Based on my energy usage projections I planned to generate 80-100 Ah/Day of energy without using the engine but when the engine was on for motoring I wanted to maximize the energy it could generate. The alternator would be a backup to solar and wind as well as a way to fully charge up the batteries once a month to recalibrate the Victron battery monitor I had installed.
First Job was removing the old alternator
I then started wiring up the high output alternator. I chose Balmar because it came highly rated in the cruising forums. Because of the engine horsepower I was limited to 80W max. With larger engines and AGM batteries (that can take almost any amount of charge) you can obviously put on much larger alternators.
The Balmar fit perfectly into the space. I also upgraded the belt since the loads were going to be higher.
The Balmar also has a smart regulator which I installed above the echocharger (blue). Once I had everything installed and started the engine the alternator worked perfectly through all the stages of charge.
However I noticed one issue. The temperature alarm light on the engine panel did not come on when I switch the engine power on. This was obviously a major problem because I needed to know if and when the engine was overheating. This problem unfortunately took a month to solve going through numerous sources.
Finally I managed to get hold of someone at Balmar with knowledge of Volvo Penta engines and they recommended installing a relay in the alternator wiring to the engine which did the trick. I was sooooo glad to get this issue resolved.
Finally I sealed the old alternator in a waterproof bag and kept it as a spare for the pacific crossing I had planned.
Total cost: around $1,000 mainly for the Balmar alternator.
Total project time: Took a weekend to get it installed and working but another month to figure out the engine temperature alarm issue and then install the relay.
Update in 2012 after 13,000 miles of sailing.
Everything worked great, no failures on any part of the system. Only used the engine to charge up the batteries a couple of times on the whole trip, but obviously it was very useful for charging up the batteries to full when motoring.