Has anyone done an energy budget for a Beneteau 343?

[Davefromoregon]

I have a reasonable how to do this, but if some else has already done it I'd appreciate making use of your efforts.

I know that your choice of electronics will be somewhat different than what is on my boat.

My boat also has three house 12v ?amp hour batteries.

How do people go about measuring remaining capacity in a battery bank?

 

[Stu Jackson]

An energy budget is a highly personal thing. It all depends on how long YOU run whatever gadgets you have onboard. It has nothing to do with manufacturer of the boat. No two will be exactly the same, but a ballpark day-to-day figure will be around 100 ah with a fridge. There are also different uses for daysails, sailing at night or anchoring. Do you have LED lights or incandescent lights and how long do you leave them on? Many folks use trawler lamps. It all depends, see?

Make up YOUR OWN budget, it's easy. Here's how:

The All-Important Energy Budget:

http://c34.org/bbs/index.php/topic,3976.0.html

Record of Daily Energy Use of 100 ah per day:

http://c34.org/bbs/index.php/topic,6353.msg41471.html#msg41471

Batteries usually have their ah ratings right on the side of the case. Take one out and look.

Remaining capacity can be done with expensive equipment or with a 24 hour test with a small load. Google it, you'll probably find a description with a search on this forum, too - use Maine Sail as author.

 

[BigEasy]

Dave,
I will try to attach a listing of amps as measured at the DC panel. ( obtained from the Beneteau 343 site).

 

[Davefromoregon]

Thanks. I appreciate the help. It makes sense that the energy budget would vary a lot my user.

My TV rarely runs. My autopilot is used for very short periods. The refrigerator runs all the time.

 

[BigEasy]

I would think that all of the values that are associated with lighting are with the stock halogen bulbs; therefore, there is a lot of potential for energy savings in the lighting department. Have you converted to LED's or still have the OEM halogen bulbs?

 

[scotmcpherson]

Don't forget that efficient use of wiring is also a factor. The longer the wire the more energy your wiring will consume. Also and this may be counter intuitive, but within reason thinner wire consumes more energy than thicker gauges because it converts more of the electricity into heat.

 

[Davefromoregon]

Don't forget that efficient use of wiring is also a factor. The longer the wire the more energy your wiring will consume. Also and this may be counter intuitive, but within reason thinner wire consumes more energy than thicker gauges because it converts more of the electricity into heat.

This boat is largely "stock" from 2008. How much is that likely to impact usage?

 

[BigEasy]

Dave,
The lighting on my 343 is stock also; however, I am thinking about coverting to LED bulbs. I am also considering changing the combination masthead / deck light to an LED fixture. Definitely not going to take it so far as to rewire! I am assuming that Beneteau engineers specified appropriate sized wiring. You can check the files on the 343 website; there is a listing of the stock bulbs and replacement LED bulbs. If need be, let me know and I will send a copy.

 

[watercayman]

I was interested in similar for my boat and wrote an app for my phone (Android) a while back. It was a fun project to see what I use during a typical day. No idea if you are interested, but here's the link:

https://play.google.com/store/apps/details?id=ky.boatamps

Its free - I don't make anything from it, just figured it might be helpful if you have an Android device.

 

[Deadhead]

On my 343 the fridge was a huge energy suck. I think I estimated 120 amp hrs per day for that alone (10 amps x 12 hrs. compressor running per day). I had a spread sheet that itemized everything from the anchor light, vhf, mfd, reading lights, etc. IIRC the entire budget for a day sailing and a night on the hook was about 200 amp hours.

 

[Syversens]

As everyone before me said, you probably should do your own energy budget. What really matters with the batteries is their AH, they could be different on each so document what you have, keep in mind one might be a dedicated starting battery.

I also worried about remaining capacity so I bought a Balmar Smartgauge last year. Before that I had nothing and this device both helps me get accurate voltage at the battery, not panel. It also has a state of charge which is very useful. It does seem to drop faster from 100 to 90 than 90 to 80 but that could be my batteries getting old.

Installation of the smartgauge was my main reason for buying it, VERY simple compared to others with shunts and whatnot.

Cheers!

 

[luken7]

As everyone before me said, you probably should do your own energy budget. What really matters with the batteries is their AH, they could be different on each so document what you have, keep in mind one might be a dedicated starting battery. I also worried about remaining capacity so I bought a Balmar Smartgauge last year. Before that I had nothing and this device both helps me get accurate voltage at the battery, not panel. It also has a state of charge which is very useful. It does seem to drop faster from 100 to 90 than 90 to 80 but that could be my batteries getting old. Installation of the smartgauge was my main reason for buying it, VERY simple compared to others with shunts and whatnot. Cheers!

Which smart gauge do you have? Make/model?

 

[Syversens]

Hey Luken, I have a Balmar SmartGauge. I think its very accurate and pretty much confirms my energy estimates as far as state of charge. In addition having a voltmeter directly to both house and engine to check alt output and systems help me diagnose issues or confirm it working well.

 

[Newport Bob]

I also have installed the Smart Gauge after reading Maine sails articles. Much better than the traditional amp, volt gauge on my previous boat.
Read and then purchase from him;

http://www.pbase.com/mainecruising/smart_gauge&page=1