The BM-2 is designed to monitor performance of 12 volt lead acid battery systems with capacities of up to 999 Amp hours. It is supplied complete with a precision 200 AMP shunt and a prefabricated cable assembly to enable simple DIY installation. The unit continuously monitors voltage, current (charge or discharge), number of amp/hours (charge or discharge), the batteries state of charge and the time to charge or discharge. This information leads to more efficient use of the battery, which can enhance battery life and reduce the risk of failure.
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How does it work? The minimum information required to monitor the state of charge of a battery is the terminal voltage and the charge/discharge current **. The BM2 measures both these parameters and computes the state of charge using a complex well proven algorithm. A simple and intuitive display shows the service battery voltage charge/discharge current state of charge and time to charge/discharge. The instrument also warns the user when the charge level is too low so that load can be shed or charging commenced to protect the battery. A resettable Amp Hour counter is provided for checking the efficiency of the charging system or keeping a track of power consumption and a second input lets the user monitor the voltage of the starter batter. The simple display format does not mean the internal software is unsophisticated. In fact two separate algorithms are used. One based on integrating amp hours over the charge and discharge cycle the second based on an adaptive internal mathematical battery model.
A unique feature of the BM2 is its ability to use information from both algorithms during the charge/discharge cycles to continually update its performance. This means that unlike many other systems that rely solely on amp hour integration the NASA Marine BM2 never needs to be re-synchronised with the battery. The algorithm includes Peukert's equation to ensure accuracy over a wide range of load currents. The BM2 does all this whist consuming a meagre one and a half milliamps. It is a true battery monitor easy to install and excellent value for money.
** Some say that they can calculate the state of charge from the terminal voltage only but as we all know the terminal voltage falls when the battery is under load and rises when under charge. This fall and rise can be quite substantial especially when a heavy current is flowing so how can the terminal voltage be used to calculate anything without knowledge of the magnitude of the current involved?.
In The Box
Display; 200 AMP shunt link to M8 Ring terminal; 5 m cable.
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We make sure to list our stock so you know upfront when your order will be with you, most items we send are sent on next-day service as standard however some orders to harder-to-reach locations such as Scottish Islands or Channel Islands may go on a 48-hour delivery to keep delivery costs to a minimum.
Due to the wide range of items we sell shipping costs can vary such as heavy batteries and inflatable boats require a pallet. To see the shipping cost of items use our shipping calculator below.
This is not indicative of the final shipping price, to see that add all your items to your basket or see the delivery costs below.
Delivery costs are as follows - Check the Shipping Type of your product on the 'More Information' tab.
Standard
Mainland UK - £0-150 - £6.5 / £150 - £250 - £3.25 / £250+ - Free
Isle of Mann, Jersey, Gurnsey - £0-150: £15 / £150 - £250: £7.5 / £250+: Free
Hazardous
Mainland UK - £0-150 - £6.5 / £150 - £250 - £3.25 / £250+ Free
Isle of Mann, Jersey, Gurnsey - Unable to ship due to courier restrictions
Long
Mainland UK - £0-500 - £23 / £500+ - Free
Isle of Mann, Jersey, Gurnsey - Please Call for Quote
Inflatable Boat
Mainland UK - £0-500 - £30 / £500+ - Free
Isle of Mann, Jersey, Gurnsey - Please Call for Quote
Heavy Battery
Mainland UK - £0-850 - £26 / £850+ - Free
Isle of Mann, Jersey, Gurnsey - Please Call for Quote
We have a 30-day returns policy so If for whatever reason you are not happy with your order we can exchange it for another or offer a full refund if you log it with us within 30 days of receipt of the goods.
Find out more about our returns policy here.