nasa battery monitor

Cactus Sailing

Cactus Sailing

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anyone got one? hate or rate?

they look quite smart, the alternatives I've found look shockingly homemade but they are a simple bit of kit so are there some decent looking alternatives a little cheaper, £90 odd seams a little steep for a battery monitor, even if they look nice :)

to be honest its a bit of a nice to have, to understand my power levels and what im using, currently i rely on mainly guesstimates and experience... i haven't run out of power yet but having something i can read from would be easier

i have a separate leisure circuit and its this im more interested in as the engine battery is isolated from the circuit to prevent any non starting issues.

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I have a BM1 connected to my domestic bank of 440AH. The screen shown above is quite useful as is the amount of discharge. The right hand button shows % charge and is just a joke to be ignored.
 
They match the other instruments in the NASA Clipper range

Some people have trouble getting them to work properly.

They MUST be wired exactly as described in the instructions.

Some people have found using better fuse holders helps

Look at the Merlin "Smartgauge" as an alternative but don't expect anyone to explain how it works!
 
I replaced my BM-1 with a Blue Sea digital ammeter/voltmeter.

The problem with the BM-1 was the shunt is a bit puny at 100ah. I couldn't get enough current through to start the engine reliably. I agree with Pasarell that the % charge is a joke. The Blue Sea ammeter/voltmeter is a much more expensive bit of kit but it comes with a 500ah shunt; plenty big enough. Just seeing the level of amps in and out is enough for me.
 
Have had a BM1 for a few years. It has become a very useful bit of kit. It takes the guess work out of things. I monitor what it says against a controlled discharge every few months and have found it pretty good, even the % discharge. ( fuse holder not ideal for marine use though)
 
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The shunt looks like it came from a Jamboree bag, i would refuse to connect the engine battery negative to it. SOC is, as others have said, a joke best ignored. I would spend a little more and get a decent one, or not bother. The Victron BMV-700 is a good one.
 
I've had a BM1 for several years, around 5.

Fantastic bit of kit. Easy to install, does what it says on the tin, reliable, clear, accurate, good price, what's not to like?

If you're not happy with the 100A shunt they do a 200A one.
BM2 also measures starter battery voltage.

The counter of Ah in and Ah out is very useful, espcially when zeroed on arrival after a trip. The next day you know how many Ah you've used overnight, and whether you have enough power to stay another night or two.

From what I've read of other people's comments on this forum the alternative makes (Merlin etc) are little or no better, just more expensive.
 
Trundlebug said:
I've had a BM1 for several years, around 5.

Fantastic bit of kit. Easy to install, does what it says on the tin, reliable, clear, accurate, good price, what's not to like?

If you're not happy with the 100A shunt they do a 200A one.
BM2 also measures starter battery voltage.

The counter of Ah in and Ah out is very useful, espcially when zeroed on arrival after a trip. The next day you know how many Ah you've used overnight, and whether you have enough power to stay another night or two.

From what I've read of other people's comments on this forum the alternative makes (Merlin etc) are little or no better, just more expensive.
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+1 useful to rely on what users have to say than opinions of non users.
 
For my basic little boat I just use a digital voltmeter with a switch to measure either battery,surprisingly accurate
and around £5 or less on ebay.They even do one that can alternate between battery percentage and voltage.
 
Another happy user. Had one on two boats. While the %age charge feature is a bit hit and miss it does agree with the voltage when fully charged and rested. Never had any problem with the shunt. Could not see ny benefit from the more expensive types for my needs.
 
Trundlebug said:
I've had a BM1 for several years, around 5.

Fantastic bit of kit. Easy to install, does what it says on the tin, reliable, clear, accurate, good price, what's not to like?

If you're not happy with the 100A shunt they do a 200A one.
BM2 also measures starter battery voltage.

The counter of Ah in and Ah out is very useful, espcially when zeroed on arrival after a trip. The next day you know how many Ah you've used overnight, and whether you have enough power to stay another night or two.

From what I've read of other people's comments on this forum the alternative makes (Merlin etc) are little or no better, just more expensive.
Click to expand...

The BM2 is supplied with a 200 amp shunt

ITYWF that both the BM1 and the BM2 now also monitor the starter battery volts
 
Trundlebug said:
I've had a BM1 for several years, around 5.

Fantastic bit of kit. Easy to install, does what it says on the tin, reliable, clear, accurate, good price, what's not to like?

If you're not happy with the 100A shunt they do a 200A one.
BM2 also measures starter battery voltage.

The counter of Ah in and Ah out is very useful, espcially when zeroed on arrival after a trip. The next day you know how many Ah you've used overnight, and whether you have enough power to stay another night or two.

From what I've read of other people's comments on this forum the alternative makes (Merlin etc) are little or no better, just more expensive.
Click to expand...

Tranona said:
Another happy user. Had one on two boats. While the %age charge feature is a bit hit and miss it does agree with the voltage when fully charged and rested. Never had any problem with the shunt. Could not see ny benefit from the more expensive types for my needs.
Click to expand...


thanks all, good to know, is it worth going for the 200A shunt just in case? i have a separate starter circuit, but there is an isolator to turn on and use the leisure side to start in an emergency, i would still like to know i could do that with this connected to the leisure side.
 
Hi, I'm a happy user of the BM1, on my domestic battery only. It gives an accurate indication of charge and discharge and a good approximation of how much charge you have left. I have found it also tells you when your battery is on its way out- when you charge your battery hard and find you only have 50% charge on the display for example. Since I don't have shore power I find it quite useful.
 
Kenneth McGrew said:
thanks all, good to know, is it worth going for the 200A shunt just in case? i have a separate starter circuit, but there is an isolator to turn on and use the leisure side to start in an emergency, i would still like to know i could do that with this connected to the leisure side.
Click to expand...

Yes
 
PaulRainbow said:
The shunt looks like it came from a Jamboree bag, i would refuse to connect the engine battery negative to it. SOC is, as others have said, a joke best ignored. I would spend a little more and get a decent one, or not bother. The Victron BMV-700 is a good one.
Click to expand...

Have to agree, I certainly wouldn't consider buying a Nasa monitor. The Victron monitor is in a different league and isn't much more money.
 
So... the score to date seems to be;-
5 members who have used them and like them
1 who is sort of neutral but has not used one
1 more who had one but changed due to 100ah shunt

2 who have not used them but think they are no use.

the OP who will have to make his mind up on the evidence provided!!
 
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