I have a boat with a Yanmar 2GM20F diesel. I normally start this engine with the battery selector switch in the "Both" position. My two batteries are also connected to an AC battery charger that I use once in a while. My question is this: would it help (in regard to minimizing drain on the batteries) to start the engine while the boat is still connected to AC power and the AC charger is "on?" Conversely, would such starting create any problems?
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Depends on the charger
It largely depends on the design of the charger. I beleive that may will "assist". My Dytek charger (3 yrs old) will "assist" in starting the motor when it's turned on. Check your user's manual to ensure that it may. Or else contact the mfg for the information.
It largely depends on the design of the charger. I beleive that may will "assist". My Dytek charger (3 yrs old) will "assist" in starting the motor when it's turned on. Check your user's manual to ensure that it may. Or else contact the mfg for the information.
starting
I have two batteries in the house bank and one starting battery. I like to start the boat with the shore power disconnected and using only the starting battery. Figure it's a good way to make sure the starting battery is up to snuff before I pull away from the pier. Just a little added peace of mind. Ron
I have two batteries in the house bank and one starting battery. I like to start the boat with the shore power disconnected and using only the starting battery. Figure it's a good way to make sure the starting battery is up to snuff before I pull away from the pier. Just a little added peace of mind. Ron
Disconnect first
Cru Why bother? The total amp hours used in starting the engine is about 2. It's a high current for a very short period. If you feel you need a "boost" your batteries are becoming questionable. Ron's idea is right: good way to check your battery's capability to actually use them to start. If you only occasionally use your charger, your batteries are not being fully charged and you're shortening their life, unless you have a solar panel keeping them up. I'd keep them charged, healthy and long-lasting, and disconnect shorepower before starting. Note that that doesn't mean leaving it plugged in all the time. Also, if your batteries are fully charged, and you keep your shorepower connected, you'll most likely see that the tach doesn't work! That's because it works off the alternator and if the batteries do not need a charge, the alternator doesn't work (even though the belt is spinning), so no tach. See the link. Stu
Cru Why bother? The total amp hours used in starting the engine is about 2. It's a high current for a very short period. If you feel you need a "boost" your batteries are becoming questionable. Ron's idea is right: good way to check your battery's capability to actually use them to start. If you only occasionally use your charger, your batteries are not being fully charged and you're shortening their life, unless you have a solar panel keeping them up. I'd keep them charged, healthy and long-lasting, and disconnect shorepower before starting. Note that that doesn't mean leaving it plugged in all the time. Also, if your batteries are fully charged, and you keep your shorepower connected, you'll most likely see that the tach doesn't work! That's because it works off the alternator and if the batteries do not need a charge, the alternator doesn't work (even though the belt is spinning), so no tach. See the link. Stu
Middle of Road Answer
I took a middle-of-the-road approach when I gave you my answer this morning. I should have gone on to say that I always disconnect shore power or shut off the charger when I start my engine. The amperage used to start the engine is replaced just be motoring out of my marina and setting sail. BUT, I will stand by my comment about the charger "assisting" the start.
I took a middle-of-the-road approach when I gave you my answer this morning. I should have gone on to say that I always disconnect shore power or shut off the charger when I start my engine. The amperage used to start the engine is replaced just be motoring out of my marina and setting sail. BUT, I will stand by my comment about the charger "assisting" the start.
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