It’s to be expected that anyone who’s ever spent any length of time off the grid understands that having a solution for generating and storing energy is mandatory. Not having power isn’t an option. That’s why campers and caravan owners routinely rely on a combination of photovoltaic panels and storage batteries to power everything from a laptop and a low amp fridge, to full-equipped studios on wheels.
Most off-gridders would probably agree though that while scalability’s a great attribute to have in a charging system, the cost and inconvenience of an excessively complex system is anything but appealing. That the time spent monitoring and musing over charging system nuances is time that could be better spent pursuing the reason they’ve gone off the grid in the first place.
Simplified charging solutions
Enerdrive understands that charging solutions that are easy to install and simply to manage, but still deliver plenty of power, are hallmarks of great engineering. Which is why they make multi-source controllers specifically to complement, and not constrict, solar panel/storage battery setups.
Unlike “pure” solar controllers, an efficient enerdrive solar controller integrates a MPPT (maximum power point tracking) solar controller with a DC-to-DC battery charger, creating a single control unit. This unit’s capable of independently recharging storage batteries from a solar source when stationary, as well as from a vehicle’s alternator while connected to the starting battery while the motor’s running.
Known as Enerdrive’s DC2DC family of chargers, they’re the perfect off grid solution for when power’s needed, but when being limited to a single source doesn’t have to be the only alternative. This is especially valuable for anyone who’s looking to get their first taste of going off grid but doesn’t want to invest immediately in a photovoltaic system. With a DC2DC unit, all that’s needed initially are the storage batteries.
There are two DC2DC versions – both programmable for five output amps and upward in vehicular or marine installations, as well as for fixed or mobile solar panels that are unregulated.
The 24V-30A DC2DC
With a maximum output of 30 amps at 24V nominal, these chargers have an output rating of 865W.
The 12V-40A DC2DC+
With a maximum output of 50 amps (hence the “plus” designation) at 12V nominal, these chargers have an output rating of 775W.
The DC2DC offers a range of settings designed to tailor the unit’s inputs as well as its outputs, from dedicated MPPT solar panel regulation to priority storage battery charging. However, there’s no overlooking the fact that these controllers are designed to prioritize starter battery input over any other sources when they’re connected. That’s to ensure the storage batteries always have a permanent source to recharge from, regardless of whether it’s a 12V or 24V starter battery, or a solar panel input of up to 45V/800W.
Other features of the DC2DC include:
Programmable LCD display indicating charging sources, statuses, voltages and amperages;
M6 screw terminals for use with large, low voltage-loss battery cables;
Temperature controlled cooling fan with override; and,
Battery temperature sensor for use with lead-acid batteries.
Staged battery charging
The DC2DC’s ability to charge the storage batteries directly from an alternator-feed starting battery isn’t unique. In fact, battery isolators that allow multiple batteries to charge inline with the alternator are fairly common. However, the DC2DC is the only unit capable of algorithmically sensing the charge and voltage specifications of the storage battery regardless of the type of alternator that’s used.
In short, the alternator (quite possibly to its own detriment) isn’t blindly trying to “muscle” a charge onto an anonymous storage battery. Instead, the starting battery itself is used to maximize the charging process throughout the staged sequence.
The battery is boost charged at its highest rate, until roughly 80% of its charging voltage is reached.
While maintaining the 80% boosted charge, the remaining 20% of the charging voltage is tapered in until the battery reaches its full charge.
Once the full (float) stage is reached, the battery’s maintained at a constant charge level and prevented from either overcharging or discharging.
DC2DCs are slow ramping battery chargers as well, placing less stress on both the starting battery and the alternator, and automatically checks the starting battery’s voltage status every three minutes to ensure the alternator’s actually doing its job. Together, it’s a controlled approach to charging that protects the entire charging system.
Regardless of the type of storage battery that’s in service, the DC2DC is capable of charging it.
Gel cell batteries
These maintenance-free lead-acid batteries use a stiff, silica-based electrolyte to create a charge. They’re very deep cycle, but are highly sensitive to over-charging.
Absorbed glass mat batteries are also maintenance-free lead-acid batteries, but use electrolyte-saturated fibre mats to create a charge. They’re also deep cycle, and recharge quickly.
Flooded, lead acid batteries
These are the traditional, refillable deep cycle batteries found in most off-grid applications. They’re highly sensitive to over-charging and to rapid discharging, but they’re the low-cost mainstay of batteries.
These maintenance-free batteries use a lithium phosphate salt electrolyte to create a charge. They’re deep cycle, and aren’t affected by deep discharging as they recharge quickly.
DC2DCs can also be programmed to accept a completely custom battery charging profile if any other battery type is being used in storage service. Again, DC2DCs prove that for charging to be highly adaptive, it doesn’t have to be exceedingly difficult.
At the end of the day, off-gridders simply want a power system that works without dragging them down into the technical weeds. Photovoltaics and MPPT regulation are the standard for generating power off grid, but it’s no secret that even in the middle of the day, solar panels can’t always be utilized to their fullest potential. Charging batteries can and as long as a charging battery’s in a good charging state, an Enerdrive solar controller can put it to use.
If you have an off-grid system that you’d like to maximize, take the time to speak with an Enerdrive retailer to find out just how much more reliable – and less complicated – they can help you to make it.