Battery monitor

[Skylark]

Based upon fairly widespread recommendations on here I bought the Victrom BMV712 in Feb/March. Sadly, it remains sitting unopened on my dining table, 250 miles away from my boat I was particularly attracted to its Bluetooth / Smart Phone App feature.

 

[LadyInBed]

I couldn't fault my old SmartGauge Electronics - Homepage

Looks good. If I were going to fit an 'expensive' monitor system that's what I would go for
Merlin Smartgauge
At £132.62 it's on the sensible side of 'expensive'.

 

[pvb]

Looks good. If I were going to fit an 'expensive' monitor system that's what I would go for
Merlin Smartgauge
At £132.62 it's on the sensible side of 'expensive'.

I wouldn't, purely because it can't tell me what current is going in or out of the batteries.

 

[GHA]

Looks good. If I were going to fit an 'expensive' monitor system that's what I would go for
Merlin Smartgauge
At £132.62 it's on the sensible side of 'expensive'.

Got one for just over a hundred on clearance little while ago. Clever bit of kit. Also an elderly bep monitor onboard. Interesting just how much of a difference temperature makes to the battery bank capacity, tracks much closer when it's warm otherwise the SG shows a greater discharge than the bep when cold. Amp counting meters will never really know accurate percent state of charge, they won't know the battery capacity. Imho, for off grid cruising it's more important to know the tail current is down near 1% so you know your batteries are actually close to full charge, any cheap ebay shunt meter will tell you that.

 

[Poey50]

Amp counting meters will never really know accurate percent state of charge, they won't know the battery capacity. Imho, for off grid cruising it's more important to know the tail current is down near 1% so you know your batteries are actually close to full charge, any cheap ebay shunt meter will tell you that.

GHA - I think you illustrate that the real battery monitor is the person taking in the numbers on the display(s) and knowing how to interpret them.

 

[GHA]

GHA - I think you illustrate that the real battery monitor is the person taking in the numbers on the display(s) and knowing how to interpret them.

Numbers on their own tell you little unless you plot them... Then a whole new world is revealed

 

[Rappey]

The nasa bm1 did what I wanted. It let me know which way the current was going and takes no time at all to roughly calculate when they need charging.
Also have solar and wind.
A year on and the nasa shows batteries running low far to quickly when boat is in use.
A disconnect of the nasa and restart cured it for a month or two but now it's back to its old ways.
You enter the A/h capacity on the nasa.
The pico 1 looks very nice .

 

[Koeketiene]

Based upon fairly widespread recommendations on here I bought the Victrom BMV712 in Feb/March. Sadly, it remains sitting unopened on my dining table, 250 miles away from my boat I was particularly attracted to its Bluetooth / Smart Phone App feature.

Great minds think alike.
Got one for the exact same reasons.
Just waiting for a chance to get to the boat and install it.

 

[Little Dorrit]

The nasa bm1 did what I wanted. It let me know which way the current was going and takes no time at all to roughly calculate when they need charging.
Also have solar and wind.
A year on and the nasa shows batteries running low far to quickly when boat is in use.
A disconnect of the nasa and restart cured it for a month or two but now it's back to its old ways.
You enter the A/h capacity on the nasa.
The pico 1 looks very nice .

I had a similar problem which was solved by completely disconnecting the battery and charging it fully. Then reconnect the battery setting up the BM as if it was a new battery. Not ideal but in my case the problem was solved by following the above procedure.

 

[Poey50]

I had a similar problem which was solved by completely disconnecting the battery and charging it fully. Then reconnect the battery setting up the BM as if it was a new battery. Not ideal but in my case the problem was solved by following the above procedure.

The problem won't be - can't be- solved . The accuracy of the state of charge measure on these will progressively deteriorate with time because of inherent limitations. You will need to set it up again and again. State of charge on these is best ignored. This article explains why. SmartGauge Electronics - SmartGauge compared to Amp Hours Counters

 

[Poey50]

I wouldn't, purely because it can't tell me what current is going in or out of the batteries.

I used a Smartguage with no way of measuring the balance of current in / current out for a couple of seasons. State of charge is certainly a useful piece of information, perhaps the single most important piece of information for safety but the addition of a Victron BMV was a revelation in being able to monitor demands of the various loads, combinations of loads, charging etc. If starting again I'd look at this Balmar (as mentioned above) as it incorporates the accuracy of the Smartguage with the current monitoring of the Victron. SG200 Battery Monitor | Balmar
But the Victron BMV712 is also a good bit of kit - as long as the instructions are followed to keep it synchronised to the true state of charge of the battery. The alarms, bi-stable relay (which I'm using with an external loud alarm) and temperature sensor, are all desirable features which I can also use in due course as an audible warning for lithium batteries nearing their charging parameters. And no need to squint at the small display - the bluetooth monitoring is excellent.

 

[doug748]

The Nasa unit will be fine for most users on a small boat, certainly I have found mine to be excellent. You don't need a great deal of sophistication to deal with a couple of lead acid batteries. As remarked, the state of charge bar chart can be safely ignored.

That Pico job looks great, I might invest if I had a complex set up and worried about batteries. The complete answer to battery anxiety, for the weekend sailor, can be summed up in one phrase: Turn the fridge off and forget all about it. -)
.

 

[Poey50]

The complete answer to battery anxiety, for the weekend sailor, can be summed up in one phrase: Turn the fridge off and forget all about it. -)

Many do. Also many kill their batteries through sulphating as they don't realise that they are not fully charged. And a few poor souls get stuck because they trusted their battery monitor state of charge display and had left their two batteries in parallel. And one or two of these might do so in a safety critical situation. Why not pay the extra £100 to get a monitor that is worth reading for state of charge?

If I had a NASA monitor I'd simply add a Smartguage. The easiest to fit of all the monitors and probably the most accurate for state of charge - while discharging. (As said above It doesn't measure anything else so the NASA and Smartguage complement each other.)