Battery monitor

[dnickj]

Hi
i am looking to install a NASA BM1 battery monitor to the domestic side of the installation on a SO40 at present all the negative feeds are connected to a common isolator and the start and domestic live feeds are taken each to their own isolator with the charging taken care of by a split charging device.
The wiring diag for the new monitor shows the shunt connected to the domestic -ve and a +ve connection to the domestic bank.
I assume i could install the shunt between the -ve isolator and the domestic switch panel with the live connected to the domestic +ve isolator
Will this work - or does anyone know better - thanks

 

[affinite]

Sounds OK but make sure that the wire from your charge splitter is connected further down the -ve circuit than the shunt or you will see discharge current but not charge current.

 

[pvb]

[ QUOTE ]
I assume i could install the shunt between the -ve isolator and the domestic switch panel with the live connected to the domestic +ve isolator
Will this work - or does anyone know better - thanks

[/ QUOTE ]No, it won't work! The BM-1 needs to be permanently connected to 12v power. The red cable needs to be permanently connected to the domestic battery's positive terminal (which is why Nasa specify it should be fused). The shunt needs to be connected to the domestic battery's negative terminal at all times. Suggest you either rewire the domestic negative straight to the domestic battery, or leave the negative isolator on all the time.

 

[Graham_Wright]

[ QUOTE ]
(which is why Nasa specify it should be fused).

[/ QUOTE ]


The fuse is supplied in the positive lead (an in-line titchy one).

 

[affinite]

oops sorry - pvb and gw are quite right - of course you cant isolate the BM - must be on permenantly