New Tools for Managing Your Battery Bank
In Part II of this three-part series, we learn that upgrading your DC electrical system will require an assessment—and the likely replacement—of its components. "Systems" from our March 2012 issue.
Managing Multiple Batteries
Even the smallest modern cruising boat is going to have at least two batteries as its DC power source; in fact, most sailboats will have more. So it’s worth taking a look at some of the components available to more effectively isolate and recharge multiple batteries or groups of batteries as well as to assist in ensuring that a proper regimen for recharging is available when and if you do decide to move up to a higher-output, externally regulated alternator system. Or perhaps you want to integrate into the mix an alternative energy source, such as a solar panel or a wind generator. Today’s solid-state technology offers us some excellent tools to do the job with greater precision.
Take the ProIsoCharge unit from ProMariner as an example. This device automatically provides dedicated isolation for your engine starting battery so it can’t go dead if you forget to switch to the dedicated house battery at anchor. The IsoCharge runs at zero-percent voltage drop, unlike traditional diode-type battery isolators, so there’s no loss of charging capability due to excessive voltage drop. Depending on the model, you can effectively service up to four separate battery banks.
L.E.D. lights on the ProNautic charger indicate a battery’s charging status.
The unit gets installed between the charging source and multiple battery banks. It’s activated via your boat’s ignition switch, and as soon as it’s powered up, it automatically monitors each of the battery banks connected to it. It begins with the start battery and charges it up to a 13.3-volt level, then moves on to subsequent batteries. Once all are brought up to 13.3 volts, all are brought back online and charged until they’re at 100-percent capacity, typically somewhere between 13.8 to just over 14 volts, depending on battery chemistry.
If a heavy load such as a bow thruster pulls down one bank below the others, the system automatically diverts charging power to that bank until it reaches parity. The device automatically prevents any back-feeding between banks. The IsoCharge can also be used as an effective charge-distribution center for solar panels or a wind generator. Sterling Power Products offers a device known as a battery-to-battery charger that works in a similar way.
Sterling Power Products’ Pro-Digital voltage regulator is billed by the company as the “most powerful and advanced alternator regulator currently available in the world.” I’m reasonably certain that there are folks at Balmar and Ample Power that would want to argue that point.
Sterling Power Products’ powerful, versatile Pro-Digital voltage regulator can be programmed to service both 12- volt and 24-volt battery banks.
Regardless, relying on the constant-rate integral voltage regulator that came with your engine will earn you a charge of gross negligence against your new high-tech batteries. To maximize your battery return on investment, you need a programmable voltage regulator and will want to set up temperature monitoring at least at the batteries and, if you’re using a high-output unit, preferably at both the batteries and the alternator. The Pro-Digital regulator offers output settings for a range of batteries: conventional flooded-cell batteries, on which you have cell access for topping up depleted electrolyte; sealed flooded and certain A.G.M. batteries; and some gel-cell models. There’s also an additional setting for other gel or A.G.M. batteries, depending upon the battery manufacturer’s specific voltage requirements. It also has inputs for temperature sensors. The software within the regulator automatically calculates the battery-bank size, charge state, and alternator output, and it sets the microprocessor to adjust appropriate charge phase-time durations.