Join Date: Sep 2008
Location: Victoria B.C. Canada
Thanked 71 Times in 62 Posts
Rep Power: 7
The better solution is to send all charging current to the house bank (4 T-105'sin series/parallel actually), from the Iota charger, the alternator, and solar/wind if you have them. The start battery is kept charged by an Echo Charge or ACR. No charge current should go through the 1/2/both switch. I install virtually every charger as a one bank charger. Most are designed for 2 or 3 banks.
What this does is the following:
1. Makes charging fully automatic - no switching by you is required.
2. The charge first goes directly to the bank needing it the most. A start battery is seldom down more than 1 or 2 AH.
Charging through the 1/2/both switch has 3 things against it and only 1 for it.
1. You have to have it on "both" to charge both battery banks.
2. If you forget and leave it on "both" you will drain all batteries.
3. If the switch is either turned to "off" or through "off" while the engine is running you will likely fry alternator diodes.
Oh yes, the one thing in its favor - It is the least expensive way to charge multiple banks and that is why most manufacturers used to do it this way - some still do.
You can hardwire the cord into the existing circuit - and it should go to a breaker that will also allow you to turn it off as well as protect the wiring.
While remotes are available for Iota, Xantrex and other chargers I don't think they are necessary. Once set for battery type (flooded, gel. or agm) it will automatically go through bulk, absorption, and float stages as designed.
The best way to monitor the batteries is with a good dedicated battery monitor like the Victron BMV-600 - $158 at Jamestown Distributors. Without one you can never know what state your batteries are really in and how many AH you have used.
Living aboard in Victoria Harbour
Last edited by mitiempo; 03-21-2011 at 10:56 PM.