Battery quest

[ansonamis]

2014 242limited S- I have two batteries currently and I want to add a 3rd since I just added a sub an 2 channel amp. Had just the sound system on yesterday for about 3 hours while I was cleaning on two fully charged batteries. Tried to start it after the 3 hours and was completely dead and would not even turn over. Turned the emergency switch to on and same result. How do I add 3rd battery and it wires correctly using the stock switches. Batteries were purchased new August 2020 and have been on charge since. Maybe I have wired the amp incorrectly?

 

[JBehrens]

What kind of batteries do you have? A sub shouldn't kill the boat that fast. I would swap the house battery for a good AGM, group 31's you can get them cheap from Sam's Club or spend money on a Northstar.

If you want to add another battery to the house side you could add a 2 position battery switch that would select from bat A or bat B on the house switch only. The engine battery and the house battery should be completely isolated so draining the battery with the stereo should not effect your ability to start the boat. Regardless, keep in mind that our boats might not be able to recharge 3 batteries dead with the engines alone.

 

[ansonamis]

What kind of batteries do you have? A sub shouldn't kill the boat that fast. I would swap the house battery for a good AGM, group 31's you can get them cheap from Sam's Club or spend money on a Northstar. If you want to add another battery to the house side you could add a 2 position battery switch that would select from bat A or bat B on the house switch only. The engine battery and the house battery should be completely isolated so draining the battery with the stereo should not effect your ability to start the boat. Regardless, keep in mind that our boats might not be able to recharge 3 batteries dead with the engines alone.

 

[Mike Clark]

I agree with JBehrens, no way you should have drained two batteries of the size you show in 3 hours. I am running group 24 batteries, only use the house battery when floating and running 10 speakers , includes 2 subs and 2 amps and can listen for 4-5 hours and still have plenty left to start engines. Batteries are 2017.

I would do an actual check to see what volts they are after full charge. Also, the main reason I only run off the house battery when floating, , I always have the "start battery" to be able to start the boat just in case. I also ahev a portable battery powered "Jump Pack" I keep on board for an extra backup. Never had to use it myself, but have let numerous other boaters at the ramps use it to get their boats started.

 

[Bluewater272]

Agree with all that 3 hours on basically any system shouldn't kill your batteries. I added a second house to mine because we are often floating for 6-8+ hours - just wire it in parallel to your existing house battery - keep it simple.

Also, keep a rechargeable jump pack on board - but that's good advice for anyone - could help you or another boater out of a jam.

 

[Gwade8808]

I agree with JBehrens, no way you should have drained two batteries of the size you show in 3 hours. I am running group 24 batteries, only use the house battery when floating and running 10 speakers , includes 2 subs and 2 amps and can listen for 4-5 hours and still have plenty left to start engines. Batteries are 2017.

I would do an actual check to see what volts they are after full charge. Also, the main reason I only run off the house battery when floating, , I always have the "start battery" to be able to start the boat just in case. I also ahev a portable battery powered "Jump Pack" I keep on board for an extra backup. Never had to use it myself, but have let numerous other boaters at the ramps use it to get their boats started.

Hopefully picking up my new (to me) 242 next weekend! Are the group 24's your using AMG style and what brand? Also, what charger are you using to keep them topped off? Thanks

 

[Gwade8808]

I agree with JBehrens, no way you should have drained two batteries of the size you show in 3 hours. I am running group 24 batteries, only use the house battery when floating and running 10 speakers , includes 2 subs and 2 amps and can listen for 4-5 hours and still have plenty left to start engines. Batteries are 2017.

I would do an actual check to see what volts they are after full charge. Also, the main reason I only run off the house battery when floating, , I always have the "start battery" to be able to start the boat just in case. I also ahev a portable battery powered "Jump Pack" I keep on board for an extra backup. Never had to use it myself, but have let numerous other boaters at the ramps use it to get their boats started.

What's the brand of batteries you are using? And do you run the sterio off the starting battery when moving then switch to house when stopped? Appreciate your help!

 

[biffdotorg]

What's the brand of batteries you are using? And do you run the sterio off the starting battery when moving then switch to house when stopped? Appreciate your help!

Brand will not really matter on batteries. The only folks who believe that are the ones that spent way too much money on some Optima blue tops or crazy lithiums. As long as someone reminds themselves, that a cheap battery may not have the longevity from season to season. But if maintained properly, you can get multiple seasons without issue.

And no, if you have a 242, you should have a good switch system in to keep your house and starting circuits separate. A group 24,27,31 Lead/acid or AGM will suffice on both. Deep cycles are fine as well. As noted in other posts, both house and starting switch are flipped on when you get in, and shut off when stored. The emergency parallel is just that, switched if the starting batteries are dead and you need juice from the house to get yourself back to shore.

Any multi battery system should use a charger to keep them topped off when back to shore. Solar panels help, but a good onboard charger with at least 10a per bank is recommended. There are many to choose from.

Good luck,