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Something Interesting I did not realize

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Scott1

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I have read that if you run your stereo at the beach for quite a while and run down the battery, but not enough to keep the boat from starting this is not a good thing.  The reason I am referring to is because once you start your boat up and take off, you have low system voltage and you will not get proper fuel pressure to your engine because of this.

Has anyone else thought about this or heard about it and what are your opinions?  I guess before I start my boat I will just put the battery selector switch to both batteries and run that way until the other one is completely charged, does that sound like the correct thing to do?

Thanks
 
Sorry, but that's a new concern to me.  As long as my motor starts, that's all that matters to me.  I have a Yamaha F150, and the fuel pump is mechanical--not requiring electricity.
 
Nope, not a concern for me. One is my house battery 2 is my float tune listening battery. Before I start and get underway I flip it to 1+2 while cruising. 
 
Yeah, not sure.  I got it off the simon motorsports website where he is selling alternators.  It made sense to me, but I really don't know.  Kind of said running your engine on low voltage means your fuel pump is not putting out the pressure it should?
 
I suppose for a company selling high amp alternators it would be a major concern, but if your battery was strong enough to start your engine, the alternator should be able to keep the AMPERAGE high enough to run the fuel pump. If the battery voltage was that low, you are probably on the phone calling for help.

One could argue that the alternator is not a battery charger, it's primary function is to run the electronics for the engine, and any surplus is to charge the battery.

If you have 2 batteries and use them properly, as mentioned above, you should have no problems.
 
One thing to note, (we'll say batt 1 is start battery, batt 2 is house), if anyone does happen to drain battery 2 while floating,  I wouldn't switch to 1+2 to start, just switch to batt 1 to start motor, then once running, switch to 1+2 to charge(making sure not to turn dial through the "off" designation while motor running). Reason I say this is if batt 2 is really drained, combining them will simply draw down the charged battery as they will equalize between each other. No point in killing both your batteries. Just my opinion. 
 
I Guess I should clarify... I start with my house battery, then flip to 1+2 after about 2 minutes.
 
I am hijacking this slightly. Mine has a fridge with its own battery. I think it also has a plug 110V to use at a dock. So the battery runs the fridge while on the water - but it is not connected to an alternator right? Just runs purely off battery juice? If so, how long can the fridge run? I have the q series with fridge. Sorry just got the boat so posting many questions
 
If your boat came with the fridge, then it is set up to charge off the alternator, unless it is some unusual situation that I have not heard about.
 
My fridge house battery does not charge off the alternator. There is a battery charging system separate from the main engine battery system. You have to plug the charger in when docked or stored to keep the fridge battery charged. The battery will last 2 days for me in mild weather. In hot weather, it will last a day. I keep my boat plugged battery charger plugged in when at the dock or when stored on the trailer. I almost never turn the refrigerator off...just leave the charger plugged in. Keeps everything in there cold with no worries.

I can't speak to all setups, but my mfr-installed setup is separate from the alternator.
 
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JeffS said:
My fridge house battery does not charge off the alternator. There is a battery charging system separate from the main engine battery system. You have to plug the charger in when docked or stored to keep the fridge battery charged. The battery will last 2 days for me in mild weather. In hot weather, it will last a day. I keep my boat plugged battery charger plugged in when at the dock or when stored on the trailer. I almost never turn the refrigerator off...just leave the charger plugged in. Keeps everything in there cold with no worries.

I can't speak to all setups, but my mfr-installed setup is separate from the alternator.
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That is a crappy deal.  Many people take vacations on lakes and camp out with no power to be found.  I would change that situation real quick.
 
Or...they thought it through at the design level and decided this was a better design due to limitations of the alternator on smaller outboards. My 200 probably has plenty of alternator. But I bet a 90 doesn't. To your point though... It's an easy modification if you are a camper or what-not.
 
My last boat came with a fridge with a battery and charger. It did not charge off the motor. I removed the fridge as soon as I bought the boat (it's still in my garage) and replaced the space with a LED lighted bar. It's too hot where I boat for a fridge. :)
 
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