Smart Gauge vs Nasa BM-1

[Waynerrr]

I have recently bought a nb with no record of how old the batteries are. I am not convinced that they are holding their charge as well as they should be (if they were at least 2-3 years old), so I am looking to replace the bank, switch to a pure sine wave inverter and install a battery monitor.

 

I have been looking at a few monitors and the Smart Gause and Nasa BM-1 get mentioned quite a bit. Can anyone tell me their experiences of each? The BM-1 is a lot cheaper but doesn't appear to have any less features. I am firm believer in 'you get what you pay for' so I need some reassurance before going for the cheaper product. Help?

[churchward]

I have recently bought a nb with no record of how old the batteries are. I am not convinced that they are holding their charge as well as they should be (if they were at least 2-3 years old), so I am looking to replace the bank, switch to a pure sine wave inverter and install a battery monitor.

 

I have been looking at a few monitors and the Smart Gause and Nasa BM-1 get mentioned quite a bit. Can anyone tell me their experiences of each? The BM-1 is a lot cheaper but doesn't appear to have any less features. I am firm believer in 'you get what you pay for' so I need some reassurance before going for the cheaper product. Help?

I guess it depends on what you are after. If you want a display that shows voltage and Amps then a BM-1 will be OK. However, if you want an accurate display of the state of charge (SOC) of your batteries that stays accurate and adapts to the batteries it is connected to then a Smartgauge is the answer.

 

The BM-1 does an approximation of SOC (no more than that) and requires you to make any necessary adjustments when its accuracy starts to wander.

 

I bought a Smartgauge it does all that it says it will do. If you want to see the level of amps being consumed you will though need to buy a separate meter.

 

If you need a simple to fit but clever split charge system a good add onto the Smartgauge is Smartbank Advanced.

[alan_fincher]

I have been looking at a few monitors and the Smart Gause and Nasa BM-1 get mentioned quite a bit. Can anyone tell me their experiences of each? The BM-1 is a lot cheaper but doesn't appear to have any less features. I am firm believer in 'you get what you pay for' so I need some reassurance before going for the cheaper product. Help?

 

In fact both do entirely different things.

 

The BM-1 attempts to track amp-hours in and out of the battery. Much has been written in previous posts on why that approach is flawed.

 

Smartgauge makes no such attempt, instead trying to ascertain batteries state of charge by voltage readings, (but not in any way attempting to track current, which it has no way of measuring).

[NB Willawaw]

Not greatly impressed with Nasa products.

 

Have used some of their NMEA driven displays for repeaters and had to send quite a few back because they failed.

 

Not had any problems with Smartgauge.

 

Slightly different applications, but quality is quality - just my tuppence worth.

[Chalky]

I've got a BM-1. The volt meter is accurate, so is the ammeter (checked against other meters). The State of Charge (SOC) calculation is very inaccurate and can't cope with sulphated batteries. I tend to ignore it now and work purely on voltage and current curves to guestimate soc. Next time I'd pay the extra and buy a smart gauge.

[bottle]

I think the previous replies answer your query but another vote for Smartgauge.

 

One little thing though, do read the manual and understand what a Smartgauge tells you.

 

I expect you have been to the Smartgauge site, if not I recomend you do so and read the 'technical info' and the user guide is available to User guide

 

ps. I have one, like many others on here.

[nb Innisfree]

I've got a BM-1. The volt meter is accurate, so is the ammeter (checked against other meters). The State of Charge (SOC) calculation is very inaccurate and can't cope with sulphated batteries. I tend to ignore it now and work purely on voltage and current curves to guestimate soc. Next time I'd pay the extra and buy a smart gauge.

 

Remember though that Smartgauge is inaccurate with batts that have less than 50% of their capacity left.

[bottle]

Yes, but if their capacity (not SOC) was that low 'you' would be thinking of replacing them.

[nb Innisfree]

Yes, but if their capacity (not SOC) was that low 'you' would be thinking of replacing them.

 

Ours have been soldiering on for the last 12 months in that state, we're managing to keep ahead due to us having eight batts staying stable and combining to meet our daily needs with 2 hours charge per day and a weekly long absorption.

[Waynerrr]

Sounds like it's worth spending the extra money then as I suspected. I had browsed the manual and it certainly looks more concise than the BM-1, although this doesn't always mean good things. Given the feedback I will spend the time reading into more detail what the Smart Gauge can do along with the Smart Bank Advanced also. Thank you all

[Justme]

Ours have been soldiering on for the last 12 months in that state, we're managing to keep ahead due to us having eight batts staying stable and combining to meet our daily needs with 2 hours charge per day and a weekly long absorption.

 

 

Wont that mean that a lot of the power you are feeding in to the bats just wont get stored so its costing you more in fuel?

[Big John]

Our NASA meter has one major drawback - it is limited to recording a charge of 102 amps.

 

Once the system is charging at 103 amps it registers a Discharge of 101 amps! So to keep its calculations below 100 amps we do not switch our Travelpower on until the original engine alternator charge is less than about 45 amps.

[nb Innisfree]

Wont that mean that a lot of the power you are feeding in to the bats just wont get stored so its costing you more in fuel?

 

Yes it's costing more in fuel but that is always the case when absorption charging, with new batts we could nearly halve our daily charge time as we could just stay in bulk instead of being mostly in absorption as we are now, but more often than not we cruise for longer than that anyway so on balance we can stick with present batts. Gibbo reckons we have about 45% of our 480ah (24v) left which is still a reasonable amount, just the same as nearly 4 batts instead of our eight.

