CharlesK
New Member
EDIT: For the latest design schematic (as of Mar 21, 2022), skip ahead to Post #31.
Background
I have a 1991 American Eagle Diesel Pusher RV. This is a Class A motorhome built on a Spartan chassis with a Cummins 8.3L 6CTA Mechanical Engine and an Allison MT643 4-speed automatic transmission. At only 90K miles on the chassis, I hope that it will be around for a while.
The goal is to update the coach to a comfortable, self-sufficient vehicle that will serve us as my spouse and I travel around the country.
Conversion to All-Electric
As part of the upgrades, the decision was made to convert to an all-electric vehicle. Well, in the RV motorhome world that means eliminating the propane systems. Sometimes that means using diesel fuel for a hydronic heating system. We decided to not go that route and only use the diesel for powering the main engine. Everything else would rely on electric power.
All of the propane systems on-board have been removed. There no longer is a propane storage tank on-board. That means the original water heater, fridge, furnaces, and stove/oven all will be replaced.
There is an on-board diesel generator. But it a) makes noise, and b) uses fuel. So, adding solar power was added to the upgrades. It is quiet, and the sun is usually available on a daily basis. If not, the generator is still available as a reliable backup.
There are many upgrades in the works. New cabinetry, seating, entertainment systems, communication systems, upgraded plumbing, etc. For the purposes of this discussion I am only concerned with the electrical upgrades. Actually, the electrical "upgrade" is more of a complete replacement for a large part of the electrical project rather than an upgrade.
The original on-board house electrical consisted of a 2000W MSW inverter, a 75A 12VDC converter, a 3-input Automatic Transfer Switch, a 50A shore power connection, a 8KW Onan 120V diesel generator, a distribution panel for 120V and 12VDC, and a few other connection/switch boxes that I still cannot identify. From what I can tell, I believe some of the extras have been wired/rewired after the original purchase. The house battery system was 4 12V flooded lead acid batteries.
For the most part, the items in the previous paragraph will be removed. The diesel generator will stay.
The Plan
Skipping a lot of the reasons why, here is a short list of the new on-board electrical appliances and systems.
Residential electric refrigerator
Dual-zone mini-split for heating/cooling (one wall unit in front, one in bedroom)
Radiant Floor Heating (in case we visit the relatives in the cold of January, expected unusual low temps of 20F)
Induction Cooktop
Microwave/Convection Oven
Electric Water Heater
TVs, laptops, LED lighting, Cellphones, Washer/Dryer, Cooking Appliances
Using the resources I found on this forum, I completed an Energy Audit.
Thanks to all who helped create this resource.
Based on the results, I have designed a house electrical system that I believe will make the coach energy-independent. Unless we get really crazy with energy usage, we should never need shore power, and only need to use our generator as a back-up system in case of prolonged bad weather.
Here are the results of the Energy Audit Spreadsheet.
The concepts
Energy independence. Depending on where we are parked, or if we are driving, I want to have a fully-functional coach. That means shore power may or may not exist, 120VAC or 240VAC may or may not be available, etc.
Based on the Energy Audit, I have determined that a 5000VA inverter will supply the AC needs. A 24V system was selected to reduce the wiring sizes, and less BMS's than a 12V system. I decided against a 48V system because of the perceived dangers. This may or may not be real, but a 48V system vs 24V may not have that much advantage anyways. A Victron Quattro eliminates the need for a separate automatic transfer switch, as it has its own internal transfer switch.
The Audit also suggests about 3KW of solar. That should fit on the 38' roof. There is about 30' of actual roof (subtracting the front and rear caps) after a number of unwanted skylights and vents, and the two roof-top Air Conditioners are removed.
I added a 12V battery to supply the RV 12VDC loads for two reasons. First, in case of a surge requirement that the Buck Converter may not be able to handle. Second, if the Buck Converter fails, we can still operate the essential 12V Loads.
I included an autotransformer. The most pressing requirement is the 240VAC dual-zone mini-split. The autotransformer will provide both 120VAC and 240VAC. It also provides load-balancing for its 120VAC outputs.
The autotransformer concept is based on a schematic found on Victron's website: https://www.victronenergy.com/uploa...-phase-120V-to-120-240V-with-Quattro-120V.pdf
The Proposed Electrical System
Already Purchased equipment:
Progressive Industries EMS-HW50C Electrical Management System (Hardwired installed. Shore power cord feeds directly into this.)
