# Nasa BM1 Battery Monitor



## grizzlyj (Oct 14, 2008)

Hi folks

I'd like to add a Nasa monitor, but wonder if small is good? The normal sized one is 110mmx110mm, so quite chunky when space is tight.

Their compact version is half the size but the blurb seems to say doesn't give you an Ah figure?

http://www.nasamarine.com/proddetail.php?prod=BMN-1_Battery

http://www.nasamarine.com/proddetail.php?prod=BM1Compact&cat=23

Does anyone have the compact version? I'm not fussed about no backlight, but is it as good a tool?

Cheers

Jason


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## peejay (May 10, 2005)

Hi Jason,

I've got the BM1 compact fitted as the Schaudt monitor shows innacurate info when a Sterling b2b and solar panel is fitted into the Hymer system.

The Nasa shows battery state as a percentage, time left in hours, battery voltage and current discharge if any.
There is a blue backlight which glows for about 30 seconds after any button is pressed.
Does what it says on the tin for me.  

Pete


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## Antonia (Apr 27, 2008)

*Thanks*

Thank you so much for bringing this to my attention folks.

I was looking for just such a thing to monitor my system. And too, Amazon is selling them for £88 including free delivery. I ordered one to arrive next week.

Thanks again MHF well worth the subscription.

Antonia


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## erneboy (Feb 8, 2007)

You might also consider the Victron, according to experts on here it has more features: http://www.savingenergyonline.co.uk/product/374

Alan.

Expert opinions on Battery Monitors towards the end of this thread: http://www.motorhomefacts.com/ftopic-116393.html&postdays=0&postorder=asc&highlight=victron&start=20


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## vicdicdoc (May 14, 2005)

I fitted the BM-1 unit a couple of years back - wouldn't be without it as I can see at a glance whats going in, whats taken out & the state of the batteries


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## pieterv (Feb 3, 2009)

You do need to realise that these can get "out of synch". For instance, if you are on a site on EHU the charger will give a trickle charge after the batteries are full. The monitor will count these in the Ah setting as surplus, so whereas 0AH is fully charged (i.e. no discharge), it will go into plus numbers (e.g. 20h of 0.5A tricle charge, will read as plus 10Ah). When you start to discharge when off EHU it doesn't start at zero as it should, but at whatever plus value accumulated. So, you need to reset the AH to zero once you stop charging.

It doesn't have the same problem with the display for % charge (this only goes to 105%), but this one is easily mislead, and will "recover" to a higher % without actually being charged.

It is a usefull instrument, but you do need to have some input yourself, and not believe it blindly.

Pieter


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## JohnWebb (May 1, 2005)

I have the big one in my sailing boat, the small one in my motorvan and I have fitted the big one into daughters narrow boat. They do what I want! They are very useful when off power for extended periods. In Holland on the islands the boat only has a solar cell and the engine so it is invaluable knowing where one is! The motorvan has both a solar cell and an Efoy so will last full time off power but one still wants to know what is happening.


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## SaddleTramp (Feb 15, 2007)

I have just fitted the Victron BMV 600S after taking advice from Eddie of Vanbitz, after I posted re battery problems, The topic started <Here> when I stated that I had a mate who had got one he didn't use, I must admit that after looking at the NASA one I do prefer the Victron.


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