battery's? help

[fshnne1]

I am looking at replacing and adding to my boat the current battery, first question is, what is the difference between a deep cycle and a standard vehicle battery? I only get out on the boat about 10 - 20 times a year, I have a 65hp merc 650 outboard, running lights, fishfinder, bilge pump, and a trolling motor maybe be adding a radio.. what I was thinking was to do a deep cylce starting for the 65hp, and hooking the rest up to a big standard battery, what would you think is the best set up? the 65 hp will run a back charge, also I have a solar charger that will be hooked up.

 

[Paul Moir]

Re: battery's? help

You've got it backwards if anything. Starting batteries are really only good for starting an engine. After that the charging system is supposed to take over. They do not survive being discharged very well as you probably already know. Like if you leave your lights on in a car and drain the battery even just once, you'll probably be replacing that battery next winter.<br /><br />Deep cycles put up with discharging better and will last far longer. But even with them you try not to drain them much more than 50%. A trolling motor necessitates a deep cycle.<br /><br />Depending on how much you use the trolling motor and whether you can start the engine without the aid of the electric starter, I would use either one deep cycle battery or two deep cycle batteries. A "starting" battery or "combo" is completely unnecessary. You will also need to invest in a good automatic charger as the outboard's charging system will not keep up with the trolling motor if you use it much, and the solar panels are normally just battery maintainers. That is to say, they keep them from self-discharging.

 

[fshnne1]

Re: battery's? help

the main thing I was thinking was I would hate to run everything off a exspensive deep cycle and get out to the middle of the lake and have it go dead because I have to many systems running off one battery, the trolling motor would maybe be used at the most a hour each time out. if I put a radio in it would just be for when we pull into back hole and have everyone taking a swim, the long running would be the fish finder and night fishing my running lights...

 

[fshnne1]

Re: battery's? help

would running everything off one battery and having a standard battery for a jump start be an ok option If I was to run the deep cycle all the way down to the point I could not get my merc 65 to start

 

[Paul Moir]

Re: battery's? help

The reason the battery is expensive is that it lasts much, much longer. The cheap starting battery will not last 6 months used with the troller, if that.<br /><br />All other current drains are negligible compared to the trolling motor. Unless that's a 1000W system you want to put in and always crank it to the max. Some people add some convenience lighting and that can add up if you leave it on most the night. <br /> <br />A second backup battery is always a good idea if starting your engine without a battery isn't easy. Some of the older outboards had pull starts as well as electric starters, so if the battery died it wasn't serious. Almost all outboards can be started with a dead battery by wrapping a rope around the flywheel and pulling though, since their ignition systems are independent of the battery.<br /><br />So you should look for a small starting battery for starting the merc, a battery isolator so the outboard can charge both at the same time, and probably a battery switch so you can start off the deep cycle if need be. The starting battery would have nothing drawing from it but the outboard.<br /><br />You could just carry the second battery for jump starting, but I think it would be far more useful just to make it all automatic. Battery switches and the tiny isolator you'll need are pretty cheap equipment.

 

[JB]

Re: battery's? help

Moving to Electrics. . .

 

[ZmOz]

Re: battery's? help

Originally posted by Paul Moir:<br />Some of the older outboards had pull starts as well as electric starters, so if the battery died it wasn't serious.

Even if it has a pull rope it's more of a cruel joke than anything useful. My 150hp Mercury has one...it might start it if it's still hot and god feels like giving you a miracle. Those old Mercurys barely start with the electric starter...<br /><br /><br />As for your starting/deep cycle problem, as Paul said you shouldn't run even a deep cycle battery below 50%; at which point you should still be able to start your engine. If you're worried about accidently running it too low, one of those portable jump starters would work great and should be on everyone's boat regardless of how many batteries they have.

 

[Paul Moir]

Re: battery's? help

Well, I never claimed to be much on old Mercs. But I do vividly recall furiously starting a smaller, newer one by turning the flywheel with my bare hands after the pull start went south. <br /><br />One of those jump boxes is a great idea since they're so handy for other things.

 

[fshnne1]

Re: battery's? help

I guess what would be the best solution! a depp cyle for the 65 hp merc, and a stardard car battery for the rest at least if I run the car batt low I can still start my merc and run to land with a spot light!!!

 

[Paul Moir]

Re: battery's? help

The car battery will not survive if connected to the troller...

 

[Silvertip]

Re: battery's? help

You seem to be hell-bent on using a deep cycle as a "starting" battery. That's not what they are designed for. Put the standard battery on the engine and use the deep cycle for everything else. If deep cycles were intended for starting duties every vehicle on the planet would be fitted with them from the factory.

 

[Ngataki]

Re: battery's? help

THIS website has some good stuff about batteries..<br />Enjoy..

 

[ZmOz]

Re: battery's? help

Originally posted by Upinsmoke:<br />That's not what they are designed for.

Actually, they are. Any standard 85+ amp hour deep cycle battery will have no problem starting your average boat/truck/car. The outboard in question here probably uses less than 100 amps for the starter, which is nothing for an ordinary deep cycle.<br /><br />

Originally posted by Upinsmoke:<br />If deep cycles were intended for starting duties every vehicle on the planet would be fitted with them from the factory.

Deep cycle batteries are heavier and more expensive than regular batteries, and there is no need for them in most vehicles. Manufacturers will not spend a cent that they don't have to.

 

[Ngataki]

Re: battery's? help

I agree with Upinsmoke you don't need a deepcycle for starting only.Of course a deepcycle can handle that..In case you only want ONE does it all battery you might go for a dual purpose Marine batteries which is nothing more then a compromise between both designs..