nasa clipper battery monitor

[VicS]

I cannot see any theoretical reason for not using a longer cable between the shunt and the battery, but it might be a good idea to make it heavier or there might be a voltage drop which the monitor could misinterpret.

The important factors are

• the connections of the black, white and yellow wires to the shunt
  
• that no other connections are made to the battery negative or the end of tha shunt that is connected to the battery

Make sure all the connections between the battery , the shunt and the negative bus bar are sound and that the wiring is appropriately heavy for the maximum load.

But perhaps I have missed something!

 

[VicMallows]

am surprised at the short length of cable supplied for connecting shunt to battery.
Does anyone actually use this in the purpose described in the manual as the shunt would have to very close to the battery?

It doesn't matter at all if the cable to the shunt is longer, as long as all the current goes through the shunt (and obviously the cable is adequate). I agree the supplied piece is just about worthless! - just keep it in case you find a use one day. (its not even decent tinned flexible cable).

I would rate my BM-1 as the single most useful bit of battery related kit I have bought. It has performed perfectly except for the one time the in-line holder developed high resistance and played havoc. Tonight I know I can safely continue to use the computer AND put the heating back on for an hour or so.

As already stated, the 'percentage capacity' indication is far from perfect, but I am only interested in the cumulative AH measurement and the present A and V. I reach my own conclusions from there.

Vic

 

[VicMallows]

VicS , sorry we 'doubled' . We slow typists

 

[Seajet]

I would rate my BM-1 as the single most useful bit of battery related kit I have bought.

Well I have made extremely sure mine is properly connected, and I disagree in a big way !

The only reason I did not get to throw it back at NASA is, just like with their wind instruments etc, they are good at delaying mails until the warranty or one's will to live expires first.

I really wish I could support this British company, but I am hardly the only one to be, shall we say, disillusioned...

I would not have had their ( or any ) masthead windspeed instrument, but it was presented to me as a gift so I felt I had to fit it; the first unit packed up after 11 months, and when I called I was, to put it basically, told to get stuffed.

A while later in a brief period with more money than sense I ordered another Clipper wind unit, mainly to occupy the bulkhead space I'd made for the first !

That one had a noticably different design masthead unit and lasted 22 months.

When I rang describing the symptoms of its' failure I was told " definitely the masthead unit, send it in ".

A couple of weeks later at a boat show I asked a rep' on the NASA stand;..." definitely the display unit, send it in ".

As each was going to cost over £100 and I have good reason to believe wouldn't last long, I have not bothered, thankfully removing the lot.

Now I just need something useful to cover the space in the cockpit bulkhead...

My BM-1 gives a clue as to what's going into the battery re. solar panel via the voltage reading, but is useless as to charge remaining or trend other than looking at the present voltage; the old 'Smiths Battery Condition Meter' I fitted to my switch panel is of a lot more use.

I am hardly the only one with these experiences; I am trained with aircraft instrumentation, so I suppose there is the point that I know all yacht ( and a lot of aircraft ) instruments are at best questionable, no matter what the price.

I am, however, rather unhappy with the responses I've had from 'NASA', and certainly won't be buying from them again.

 

[double_ender]

I echo all your comments Vic about it being a most useful bit of kit. I fitted the BM version a year ago. I think the most astounding thing about it in my case is the detailed study of the charge/discharge value by my wife; she is so much more concious of lights/instruments/ etc now;and is always commenting to me on the electrical goings on, and snicking off light switches etc.
A real example of the law of unexpected consequencies!!
Malcolm

 

[Playtime]

My BM-1 gives a clue as to what's going into the battery re. solar panel via the voltage reading, but is useless as to charge remaining or trend other than looking at the present voltage; the old 'Smiths Battery Condition Meter' I fitted to my switch panel is of a lot more use.

Have you tried using the cumulative Ah reading on the BM1? This is particularly useful if you zero it when charging ceases.

Also, the Amp readings give valuable real time information for the consumption of each piece of equipment as it is used.

I agree that the Capacity Remaining info is pretty much a waste of time but, with the A and Ah readings and an understanding of battery capacity, you have all the data you need.

 

[VicMallows]

but is useless as to charge remaining or trend other than looking at the present voltage;

I think it may be a question of expectations. I specifically wanted a device to tell me cumulative AmpHours in/out. Anything extra was really just a convenient bonus as I had other means to monitor them. Certainly the voltage and current indications on my unit are accurate when compared to calibrated standards.

For all I know NASA may have quality control problems and you have been unlucky? All I can say is that my experience over several items has been good, and I don't think anyone will argue against the price.

Vic

 

[Allan]

I fitted a BM1 about a year ago. I would add a warning, that I don't think has been said yet. You can get obsessed! I have a Rutland, a small solar panel and no power on the pontoon. Every week I arrive at the boat and look at the meter, to see how much charge has been added to the two domestic batteries. I then turn on the main switch and one of the LED lamps (0.1A), which I bought to stop the BM1 going down! After I have made tea, the gas solenoid MUST be turned off (0.4A). I then have light the oil lamp (0.0A). The radio (0.5A) is often on, as watching TV, using the inverter (4.2A) is pretty much out now! The laptop can only be used while it's internal battery is charged as using the inverter(2.2A, battery removed, 6.1A, battery fitted!) is too painful. Next I HAVE to buy an LED tricolour to use when I am sailing, with the chart plotter display turned down (saving 1.4A). Before I leave the boat I have to turn off the main switch and wait for the display to settle so I know the battery state.
A great bit of kit, which I wish I had never bought!
Allan

 

[VicMallows]

Every week I arrive at the boat and look at the meter, to see how much charge has been added to the two domestic batteries.

