New Project, Solar for Class C

[SargeW]

Nice work and write up Bill. Running an AC unit and only reducing the SOC by 11% is impressive. Just for info, were you running 1 AC, and was it a 15,000 BTU unit? Did you happen to note what the recovery time was on the batteries once the load was removed?

 

[HueyPilotVN]

It was one 15,000 BTU unit. The outside temp was 102 and the compressor ran for the full hour.

Here is some more data. This is still somewhat theoretical until I do a very detailed and longer run of the system with time benchmarks and power curves.

I do have three different data monitors for measuring both the Blue Sky system for the solar component and the Xanbus network system for the Invertor.

The SOC shows a net usage of approximately 92 amps during the hour. I had hoped for a difference between solar charging and output of something more like 50 amps an hour.

Parasitic loads and conversion factors may have played a part in the higher than expected net loss.

The isolation of the front DC system from the rear A/C power generating system splits the amount of charging that I get from solar. If they were combined into one 1,200 amp hour battery bank with 130 amps from the panels than the operation would have been closer to a lower net operating loss.

The only load that I believe was drawing power other than the A/C was the LIthium charger for the front 300 AH battery that services the DC loads. It should have been on float.

I did not monitor the recovery time for the battery bank after shutting off the A/C. However. I can make a guess based on prior data. The solar input for the back battery bank alone is about 100 amps and would recharge the system in a little less than one hour with no other loads.

If I turned on shore power or the generator I would have a faster recovery time as the Invertor/ charger has been measured to charge at a rate of 149 amps. The two inputs should recharge the batteries is less than 1/2 hour. This also depends on if the voltage had dropped enough to trigger bulk charging rather than absorbtion.

One of these days I will do a much more detailed test with real world data.

 

[HueyPilotVN]

I could not sleep so I thought I would update the latest data on the run times for providing Air Conditioning using the Bubba Edison System.


Here is the short version and I will post a longer version with data points later.

Lots of measurements but still some unknown variables.

I now believe that the system will deliver 24-hour Air Conditioning with an assist that I will explain.

The system operates at an average net loss from the battery bank capacity of about 75 amps per hour during the day with solar input. The previous 92 amp per hour measurement was at 102 degrees. The solar panels provide just over 100 amps, and the Invertor draws about 175 amps DC. This gives it a run time of about 6 hours to get to 50% (SOC) running on just the 900 amp/hour Lithium batteries in the rear system.

At 6 hours, or 50% soc. the AGS starts the generator to augment the system.

The 4,000-watt generator takes over and continues to power the Air Conditioner and it also provides 150 amps of charging to the battery bank through the Invertor Charger.

During the day the solar panels also provide another 100+ amps per hour to recharge the battery bank. Without the 175 amp load, In 2 hours the battery bank is back to 100%.

The generator shuts off and the cycle can restart. During this second 9 hour cycle the Air also runs continuously.

The second cycle ends in the evening with little or no solar power input, so the recharge time is just over 3 hours to 100%.

If the first cycle begins at 8 AM, then the first recharge would begin about 2 PM and last till 4 PM. The second cycle would last till about 1 AM and would take longer to recharge without solar. At this time the Air Conditioner would have run continuously for 17 hours, and it would be about 1 Am in the early morning.

At this point you would have two options. First option is to run a third cycle if the night is very hot, or the second option would be to shut off the Air.

With either option the battery bank would be fully charged in the morning for a repeat if needed.

At about $ 13,000, it is not a cost-efficient solution, but it was always mostly an experiment to see if it was possible.

It is 3 AM right now so I will give more specific data later.

 

[Ex-Calif]

Hard to follow the data in narrative form. Can you summarize something like this:

24 hour consumption = XX amps
24 hour solar collection = YY amps
24 hour generator collection = ZZ amps & AA run time

 

[Frank B]

"At about $ 13,000, it is not a cost-efficient solution, but it was always mostly an experiment to see if it was possible."

Understood. An extreme system for an extreme climate. In those kinds of temps, most of us would hunker down at home with the central AC turned on. Few of us in Canada winter camp in our RV's either. But in what the RV parks call the "shoulder season" it is not only possible, but can be quite enjoyable.

What interests me more is that it might be quite possible to run the AC part of the time when temperatures are uncomfortable, but not as extreme all day long.

We are doing that now in Alberta. It is in the high 80's (31C) during the day, but cools off well in the evening. Not hot for the desert dwellers, but plenty warm for us northerners. I am running the AC off a Honda 2K genny for a few hours in late afternoon and early evening. Fantastic fans care for the ventilation otherwise when we are not sitting outside in the breeze under the awning.

Using AC with the genny works just fine, but it is SO quiet here otherwise that I hate the constant drone. I would love to upgrade my system a bit to be able to run the AC off solar for a few hours a day.

 

[HueyPilotVN]

Hard to follow the data in narrative form. Can you summarize something like this:

24 hour consumption = XX amps
24 hour solar collection = YY amps
24 hour generator collection = ZZ amps & AA run time

_____________________________________________________________________________________

This is a complicated supply and usage situation with variables dependent on run time and hours of sunlight.

