Tracer Remote meter accuracy.

[canals are us?]

I have a tracer 40A MPPT solar controller and the remote MT50 meter. I also have a NASA BM2 battery monitor.

Is the tracer remote battery indicator accurate? As the MT50 meter shows half full and the NASA BM2 as 104% SOC. I would of thought both should be full as charger on permanently on the Victron inverter/charger. Voltage reading 13.3v on both. 0.3A charge according to BM2. Is it also normal for a victron inverter/charger to hum/buzz slightly?

What is the voltage when at 50% SOC? I can then see if it tallies with my battery monitor.

James 

Edited March 29, 2018 by canals are us?

[TheBiscuits]

35 minutes ago, canals are us? said:

I have a tracer 40A MPPT solar controller and the remote MT50 meter. I also have a NASA BM2 battery monitor.

Is the tracer remote battery indicator accurate?

No.  It's a basic amp hour counter and can only work if all your loads are connected to the LOAD terminals on the MPPT unit.  Don't do this as it is current limited to 40 Amps.

Just entirely ignore it.  It is meaningless on a typical boat setup.

35 minutes ago, canals are us? said:

the NASA BM2 as 104% SOC.

Then you need to reconfigure your BM2 - your batteries now have a smaller capacity than the BM2 has been set to, which is the point of a Smartgauge.  I think @Mike the Boilerman has a spare one ...

Edited March 29, 2018 by TheBiscuits
speeling

[canals are us?]

8 minutes ago, TheBiscuits said:

No.  It's a basic amp hour counter and can only work if all your loads are connected to the LOAD terminals on the MPPT unit.  Don't do this as it is current limited to 40 Amps.

Just entirely ignore it.  It is meaningless on a typical boat setup.

Then you need to reconfigure your BM2 - your batteries now have a smaller capacity than the BM2 has been set to, which is the point of a Smartguage.  I think @Mike the Boilerman has a spare one ...

You reminded me.

About a week ago I fitted 2 new Trojan T105's to my existing 2, so now have 4 batteries of around 440AH or a bit less caused by sulphation which I did an equalisation and SG readings.

I have just changed both monitors to show the size of the battery bank. Before put 200ah in. What else should I do?

James

[WotEver]

Just now, canals are us? said:

What else should I do?

Give up on expecting the BM2 to ever give you an accurate SoC reading. It never will. 

[Dr Bob]

42 minutes ago, canals are us? said:

 Is it also normal for a victron inverter/charger to hum/buzz slightly?

What is the voltage when at 50% SOC? I can then see if it tallies with my battery monitor.

James 

Yes, My victron combi will hum/buzz slightly when under load.

I work on 12.1V for 50% SoC BUT it has to be read at rest with NO solar.....difficult unless you do it at night time.

[WotEver]

1 minute ago, Dr Bob said:

I work on 12.1V for 50% SoC

Others work on 12.2V. It’s not critical. There or thereabouts. 

[Dr Bob]

6 minutes ago, WotEver said:

Give up on expecting the BM2 to ever give you an accurate SoC reading. It never will. 

I dont think any meters give accurate SoC numbers when nearly full or fully charged. I just dont look at SoC. Get in the habit of looking at Voltage early in the morning with little  or no load (or late at night) and understanding AHrs out before the days charge.  Keep an eye on tail current and you can then 'estimate' your own SoC. It only takes a few seconds each day to look at the meter 3 or 4 times. 

[canals are us?]

14 minutes ago, WotEver said:

Give up on expecting the BM2 to ever give you an accurate SoC reading. It never will. 

 

11 minutes ago, Dr Bob said:

Yes, My victron combi will hum/buzz slightly when under load.

I work on 12.1V for 50% SoC BUT it has to be read at rest with NO solar.....difficult unless you do it at night time.

 

9 minutes ago, WotEver said:

Others work on 12.2V. It’s not critical. There or thereabouts. 

Thanks for the info. So long as I never let the battery voltage drop below 12.2 volts at night, that should keep them healthy so long as I charge them everyday. When in the Marina I'm using a Victron inv/charger.,  When out crusing start re-charging at 12.2v or before preferably.

James

[canals are us?]

22 minutes ago, Dr Bob said:

I dont think any meters give accurate SoC numbers when nearly full or fully charged. I just dont look at SoC. Get in the habit of looking at Voltage early in the morning with little  or no load (or late at night) and understanding AHrs out before the days charge.  Keep an eye on tail current and you can then 'estimate' your own SoC. It only takes a few seconds each day to look at the meter 3 or 4 times. 