Don't trust that! ... the zero-drift over time can give wild readings, especially if the temperature has changed a lot.

(I even disconnect mine to save the small but significant drain over several weeks)

Vic

 

[Allan]

Don't trust that! ... the zero-drift over time can give wild readings, especially if the temperature has changed a lot.

(I even disconnect mine to save the small but significant drain over several weeks)

Vic

I am rarely away from the boat for more than 3 or 4 days and during that time the turbine and solar panel put much more in than the meter takes out. Any readings of 85% plus seem unreliable, most of the time even a small current flow will take the reading down to below this figure. As said before, it is good but not perfect. Interesting to learn how much power each thing uses, but it can drive you as mad as it has made me!
Nasa advise not to disconnect as the unit "learns" as it goes. I'm not sure this means too much.
Allan

 

[whipper_snapper]

I am about to install one of these and am surprised at the short length of cable supplied for connecting shunt to battery.
Does anyone actually use this in the purpose described in the manual as the shunt would have to very close to the battery?

I am hoping to position the shunt quite close to the negative bus bar and therefore use the supplied cable for this connection and my existing cable for battery to shunt.
Does anyone see any issue in this approach?

Thanks

That's sort of what I did. I put the shunt between the neg bus bar and the existing feed to the busbar. Did not use the supplied bit of wire. Works perfectly.

 

[GrahamM376]

I've got one of these sat in a box. I tried to fit it but you can only fit the shunt on the negative side of the circuit (I checked this with NASA). Not very good if you have multiple batteries and multiple earth returns.
If I could have fitted the shunt on the positive side then it would be fine.
I could do with selling it if anyone is interested.
It does seem to be a nice piece of kit though.

I have 2 house banks + engine start, all negs connected together and didn't find it difficult to install 2 x battery monitors, 1 to each house bank.

All you need to do is - remove all the negative cables from your house bank and insert the shunt between the cables and the battery. Then connect the monitor wires as per instructions. No need to touch the engine battery.

As long as all the negatives are connected to the shunt or the engine battery negative, the monitor will sense all current drawn by any items which are powered from the house battery positive.

Make sure the batteries are fully charged and then left to settle off charge. Then connect the monitor with no loads switched on.

 

[GrahamM376]

I am about to install one of these and am surprised at the short length of cable supplied for connecting shunt to battery.
Does anyone actually use this in the purpose described in the manual as the shunt would have to very close to the battery?

I am hoping to position the shunt quite close to the negative bus bar and therefore use the supplied cable for this connection and my existing cable for battery to shunt.
Does anyone see any issue in this approach?

Thanks

As long as all your negatives go to the bus bar, no problems. In my case, the Aerogen, solar panels, Eberspacher and fridge negs all go direct to the batteries so I had to put the shunt there or, re-route them all.

 

[mcframe]

I fitted a BM1 about a year ago. I would add a warning, that I don't think has been said yet. You can get obsessed! I have a Rutland, a small solar panel and no power on the pontoon. Every week I arrive at the boat and look at the meter, to see how much charge has been added to the two domestic batteries. I then turn on the main switch and one of the LED lamps (0.1A), which I bought to stop the BM1 going down! After I have made tea, the gas solenoid MUST be turned off (0.4A). I then have light the oil lamp (0.0A). The radio (0.5A) is often on, as watching TV, using the inverter (4.2A) is pretty much out now! The laptop can only be used while it's internal battery is charged as using the inverter(2.2A, battery removed, 6.1A, battery fitted!) is too painful. Next I HAVE to buy an LED tricolour to use when I am sailing, with the chart plotter display turned down (saving 1.4A). Before I leave the boat I have to turn off the main switch and wait for the display to settle so I know the battery state.
A great bit of kit, which I wish I had never bought!
Allan

So, can I interest you in a NEMA version that forwards the in/out AH display to the main, cockpit visible instruments allowing you calculate VMG/AH and Expected capacity (heater/fridge hours available) at Destination ? ;->

I've got a BM1 and the ships's boy (a _Numberjacks_ fan) is very good at relaying current(sic) charge rate to the helm so I can decide how soon after leaving our mooring I can "engage the silent drive".

 

[Allan]

So, can I interest you in a NEMA version that forwards the in/out AH display to the main, cockpit visible instruments allowing you calculate VMG/AH and Expected capacity (heater/fridge hours available) at Destination ? ;->

I've got a BM1 and the ships's boy (a _Numberjacks_ fan) is very good at relaying current(sic) charge rate to the helm so I can decide how soon after leaving our mooring I can "engage the silent drive".

Many thanks for the offer but I can put on the autohelm (2.3A) for short while and go below to do the calculations.
Of course, if you had some way to get the BM1 to text me the situation while I am at home, I would be really interested.
Allan

 

[Interlude]

It is worth checking that the amps reading hasn't drifted over time - I found about a 1 amp error which crept in over about 2 years on a BM-1. With solar charging always connected it was not obvious until all charging and load was switched off. Easy to fix once noticed.

 

[ianj99]

1 bm1 , 2 batteries

I fitted a 4pole 3position rotary switch to my BM1 so I can monitor 2 batteries and the alternator (or a 3rd battery). (along with a shunt for each input)

Obviously the charge remaining feature is useless, but I prefer to use the voltage as an indicator of battery state anyway, so not a problem for me.

I

 

[colvic987]

Of course, if you had some way to get the BM1 to text me the situation while I am at home, I would be really interested.
Allan

This item might be of interest to you http://www.yacht-sentinel.com/boat-security/ although it wont text you the bm1 info, it will text you the state of your batteries, and much more...