Single or dual battery for an 18' dual console?

Brian N

Brian N

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When I picked up my Edgewater 185, it had two batteries set up on a switch in the storage area on the starboard side of the boat.

When I was having an electrical problem this summer, we found that the switch was failing, so as a quick fix we pulled out the switch and removed one of the batteries. I went all season with zero problems, and now I'm debating whether to wire the second battery back in or just stick with a single.

The only real draw on the battery when the engine is not running might be:

Bilge pump, but that rarely ever kicks in since the boat is an outboard with a self-bailing cockpit.

Live well, which I have not used yet but probably will when we start doing some fishing this summer.

Fishfinder/GPS, stereo, and VHF.

My thought was to keep a jumper pack in my tool kit in case I somehow run it down enough to need a jump.

Sounds like a good plan? Or should I re-install the second battery?
 
I would not rely on a single battery. Do it right, put a new switch and reinstall the second battery. Those jumper packs don’t always work and they have to be kept charged.

just make sure you put in a better switch than the cheapest possible junk the builder installed.
 
I just read in another thread that separating your primary load from a supplemental power grid may ultimately prove unwise. I’d keep the second battery.

Oh, and don’t rely on solar for backup! 😁
 
I prefer a marine starting battery just for the power plant and a Marine deep cycle for the house/electronics battery both being feed from a isolator. The switch is only used if a battery fails.
 
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PilotError said:
I just read in another thread that separating your primary load from a supplemental power grid may ultimately prove unwise. I’d keep the second battery.

Oh, and don’t rely on solar for backup! 😁
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Had not noticed your sense of humor before
 
I have a 22’ center console with an outboard. Batteries are fairly new but boat is older with some very suspect wiring added over the years. It seems like at least once per year the second battery saves my ass. I am more comfortable with two.
Jim
 
I am going to go ahead and disagree with the consensus - on a small boat with essentially no house load - and one alternator, I think having two batteries is a bad design. Especially if you have no shorepower to keep both batteries fully charged. Even worse If you are just combining the batteries with a switch, and not using a smart combiner to charge them. you will never fully charge both of them off your alternator - well not never, but it will take a long time.

Imagine you have one battery at 90% and one at 50% - you fire up the motor and throw the switch to start charging them both. But first they are going to equalize, which will take a while. Only then will they really start charging, which will take even longer. Twenty minutes later you shut off your boat, and end up with two batteries at 70%, where if you only had one, it would be at 100%. What have you gained? I suspect a lot of people that are relying on their second battery are only needing a second battery because their design prevents the first one from fully charging.

of course if you want to run the stereo all day when anchored, and things like that - a second battery is wise. But put in some type of smart combiner, that isolates the house battery until the starting battery is fully charged. the old 1-2-both switch is not going to get it done. Unless you run the boat for a while on 1, until the battery is 100%, then switch it to 2, run that a while to charge that one. Or have shore power, and leave in the morning with battery 2 as a fully charged backup.
 
I only run one battery at a time and rotate each time out. I go out at least 4-5 times per week so they are always fully charged. The they only downside I see to having two batteries is the additional cost and the weight.
Jim
 
32carv said:
I only run one battery at a time and rotate each time out. I go out at least 4-5 times per week so they are always fully charged. The they only downside I see to having two batteries is the additional cost and the weight.
Jim
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The weight, that’s a very good point that I forgot. The first couple summers I had my bowrider, I had a second battery.it never quite sat right in the water - no matter where i put the battery.

I was a weekend boater, and always tried to remeber to rotate from one battery to the other, but never did. Your method works, no doubt. But it seems most people run around on the same battery all the time, or with the switch on ‘both’.
 
Given your circumstances, I'm with alk on this one. And, given a decent or better booster pack, they are great and last a long time.
 
I have had multiple boats with one battery, never had a problem.
 
Brian, what size battery? That’s an important part of the question. Maybe with one large battery like a G31 otherwise I d stick to two. All it takes is something to left on by accident and the lil g24 won’t crank. Like someone hitting a couple of switches and your bilge pump stays on while anchored for a couple of hours.

I ve had this happen a couple of times on the 15’ RIB we have on the boat I run. Luckily it happened when it was tied up but had it happened out at a beach it would have been a problem. I ve been thinking about adding a second battery
 
I had a stator go bad and ended up stranded 20 miles offshore. The problem was the stator charged when running at speeds over 2000 RMP's, but produced no charge at low RPM's. I always watch my gauges, especially at higher speeds, but we were trolling and a friend was at the helm. Made a number of mistakes that I 'learned' from. 1- Never run on the 'both' setting. This prevents a drawing down of both batt's below the needed 12V. 2- also carry a jumper pack. This will allow voltage for your VHF use and in my case allowed for a restart and getting rpm's up for the run home. Protects from the dreaded dead 2 batts. (thanks to SeaTow for the use of their jumper pack).
Anyway, my thinking is redundancy is good. It's never fun to call for help. Self rescue is best and does not embarrass. Being stranded is not fun anywhere and can be deadly or at least uncomfortable. BTW--Did I ever tell you about the blown engine and sitting for 12 hours, waiting for a tow to arrive.
 
2o miles off shore is different that I considered. Back up on stuff is a good idea.

Not sure what a second battery would help with a blown engine [:D]
 
This pretty much the internal debate I have been having. We will not be going offshore in this boat. it's just too small to go offshore in New England. We primarily cruise around lakes, harbors, etc. There is basically no house load aside from the stereo, lights, and bilge pump. The weight of a second battery is a factor on this small of a boat. Maybe upsizing the battery like Pascal suggested would be a good happy medium? It is currently a normal sized starting battery that was new from the prior owner.
 
Brian N said:
This pretty much the internal debate I have been having. We will not be going offshore in this boat. it's just too small to go offshore in New England. We primarily cruise around lakes, harbors, etc. There is basically no house load aside from the stereo, lights, and bilge pump. The weight of a second battery is a factor on this small of a boat. Maybe upsizing the battery like Pascal suggested would be a good happy medium? It is currently a normal sized starting battery that was new from the prior owner.
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Then you need a bigger stereo with a big amp :)
 
"I have had multiple boats with one battery, never had a problem." - pdecat

The concept is similar to:

There are two kinds of boaters: Those who have run aground, and those who will...

IMHO, redundancy is your friend.
 
getakey said:
Then you need a bigger stereo with a big amp :)
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I hardly use the one I have...I go on the water for peace and quiet. The only music I want to hear comes from the Yamaha hanging off the back. ;)
 
I installed a big amp and speakers on the ski boat. We played one hit wonders (loud)
 
As long as you are not around narrow channels with large vessels, dangerous areas with currents and winds, etc., and don't mind sitting and waiting for help then go with one battery. I would point out that you need to remember who you are....you pretty much used up your lifetime supply of good luck when Linda agreed to marry(rescued) you.
 
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