Tuesday, October 17, 2017

Going off-grid in a 2017 Keystone Cougar Fifth Wheel as part of our Solar CITIES research/demonstration project at Rosebud Continuum

This is just a diary to jot down what we are observing in our quest to go off grid.
The first problem we have had was a bad battery in the new RV.

Perhaps it was a hidden blessing.  Our brand new RV -- a 2017 Keystone Cougar Fifth Wheel -- was delivered on Thursday night (October 12th), the on-board battery was used when it was moved in position and decoupled from the delivery truck to level the jacks and to demonstrate the unit to the family at Rosebud Continuum (lights turned on for about 15 to 20 minutes) and then we shut everything down and went to sleep in the house.  The next morning the battery -- a brand new battery mind you -- was dead.  My wife called me to say the lights wouldn't turn on.  I advised her to leave everything off and wait for me to troubleshoot.
I got home too late, after dark, to do any work on the issue, so on Saturday morning I hauled out the multimeter and checked the battery.
It read an appalling .009 volts -- as dead as a dead battery can be.
After calling the Camping World tech in Illinois and going through troubleshooting it was advised that I disconnect the battery from the vehicle's converter (which I was told draws 10 amps and could blow a fuse) and hook the battery to a charger to see if we could bring it back to life.
The first thing I did was haul the 3.2K Predator generator from the house to the RV and fire it up on gasoline (it can run on both gasoline and biogas, but we didn't have enough biogas to run it for the required hours the tech said we needed) and plug in the deep cycle battery charger I got at Walmart (INSERT TYPE HERE) and connect it to the terminals.
After several hours the battery at most reached 2.5 Volts and when taken off the charger, even though not under any load, quickly drained to between .3 and .5 volts.  Not good. And I was running out of gas.
Next I got two very long outdoor AC cables and ran them from the tennis court outlet to the RV, hooked the charger to the house current and let it charge that way.  After 5 hours we had reached 11 Volts on the charger, but when it was disconnected it quickly drained down.
The next trial was to hook the house current to the RV Alternating Current cord itself (with a 50 amp to 15 amp adapter) and try charging the battery from the in-RV converter.
This seemed to work, and the multimeter after a few hours read 13.5 at the battery, which is great. But when we disconnected the battery and read the voltage it steadily dropped.
We charged it up again to 13.5 until late evening and then disconnected it overnight to see if the battery would hold its charge.  The next morning it read 3 volts and then dropped to 2.7 which is where it stayed Sunday morning.
Thomas, the grandfather of Kylen Newcomb, our Blake High School student environmental artist, came to pick him up when he was working on the dragon biodigester sculpture and it turned out he spent his career building deep cycle batteries.  He checked the battery and said "it must have an internal short.  Only one of the cells is functioning".  12 volt batteries generally have 6 cells with a nominal voltage of 2.1 Volts.  In this case 4 or 5 could be bad.
The folks at Camping World were concerned that parasitic loads on the battery that first night, without being hooked up, could have drained the battery down to zero. They said that RV's aren't made to go camping and not be hooked up to some source of battery charging energy.  Still this didn't sit well with me -- with everything turned off, parasitic loads shouldn't drain the battery down to 0 over night...

At any rate, the blessing is that with the battery not working my student Li Zhu and I were forced/inspired to start measuring all the loads in the new Fifth Wheel and to set up my solar charging battery bank and 1500 watt inverter so that we DO have a source of battery charging energy without relying on house current.

Here is what we found:

With the inverter supplying energy to the RV and the connector turned on and the bad battery connected we saw a spike of 400 W that settled down to 280 watts as the inverter was supplying energy to charge the battery.  We don't know if the converter on the RV is a three stage (preferred) or a single stage (not great) for sure; the tech from Camping World Illinois seemed to think it is just a single stage.
At any rate the battery was pulling 280 watts continuously off the solar inverter.
With this base load we then tested all the loads in the RV

Living room ceiling lights: 50 W
Kitchen lights: 10 W
Flood Lights: 20 W
Step lights: 0 W (this is what the inverter displayed, meaning low enough that it is hard to measure for that inaccurate inverter).
Bedroom lights: 40 W
Stove light: 30 W
Stove fan: 30 W

When the "Reception" Circuit Breaker was put on the inverter showed a dancing wattage of 270 to 280.

With reception on the outlets and lights in the living room of the RV work.  By seeing how each appliance affected the base wattage of 270 to 280 we were able to calculate the load from that appliance.
Our cylindrical fan consumed 30 W
The Round Fan: 30 W
Vent fan: 10 W
The living room vent motor consumed 30 W
The microwave light: 20 W
The microwave: spikes at 910 W, settles to between 840 and 870 W
Microwave circuit breaker on (phantom load of MW): 20 W
The Water Pump: 100 W
Dining Room light:  20 W
Awning Light: 10 W
Loft Light: 10 W (for 2 bulbs)
TV Living Room: 50 W
Middle Room Light:  20 W
TV Middle Room: 40 W
Bathroom Light: 30 W
Bathroom Fan: 30 W

The next test was to disconnect the battery and see how the draw on the inverter registered.
Here we saw:
Ceiling light in living room: 130 W
Pendant Kitchen lights: 10 W
Flood light: 20 W or 90 W.
Flood light and ceiling light together: 150 W
Water pump: 190 W
Water pump and living room ceiling light together: 230 W

From this, knowing that the ceiling lights drew 50 W when it was coupled with the battery charger converter, it appears that when you aren't charging the RV battery the basic use of the converter circuit breaker on to the converter consumes 80 to 100 W for making power available to the 12 V side, so no matter what 12 V appliance you use it will consume its wattage PLUS 100 Watts.
For this reason, the bathroom light, which should consume 30 W, showed 110 W when used alone.

The water pump is 100 W, and the ceiling light 50,  but when used with the converter and no battery it draws an additional 80 W.

The refrigerator, if run on electricity, draws 360 W (but dances up to 380 and 390).
Bathroom light alone shows 100 W, but when combined with the fridge shows about 50 W.

Our big white floor fan used 130 W on highest setting, 120 on middle and 110 W on lowest setting when used with converter circuit on  by itself.
When the battery was connected it consumes 80 W on highest setting, 70 on middle and 60 on lowest.

What we seem to be observing is that the RV needs to use a 12V battery to use the lights and many of the loads and if you don't have a good battery (or if the battery is disconnected) you still need to run the converter to provide that, and the converter draws between 80 and 100 W.  The AC outlets work without the converter circuit running, so we brought an LED lamp into the RV that could be powered off of a wall socket.

In this way the RV industry is making it a bit difficult to go off grid.  The connection of the two systems and the need to constantly have a battery on board that constantly needs charging is a bit problematic.
Our RV is 150 feet away from the sunny area (it is under the shade of trees) so running DC current from the solar panels to the battery in the RV, even though it has a solar charging port) is unfeasible as the line losses (voltage drop) for long runs of 14 gauge wire (the only thing affordable) were about 12% (we see a voltage of 16 V  20 feet from the panels and 14 V 150 feet from the panels).
So it is better to charge the batteries next to the panels (within 15 feet) and invert to 110 and run a standard garden AC extension cord to the RV and do everything through the RV circuitry (which means using the converter to go back to DC to charge the onboard battery).

In future we will see if trickle charging the RV battery from the solar panels is effective without investing in thick cables. Perhaps we can use 10 gauge...

The journey is just beginning...lots to experiment with and learn.


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