My charger is always on as I live in a Marina for work purposes. The charger is generally in float and reads around 13.3 volts. This drops slightly at night to around 13v. Why, I don't know.

I noticed yesterday and the day before the solar controller was doing an equalisation charge as I had set it up to do it at 15.5A weeks ago and have now disabled it as don't want to do one every time its sunny! Have mastered doing it on the Victron. So re altered the max voltage and EQ voltage.

When I'm out I'll ignore the SOC and see when I start the engine how much current is going in on the BM2 and how long it takes to get less to about 5A? I hear the last tail current can take a long time.

I also think it will be good for the batteries to cycle them a bit, and recharge with use, as I never have, due to being permanently on a charger. They might like the excitement of powering my 12 volt freezer and fridge and not having a lazy life on a charger.

James

 

 

Edited March 29, 2018 by canals are us?

[Richard10002]

1 hour ago, WotEver said:

Give up on expecting the BM2 to ever give you an accurate SoC reading. It never will. 

+1!!!

The %age state of charge on the NASA BM1 or BM2 is worse than useless. The voltage reading, the cumulative amp hour reading, and the instantaneous Amps reading, are great. I use it to keep an eye on everything, and to assess when the tail current is low enough to stop charging.

The Amp Hours needs resetting once “full” as it doesn’t zero itself like some.

I use a Smartgauge for state of charge, but don’t trust it at all if it’s reading above 80%, whether charging or discharging, so it’s no use for telling you the batteries are full. 

[Detling]

The Tracer SOC battery indicator is well known for it's total inability to reflect the charge level of the battery.  Mine often displays 40% when the voltage is 14.4 and the alternator is only able to push 1 amp int 600 Ah of batteries, somehow I recon they are full even if Tracer doesn't.

[canals are us?]

6 hours ago, Richard10002 said:

+1!!!

The %age state of charge on the NASA BM1 or BM2 is worse than useless. The voltage reading, the cumulative amp hour reading, and the instantaneous Amps reading, are great. I use it to keep an eye on everything, and to assess when the tail current is low enough to stop charging.

The Amp Hours needs resetting once “full” as it doesn’t zero itself like some.

I use a Smartgauge for state of charge, but don’t trust it at all if it’s reading above 80%, whether charging or discharging, so it’s no use for telling you the batteries are full. 

What tail current on the nasa would you stop charging?

5 hours ago, Detling said:

The Tracer SOC battery indicator is well known for it's total inability to reflect the charge level of the battery.  Mine often displays 40% when the voltage is 14.4 and the alternator is only able to push 1 amp int 600 Ah of batteries, somehow I recon they are full even if Tracer doesn't.

I'll stick to this method when out cruising and not take any notice of SOC.

This evening I turned off my mains charger and the voltage went down from 13.2 volts to 12.7 volts after around 1 hour with a discharge of 5 - 7A with 12volt fridge or freezer running plus lights and 12 volt tv and when these items were on the voltage went down to 12.5volts and stayed there unless fridge/freezer switched off then recovered to 12.7volts. SOC saying 75 or 85%. I tried it for 2 and a half hours, just to see how the voltage and batteries would react. Seems ok to me?

I gave up as ready to cook food in my electric mini oven and switched the charger on and it showed 70a very briefly and continued to fall to around 18a then walked away.

Thanks. James

Edited March 29, 2018 by canals are us?

[Richard10002]

My Battery bank is about 200Ah, so I consider it to be full when the tail current is below 4A when charging at 14.4V. It is generally accepted that when the tail current is between 1% and 2% of the battery banks actual capacity, the batteries are as good as full.

Your described experience is about what is to be expected. 12.7V with little power being drawn is full. When something draws significant power, (the fridge), you would expect the voltage to drop a little, then rise when the fridge cuts out.

[WotEver]

8 hours ago, Richard10002 said:

It is generally accepted that when the tail current is between 1% and 2% of the battery banks actual capacity, the batteries are as good as full.

Or when the current hasn’t dropped by a percentage point over a period of around 45 minutes. 

[canals are us?]

Thank you both for the info. It's something I'll need to know when out cruising.

James

[WotEver]

27 minutes ago, canals are us? said:

Thank you both for the info. It's something I'll need to know when out cruising.

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