 

Difficult call but as batts are giving stable supply I think sticking with them is still ok for a while besides being a northern git I am a bit reluctant to spend money.

[bottle]

If you are happy with the existing then this may appeal to

being a northern git

get rid of the eight and just buy four.

 

This will of course affect the amount of available amps, perhaps a power audit may help.

 

ps. I have six @ 24v... 339 Ah when new.

[Timx]

This is getting frightening,if I dont have a clue about electrics ,batteries etc would it be foolhardy to buy a nb,for liveaboard,cc, if i dont envisage having loads of dosh to keep taking it to a boat yard everytime something goes wrong....?

[Gunna Do]

I think there is a case for both. I used a BM1 on a trans-atlantic sailing trip where I needed to watch power usage very closely. It was brilliant for my requirements then. Having gone through the decision wrangling that this OP is doing now, I chose the Smart Gauge for the Nb. Initially I was disappointed with it because the one feature that I wanted was a record of how much power each appliance was using. For example I don't know how much juice our fridge consumes. It's not in the literature (in recognisable form!) and it's very difficult to remove said unit and read the data tag. If Smart Gauge has this feature it would be as near perfect as could be. However it does exactly what it says and is definitely worth having. If I wasn't so tight, I would buy another BM1 as well!

[bottle]

would it be foolhardy to buy a nb,

 

Yes

 

 

 

 

but that is true even if you know everything there is to know about boats.

 

 

If you do have problems there is the fount of knowledge on here, you could read up about it on the 'net

 

here is a start:

 

http://www.batteryfaq.org/

 

and of course

 

http://www.smartgauge.co.uk/ (click on 'technical info')

[Timx]

Ha, thanks for that...i think...

[bottle]

That's OK

 

Here is another site http://www.tb-training.co.uk/ Tony Brooks (member of this forum) place of learning.

 

This site is the notes for a maintenance course that he regularly performs.

Edited February 22, 2011 by bottle

[alan_fincher]

I think there is a case for both. I used a BM1 on a trans-atlantic sailing trip where I needed to watch power usage very closely. It was brilliant for my requirements then. Having gone through the decision wrangling that this OP is doing now, I chose the Smart Gauge for the Nb. Initially I was disappointed with it because the one feature that I wanted was a record of how much power each appliance was using. For example I don't know how much juice our fridge consumes. It's not in the literature (in recognisable form!) and it's very difficult to remove said unit and read the data tag. If Smart Gauge has this feature it would be as near perfect as could be. However it does exactly what it says and is definitely worth having. If I wasn't so tight, I would buy another BM1 as well!

If you were to have the Smart Gauge and independently fit just a good shunt ammeter, you would get your current readings for far less pennies than Smart Gauge + BM1 !

 

I have neither, but if I felt it necessary, would probably do that. I do have a very basic ammeter, as I like to actually be able to see the current situation, (no pun originally intended!), for overall amps in or out at a point in time. For my purposes, I'm happy that it's not a precise number, but if I wanted that, I'd simply substitute something more accurate. Far cheaper than a BM1, which I am not convinced is worth it's cost in narrow boat use for most people.

 

I wish there was a Smart Gauge that incorporated the ability to read amps using a shunt. I realise it doesn't need it for it's SoC calculations, and cost would be higher, but I'd be more inclined to buy one if it had that capability, so I could have that as an option of a read-out.

[Timx]

That's OK

 

Here is another site http://www.tb-training.co.uk/ Tony Brooks (member of this forum) place of learning.

 

This site is the notes for a maintenance course that he regularly performs.

Thanks have added it to favourites for future reference

[Gibbo]

I wish there was a Smart Gauge that incorporated the ability to read amps using a shunt.

 

It's still some considerable way off but the prototype is right in front of me as I type

[RLWP]

This is getting frightening,if I dont have a clue about electrics ,batteries etc would it be foolhardy to buy a nb,for liveaboard,cc, if i dont envisage having loads of dosh to keep taking it to a boat yard everytime something goes wrong....?

 

HI,

 

No, don't worry about it. For me, there are two approaches to batteries, one a science, the other a craft.

 

What you are seeing here is the scientific approach around capacity, charging times and states, energy surveys and all that. This is the "correct" way to do the job and will give the best results

 

The craft approach is - what have I got, what will it do, how do I use it. You can find this out by trial and error without a multimeter or knowledge of Peukert

 

Richard

[Albion]

It's still some considerable way off but the prototype is right in front of me as I type

 

Ah, that'll be the one that you canvassed for suggested features a while ago and ended up with suggestions that would have made it so complex that it would have cost nearly as much as the rest of the electrics put together then?

Roger

[Gibbo]

Ah, that'll be the one that you canvassed for suggested features a while ago and ended up with suggestions that would have made it so complex that it would have cost nearly as much as the rest of the electrics put together then?

Roger

 

That's the one. It was a useful excercise.

 

The result is a "measurement" unit that goes near the batteries and a separate display. This was MP's idea and massively simplifies installation and cabling. However there's no bluetooth, no ethernet and no teasmade.

 

I'm still pondering the exact features and functions but the hardware now exists, huge parts of the software are done and it's actually up and running.