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Old 06-07-2012, 07:25   #1
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NASA Battery Monitor

Have a NASA BM-1 monitor and some time it says like 13.2v but it will show around 80% on the right. Any one know why it does says that would 13.2v mean the battery is fully charged.

Thanks
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Old 03-09-2012, 22:50   #2
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Re: Nasa battery monitor

Sorry, don't understand why it would say that either. However we were thinking of buying one of these battery monitors ourselves. Did you sort it out & how have you found the monitor? Anyone else with a Nasa BM1 battery monitor have some thoughts please?
thanks
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Old 04-09-2012, 00:42   #3
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Re: Nasa battery monitor

Actually we gave up even trying to have any dependency on the SOC and just use it for monitoring the Voltage and AH usage.

Also the LCD screen seems to be having some issues now with pieces of numbers missing.

Unit is less then 6months old.

Personally maybe I would look at other options if I was to buy again.
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Old 04-09-2012, 02:11   #4
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Re: Nasa battery monitor

Send it back. I have found NASA Marine have a very good service. The BM-1 like all other State of Charge units that use amp counting tend to become inaccurate as you will find reading posts on here about other units. For measuring volts and amps the BM-1 should be good.

My previous boat had all NASA instruments and it worked well at a fraction the price of the competition. It just does not have the network functionality of others.
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Old 04-09-2012, 02:30   #5
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Re: Nasa battery monitor

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Originally Posted by deepthought View Post
Have a NASA BM-1 monitor and some time it says like 13.2v but it will show around 80% on the right. Any one know why it does says that would 13.2v mean the battery is fully charged.

Thanks
To get an idea of the state of charge from the battery voltage the battery needs to left 24 hours or longer with no charge input, or load output.then you need to compensate for temperature.
To get a voltage of 13.2v the battery must be under charge ( or just come off charge) and it is impossible to determine the SOC from this voltage alone.
So 80% could be the correct SOC despite the 13.2 voltage.
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Old 04-09-2012, 02:37   #6
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Re: Nasa battery monitor

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Originally Posted by dmgf View Post
Sorry, don't understand why it would say that either. However we were thinking of buying one of these battery monitors ourselves. Did you sort it out & how have you found the monitor? Anyone else with a Nasa BM1 battery monitor have some thoughts please?
thanks
Denise
NASA equipment is popular in the UK. It is mostly budget gear and they have had some quality problems with their LED tricolour lights and wind instruments.

The battery monitors, however, have proved quite reliable for low priced equipment. (Despite the experience of Deepthoughts.)

The battery monitor uses a strange method to determine SOC. I am a little wary of this, but it seems to work OK if wired correctly.
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Old 04-09-2012, 05:36   #7
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Re: Nasa battery monitor

NOELEX has it right. I have the same unit and have found it to be useful and trouble free (so far). The information that comes with the instrument is helpful to a point but you may want to read more. The info supplied is woefully thin and needs lots more info. NASA distributes the monitor through CWR electronics in the US. You might get help by calling (732) 237-9300 ext 110 and speak with the one and only person in North America who can give you further assistance.
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Old 04-09-2012, 10:04   #8
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Re: Nasa battery monitor

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...and speak with the one and only person in North America who can give you further assistance.
I am suddenly aware of the voice of experience...

I see the British NASA folk at the Toronto Boat Show every year. I don't like their LEDs but the instrumentation seems decent. I quite liked their AIS unit until I realized that the features of the far less inexpensive Vesper WatchMate matched my needs more closely.

But it looks like decent gear and it's not expensive compared to more mainstream brands.
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Old 04-09-2012, 11:36   #9
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Re: NASA Battery Monitor

I am not sure how advanced NASA is but otherwise bat monitors do not relate the 80% to voltage. Most any unit I have seen calculates the % from Amps in vs. Amps out with some help of an overhead factor (and some logics that may include Voltage as one of the inputs).

Such devices have to be set up properly from the start (batt Ah, the charge factor, etc..) and then re-calibrated from time to time.

At least this is how things are done with Link, Trimetric, etc..

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