Quote:
Originally Posted by Stevens10
Took our unit for its second big trip. We left Indiana and headed for the southwest. Spent 3 weeks wandering in the warm and sunshine. Visited the Grand Canyon for the fifth time, but first with snow! Did our first boon-docking, loved it. Tested our new solar install, 600 watts of Renogy panels. It worked great, but we need more battery, when it was cold at night it usually ran out of power to operate the furnace about 4 am. But in general we loved the RV life and really did not want to return to the cold and snow, prior commitments required it. A few pictures. The first is boon docking in the Kaibab national forest just south of the grand canyon national park, the second shows my solar install at home before leaving. Good times!
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Some information about our solar installation and now a new Lithium Iron Phosphate battery bank.
We purchased Renogy solar panels, six 100 watt units and a ROVER ELITE 40A MPPT SOLAR CHARGE CONTROLLER. I built an aluminum framework to support the panels and screwed it to the roof support ribs using Lexcel caulk to seal the connections. You can see the install in my previous post.
I purchased the matching connector fittings from Renogy and used some SJO 10 gauge cable to connect the 6 panels in combination series parallel to give 24 volt feed to the controller.
The controller will then modify the voltage and increase the current to match the needs of the battery bank. The charge controller can be set up to match either flooded, gel, or lithium batteries.
We used the unit on a three week trip, most of which we needed to run the furnace during the night to keep warm, but had issues with the 320 amp-hour flooded battery bank not being able to last through the night. My batteries were 2 1/2 years old, but I had neglected them and let them get fully discharged numerous times, so they were not up to the job.
Upon returning home I started researching lithium batteries. I found out that unlike lead acid, in which the voltage drops off rapidly once you have used up about half of the rated amp hours, the lithium maintains its voltage until nearly all of the capacity is used, according to the supplier literature.
I also found out that most of the actual lithium cells are manufactured in
China, US supplier buy the cells and assemble them into battery banks.
I chose to purchase a Chinese assembled battery, for a significantly lower price than the various units that are assembled in the US. I purchased two 300 amp hour batteries, the cost was close to $2600.00 for the pair.
I also purchased a Renogy DC to DC battery charger so that I could fully charge the lithium batteries from the engine alternator. Lithium batteries need 14.8 volts to realize their full capacity, which is beyond what the typical lead acid charging alternator can deliver, and the lithium batteries can charge much faster and would probably overload the alternator without the battery charger, which limits the maximum charge rate to 60 amps.
The lithium batteries were too large to fit two into the space where two of the lead acid batteries were, so I installed one there and the second one under the refrigerator next to the inverter /charger. I installed the DC to
DC charger in the rear compartment where the other two lead acid batteries formerly resided. I was able to use the existing battery cables to connect the charger and the two batteries, but had to make two more cables to go from the last battery to the inverter.
To test the system I plugged a 1500 watt electric heater into the 115 volt outlet, the inverter ran it with no issues. Before the inverter would immediately shut down because the input voltage would drop too low. In fact it ran the heater and the input voltage stayed above 12.5 volts. I then added the microwave to the load and it still worked perfectly and maintained 12.1 volts.
I have not yet used the unit overnight, but I am confidant that I will be able to boon-dock indefinitely with this system. The solar system is able to recharge the battery bank much better, since it will take all the amps the unit can produce, unlike the lead acid batteries which charge much slower.
In the event that the sun does not shine enough, the generator will be able to recharge the batteries much quicker since they can take all the capacity it can deliver.
We are heading out this weekend for a short trip, and then on the 21st for a longer stay in the south. I will report back on how the system worked.
I will be glad to answer any detailed questions anyone has about what I have done and how it works, and can take pictures if needed.
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