How often do you use your boat? If you are regularly using your boat, the engines will be charging the boat batteries and there isn’t such a big need to use a battery charger.
Most engine gauges indicate the voltage output of your battery and whether it is charging or not.
You can also check to see if the engine is charging the battery by putting your meter on it while the engine runs.
When you do check, you should see somewhere around 14 volts with the engine running. (Sometimes slightly more or less depending on engine RPM’s as well as the age of the engine).
If you advance the throttle just a bit, you should see the voltage steadily climb a little bit towards 14 volts.
To learn all about Outboard Alternators Outboard Charging Systems, read that article that we wrote about them.
What you DON’T want to see is 15 or 12 volts. This means your engine is either overcharging or not charging at all!
Either of these cases will wear out the battery and shorten its lifespan.
Marine Battery Life
By now we’ve covered cleanliness and other battery information. But it’s also important to break down critical information regarding battery terminals.
When it comes to battery terminals, loose or dirty connections can wear out your battery! Along with parts of the engine starting system due to it not receiving the right amount of amperage.
Think of this scenario like breathing through a straw. Yes, you can do it (for a short period of time that is). But if you do it for too long (and with a small enough straw).
You will eventually pass out! With your engine parts, on the other hand, they will eventually just die out, costing you lots of money.
This is why we recommend using something like a CRC battery terminal protectant to help keep the connections free from dirt and corrosion.
Whenever you first start the boat, you can start it using either battery or both. You can even start it twice, checking both batteries one at a time. To make sure they can start the boat individually.
Once the engine is running. Simply turn the switch to the “both” or combined position while being careful not to turn it to the off position while the engine is running.