The actual average amperage consumption for the 15,000 BTU air conditioner is approximately 126 amps DC or just over 10 amps AC without any other loads. If it ran for 24 hours it would consume just over 3,000 amps, (3024). The supply for usage comes from three sources of energy, (the capacity of the bank, the contribution of the variable solar input, and the augmenting of charging from the generator). When the generator is running there is not only no depletion of the bank but actually a recharge of the bank.

The solar collection is from 1,200 watts of panels feeding the bank through three charge controllers that provide when measured in full sun of 33, 35 ,and 36 amps, for a total of 104 amps to the 900 amp/hour bank. This is only available during the day and is also variable based on sunlight. This is s snap shot of solar collection.

The generator takes over the load of the Air conditioner when it is running to recharge the battery bank removing the depletion of the batteries. In addition the generator contributes approximately 150 amps of charging to the batteries, (actual prior measurement was 149 amps) The variable here is the run time, and is dependent on the solar contribution and the SOC.

All of these numbers can be influenced by several factors.

The amount of sunlight and the duration of the sun shining.
The outside temperature.
The cycling of the A/C compressor.
Other loads on the 120 volt system.

A major influence on the power consumption for Air conditioning is how long you continuously use the cooling. If you turn off the A/C for any period it will allow the solar if available to help catch up on recharging,

This is not an all or nothing system. Shorter run times will extend the batteries.

 

[HueyPilotVN]

Frank,

Using the system for shorter periods of time will greatly aid in recharging the batteries by removing the constant depletion of the SOC and allowing for the solar to add to the SOC.

You might even be able to use the A/C for shorter periods and only recharge from the panels and not need the generator.

The basic numbers above may help in designing a smaller battery bank for shorter runs.

 

[Frank B]

Frank,

Using the system for shorter periods of time will greatly aid in recharging the batteries by removing the constant depletion of the SOC and allowing for the solar to add to the SOC.

You might even be able to use the A/C for shorter periods and only recharge from the panels and not need the generator.

The basic numbers above may help in designing a smaller battery bank for shorter runs.

I have 1230 watts of panels, but am currently limited by my storage (6 x GC-2 fla) and the location of my 2500 watt Sunforce pure sine inverter inside a storage cubby. Not enough airflow to keep it cool. I only have a single 1350 AC, however. I can run the AC now with what I have, but not for very long.

Swapping out the GC-2's for some lithium batteries, and relocating my inverter might make part time AC possible for me. But that is another project for another day.

 

[Ex-Calif]

This is a complicated supply and usage situation with variables dependent on run time and hours of sunlight.

Yeah I get all that. I was just asking for a summary of your "real world" data collection. I also know that for the data to be representative and valid you'd need a lot more data collection.

 

[HueyPilotVN]

I had to make a new change to the system that I thought I should share for safety.

Recently I added a method of connecting the 12 volt supply to a external load. In this case the Macerator pump by way of an extension and a connector.

As I was working on adding this capability, I found that my disconnect switch from the battery bank to the Invertor was welded in the closed position, which prevented me from shutting off the battery connection.

I was able to disconnect the switch by removing the nuts from the switch.

The standard disconnect switch is rated at 275 amps and I replace it with one rated at 600 amps.

Amazon.com

 

[Frank B]

I had to make a new change to the system that I thought I should share for safety.

Recently I added a method of connecting the 12 volt supply to a external load. In this case the Macerator pump by way of an extension and a connector.

As I was working on adding this capability, I found that my disconnect switch from the battery bank to the Invertor was welded in the closed position, which prevented me from shutting off the battery connection.

I was able to disconnect the switch by removing the nuts from the switch.

The standard disconnect switch is rated at 275 amps and I replace it with one rated at 600 amps.

Amazon.com

Oh my!

 

[Kevin Means]

LOL! Now THAT's a solar system!

 

[candydonzs]

I’m another one looking forward to seeing this out in the field. I’m interested in seeing those batteries perform.

 

[HueyPilotVN]

Update:

I am posting this after the fire that destroyed the RV and most of the Bubba Edison components.

I have purchased an almost identical replacement RV, and I am rebuilding a new system.

I am going to make a few changes to "Bubba Edison Version 2.0".

The old system had three 300AH Lithium batteries in the back compartment that provided the input of 30 amps AC to the main electrical panel of the RV for constant power, like plugging into shore power all the time.

I had a separate 300 AH battery up front under the couch to power the DC needs of the RV. It was charged from the replacement Lithium bottom section charger in the WFCO convertor/charger as well as with 400 watts from two panels on the roof.

It had a separate monitor and every time I looked at it, the front battery was at 99% SOC.

The solar input was redundant because the constant power from the Invertor to the convertor/charger kept the battery fully charged all the time and the charge controller from the panels was basically always on float.

The new system will have four 300 AH batteries in the back instead of three, and all 1,600 watts of solar will feed the larger back battery bank.

