Is my one battery boat going to start in an hour??

I just posted about what stereo equipment to buy on a budget and of course went a little over. Now that I have the stereo figured out, what about a battery setup. My finances are tapped so I need to decided if I NEED a second battery setup. I picked up 2 amps, 1500w total. I plan on listening to the stereo on the beach for a hour at a time before getting back on the boat. The stereo won't be fully cranked because fighting stereos with everyone is annoying. SOOO, is my one battery boat going to start in an hour?? I was thinking as a backup, I could carry on board one of those cheap battery jumpers in case the boat would not start. I would just need to make sure that the cheap battery jumper is charged every night. Also, will that be really hard on my battery killing its life span?

It'll probably be dead in an hours time even at half volume. Most on here highly recommend at least a 2 battery set up, one for cranking and one for the house needs. If you do use yours in the manner you are describing it will absolutely shorten the life of your battery. Those jump boxes are great and would be good to have on hand for sure.

remember that running a single battery down and trying to use it as your starting/only battery is going to shorten the life of all your electronics in the boat. You will burn up your alternator, starter, gauges, senders, computer, switches, blower, bilge, etc....

You should have at the minimum a one extra battery. There are a number of ways to hook the batteries up so you don't leave yourself unable to start while protecting your boats vital systems.

Do a search of the forums. There are multiple threads about it.

I have been reading a lot about the batteries. I guess it looks like a second battery and a perko switch. Sounds like it will keep my investment in order. It's just money, right?

Originally Posted by RanchDweller

I have been reading a lot about the batteries. I guess it looks like a second battery and a perko switch. Sounds like it will keep my investment in order. It's just money, right?

It is just money, but like you said it is protecting your investment. Boats have enough problems when they are setup correctly. Take it from me. You don't want your boat to die and not start in the middle of the water on seafair. My boat didn't have a dead battery but it did have a bad starter which was probably the result of the previous owner not wiring the boat correctly. Every electronic piece of equipment in the boat was acting up when I owned it.

If I have my normal starting battery isolated from my stereo battery, won't the stereo battery life span be affected after listening to the stereo a few times a day on the beach and constantly running it down? It sounds like I will have a good starter battery and a stereo battery that will have its life cut short. Is that right?

It depends on what type batteries you use. What kind of battery do you currently have and how old is it?

I am not sure how old my starter battery is. Probably OEM, could be 3-4 years old. I think that it would be overkill to get 2 6volt deep cycle batteries for my stereo and 1 12v starter. If I have 2 12v it should work. But back to my original question, if my stereo battery is draining 4 times a day on the lake, the life would be very shortened. Am i looking at this wrong?

I know you are on a budget but it generally isn't a good idea to add brand new batteries to old batteries if they are going to charge up together which yours will. In an ideal situation you would try and have all batteries be the same in your application. Deep cycle batteries are meant to be depleted and then brought back up. They have very thick plates that can withstand being cycle down a lot. Starting batteries have thin plates but more surface area. This is why they can have high CCA's.

If you could do a deep cycle group 31 marine battery for starting and one or two for the stereo that would be a good way to go. The group 31 deep cycle should have enough CA's to start the boat fine unless you are in a crazy cold area or have some crazy huge engine. Another option that people have had luck with is dual purpose battery for starting and then 2 6v batteries in series for the stereo. 6v golf cart batteries are probably your best bang for buck when it comes to play time and longevity. Downfalls are they are big and require you adding water occasionally.

Another thing to consider is if you have a stock alternator and add a couple batteries you are going to give your alternator a really hard time unless you know when and where to flip the perko. Your stock alternator doesn't have a chance in hell of charging up a completely drained deep cycle bank like you will want it to. You really need an onboard charger to charge up the batteries to what they need to be at every night.

Unfortunately too many people do what you did and don't budget the charging system into their stereo install. It is why most car stereo shops have no business putting a stereo in a boat.

I am guessing most guys are gone for the holiday weekend but you might get some good feedback after that from some of the experienced boat stereo installers. There are many on this board that know how to do things the right way.

The very reason i immediately scrap the perko on every boat and add an Automatic Charging Relay (ACR) like the Blue Sea Systems 7650 along with a second deep cycle batt. Never had issues yet and the stock alt has no problem keeping them charged.

Run it as is for now.
Carry jumper cables and hang out with people that will help you out if needed. If you are alone don't play the stereo without the motor running or you will likely get stranded.
When you learn how your demand drain your battery make an intelligent decision.
I ran my old boat with 1500 watts on a single battery for 2 years, I rarely hung out with the stereo playing.
When you do add a battery do it as Razzman, myself and many others have done using an ACR, add a digital voltmeter at the same time. I look at my digital voltmeter more than any other gauge in my boat whenever the motor is off.