Sample rate of battery monitor

roaringgirl said:
In this discussion, have we not already discounted a wiring problem as the solar and alternator charge does register on the monitor? All charge sources are connected to the same negative bus (and therefore to the same shunt)
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No, that only demonstrates that the monitor correctly registers charge currents which are correctly connected. You need to check your wiring!
 
pvb said:
No, that only demonstrates that the monitor correctly registers charge currents which are correctly connected. You need to check your wiring!
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1.The wind and towed gen are definitely charging the battery successfully
2. The wind and towed gen are connected to the same negative bus as the alternator and solar chargers
3. The negative bus is connected to the battery via the shunt
4. The current from the alternator and solar chargers does register on the battery monitor
5. The wind and towed gen's currents do not register in realtime on the battery monitor (which I think is the cause of the incorrect capacity tally)

Given 1-5 above, I can't see how it can be a wiring fault.
 
roaringgirl said:
1.The wind and towed gen are definitely charging the battery successfully
2. The wind and towed gen are connected to the same negative bus as the alternator and solar chargers
3. The negative bus is connected to the battery via the shunt
4. The current from the alternator and solar chargers does register on the battery monitor
5. The wind and towed gen's currents do not register in realtime on the battery monitor (which I think is the cause of the incorrect capacity tally)

Given 1-5 above, I can't see how it can be a wiring fault.
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OK, so has the monitor miraculously developed intelligence and decided to snub your wind generator? :rolleyes:
 
pvb said:
OK, so has the monitor miraculously developed intelligence and decided to snub your wind generator? :rolleyes:
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I don't know why it's not picking it up, hence my original post. I think it's either that the monitor's sensitivity isn't good enough, or the wind gen's input fluctuates so much that the monitor's low sample rate frequently fails to capture its current.
 
roaringgirl said:
I don't know why it's not picking it up, hence my original post. I think it's either that the monitor's sensitivity isn't good enough, or the wind gen's input fluctuates so much that the monitor's low sample rate frequently fails to capture its current.
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Battery monitors usually have a fast sampling rate. Mine samples every 100ms.
 
roaringgirl said:
Ok, that's interesting. Can you think of some tests I could do to figure out why else the wind gen isn't registering? I'm all out of ideas, which is why I'm here!
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Switch off the solar panel input and windgen input. Use some battery power, so that the SOC is lower. Then turn on the solar input which, if the sun is shining, should show a charge - you then know that the battery monitor can register a charge current. Turn the solar input off. Then turn on the windgen input which, if the wind is blowing, should show a charge. If it doesn't, there has to be a wiring problem.
 
pvb said:
Switch off the solar panel input and windgen input. Use some battery power, so that the SOC is lower. Then turn on the solar input which, if the sun is shining, should show a charge - you then know that the battery monitor can register a charge current. Turn the solar input off. Then turn on the windgen input which, if the wind is blowing, should show a charge. If it doesn't, there has to be a wiring problem.
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Ok, I have already done these tests so I'm thinking about wiring...

If there were a problem with the screen wiring, how could it show a current for the solar?

If there were a problem with the windgen wiring, how could it charge the battery?
 
You have already stated that you have seen positive values of 2-5a on the meter, and it is reading sensible volts. This would suggest to me that the wiring is OK but you have fallen foul of the meter's logic in some way. Can you run the engine to get alternator charging? This should record a much higher amperage for a while, then as we suspect the battery bank is fully charged, this should be seen to quickly fall away. With factory settings, once the charge has dropped back below 5a for a while the capacity readout should reset itself to your calibrated maximum.
 
ithet said:
You have already stated that you have seen positive values of 2-5a on the meter, and it is reading sensible volts. This would suggest to me that the wiring is OK but you have fallen foul of the meter's logic in some way. Can you run the engine to get alternator charging? This should record a much higher amperage for a while, then as we suspect the battery bank is fully charged, this should be seen to quickly fall away. With factory settings, once the charge has dropped back below 5a for a while the capacity readout should reset itself to your calibrated maximum.
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I can easily reset the meter to whatever maximum reading I wish. My question is: "*why* is the tally wrong?"
 
roaringgirl said:
I can easily reset the meter to whatever maximum reading I wish. My question is: "*why* is the tally wrong?"
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I think - because these meters are not sensitive enough to low currents and have a somewhat complicated logic that interrelates various factors. It may even be that the current is below its threshold to charge an empty battery.

Note; there is a difference between the settings for maximum capacity and the current (remaining) capacity, you would need to set the latter which seems to be zero.
 
Use an ammeter (or multimeter set to amps) to check the output from the wind gen and compare it to the battery monitor, if they don't agree, replace the battery monitor.
 
Reading between the lines of the manual and what I have seen with my own installation, I have a feeling that the BEP DCM-600 does not increase the amp hour count for a charging voltage less than 13.5v.
 
roaringgirl said:
Yes replace the battery monitor - but I want to make sure I replace it with something that doesn't have the same failings, so i want to know what the problem is!
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If you want to know what the problem is, do as i suggested. If an ammeter/multimeter shows a charge current from the wind gen that does not show up on the battery monitor, it's clearly an issue with the monitor.

But first, remove the cables from the shunt and give them all a good clean, including the shunt. Very often, a poor contact will pass at least some of a high current, but won't pass any of a low current. If, after cleaning, there is no difference, follow paragraph one. If the monitor doesn't agree with the ammeter, replace it.

To be honest, a battery monitor that has a resolution of a mere 0.5a is crap and i'd suspect this might have a bearing on your issue. As a comparison, by Victron monitor has a resolution of 10ma (0.01a)
 
ithet said:
Reading between the lines of the manual and what I have seen with my own installation, I have a feeling that the BEP DCM-600 does not increase the amp hour count for a charging voltage less than 13.5v.
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Not overly familiar with the BEP monitor, but if that's the case, it wants putting in the skip. How does it work with batteries on a 13.4 float charge /
 
PaulRainbow said:
Not overly familiar with the BEP monitor, but if that's the case, it wants putting in the skip. How does it work with batteries on a 13.4 float charge /
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In that case I think it would have already reset to max capacity as the charge current dropped off. From the manual:

Amp hour capacity reset Amp Hour Capacity reading is reset to Max Battery Capacity when the following conditions occur. The Battery Voltage is greater than 13.5V (factory default). The Charge Current is less than 5A (factory default). See note (a) Conditions 1 & 2 must be met for 5 minutes. (a). This should be changed to 4% of amp/hour rating of battery bank ie 220amp/hour bank = 220*4% = 8.8 use 9amps

Which is from where I deduced about the 13.5v threashold. Also mine seems to behave in that way when on solar also.

I do not disagree with your summing up though! I mainly use mine as a voltmeter and ammeter for higher draws (eg fridge).
 
PaulRainbow said:
If an ammeter/multimeter shows a charge current from the wind gen that does not show up on the battery monitor, it's clearly an issue with the monitor.
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My understanding from the OP was that the meter is showing a charge current, but the amp hour capacity display is not increasing.

I think it is working 'as designed' although that is not very useful in this case.
 
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