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Frankieboy

Battery Level Meter

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Hi,

When we get our boat up and running am hoping to fit a battery level meter so can keep an eye on the leisure batteries (The wife loves to watch tv all day and kill them).

Are there any good cheap meters that will allow me to monitor the levels?

Ideally I would like one that doesn't use too much current itself, or that I could just switch on briefly to check the levels.

Cheers

Frank

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Hi,

When we get our boat up and running am hoping to fit a battery level meter so can keep an eye on the leisure batteries (The wife loves to watch tv all day and kill them).

Are there any good cheap meters that will allow me to monitor the levels?

Ideally I would like one that doesn't use too much current itself, or that I could just switch on briefly to check the levels.

Cheers

Frank

 

I had the same idea myself, but I've been advised not to bother as they are not particularly accurate. There's a bit in the Waterways world this month that says much the same thing, but I'm afraid electrics is my nemesis so I would get some further advice...

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I bought one off ebay for less than it was in the chandlers. Waste of time. I could use a set of dice to get a better indication of Battery state of charge. Splash out on a Smart Gauge. You'll get one eventually after realising that the cheap ones don't work well, so save some money and buy one first.

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Maplins now stock them too.

Question - does it come with cables /fuses etc, if not, what does one need to purchase to get it all up and running.

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Maplins now stock them too.

Question - does it come with cables /fuses etc, if not, what does one need to purchase to get it all up and running.

The ones from Maplins come with fuses, you only have to supply cable.

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There's only one really

Smartgauge

 

Agreed and the best thing about a Smartgauge is that it 'self learns' after you have done the initial set up for battery type, capacity etc so the results get more accurate as time goes on. With the other gauges that I have had they lose synchronisation with the state of charge and need manual intervention every so often to get them back in sync otherwise they get less and less accurate. If you want a reliable, state of charge at a glance type product then an SG is the way to go.

Roger

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Victron battery monitor

 

http://www.energy-solutions.co.uk/victron/bmv600.html

 

 

Standard information and alarms

Battery voltage (V)

Battery charge/discharge current (A)

Ampere-hours consumed (Ah)

State of charge (%)

Time to go at the current rate of discharge

Visual and audible alarm: over- and under voltage,

and/or battery discharged

Programmable alarm or generator start relay.

 

 

Charles

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Victron battery monitor

 

http://www.energy-solutions.co.uk/victron/bmv600.html

 

 

Standard information and alarms

Battery voltage (V)

Battery charge/discharge current (A)

Ampere-hours consumed (Ah)

State of charge (%)

Time to go at the current rate of discharge

Visual and audible alarm: over- and under voltage,

and/or battery discharged

Programmable alarm or generator start relay.

 

 

Charles

 

Yep, that's one of the ones that doesn't stay in sync with the state of charge of the battery. Been there, done it, got the T shirt etc.

Roger

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As long as you don't expect the batteries to be fully charged simply because it reads 100%

 

I think you're probably after a state-of-knackeredness-meter as well as a state-of-charge-meter. I'm not sure if anyone makes one of those ?

Edited by Graham!

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I think you're probably after a state-of-knackeredness-meter as well as a state-of-charge-meter. I'm not sure if anyone makes one of those ?

Sorry, I can't see the point you are trying to make.

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I think you're probably after a state-of-knackeredness-meter as well as a state-of-charge-meter. I'm not sure if anyone makes one of those ?

 

Could always fit Smartgauge and Ah counter.

 

Ah out x 100/(100-Smartgauge reading)= bank capacity.

 

Iain

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I just look at the voltage

 

Which is a good method as long as you take into account surface charge on the battery plates immediately after charging and compensate for it by turning something on for 10 mins or so. The other thing to bear in mind is that voltage will never be entirely accurate unless there's been no charge or discharge for 24 hours, which for a liveaboard is virtually impossible to implement. Then there's slight temperature adjustments, but all in all it's a good method.

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As long as you don't expect the batteries to be fully charged simply because it reads 100%

I'd agree it's not 100% when a SmartGauge first shows 100%, probably more like 90%. I have an ammeter as well and typically the SmartGauge shows 100% when the charge current has dropped to ~9 amps. However, even with another 4 hours charging (by which time the charge current has probably dropped to ~5 amps) I've probably only put another 20-30Ah into the batteries and got them up to ~95%. Another 8 hours of charging might get the next 3% in, and so on. Unless you've got the luxury of shore power and a mains charger you're probably not going to achieve 100%.

 

The benefit of the SmartGauge is that it is a simple-to-use tool to manage your batteries. If you never let the SmartGauge reading drop below 50% and try and charge to 100% most days and you'll get good battery life. Occasional longer charges will definitely be of benefit when you have the opportunity to do that.

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Smartgauge can be up to 10% out when in charging mode.

 

It's also inaccurate if batteries have lost more than 50% of their original capacity.

Edited by nb Innisfree

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Hi,

When we get our boat up and running am hoping to fit a battery level meter so can keep an eye on the leisure batteries (The wife loves to watch tv all day and kill them).

Are there any good cheap meters that will allow me to monitor the levels?

Ideally I would like one that doesn't use too much current itself, or that I could just switch on briefly to check the levels.

Cheers

Frank

Smartgauge - very user friendly.

Basic (but accurate to 0.5%) voltmeter - cheap but not as user friendly.

Amp hour counter - don't go there unless you really understand them.

 

cheers,

Pete.

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Just thought i would ask, has anyone used the nasa bm-1 battery monitor?

Isn't that just another (inaccurate) AH meter?

 

Tony

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Just thought i would ask, has anyone used the nasa bm-1 battery monitor? and if so, how reliable has it been?

 

Depends what you mean by "reliable".

 

If you mean "reliable" as in "Will it still be working in 3 years time?" then the answer is almost certainly yes.

 

If you mean "reliable" as in "Will it accurately tell me the state of charge?" then the answer is almost certainly no.

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