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Old 06-25-2016, 10:48 AM   #26
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thomasonw's Avatar
City: San Juans, WA
Vessel Name: Viking Star
Vessel Model: 45' Monk / McQueen
Join Date: Apr 2014
Posts: 34
Monitoring battery current...

Originally Posted by ReedStr View Post

Which leads to one of the tricky settings for the Balmar regulators. How do you target when the regulators should drop to float? The catch of course is that alternator load is not just the load of charging the batteries but also includes the load of running the boat. This would all be much easier if external regulators could read the same ammeter my battery management system does and determine the charging regimen by the battery CAR. Or if they had a switch for “going to float now” since I can see the CAR via the BMS. But they don’t.

ReedStr: I too have noted this issue with common regulators - they just have no way to tell what is happening back at the battery. Add not only the common loads you describe, but some boats also run heavy cyclical loads via an inverter: AC Refrigerators / freezers, washer/dryer units. It makes it very difficult for a voltage only regulator to understand. Looking at field drive strength can help some (only if used in conjunction with RPMs truth be told), but still that only gives an indication of what is being produced - not where it is consumed.

I do not post too often here, we are fill time cruisers and web forums are hard to gain access to from remote areas. But I did want to comment that not only do I think you are spot on, that I too had this same issue (and more seriously with the regulator going into Float too soon leaving the batteries consistently undercharged), and that I have created an open-sourced alternator regulator which does sense battery acceptance current as you described. With that am able to fully implement battery manufactures recommended charging profiles. It is currently being used in several deployments using not only LA batteries but increasingly LiFeP04 technologies.

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