Thread: No generator
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Old 09-16-2014, 08:34 AM   #6
DavidM
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City: Litchfield, Ct
Join Date: Aug 2012
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Figuring out your DC needs requires an energy calculation that balances consumption, storage capacity, charging capacity, days at anchorage and hours of cruising time between anchorages.

Most boaters who anchor out for a couple of days at a time over weekends can get by with 200-300 amphours of battery capacity and no additional charging sources.

Here are some parameters to help you:

1. You will use 60-120 amphours per 24 hours from your house batteries while on the hook. Refrigeration is the biggest consumer.

2. Don't routinely run down your house batteries below 50%.

3. The OEM alternator on your propulsion engine can put out at best 50 amps, often less.

4. A battery monitor- about $200 is a big help in figuring out how much energy you use.

So here are some solutions, in approximate order of cost to make the balance work if it doesn't, ie you are staying on the hook longer than 2 days, your usage is high, etc:

1. Add additional batteries. A pair of 6V golf cart wired in series to produce 12V and supply 220 amphours will cost about $300 for batteries, cables and battery box.

2, Add solar panels. 250 watts of panel will add 80 amphours daily on a sunny day (I know that doesn't always happen in the PNW) and will cost about $500 for parts.

3. Upgrade your propulsion engine alternator with a high output one with an external regulator- about $1,000.

4. Buy a Honda EU2000i and make sure that your shore power charger is big enough to limit its running time but not too big to overload it. $1000 for the Honda and $300 for a bigger charger if needed.

David
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