cdn_downunder
New Member
- Joined
- Mar 30, 2021
- Messages
- 2
I'm building a 25kwh house battery for my 31' Bluebird Wanderlodge and am looking for some feedback on my plans, options for equipment and in particular selecting an appropriate BMS for this system.
My hope is that the brains trust here can validate my plans and offer some suggestions, thank you in advance for your time.
Vehicle:
1978 31' Bluebird Wanderlodge, CAT3208NA, sprung suspension, completely redesigned for long term overlanding for 2 people. Systems include: diesel hydronic heating/hot water/engine preheat (180gal diesel tank), all electric cooking (induction hotplates, air fryer); marine compressor fridges(2) & freezers(2); very high thermal efficiency for all climates (double glazed windows, aerogel insulation, thermal braking, etc) with passive cooling ( humidifier. dehumidifier, evaporative cooling unit, 3x920cfm fans but no traditional AirCon); no propane; no generator.
Currently I have installed:
Reasoning and Considerations:
Why Yttrium instead of LifePo4? I'm using the Yttrium cells as they can be safely charged down to -20c, where LifePo4 need a heater below 5c and we are based in Canada, so colder temperatures are more common than extreme heat (though we have been in -25c to +52c in the vehicle)
Why 24v rather than 48v? This is primarily due to 1) the PV panels being 12v (I could drop a panel and run 48v, but have less PV, but I have no room to add a 10th panel unfortunately); 2) the availability/cost of 48v Alternator/Generators (double the price, far less options); and 3) Magnum does not make a 48v Hybrid inverter/charger (although Victron and others do).
60-cell PV panels have come a long way however, I could (just) fit 6-8 375w (eg LG Neon R) panels, which would add 50%-100% capacity (at substantial cost...) and sell the Grape Solar panels, this would eliminate my PV capacity concerns mentioned above
I have not bought the Magnum Inverter/Charger, but have determined a hybrid model is desirable given how often we only have 15a or 30a hookups and the the size of the battery I am installing, I do however have their Charge Controller and other accessories, so changing brands would require some chopping and changing. Its for a mobile rig that is off road as much as it is on highway, so durability in those conditions is essential, which is why Magnum was my first choice.
Why such a big battery? The goal is to match the vehicle systems (fresh water, waste water, fuel supply, battery endurance) to allow for a minimum of 14 days completely 'off grid' for 2 adults in all climates when solar is available, or 5 days with zero solar. We have achieved this with upgrading the other systems thus far so now it's time to tackle the house battery, which is the linchpin to the whole 'electric coach' idea. My thoughts are oversize rather than 'just enough' as it will allow me to work the batteries less (ideally 70% DOD as much as possible), extending their usable lifespan. My PV array is clearly undersized for such a battery, but I was limited in options when I designed the 12v system 5 years ago, thus I'm considering upgrading to 60 cell panels.
Thoughts, suggestions and comments would all be appreciated. Thanks again for taking the time.
Curtis
My hope is that the brains trust here can validate my plans and offer some suggestions, thank you in advance for your time.
Vehicle:
1978 31' Bluebird Wanderlodge, CAT3208NA, sprung suspension, completely redesigned for long term overlanding for 2 people. Systems include: diesel hydronic heating/hot water/engine preheat (180gal diesel tank), all electric cooking (induction hotplates, air fryer); marine compressor fridges(2) & freezers(2); very high thermal efficiency for all climates (double glazed windows, aerogel insulation, thermal braking, etc) with passive cooling ( humidifier. dehumidifier, evaporative cooling unit, 3x920cfm fans but no traditional AirCon); no propane; no generator.
Currently I have installed:
- 9x 180w 36cel Grape Solar PV Panels (nominally 1620w)
- Magnum Dimensions PT-100 charge controller
- 50A split phase AC electrical system
- 520AH AGM 12v battery bank (4x6v GC2H), 2000w Xantrex Inverter, 55a deck charger, 160a alternator, all of which will remain as the vehicle power & redundant house backup system
- 8S Winston LYP 1000AH cells (25.6v) for a roughly 25kwh bank
- Magnum-Dimensions 4000w Inverter MSH-RE (267A max draw, 110A DC charging)
- 24v-12v smart battery charger (looking for options)
- BMS that will handle this size of bank, and LYP chemistry (looking for options)
- 24v-12v DC-DC converters to handle combined house/vehicle loads (looking for options)
- 24v DC Alternator / Charger with external smart regulator (looking at American Power, Balmar & Zena) likely in the 200-250amp range
Reasoning and Considerations:
Why Yttrium instead of LifePo4? I'm using the Yttrium cells as they can be safely charged down to -20c, where LifePo4 need a heater below 5c and we are based in Canada, so colder temperatures are more common than extreme heat (though we have been in -25c to +52c in the vehicle)
Why 24v rather than 48v? This is primarily due to 1) the PV panels being 12v (I could drop a panel and run 48v, but have less PV, but I have no room to add a 10th panel unfortunately); 2) the availability/cost of 48v Alternator/Generators (double the price, far less options); and 3) Magnum does not make a 48v Hybrid inverter/charger (although Victron and others do).
60-cell PV panels have come a long way however, I could (just) fit 6-8 375w (eg LG Neon R) panels, which would add 50%-100% capacity (at substantial cost...) and sell the Grape Solar panels, this would eliminate my PV capacity concerns mentioned above
I have not bought the Magnum Inverter/Charger, but have determined a hybrid model is desirable given how often we only have 15a or 30a hookups and the the size of the battery I am installing, I do however have their Charge Controller and other accessories, so changing brands would require some chopping and changing. Its for a mobile rig that is off road as much as it is on highway, so durability in those conditions is essential, which is why Magnum was my first choice.
Why such a big battery? The goal is to match the vehicle systems (fresh water, waste water, fuel supply, battery endurance) to allow for a minimum of 14 days completely 'off grid' for 2 adults in all climates when solar is available, or 5 days with zero solar. We have achieved this with upgrading the other systems thus far so now it's time to tackle the house battery, which is the linchpin to the whole 'electric coach' idea. My thoughts are oversize rather than 'just enough' as it will allow me to work the batteries less (ideally 70% DOD as much as possible), extending their usable lifespan. My PV array is clearly undersized for such a battery, but I was limited in options when I designed the 12v system 5 years ago, thus I'm considering upgrading to 60 cell panels.
Thoughts, suggestions and comments would all be appreciated. Thanks again for taking the time.
Curtis