LiFePO4 battery technology (4 sets of 8s 3.2V 272Ah cells. Cells are on order from @Michael B Caro) (Four 8s Overkill BMS - Ordered and received.)
Victron BMV-712 Shunt
Proposed Purchases:
Victron Quattro 24/5000/120 Inverter/Charger
Victron 100A Autotransformer
Busbars (possibly Victron Lynx system)
100A 120/240VAC Breaker Box
~3KW roof-mounted solar panels
Victron Solar Charge Controller(s)
Victron CERBO GX
Victron GX Touch 50
Victron DC 24V-12V Buck Converter(s)
12V Battery
Various cables/fuses/switches/etc.
There are lots of details NOT INCLUDED at this point. Before I dive into the necessary details, I want to be certain that my overall design is sound. Just like planning a trip/vacation, there is no sense trying to determine what roads to take until one knows where they are going.
American Eagle Diesel Pusher V0.2
Comments, suggestions, questions, etc. are welcome.
I have learned a lot about DIY Solar and more since I joined this forum. I appreciate the sharing of knowledge and hope to be able to contribute a small part of what I have learned sometime in the future. But, right now, I am still climbing the learning curve and need to learn a lot more before I feel that I can safely contribute.
Thanks!!!
Charles
Background
I have a 1991 American Eagle Diesel Pusher RV. This is a Class A motorhome built on a Spartan chassis with a Cummins 8.3L 6CTA Mechanical Engine and an Allison MT643 4-speed automatic transmission. At only 90K miles on the chassis, I hope that it will be around for a while.
The goal is to update the coach to a comfortable, self-sufficient vehicle that will serve us as my spouse and I travel around the country.
Conversion to All-Electric
As part of the upgrades, the decision was made to convert to an all-electric vehicle. Well, in the RV motorhome world that means eliminating the propane systems. Sometimes that means using diesel fuel for a hydronic heating system. We decided to not go that route and only use the diesel for powering the main engine. Everything else would rely on electric power.
All of the propane systems on-board have been removed. There no longer is a propane storage tank on-board. That means the original water heater, fridge, furnaces, and stove/oven all will be replaced.
There is an on-board diesel generator. But it a) makes noise, and b) uses fuel. So, adding solar power was added to the upgrades. It is quiet, and the sun is usually available on a daily basis. If not, the generator is still available as a reliable backup.
There are many upgrades in the works. New cabinetry, seating, entertainment systems, communication systems, upgraded plumbing, etc. For the purposes of this discussion I am only concerned with the electrical upgrades. Actually, the electrical "upgrade" is more of a complete replacement for a large part of the electrical project rather than an upgrade.
The original on-board house electrical consisted of a 2000W MSW inverter, a 75A 12VDC converter, a 3-input Automatic Transfer Switch, a 50A shore power connection, a 8KW Onan 120V diesel generator, a distribution panel for 120V and 12VDC, and a few other connection/switch boxes that I still cannot identify. From what I can tell, I believe some of the extras have been wired/rewired after the original purchase. The house battery system was 4 12V flooded lead acid batteries.
For the most part, the items in the previous paragraph will be removed. The diesel generator will stay.
The Plan
Skipping a lot of the reasons why, here is a short list of the new on-board electrical appliances and systems.
Residential electric refrigerator
Dual-zone mini-split for heating/cooling (one wall unit in front, one in bedroom)
Radiant Floor Heating (in case we visit the relatives in the cold of January, expected unusual low temps of 20F)
Induction Cooktop
Microwave/Convection Oven
Electric Water Heater
TVs, laptops, LED lighting, Cellphones, Washer/Dryer, Cooking Appliances
Using the resources I found on this forum, I completed an Energy Audit.
Thanks to all who helped create this resource.
Based on the results, I have designed a house electrical system that I believe will make the coach energy-independent. Unless we get really crazy with energy usage, we should never need shore power, and only need to use our generator as a back-up system in case of prolonged bad weather.
Here are the results of the Energy Audit Spreadsheet.
