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Individual battery bank monitor


Collectors

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Monitor possibly but that depends if you mean monitor or measure.

 

When cells sulphate the lead sulphate takes up more space than the lead oxide so the ends and occasionally the top of the battery starts to bow out. That is a  good sign that batteries days are numbered.

 

When a cell eventually develops a short will get hot when under charge in the area of that cell. that cell will need a lot more topping up than the rest and it will be seen to gas before the rest. You will also find the whole bank takes longer to recharge and  discharges much faster.Unless you go for complicated switching to take individual  batteries out of the parallel connection and the fit monitors to each battery I doubt you can economically measure the individual cells state.

 

Edited to ad - if the brass and copper around your batteries go silver and black and the whole area smells of rotten eggs you have a faulty cell.

Edited by Tony Brooks
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2 hours ago, Collectors said:

Hi, is there a way to individual monitor each of batteries condition in a bank "of 4". Total 12 volt = 480amp/h .

 

Depends on the type of battery. If it is a wet cell type, then you can use a hydrometer or refractometer to measure the specific gravity of the acid in each cell.

 

Cells that are sulphated and shorted cells will show lower specific gravities with the battery bank fully charged.

 

However if you want remote monitoring without any input from you other than reading a meter, then the answer is no.

Edited by cuthound
To add the last sentence.
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4 hours ago, Collectors said:

Hi, is there a way to individual monitor each of batteries condition in a bank "of 4". Total 12 volt = 480amp/h .

You can do, but I’d question if it’s worth it. You could fit a shunt based meter such as a BMV700 series meter to each battery’s negative lead, the batteries being connected in a star circuit. ie 4 BMV  monitors. Add a Smartgauge to give the absolute SoC of the whole bank. This would allow you monitor the AH in and out of each battery and thus the health of each battery. Expensive though!

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6 hours ago, Collectors said:

Hi, is there a way to individual monitor each of batteries condition in a bank "of 4". Total 12 volt = 480amp/h .

 

Yes there is as explained by Nick, but in classic internet style, I would ask why would you want to?

 

 

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27 minutes ago, Mike the Boilerman said:

 

Yes there is as explained by Nick, but in classic internet style, I would ask why would you want to?

 

 

I fancy if the OP buys 4 BMVs they'll become...

 

 

"Collector's Items". :D

 

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6 hours ago, Collectors said:

Hi, is there a way to individual monitor each of batteries condition in a bank "of 4". Total 12 volt = 480amp/h .

If you just want to occasionally check they are OK rather than continually monitor them, the easiest way is to remove one battery from the bank, charge it, capacity test it etc then repeat for the other three in turn.

 

This is cheaper than @nicknorman's (correct) suggested method, but not as convenient. 

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15 hours ago, nicknorman said:

You can do, but I’d question if it’s worth it. You could fit a shunt based meter such as a BMV700 series meter to each battery’s negative lead, the batteries being connected in a star circuit. ie 4 BMV  monitors. Add a Smartgauge to give the absolute SoC of the whole bank. This would allow you monitor the AH in and out of each battery and thus the health of each battery. Expensive though!

Hi, it was just to make life easy & look at a panel/meter that would give me the info if 1 battery on a bank is starting to break down, to save having to take hydrometer readings & alike. I see there is plenty of meters to read a bank or even 2-3 banks, but not individual batteries in a bank. I would have thought larger boats with larger banks would have this facility. May look into 1 meter & 4 shunts with a rotary switch to select each battery or similar 

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I guess it would be worth thinking more carefully about what exactly you want to monitor. In your OP you say 'condition', but here you say you want to look out for a battery 'starting to break down'. 

 

'Condition', I think, we took to mean state of charge but maybe not, in the light of your latest post. 'Breaking down' could mean losing capacity from sulphation, or could mean a cell shorting from plate shedding material accumulating in the bottom of a cell chamber. Could you expand a bit on exactly what you are wanting to monitor?

 

Possibly larger boats do have such monitoring but this is a site for small canal boats, typically having 4 x 110AH 12V batteries where if one (or all) starts going wrong it is generally obvious from the drop in performance of the bank. Identifying the culprit takes a bit of investigation. Designing a monitor to tell you remotely starts with accurately defining the faults to be monitored for, I would say.

 

 

  • Greenie 1
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If the OP gets to know what his expected battery voltage readings are at certain times during 24 hours and like wise the expected charging currents are at various times during the charging cycle a failing battery will soon become apparent.

 

Compared with "normal" and after allowing for abnormal electrical use:-

 

Short recharge time at "normal" charging current and short discharge = sulphated batteries

High charging current and long time to fully charged plus higher than normal tail current = shorting battery cell or cells.

 

I detailed in post the signs to confirm the above, as will hydrometer readings.

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1 hour ago, Collectors said:

May look into 1 meter & 4 shunts with a rotary switch to select each battery 

Note that it will require a quality switch with very low resistance contacts. The voltages in question are very small - tens of millivolts or less. 

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15 minutes ago, WotEver said:

Note that it will require a quality switch with very low resistance contacts. The voltages in question are very small - tens of millivolts or less. 

And you would need not 4 but 5 shunts so you can still monitor the whole bank. 

 

If you think one of your batteries is on the way out, you could replace most of the bank for the cost of the monitoring ... but without a monitor your new bank might end up in the same state quite soon!

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