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Subject: TWL: RE: Battery combiner - Heart Pathmaker
From: Joe Engel (Joe@XXX.XXX)
Date: Mon Apr 02 2001 - 12:44:18 EDT
Hi Bob:
We have the same model combiner on our boat. We have twin 100 amp engine
alternators and a 150 amp charger. It works great. Also have installed
some on others. The reason a 100 amp combiner is adequate is because
ratings figures of 100 amp alternators and 150 amp chargers are absolute
maximum RPM into a dead short and there never is close to 100 amps across
the combiner bus. IOW with 2 each 100 AMP alternators we have a
theoretical output of 200 AMPS. But reality is more like 50-80 amps for a
few minutes.
The trick is to insure that you are not trying to push the starting current
through your combiner. Some of the Heart literature is very vague on this
point, suggesting that the combiner can be forced on and used as an
emergency starting combiner. I don't think this is really correct (I don't
have the literature here so I could be wrong). Anyway, I would not do it
that way. But Heart's drawings are correct except they leave out the switch
combinations (optional) to enable manual cross connects and battery
selection. Run the start wires from the + starter battery post, though a
battery switch to the + starter relay connection. Not though the combiner.
Remember the combiner is either all on or all off. The three bank model
does not select or drop the 3 individual banks depending upon their
respective charge. So an argument can be made for the downside of charging
dissimilar banks simultaneously on a common bus. That's why
equalization is important. Over time, the banks all come into a common
charge state. Also the combiner is pretty smart with overvolt and undervolt
adjustable trips. Any serious dissimilarity in the various banks, such as a
shorted cell, would trip the combiner off with the appropriate signals and
lights.
As best I can tell though, common 2 and 3 bank chargers also do not monitor
the individual legs, but base their charge voltage controls on an aggregate
of all connected banks (same as a combiner).
This all sounds more complicated than it really is. The main point is to
not use the combiner to regularly carry starter loads.
Joe & Debbie Engel
Marine Computer Services & JRE Consulting, Inc.
MV Freda Fly - 40' Tollycraft Tri-cabin
Portland, OR
-----Original Message-----
From: Bob McLeran [mailto:rmcleran@XXX.XXX]
Sent: Saturday, March 31, 2001 9:19 AM
To: Trawler World List
Subject: TWL: Battery combiner - Heart Pathmaker
I'm going to have some battery/electronic work done on Sanderling this
June. One of the items I'm looking for is a battery combiner, and so far
have more or less settled on the Heart Pathmaker (100 Amp, 3 bank model)
available through Defender for less than $200.
I'll be charging 2-4D batteries for the house bank, and a series 27
battery as a backup starting battery for the genset. Sanderling has two
alternators each rated 70-80 amps, and a TrueCharge 20 amp 120 volt
charger.
Have any of you had any experience with the Heart Pathmaker 100 amp
combiner? Do you think it will be sufficient for my rather meager needs?
-- Bob McLeran rmcleran@XXX.XXX M/V "Sanderling" Docked at Point Patience Marina Hailing port: Wianno MA Solomons, MD Hampton 35 Trawler
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