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Old 05-21-2014, 09:12 PM   #1
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12VDC Battery Monitor question

Recently I acquired a Clipper BM-2 battery monitor system. It came with a 100A shunt. Before I install it I have a concern.

My motor home has two Interstate 6V batteries rated at 220AH capacity. The primary 12VDC system fuse located near the batteries is rated at 250A.

The motor home charger has a maximum charge rate of 45A. There are NO large current draw devices pulling from the 12V system....the Inverter is rated at 750W and only runs the TVs and entertainment system.

My Question: Is the installation of the 100A shunt in my 12VDC battery line likely to cause any problems? Remember, There is no reason I should either be charging or discharging more than 50A from the batteries.

It is the existence of a primary fuse rated at 250A that is causing me to ask this question. Any thoughts or comments appreciated.

Ed & Lynn on the Oregon Coast
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Old 05-21-2014, 09:17 PM   #2
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The shunt should be fine and that 100Amp should be the continuous rating so even if you eventually install a larger inverter it should carry more than 100 amp without problems.

250A fuse is there as a catastrophe fuse to protect against major faults (eg you shorting a wrench from positive to the chassis) rather than to protect anything in the coach itself. Generally installed if there is a large (say 1.5kW) inverter/charger installed

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Old 05-22-2014, 07:16 AM   #3
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The 100A shunt rating has to do with the proper meter to install and use. The shunt will not limit the current flow and the 250A fuse will protect the wiring. JM2...
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