# NASA Battery Monitor Connection Help



## boggy (Sep 24, 2007)

I’m in the process of fitting a 2nd battery and NASA battery monitor, an inverter is already connected to the single battery.

Looking at the NASA wiring diagram (single battery) it shows that existing negative connections i.e. Loads & Chargers should be removed from the negative battery terminal and connected to one side of the supplied shunt. The other end of the shunt is then connected by a supplied short cable to the negative battery terminal.

Here are my concerns for your recommendations.

1. Do I connect all existing negative connections to one side of the Shunt, I'm guessing these are the following
1.1.On board charger 
1.2.Inverter
1.3. Other negative connections from the Schaudt EBL
1.4. New 2nd leisure battery negative

2. Connect the new 2nd leisure battery negative to the existing negative battery terminal 

3. Connect the supplied NASA cable to the existing negative battery terminal and to the other end of the Shunt.

I hope all above is clear but if any additional info required please ask, I look forward to your recommendations

John


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## PeterandLinda (Feb 21, 2009)

Hi

All a bit technical for us, but why not try contacting the experts:

http://www.outdoorbits.com/nasa-clipper-battery-monitor-12v-p-1364.html

P&L


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## dipsticks (Aug 2, 2007)

The shunt needs to be connected in series with the negative battery/ies connection to all the loads you wish to monitor with the NASA.

Any load not passing through the shunt will not be shown on the battery monitor.

Good luck couldn't be without ours now.


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## CliveMott (Mar 10, 2008)

The data on the ODB web site is conflicting. It says 
"Power consumption - 1.5mA"
and then a few lines lower it says
"Supply current 3 milliAmp".
Come on!

This instills me with confidence in the product!

However its basicly a digital millivoltmeter with a 100 amp 50mV shunt and suitable multipliers for 12 volts. A bit of software and it can count ampere hours in and out and give an aproximation of percentage battery used.

But WHY do you need it?

C.


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## dipsticks (Aug 2, 2007)

NASA themselves don't seem to mention 1.5mA

>NASA<

They have been making products for the Marine Industry for many years.


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## rolyk (Aug 24, 2007)

It's 3mA for the BM1 (The original Nasa battery monitor)
and 1.5mA for the new BM1 Compact with fewer functions

Anyway, what's 1.5mA between friends! A drop in the battery ocean, methinks.

A great bit of kit, nevertheless, and one that I wouldn't like to be without.

Roly


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## Ifor (Oct 21, 2006)

You need to conect the two leisure batteries together ignoring the shunt initaly. e.g. neg to neg pos to pos double fused if a long cable run on the positive. Once conected you just treat them like one bigger battery. Conect the shunt to one of the negatives and then all the other negative conections including any to the van chasie to the other side of the shunt.

A battery monitor is a great tool to have. Just learning how much curtent your different devices take is improtant and then how much driving is taken to charge the battery lets you manage your usage far better if living away from hookup.


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