With an interest in sustainability which goes back twenty years, Marc Stevens of Off-Grid Solutions walks the walk; he and his partner Lisa Derby live off-grid in the Pine Ridge Forest of Nebraska.
Not only do they benefit from the daily experience of living with the technology they install, but Marc has worked in relief zones in Sudan and Haiti for the humanitarian medical non-governmental organization Médicins Sans Frontières, providing remote power for refrigerating vaccines – as well as the simple convenience of lighting.
At home this year they’ve made a big change to their power storage. After using Lead-Acid batteries and installing them widely for clients, Marc and Lisa have switched to lithium – choosing Discover AES LiFePO4 Batteries. He says: Though Discover AES batteries can be setup as a “drop in” lead acid replacement – sometimes referred to as Open Loop – they can also be configured with Victron Energy’s power equipment in a Closed Loop communication configuration.
Lisa Derby, Marc Stevens
What does Closed Loop Communication mean?
The Discover lithium batteries have their own battery management system – and the Victron Quattro Inverter/Chargers and Solar Chargers also have their own management device, (in Marc’s case the Octo GX) – but the two systems can communicate with each other via Discover’s LYNK Gateway Communication device. The battery Charge and discharge settings are dynamically controlled by the Battery Management System (BMS) of the AES Battery – the LYNK Gateway provides the datacoms. The manufacturers claim this topography can provide up to 25% faster battery charging.
The arrangement allows the charge characteristics of the Quattros and MPPTs to be governed by the Octo GX (or any of the other Victron GX devices, such as the Color Control GX, Venus GX, or Cerbo GX) with instructions from the connected AES battery storage module.
Insulated battery box, recessed into the floor.
Marc has his Discover AES Batteries installed in a purpose-built insulated battery enclosure which is partially recessed in the workshop floor to provide a more stable temperature environment.
Marc uses twelve 200W panels. He finds this sufficient in an area which benefits from an annualised average of 5 hours sunshine per day. Though later this year he will add a 1kW turbine to his installation.
He says; In the past, while configuring off-grid systems there were sometimes a few unknowns using different lead acid batteries concerning charging set points – such as temperature coefficients, and Absorb times. This Closed Loop battery management technology is an installer’s dream with easy set-up and adaptive interaction, and as system owner’s we have seen improvements in recharge times, turning a great system into an even better one.
Victron Energy has invested a lot of time in third party product compatibility with other leading electronics manufacturers. This level of system integration allows the installer to design intelligent private energy systems at large scale; in high ambient temperatures; for optimised Energy Storage Systems; and which are tailor made for any unique requirements a user might have.
You will find more information about configuring Discover AES LiFePO4 and Victron Energy systems on this page.
Blue sky thinking? Marc and Lisa get an average 5 hours sunshine per day at their homestead in the plains of Nebraska.
In the case of Discover AES LiFePO4 batteries, the manufacturer states that their product can be continuously operated in a partial State of Charge (SOC); or, alternately discharged and recharged to 100% of its rated capacity without loss of performance. They say their LiFePO4 batteries will retain more than 90% of original capacity for at least ten times longer than a high-quality lead acid battery – and back up that claim with a 10-year, unlimited cycle, warranty.
Marc and Lisa’s off grid installation comprises:
- Two 5kVA Quattro Inverter/Chargers programmed in a Split-Phase configuration
- 2.4kW of Photo-Voltaic capacity
- Two 250/60 Smart Solar MPPTs
- Octo GX and
- Two 42-48-6650 Discovery AES batteries providing 13.3 kWh of energy storage
The System is located in a semi-heated workshop.
This system allows them to use normal energy-efficient household appliances in tandem with propane for cooking and wood for heating. The system also supports seasonal irrigation for a large garden. Opportunity loads are applied when the batteries are fully charged …the excess energy being used for space- or water-heating, and for pumping water from a borehole with a depth of 100m (330 feet) into a storage tank for future use.
In so many ways, then, they’ve got the future covered.
The headline image for this article is the work of Ken Lund, and is reproduced with slight cropping.
