2004 Sea Ray 260 house batteries

[businessjett]

Hello

new to me. The 2 house batteries are start batteries not deep cycle. I read I need to measure the amp hours of every device. Eg. Fridge , cabin lights, cockpit lights, anchcor light, water pump. Vacuflush .

i don’t even know how to do any of that. Has someone else already worked this out ? Or can I just get some really big batteries to have extra on hand ? Or does anyone know how to measure the amp hours with a multi metre ?

I hope to not just get new house batteries , but some bigger solar at the same time , so would like to do it right .

Thank you

 

[bobeast]

Amp hours is simply Current draw over time. If a device draws a constant 4 amps and you let it run for an hour, you have used up 4 Amp-hours from your supply. Typical AGMs will have an AMP-hour rating of around 100. You should never use more than 50% of your capacity or it will shorten the life of your batteries.

So two 100 amp-hour AGMs wired in parallel will give you a 200 amp hour bank, of which 100 is safely usable. As such, that 4 amp device I mentioned, could safely be run for 25 hours on this bank.

Now figuring out what your total amp-hour draw is a bit tricky, because all your devices probably don't run constantly, or all at once. Say a fridge draws 4 amps while the compressor is running, bit then drops down to .5 amps when it has reached temperature. The more often it cycles, the longer you spend at the higher tier, and the more of your capacity you will burn through. So in this example, making sure you limit how often you open the fridge, and making sure the door seals are doing their job would help minimize the run-time. A cooler full of ice to hold your drinks or items you need to get at often will help here.

Now items like your fridge, a 12volt tv, a stereo, and even your light bulbs have specs that you can look up and that will give you the worse-case estimate. All that said, the only way to really know how much current you are drawing is with a current meter attached to your battery bank through a shunt.

My favorite trick to gain insite is to anchor in place. That is to say, go to your marina for a weekend and unplug your shore-power. Now run your boat as you normally would at anchor (including the anchor light at night). Next morning see how easily the engine on your house bank starts. If it turns over slow, or not at all, you definitely are over-drawing the capacity of your current batteries

One final point. Conservation is always cheaper than new batteries. I'd start by replacing all your light bulbs with LEDs. That will give you the most bang/buck. Then look at what pieces of equipment are getting long in the tooth and are probably not as efficient as a newer unit. The fridge is a great candidate here. Finally, don't crank your stereo. No one else wants to hear it anyways.

 

[Lazy Daze]

Well, I'm not going to try and type anything near as coherent and informative as Bob did - that's quite informational!

But, here is what I used for many seasons using our 260DA (although the model doesn't really matter... just the "use) for overnights and extended weekends away from shore power. I used a cranking battery and a the largest group 27 deep cycle I could get my hands on. I once ran all the things you are talking about on that 27 for 3 days and nights. I kept it on the 27 the whole time - I did start the engine on it twice. Once around the second day for a little run of about 30 or 45 minutes. And once on the last day to go back to the dock - and it still started the engine fine that last day. If you wanted to, it wouldn't be a bad idea to even bump up to a group 31 DC.

"Technically" you shouldn't start an engine with the DC battery - but I was experimenting

 

[bbwhitejr]

Well, I'm not going to try and type anything near as coherent and informative as Bob did - that's quite informational!

But, here is what I used for many seasons using our 260DA (although the model doesn't really matter... just the "use) for overnights and extended weekends away from shore power. I used a cranking battery and a the largest group 27 deep cycle I could get my hands on. I once ran all the things you are talking about on that 27 for 3 days and nights. I kept it on the 27 the whole time - I did start the engine on it twice. Once around the second day for a little run of about 30 or 45 minutes. And once on the last day to go back to the dock - and it still started the engine fine that last day. If you wanted to, it wouldn't be a bad idea to even bump up to a group 31 DC.

"Technically" you shouldn't start an engine with the DC battery - but I was experimenting

Like Dennis above, when we had a 260, I upgrade to 2-new Deka Grp 31s DC and a new Pronautic 1240p charger. We could run days without starting the gen or the engines.

Changing to all LED light bulbs is one step well worth the money.

Bennett