Low Voltage Demands: Why Battery Management is More Critical Than Ever

Posted on Apr 19, 2016

Modern commercial vehicles have more auxiliary units drawing battery power than ever before. In the past, when vehicles were powered off, all electrical loads were also, but many of today's commercial trucks require electricity full time, especially those with sleeper cabs. 

For this reason, low voltage demands are a greater concern of fleet managers than ever before, as the increased loads can cause stalls and breakdowns at unexpected moments, costing time and money for fleets. 

Enter battery management to the rescue. Learn what components you need to keep from draining batteries and stalling vehicles.


Low Voltage Disconnects

Even when a vehicle is turned off, parasitic loads continue to drain the battery but discharging batteries beyond a critical low voltage can damage them and require a longer recharge interval.

One way to control this is to use low voltage disconnects (LVDs). These solid state electronic modules protect the starting power and life of the primary battery by terminating connection to non-essential components when voltage drops, preventing excessive draw.

They do this, a semiconductor switching circuit measures battery voltage; when it dips too low, predetermined auxiliary loads are switched off to ensure the battery has enough power left for engine starting. 

So then, how to power applications like APUs and radios without risking breakdowns? For trucks with sleeper cabs, a smart solution can be to utilize a "split" battery system where hotel loads run batteries separate from the "main" cranking batteries.

Master Disconnect Switches 

Battery disconnect switches cut-off electrical power to protect batteries from excessive drain, help protect against electrical fires and provide a reliable shutdown of power during maintenance.

Designed to isolate the battery from the electrical system, master disconnect switches keep batteries from depleting by preventing parasitic loads and leakage from slowly draining batteries, especially while vehicles are parked for long periods. 

When spec’ing these components in, be sure to consider both continuous and intermittent duty ratings, says Geoff Schwartz, Senior Sales Applications Engineer for the Cole Hersee Co. He instructs fleets to match the continuous rating of the switch to that of the alternator, and the intermittent duty to that of the CCA (Cold Cranking Amps) of the starting battery bank. For this reason, we offer an extensive selection in different amperages, here are a few of our top sellers:

Battery Isolators

Battery Isolators act as a check valve between the batteries and the alternator, allowing current to only flow in one direction, from the alternator to the batteries.

Often utilized in multi-battery bank applications, battery isolators allow you to charge multiple batteries from a single charging source without the risk that one run-down battery will affect the other.

The two basic types are one-way diode isolators and “smart” isolators or combiners, sometimes called separators. Diode versions link a single alternator to two or three battery banks via a diode bridge. While Diode styles have the advantage of constant connectivity with no moving parts, smart isolators do offer unique features such as start boost, where a switch hooks in the auxiliary batteries to aid in starting. One smart choice: Cole Hersee Smart Battery Isolator, 85A, 9-16

Low voltage demands are a critical issue for today's fleets, and Waytek is Wired To Serve™ your battery management needs. If you have any questions about the products featured here, please contact us