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"The echo-charge will turn ON any time the house battery is above 13 volts, regardless of the charging source." Since the echo charge is only a relay, whenever a charging source is available, it will act to allow current to flow through it. The answer is YES, within the following constraints. The Echo charger is the same as a combiner except with limited amp output to about 15 amps. As such, it is NOT the right equipment to use when you have alternating two large banks, because one of the banks will never get fully charged unless plugged in for a long time because of the limited amperage output of the echo side of the connection. The other bank receives the full charge of the Freedom inverter/charger charger side. An echo charger is, however, a perfect application for a large house bank and the start bank on the echo side. That's because the few amps needed to recharge a start bank after it is used to start the engine is very small. Most alternator outputs on boats are wired to the C post of the 1-2-B switch. So the source for charging when motoring is: alternator output, to C post, to batteries. That's why when wired like this you NEED to start the engine with the switch on Both or else the second battery bank wouldn't get any charge from the alternator. With the echo charger, you HAVE to know how your wiring is connected to determine how it works. Most likely, the echo charge will "see" a charging source regardless of how you're wired, but it could be connected to the switch post instead of across the batteries, and we just don't know how you operate your switch. If the alternator is connected directly to the house bank (a much preferred way to do it) then the echo charger will charge the second battery because the echo charger "sees" a charging source via the connection of the charger output to the house bank. This is because the Freedom inverter/charger wiring goes from the I/C to the house bank. You will need to determine if anything other than the battery outputs are wired to the 1-2-B (other than the starter solenoid and DC panel). So, I recommend that you personally trace out the wiring on your boat and figure out where the connections are made, from the I/C to the banks and how the switch is wired, and where the connections of the echo charger land (switch? battery bank?). Once you know that, you can figure out how it works. Since you're adding the starting bank, do NOT get rid of the echo charger, it is far superior to the combiner because it won't overcharge your new start bank. It was wrong to use for your old setup, where a combiner would have been much better. The simplest way, I would suggest, is this: Freedom I/C charger output to house bank, not through the switch. Alternator output directly to the new big house bank, not through the switch. Echo charger output wiring from I/C to new start bank. ONLY the battery + wiring to the 1-2-B switch. Start the engine with your start bank, NOT BOTH. Since the alternator output goes directly to the house bank, there is NO LONGER a problem with switching the 1-2-B switch when the engine is running, so you have complete freedom of action with the switch. The ONLY things that need to be on the 1-2-B switch are: +1 post - input from battery 1; +2 post - input from battery 2 (your choice of numbering house and start, just get the echo charge wiring to the correct start bank); C post - To starter solenoid and TO DC panel. It's very simple, no extra switches needed. I disagree with West Marine's three switch setup, use the 1-2-B switch like this and you'll see what I mean. Their idea if you examine it, retains the alternator output through a switch which I think is worthless.
