I find it helpful to summerize what I've learned from the many contributed experiences above:
2) Kyocera 130 watt solar panels can top off battery better than an alternator or perhaps even a generator.
To put this in perspective topping off batteries to 100% state of charge (SOC) can take many, many, many hours of charge time. The more full a battery gets the less current it will accept thus the last 15% can take a very long time to replenish no matter the charge source or how big.
This is why many cruisers cycle their banks between 50 & 80% SOC, not 50% & 100% SOC. A solar panel can run when you are not there and will top off the batteries to 100%, something an alternator or generator just won't do unless you want to run it for hours and hours on end. This is why the statement was made that a solar panel can "top off" batteries better. Of course of your boat is on a dock most of the week then a shore side charger also has the time to do this.
We are often off hiking or exploring some of the many islands along the Maine coast. On a sunny day we can leave our boat at 80% SOC and come back at the end of the day well over 90% SOC and sometimes darn close to 100% SOC because of the solar panel.
4) The Honda 2000i is the one to buy if I go that way.
If you think you really need a small portable gas generator then the Honda's are worth the money.
5) Get a Victron BMV600 battery monitor
A true battery monitor may show you that you really don't need to change much at all or that you really do. Ah spread sheets are only as good as what you put into them, and guess at, especially with variable load items. The old moniker "garbage in garbage out" seems to often fit with some of the calculations sheets I've seen and how they compared in real life to actual Ah consumption. Can you get close? Yes, you can get very close but it takes accuracy and careful monitoring of your cycle use and loads.
Many Ah spread sheets I've seen are often off by as much as 20-30% and a good one would be under 10%. Variances of 20-30% are not bad when it favors the batteries but are really bad if it is not in their favor. An amp hour counter/battery monitor is actually keeping track of the actual usage and what has actually been put back. Provided you keep them well calibrated I feel they are one of the best investments you can make especially for their under $160.00 price tag, or less than one decent quality battery.
I have not yet had one person say to me they wished they never installed one. Most everyone who has one says the same thing "How did I ever live without one?".
My neighbors were going through battery banks every season and a half, or sooner. Bill had done an Ah use spread sheet but his calculations, despite all his best efforts, were off by over 20% in the real world and not in favor of the batteries. Add to this the fact that he thought running his 100 amp alternator for an hour actually put back 100 Ah's and he was drastically and chronically using more than he thought and under charging on top of this.
Once the monitor was installed, the next bank which was the same exact brand and size, was still going at year five when they sold the boat. The only change they made to the system was a battery monitor and they added at least 3.5 years of service life to their battery bank. What he found was that he had been drawing his bank to 20% SOC from a full 100% charge. Then because he never got back much above 70% SOC from the alternator, when he thought he was back at 100%, he was literally taking them to dead the next day and often had to use his reserve bank to start the engine. Despite having a small solar panel (20 watts) he still killed banks like street gangs do drive by killings in LA.
When Bill added the monitor he was amazed at how little he understood about his use and charging system, this is not uncommon. He simply switched to a 50% to 85% use scenario and added a lot of life to his bank but did have to charge more often than once ever three days as he had been doing. Based on Bill's experience the battery monitor actually cost them nothing due to the extended life of the banks they were not replacing every 1.5 seasons. Again, nothing was added or changed except for adding a battery monitor and charging when it told them to.
BMV-600 Battery Monitor $158.10
Scott (thesnowcrow@gmail.com)
