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Old 06-01-2017, 04:17 PM   #29
twistedtree's Avatar
City: Walkabout Creek
Join Date: Jan 2013
Posts: 7,913
Just restarting this thread....

Reedstr, for the past 3 years I too thought Ffl was the current threshold for the absorb to float transition, but after talking to Balmar today, I learned that it isn't. Their documentation is really quite poor in explaining all this, with sloppy use of terminology, and contradicting statements. Here's what I learned

First ffl sets the field threshold for transitioning from Float to Abs. It does NOT play a role in the transition from Abs to Float. The problem I have been having is 24hrs into a 56hr cruise, the regulator kicks back into absorb every time someone uses the microwave. The load causes the alternator output to rise, exceeding the ffl threshold, and it goes back into abs mode. To solve this, ffl should actually be set to a high value, allowing heavy external loads on the alternator without going back into absorb.

Second, Balmar's notion of Bulk and Absorb do not correspond to the industry norms for those terms. It's probably better to think of it as one single phase that encompass both.

Their Bulk stage runs until all three of the following conditions are met:

1) the bulk voltage is attained. Using industry standard terms, this is when "bulk" ends, but it is NOT when Balmar bulk ends. The next two conditions must also be met.

2) the bulk time has elapsed. This sets a minimum time in bulk mode.

3) the field voltage had dropped below FbA. This is where Balmar has smushed together the industry definitions of bulk and absorb. By industry norms, dropping below a threshold acceptance current is when absorb ends. So when this happens on a balmar, your batteries are charged, assuming you have this value set correctly.

So when a Balmar comes out of Bulk, by all other industry definitions is is actually coming out if absorb since it has BOTH achieved. The target bulk/absorb voltage, and the battery acceptance current has dropped to a prescribed level.

Now Balmar's "absorb" stage begins, and is really just a top off before going to Float. The same three criteria above must be met, except it uses the absorb voltage (Av) rather than the bulk voltage. And the regulator will only let you set the absorb voltage to something less than the bulk voltage. So all absorb really does is continue bulk/absorb for a little longer at a slightly lower voltage. Critical to note, exiting Absorb and going to float is based on FbA, just like transitioning from Bulk to absorb.

It's no wonder people find these things hard to program, or not performing as expected.
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