Unless you need to charge both banks of batteries from multiple sources, a
heavy duty relay will also give excellent results at much less cost. Also,
you really want devices with real terminals. Avoid encapsulated stuff with
under sized wires embedded into them.

Another problem with combiners during alternator charging is that if the
alternator does not keep up with the load such as when idling with the AC
on they may cycle as the battery voltage falls. This prevents the house
batteries from also supporting the chassis battery during these times. You
want one that is adjustable to avoid this or with a remote trigger so you
can keep it tuned on.

For the charge line you need to consider not only the drawing capability
of the batter bank but also any appliances that will be used while the
batteries are being charged. If you want the alternator to charge the
batteries while feeding a 30 amp inverter and/or the fridge, you need
capacity.

Since you are going with is a large bank, (225 A/H is large) you will want
the charge line directly off the alternator. A #8 feed would be a good
choice for wire size.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Taeke Takeon
Sent: Thursday, May 15, 2008 9:13 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Yandina combiners, charging and wire gauge

I am looking to charge a 220AH house battery bank, mainly from the stock
90A
alternator and very, very seldomly shore power.

http://www.yandina.com/c100Info.htm I have one of these and am currently
(ho-ho!!!) second guessing my decision to use this item.

The people at yandina say that the 4 feet of 10 ga wiring will barely slow
down the amperage into the battery, like a 1/2 of a percent the rate of
charge.
Is this too good to be true?  I don't know enough to say for sure.

Thanks.