Electrical Q's: Charging, motor, batteries

[sPk]

I have an O'Day 25. I currently have a 15w solar charger with charge regulator & two deep cycle batteries connected in parallel. But I tend to run low on power over a weekend as I have a Coleman Stirling cooler that is rather power hungry. I also have a Genius 2 bank charger that is currently using only 1 bank to charge both batteries (the solar charger is also connected to these batteries.).

I am updating the outboard motor which will now charge the batteries too plus I was going to add a starting battery which I was planning on just using a motorcycle battery that I already have and use the 2nd bank charger to keep it charged. It isn't a big deal if I have to manually start it.

Is there an issue with having the motor's alternator (80W 6A) , solar charger & the Genius 2 bank all connected to the two batteries? I have a "1 -2 -both" switch I have never insalled. Is there a better way to hook this up?

 

[thinwater]

A few thoughts:

I have an O'Day 25. I currently have a 15w solar charger with charge regulator & two deep batteries connected in parallel. But I tend to run low on power over a weekend as I have a Coleman Stirling cooler that is rather power hungry. I also have a Genius 2 bank charger that is currently using only 1 bank to charge both batteries (the solar charger is also connected to these batteries.).

I am updating the outboard motor which will now charge the batteries too plus I was going to add a starting battery which I was planning on just using a motorcycle battery that I already have and use the 2nd bank charger to keep it charged. It isn't a big deal if I have to manually start it.

Is there an issue with having the motor's alternator (80W 6A) , solar charger & the Genius 2 bank all connected to the two batteries? I have a "1 -2 -both" switch I have never insalled. Is there a better way to hook this up?

I used to have a similar-sized boat and used it in a similar way. I did cruises up to 2 weeks, though I did stop at marinas every 2-4 days, in part to re-charge and in part to shower properly!
http://sail-delmarva.blogspot.com/search/label/Stiletto Stuff

* Ditch the Stirling cooler. Inefficient. You would be better off with a large well-insulated cooler (or wrap a standard cooler in a sleeping bag) which should hold ice for 3-4 days. Figure at least 15 pounds of ice. I now have a propane fridge tha works well, but for over-night I just use ice in a cooler. Simple and nothing to re-pack from home.
* 15w solar is just for battery maintanance. Figure (with shading and clouds) about 5 amp-hours (AH) per day. If you consider that the batteries are perhaps 75 AH, you can see this is trivia. I threw the 15W pannel in the trash.
* Engine charging from an outboard is trivial. If you run for 1 hours, that's 6 AH, IF you are at full throtle. But you probably arn't so figure 2-3 AH.
* Are your batteries fading? Add up your AH of use; watts x hours/12 = AH. Compare this to ~ 50% of your battery rated capacity. They may be tired. 2 deep cycle (group 24?)batteries sound about right for the boat, but it all depends on your energy budget. Consider going to group 27, if they can fit.
* If it's easy to pull-start the engine, forget the starting battery. Put everything on both batteries in parrallel. Skip the 1-2 switch (I assume you have a both/off switch now).


Good luck!

 

[sPk]

Re: A few thoughts:

Thinwater: Thanks for your insight. I don't have any battery switches installed now. The two batteries are Napa 8270's (group 27) & unfortunately only one is new. The other is a couple years old.

 

[sailaway78]

Trivial charging

Agree that what you have with solar and the motor alternator is a trivial amount. Very few amp. hours. The small solar is only good for maintaining, and the alternator not much more.
Figure out your energy usage, and adjust to that. You can wire all three charging sources up together with no problem. Is there room for one more battery. That would probably do you more good than anything. Or maybe a pair of golf carts. Two golf cart batteries will give you about 225 amp hours.

 

[Bill Roosa]

I have a spread sheet that will calculate the energy used and state of charg on the batteries. email me at william-roosa@us.army.mil if you want a free copy

 

[Bill Roosa]

Given a 25' sailboat and outboard motor I'd opt for bigger batteries and a shore powered charger. You can never go wrong with more storage. Your setup is not conducive to larger panels or an engine driven alternator. but with a couple of decent batteries you can last out the weekend and recharge at the dock during the week.

Also ditch the electric cooler and go with a quality insulated one and block ice. I find that 1 gal milk jugs frozen work well and don't make a drippy mess

 

[thinwater]

Given a 25' sailboat and outboard motor I'd opt for bigger batteries and a shore powered charger. You can never go wrong with more storage. Your setup is not conducive to larger panels or an engine driven alternator. but with a couple of decent batteries you can last out the weekend and recharge at the dock during the week.

Also ditch the electric cooler and go with a quality insulated one and block ice. I find that 1 gal milk jugs frozen work well and don't make a drippy mess

Agreed. I should have added that my Stiletto had a good shore power charger. They aren't expensive. Something like this is all you need:
http://www.westmarine.com/webapp/wc...toreNum=10109&subdeptNum=10544&classNum=11279

The interesting thing about frozen bottles (my wife likes to freeze ~ 15 x 12 oz water bottles) is that you get a bit less cold, but they last longer.