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charlies3 asked

Victron 602 state of charge

My Victron 602 has never done a good job of showing the state of charge correctly. It seems to accurately reflect the amount of current leaving the batteries, but does not accurately reflect the charge inflow, which it under reports. For instance, I will use 200 amps of power, it will charge all day, with the solar system showing production of 240 amps, the battery voltages are fully up and the system goes into trickle, but the 602 will show that I have only replaced 150 amps and I am still 50 short. Over several days, this error can become quite large. Sometimes it will fix itself with the settings to sync, when the charge rate slows enough, and I can change these settings to sync more liberally, but I would prefer accurate data. Thoughts?


BMV Battery Monitor
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2 Answers
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wkirby answered ·

There are settings that need to be tweeked to make this more accurate. There is the CEF (charge efficiency factor) and Peukert exponent. Since it will generally take more energy to charge a battery that what previously went out, these settings ned to be adjusted to suit your battery bank and teeking is ofter required to get it bang on for your particular setup.

Section 2 of the manual explains CEF and Peukert setup.

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charlies3 answered ·

Yes, however, the problem is the opposite. Peukert is for a high discharge rate, which I rarely have, but I have it set to the numbers provided by the battery manufacturer. CEF is a constant to decrease the input current to reflect charge inefficiencies. The problem I have is that my system shows less charge than I am actually getting. I would need to set the CEF to greater than 1, and/or the peukart to less than 1, in order to get to the correct numbers. I have already set these two constants to show max charge, ie CEF to 1 and peukart to the specs from the manufacturer. I would need to set the CEF to about 1.2 or 1.25 in order for the numbers to be working. In other words, the numbers I am seeing are less than the actual charge going into the batteries, not more, even with a 1.0 CEF setting.

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