250 Express Cruiser Battery Question

[djstewy]

Hello All,

I just purchased my first boat a couple months ago and have a question about my batteries on my 1994 250 Express Cruiser. She has two batteries and I have the 1/2/All switch next to my engine. When I'm charging at the dock, underway, and starting her up I have it set to "All" and when I'm sitting out on the water listening to the radio and have my VHF radio on I switch her over to #2 exclusively. Is this the perferred way to handle the batteries on a boat, and if not what different should I do?

I also noticed that #2 never seems to have the starting power that my #1 battery does when I try to start the boat when I select them individually. I'm assuming that #1 is considered my starting battery and #2 is my house battery, looking at the batteries they're not the same model. Is this the way they should behave and is there a standard configuration that Sea Ray places the batteries, like #1 on starboard and #2 on port? I know I can stick my head down in the engine compartment to trace them out, but I'd thought I'd ask first if there is an easy answer. :smt001

I'd appreciate any advice you could provide this boating newbie.

Thanks,

Derek

 

[Sundancer]

Any idea how old the batteries are? They should both be able to start the motor independently so #2 is either getting old, not getting charged or there are some cables that need cleaning. I had a similar setup on our 250 DA and the ONLY time I ever connected both batteries was when I need both to start the motor. The rest of the time I used the #1 on odd days and #2 on even days routine. That way I always had one bettery that was set aside ready to go should the other one get drained or give up the ghost. If you have one that is in good shape and one that is drained, the good battery will try to charge the bad battery when connected in the "both" position. Then you may not have enough juice when you need it.

I have seen some folks that use #2 as a house battery. Since it's never used as a starting battery, it can get drained below 50% which will shorten it's life. And since they don't start the engine from that battery, they don't realize it's not up to snuff.

 

[KC WV]

Is #2 a deep cycle for house power while the engine isn't running? If so, it shouldn't be on when the engine is running or it will shorten the life of the battery. A deep cycle battery needs a trickle charge, and the alternator puts out too many amps.

I always alternate between one and two (both are starting batteries). For a day trip, I'll switch from one to the other half way through the day. Never run both unless the cranking power of either independantly wont start the engine. Then switch to both and cross your fingers. Once the engine starts, you should switch back to either one or two, not both. I've heard this is hard on the alternator.

 

[rabyers1]

If #1 is a starting battery and #2 is a pure deep cycle battery (not a dual purpose), then you may notice a difference in engine starting capbilities even if both batteries are in good condition. That is due to the difference in "cranking amps". The starting battery has thin plates that are designed to deliver a lot of peak amps when called upon by your starter motor. The deep cycle doesn't deliver anywhere near as many amps when asked to perform the starting function, but its thick plates allow for repeated discharging without deterioration.

So, you can notice the delivered amps difference in the revolutions the starter motor is making which determines the speed at which the engine is turning over while attempting to start.