System size calculations | ||
Full Load W-hrs. | 10776.5 | W-Hrs. |
Full Load Watts | 3834 | Watts |
AC Watts | 3709 | Watts |
AC Surge wattage | 1020 | Watts |
AC Watt-Hrs | 10418.5 | W-Hrs. |
DC Watts | 125 | Watts |
DC Watt-Hrs | 358 | W-Hrs. |
Inverter Sizing | ||
Inverter efficiency | 94.00% | % |
Min continuous Inverter size | 3946 | Watts |
Min Surge Inverter size (Input Watts) | 5031 | Watts |
Battery Sizing | ||
Daily Storage Requirement | 11442 | W-Hrs/Day |
Max discharge from full CHARGE | 90.0% | % |
# days of storage capacity | 1.0 | Days |
System Voltage | 24.0 | Volts |
min Battery capacity W-Hrs | 12712.8 | W-Hrs. |
min Battery capacity A-Hrs | 529.7 | Amp Hours |
Max continuous current to DC Loads | 5.2 | |
Max continuous DC current to Inverter | 164.4 | |
Max continuous current from bat. | 169.6 | Amps |
Max Continuous discharge rate | 0.32 | C |
Solar Array Sizing | ||
# sunny days to recharge while under load | 3.0 | Days |
Required Total daily Solar output (Sunny) | 15255.3 | W-Hrs. |
Insolation # (Equivelent hours of full sun) | 5.0 | Hours |
Min Solar Cell Wattage | 3051.1 | Watts |
Max Charge Current | 127.1 | Amps |
The concepts
Energy independence. Depending on where we are parked, or if we are driving, I want to have a fully-functional coach. That means shore power may or may not exist, 120VAC or 240VAC may or may not be available, etc.
Based on the Energy Audit, I have determined that a 5000VA inverter will supply the AC needs. A 24V system was selected to reduce the wiring sizes, and less BMS's than a 12V system. I decided against a 48V system because of the perceived dangers. This may or may not be real, but a 48V system vs 24V may not have that much advantage anyways. A Victron Quattro eliminates the need for a separate automatic transfer switch, as it has its own internal transfer switch.
The Audit also suggests about 3KW of solar. That should fit on the 38' roof. There is about 30' of actual roof (subtracting the front and rear caps) after a number of unwanted skylights and vents, and the two roof-top Air Conditioners are removed.
I added a 12V battery to supply the RV 12VDC loads for two reasons. First, in case of a surge requirement that the Buck Converter may not be able to handle. Second, if the Buck Converter fails, we can still operate the essential 12V Loads.
I included an autotransformer. The most pressing requirement is the 240VAC dual-zone mini-split. The autotransformer will provide both 120VAC and 240VAC. It also provides load-balancing for its 120VAC outputs.
The autotransformer concept is based on a schematic found on Victron's website: https://www.victronenergy.com/uploa...-phase-120V-to-120-240V-with-Quattro-120V.pdf
The Proposed Electrical System
Already Purchased equipment:
Progressive Industries EMS-HW50C Electrical Management System (Hardwired installed. Shore power cord feeds directly into this.)
LiFePO4 battery technology (4 sets of 8s 3.2V 272Ah cells. Cells are on order from @Michael B Caro) (Four 8s Overkill BMS - Ordered and received.)
Victron BMV-712 Shunt
Proposed Purchases:
Victron Quattro 24/5000/120 Inverter/Charger
Victron 100A Autotransformer
Busbars (possibly Victron Lynx system)
100A 120/240VAC Breaker Box
~3KW roof-mounted solar panels
Victron Solar Charge Controller(s)
Victron CERBO GX
Victron GX Touch 50
Victron DC 24V-12V Buck Converter(s)
12V Battery
Various cables/fuses/switches/etc.
There are lots of details NOT INCLUDED at this point. Before I dive into the necessary details, I want to be certain that my overall design is sound. Just like planning a trip/vacation, there is no sense trying to determine what roads to take until one knows where they are going.
American Eagle Diesel Pusher V0.2
Comments, suggestions, questions, etc. are welcome.
I have learned a lot about DIY Solar and more since I joined this forum. I appreciate the sharing of knowledge and hope to be able to contribute a small part of what I have learned sometime in the future. But, right now, I am still climbing the learning curve and need to learn a lot more before I feel that I can safely contribute.
Thanks!!!
Charles
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