[malach]

We have a 26' sailboat that we are using on weekends. The boat is moored in the North East. The outboard is powered by a West Marine 650 Starting battery and the specs mention that it requires 465 MCA. The battery also supplies power for the VHF, depth finder, and lights.
I am planning to install a 3700 Rule Bilge pump, 14A, for emergencies. The total daily requirement for the lights, the depth finder and the VHF is around 14 Ah. That would require a battery of about 33 Ah, before adding the bilge pump.
I know that it is recommended to use a separate battery for starting the engine, but I am not sure if that applies to a small outboard or only to big inboard motors. My understanding is that the bilge pump would maybe benefit from a deep cycle battery. Or would the existing battery suffice for starting the outboard and operate the bilge pump in an emergency? Any thoughts on this?

I am thinking to use a small solar panel as a charger, but I need to decide on the battery setup first.
Thank you!

 

[deltaten]

I'd keep the starting batt andthe house batt seperate. Use what ya have for start. Add a group27 (true) deep cycle marine and. use the outboard. to charge with asmall panel to top off.
I got a deal on an Interstate 27 hybrid FLA with some sorta mats like an AGM . 180AH (20a/70-some degrees test) Figure half as useable untill ya need to bulk it u, so 90Ah hr +/-available. at 400 or.so full cycles !
All I need yet is a good CCA start battfor my recalcitrant lil'diesel and I'll be set..
Yadon't want a wonkybilge pump or a left-on radio/lites, etc.. to. kill your start battery!

 

[Delezynski]

Malach,

You say it's a week end boat. Do you keep it at a dock, with power available? Or on a mooring or place with no power?

I agree, you shoul pick up another battery, like a group 27 deep cycle. If you don't keep the boat at the dock with power, you should think about a small solar system to top up the system during the week. You should be able to pick up one for not a lot of $$.

Greg

 

[christian.hess]

word...Ive been looking recentlty, everytyhing from renogy panels to small flexible 20watters can be had for less than a 100, get a simple controller and battery and you wont have to worry about the battery when youre not on the boat

Im in the market too

 

[hellosailor]

"The outboard is powered by a West Marine 650 Starting battery "
Starting batteries, called SLI (Starting, Lights, Ignition) are designed for starting loads and are rapidly destroyed by deep cycling them to any extent.

So if it is an "old" battery, 3-4 years old or testing out at 60% of original power or so? I'd replace it with a bigger "dual purpose" or pure deep cycle battery. Going to a dual-battery system will make keeping TWO batteries separated and charged a more complex proposition. Like putting a solar charger with controller on the starting battery, PLUS another hundred bucks for an "Echocharger" or "combiner" to ensure the house battery is charged, plus a switch, plus cabling....
More efficient and durable, yes, but lots more money and decisions to make.

So on the basis of KISS, I'd say consume the existing battery (unless it is brand new and really worth idolizing(G) and then replace it with one better battery.

Personally I like AGM because it costs me less in acid burned clothing and the like, but a conventional flooded lead acid battery will cost substantially less. And oddly enough, WalMart and Sam's Club apparently have the best prices, with WalMart often having the longest warranty with no questions asked.

As to the emergency bilge pump...Electric is nice but I hope you have a manual pump installed, because electric bilge pumps are "consumable" items that tend to go bad on a regular basis. If you install two, you can expect ONE to be working when you really need it.

 

[malach]

I decided to get a deep cycle with a small 5W solar panel to keep it charged. The emergency bilge pump is connected to it (I also have a manual pump).

 

[newhaul]

Cool that should work and thank you for the update

 

[JimsCAL]

I decided to get a deep cycle with a small 5W solar panel to keep it charged. The emergency bilge pump is connected to it (I also have a manual pump).

You never mentioned if your outboard has an alternator or if it is electric start. I assume you can start it manually. That would eliminate the need for a second battery. A 5 watt panel is really not capable of recharging even a small battery. Will keep one topped off, but that's about it. If you are relying on the solar panel to recharge the battery, I would get a 20 or 30 watt panel with a controller.

 

[newhaul]

You never mentioned if your outboard has an alternator or if it is electric start. I assume you can start it manually. That would eliminate the need for a second battery. A 5 watt panel is really not capable of recharging even a small battery. Will keep one topped off, but that's about it. If you are relying on the solar panel to recharge the battery, I would get a 20 or 30 watt panel with a controller.

Actually Jim I used one of those little 5 watt units that plug into a CIG lighter on my islander works just great. Lights are all led. Also i have an independent solar anchor light. The only other draw is my cell phone charging every three days for about 2 hours.