Batteries, batteries, batteries

[Road Head]

I got some good info from searching, but had a couple more specific questions. I have a 21' Chaparral with a 5.7L mercruiser. Current battery is dead.<br /><br />For next couple weeks/month I want a battery that will start my boat reliably. The only thing I might run with the engine off is the radio, but I dont have to do that. I would rather make sure I get my boat started rather than listen to music. <br /><br />Eventually (sooner than later) I want a dual setup, using the standard 1,2,both,off switch (like you find at Bass-Pro). I will be using the radio with this setup - mainly, I want to ensure that I get home after being out on the water for the day.<br /><br />So I guess my questions are, what batteries do I need?<br /><br />A. #1 dual purpose, #2 deep cycle<br />B. #1 dual purpose, #2 dual purpose<br />C. #1 starting only #2 dual purpose<br />D. #1 starting only #2 deep cycle<br /><br />Also, what brand - it seems like many people have success with the Everstart Marine Maxx - but which one do I need?<br /><br />Thanks

 

[Road Head]

Re: Batteries, batteries, batteries

http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000026 <br /><br />Well, I just read that (the FAQ about dual batteries) and that pretty much answered my questions. D seems to be the answer based off of that - and I just cannot run the radio until I get the deep cycle. <br /><br />Here is one question though, lets say my batteries are both charged. I use the starting battery to start the boat, and head out, do some tubing, skiing, whatever. We then anchor the boat, eat our lunch, swim, etc. Switch to deep cycle and listen to the radio for 2-3 hours. We switch back to starting battery to head home, and wont start (no reason it shouldnt, but lets just assume it dies). Will the deep cycle be able to provide enough juice to start the boat?<br /><br />Also, if anybody has any preference for brands I would appreciate it.

 

[tommays]

Re: Batteries, batteries, batteries

<br /><br /> http://www.iboats.com/mall/index.cg..._id=216584&list_time=1149030934&view_id=52589 <br /><br />I like the battery Isolators like this because the batterys allways get charged when the motor is running with out worrying about turning the switch<br /><br />Of course you stil have to keep the house load off the starter battery<br /><br />and a switch and the Isolator would be the best setup<br /><br />if a switch is flakey moveing it when the motor is running can damage the alt if the chargeing is going through the switch<br /><br />tommays

 

[Silvertip]

Re: Batteries, batteries, batteries

You can only protect against so many possible scenarios. If you are that worried about the start battery, carry a jump start unit with you. Then make sure the engine is tuned properly and that you really understand the start procedure. You'd be surprised how many people don't know how to properly start a carbureted engine since everything nowadays is fuel injected and you just turn the key. Chances are you'll never have to use the jump pack. Also, unless your stereo is feeding a gazillion watt stereo, it should run all day without affecting the start battery. Buy the biggest capacity start battery and biggest capacity deep cycle battery you have room for and enjoy your boat. By biggest, I mean AMP/HR rating, not just physical size although that has some bearing on capacity.

 

[Boatist]

Re: Batteries, batteries, batteries

I also like battery isolators as they will charge both batteries and protect your alternator. To destroy the alternator you would have to disconnect both batteries at the same time.<br /><br />Battery switches with out the isolator I feel is the number one cause of blown up alternators. Cheap switches can blow alternator if turn with the motor running. Even the best will blow alternator if you turn thru off with motor running.<br /><br />Battery switch and isolator will protect the alternator but does not isolate both batteries from each other unless you turn your switch off. Battery you have selected can be discharged by the other battery. Example battery 1 starting, Battery 2 house. Switch set to number one for starting. When you stop and play the radio or run the trolling motor all day off of battery 2 it will discharge both batteries. The reason this happend is when the switch is in position one it shorts out one of the isolator diodes and allow current to flow to the center post of of the switch. From the center post current can flow thru the diode to charge battery 2 just like it does while running the engine.<br /><br />My self I have a battery isolator and no switch and it works great, but if for some reason the starting battery fails I either have to swapp batteries or with a single jumper cable jump from one positive to the other.