This will give me 25% more capacity with 1,200 AH to the Invertor to run the AC power to the main panel.

Currently, the new RV has two AGM batteries under the steps for the coach DC loads, and I do not think that I need a LIthium replacement because it is constantly being charged by the 24/7 AC from the Invertor, so capacity is not an issue.

I will update as it comes together.

 

[Frank B]

Update:

I am posting this after the fire that destroyed the RV and most of the Bubba Edison components.

I have purchased an almost identical replacement RV, and I am rebuilding a new system.

I am going to make a few changes to "Bubba Edison Version 2.0".

The old system had three 300AH Lithium batteries in the back compartment that provided the input of 30 amps AC to the main electrical panel of the RV for constant power, like plugging into shore power all the time.

I had a separate 300 AH battery up front under the couch to power the DC needs of the RV. It was charged from the replacement Lithium bottom section charger in the WFCO convertor/charger as well as with 400 watts from two panels on the roof.

It had a separate monitor and every time I looked at it, the front battery was at 99% SOC.

The solar input was redundant because the constant power from the Invertor to the convertor/charger kept the battery fully charged all the time and the charge controller from the panels was basically always on float.

The new system will have four 300 AH batteries in the back instead of three, and all 1,600 watts of solar will feed the larger back battery bank.

This will give me 25% more capacity with 1,200 AH to the Invertor to run the AC power to the main panel.

Currently, the new RV has two AGM batteries under the steps for the coach DC loads, and I do not think that I need a LIthium replacement because it is constantly being charged by the 24/7 AC from the Invertor, so capacity is not an issue.

I will update as it comes together.

Oh my! SO SAD that it burned! RV fires go SO fast.

No one hurt, we hope?

 

[HueyPilotVN]

No one hurt

 

[HueyPilotVN]

The story continues:

I have ordered and received almost every item that i need to rebuild the system.

I have lined up a couple of guys to do the physical labor for the installation.

I am assembling all the panels, cradle mounts and wiring for the roof in my garage.

I have a fellow, Mr Hawks, who power buffed out my old RV, picking up the new one tomorrow night to do the same process on restoring the exterior.

After that we will install the panels and get going on all the rest.

I will post pictures tomorrow.

I also got in contact with Paul from ARP about having him do an install of the Fridge Defend at Quartzsite. He installed the one on my old Country Coach DP years ago. I eventually replaced that Norcold with a residential fridge.

He is not going to be at Q, so I will just order it and have it installed.

 

[HueyPilotVN]

I spent most of the night working on the Bubba Edison Version 2.0 replqcement AC power generating system.

Years ago when I replaced the Norcold refer with a residential model in my DP, I saved the Stainless Steel door inserts thinking I might use them someday for something.

Tonight I found a use for one of them.

I mounted three of the four charge controllers, input and output DC circuit breakers, and the shunt for the battery monitor on the stainless steel panel.

Solarman, has mentioned the advantage of mounting on metal for heat dispersion.

The other controller is the Master controller and these three are networked as slave controllers.

The Master controller is recessed into the wall in the bedroom like before with the battery monitor next to it.

It will hang this equipment panel with a J channel on the wall of the rear storage compartment above the four batteries.

Without pictures...well you know the rest.

 

[HueyPilotVN]

More progress:

This afternoon and evening I got a lot accomplished.

I built the enclosed shelf and test fitted the components. I will figure out where to run the wires and cables. The batteries are easy, a solid straight black line across the top and a red line across the bottom.

The equipment that is mounted to the stainless panel will hang on the wall above the shelf and to the left of the Invertor.

I am not sure yet, but I think that I will leave the Invertor exposed on top of the shelf for cooling.

The battery section is like a wind tunnel with pusher fans on the left and puller fans on the right.

I will put the vent grates on the side doors with inside plexiglass covers for winter.

I am going to have a 90 inch by 11 inch detachable front plexiglass panel in front of the batteries with the following in gold letters.

BUBBA EDISON SOLAR ELECTRIC POWER COMPANY VER 2.0

Once I figure out where all the holes need to be I will remove the parts and paint it white like before.

Here are some pictures of the empty storage compartment and the components.

 

[HueyPilotVN]

The primary difference between the original system and the new system is that there were three 300 AH lithium batteries in the back storage compartment.

They were providing constant 120 volt AC to the main electrical panel thru the Invertor, just like being on shore power.

A fourth 300 AH lithium battery replaced the factory set up for DC needs by two AGM batteries and had a 400 watt solar charging system by itself.

I discovered that the SOC of the front battery never dropped below 99% because the converor/charger was constantly keeping the front battery full and the solar was wasted and charging on float all the time.

The new system now has four batteries in the back and receives all 1,600 watts of solar charging into the 1,200 AH of battery bank capacity.

I am not going to replace the front AGMs because there is no advantage to using lithium if they are always fully charged by the convertor/charger.

I also do not have to change the lower section of the WFCO charger to lithium.

I also now have hopefully 25% more run time for Air Conditioning.