A qupte form a recent Practical Sailor pasted below:
--
Ken Heaton & Anne Tobin
Cape Breton Island, Canada
kenheaton at eastlink dot ca

wrote in message
.. .
Practical Sailor reviewed this model and several similar in the past
year. Check their website and get the article from them. Even if you
have to pay a few $ it is worth the read and will answer your question
and more. Some chargers can be independent to each bank.

Xantrex's New XC Line are Multiplex Masters
This "ultra-smart" charger handles multiple battery types with no worries.




To put it mildly, the battery test on the previous pages presented a
recharging nightmare. Ideally, what we needed was an intelligent multi-bank
battery charger that could independently recharge any combination of battery
chemistries at the same time - with speed, accuracy and temperature
compensation. Consider a common recharge sequence that we carried out during
our test:

.. Battery No. 1 is an absorbed glass mat (AGM) battery requiring 50-plus
amps of bulk recharge current,

.. Battery No. 2, also an AGM battery, needs a .5-amp float charge

.. Battery No. 3, a gel battery, needs 20 amps of absorption charge.

This, and many other variations of this recharging sequence would need to be
repeated 24 hours a day for more than 20 days.

To our good fortune, in the fall of 2005, Xantrex Technologies Inc. formally
introduced its line of XC battery chargers, which featured new multiplex
charging capability, just the technology that we needed. Xantrex sent us the
XC 5012, a 50-amp, three-bank multiplex charger for our evaluation.

Once you program the charger and tell it what type of battery chemistry that
you have connected to each of its three independent banks, the charger will
check each battery bank and then start a recharging profile on the battery
bank with the lowest state of charge.

Once this particular battery bank responds to the XC's charge profile, the
charger will put that battery's charge profile on hold and switch its
recharge energy over to the next battery bank in numeric sequence and apply
a new charge profile.

The charging sequence is repeated for the third battery bank, and then
charging switches back to the very first battery bank and picks up where it
left off. This rolling recharge sequence allows the charger to briefly focus
all of its energy into one particular battery bank.

Our experience with Xantrex's XC5012 convinced us that this is the best
battery charger in its class that we have tested to date. The XC5012
regularly delivered 53 amps in the initial bulk charge phase (more than its
rated output) in stone silence. And silence is something that any sailor can
appreciate.

Bearing in mind that the fastest way to ruin a VRLA battery is to recharge
it without a temperature compensated charge, we fitted each battery bank
with a Xantrex battery temperature probe (each unit ships standard with one
probe). We scrutinized the XC's recharge voltages during each of its
charging phases for each type of battery chemistry. All parameters measured
across the board were in range for a safe and fast recharge without a hint
of over- or under-charging.

It was apparent that this new charger was powerful and capable, but was it
durable? The XC series is rated for true reverse polarity protection, so we
reverse-connected one set of the battery output leads (on purpose), stepped
back a few feet and plugged the charger in. The result was uneventful, to
say the least. No sparks, no smoke, no Gabriel's horn. All that happened was
that a fault message was displayed on the unit's LCD display.

Costing about $335, the XC 30-amp charger (approximately $100 more for the
50-amp XC5012) is one serious battery charger that will finally allow a
vessel with perfectly functioning lead acid start batteries to upgrade the
house battery bank to AGM or gel technology without having to add a second
battery charger to the system.




Contact - Xantrex Technologies Inc., 800/670-0707, www.xantrex.com.