in series to give a 180 amp-hours battery pack at 13.2 V nominal. The 4 battey packs are then put into series to provide a battery suite at 180 amp-hours at 52.8 V nominal (the suite floats at about 54.7 V). 180 amp-hours at 52 V or so nominal is 720 amp-hours (actually closer to 800 amp-hours) at 12 V. So it is probably easier to put things in absolute terms, that is, the system has about 9500 W-hours of which 80% is usable for several thousand cycles (7800 amp-hours) and 90% usable (8500 amp-hours) for perhaps a 1000 or more cycles. Liberty Coaches claims 2000 cycles at 90% usage (10% left)

We have used system since June when son Cary designed and fabricated the system. We have hooked into line/generator power once (other than testing system). We have gone a week in shade (about zero solar) and three or four days in snow (8" on roof) with forced air heater running at 20F. We use the microwave more than the stove for making coffee/tea/soup since the power is free. We generally turn the refrigerator to inverter and run off solar during sunny days, If we know it will remain sunny, we just leave the refrigerator on inverter overnight and that has us at 60% power in the morning.

The one time we did charge up, son Charlie came out (we were parked in their backyard) to say "Dad, the radio just said the power lines may go down in this flood, you better make sure the batteries are charged since we may all be camping out in the trailer!" Plugged in with 15 amp cord through the battery chargers and we were charging at, surprise, 1500 W and it took two hours to charge, um 1500 W x 2 hours gave us 3000 watts and we were at full charge (it was overcast but we were still pulling in 300 W).

The LFP charge almost linearly to full charge as opposed to PbS. The following is ripped off from Technomadia (who ripped it off from a technical journal)
"LiFePO4 batteries can be ďfastĒ charged to 100% of capacity. Unlike with lead acid, there is no need for an absorption phase to get the final 20% stored..."

Our experience was noted above.

Also from Technomadia "Another huge advantage of lithium batteries is that Peukertís losses are essentially non-existant. This means that LiFePO4 batteries can deliver their full rated capacity, even at high currents. Whereas lead acid can see as much as a 40% loss of capacity at high loads. In practice, this means that LFP battery banks are very well suited to powering high current loads like an air conditioner, a microwave or an induction cooktop." Have attached a lithium-power curve also ripped off. Not sure it uploaded.

We use, as noted above, the microwave quite a bit and have used the air conditioner several times but prefer to avoid the areas where we would have to use it.

We probably have way to much battery storage - but then is there ever enough. Cary noted there was easily room for another two batteries and perhaps four more but near 20,000 amp-hours would be even more absurd than what we have. Cary has harassed me about his system "Dad, you just have it to show off!" Cary, you were the one that talked me into it." "Yeah, Dad, but you now have it.

You have about 450 or so amp-hours at 12V nominal or about 200 to 225 amp-hours usable. Two of the battery suites such as we have we provide 360/400 amp hours at 12 V of which 320 amp-hours at 12 V would be available for 2000 to 5000 cycles and about 360 amp-hours for 1000 to 2000 cycles. The power level nose-dives at 15% capacity. This would weigh about 130# Weight/volume are important to us. We had about the same amount of PbS batteries as you (glass mat) on first two iterations of rigs and they weighed in excess of 300# (about 0.7# per amp-hours as I gather from literature - maybe worse for glass mat)

Hope to hear more from your experiences

Reed and Elaine
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