Battery selection advise needed please

[flyhop]

Great Responses! And....

The responses have been diverse, which I expected, and full of great information, all of which I am grateful.Our plans are to be able to anchor out for 3 days/2 nights without running low on lights/music. Several of you were quick to point out, and rightfully so, that our worst case would be a pull-rope start to the O/B. So, it stands to be determined what we choose for a house system. I also appreciate your thoughts (thanks Bob) about the charger. It is a 1988 model, and I too have had difficulty gathering information about it. At this point, I am leaning toward a pair of 6V Trojan (T-105) and a Xantrex 10amp charger, all of which should set me back about $300 +/-. Any more comments though would be most welcome.

 

[Tom Spohn]

Best thing

we did on our boat was to go with 2 golf cart batteries. Specifically we have two Dyno D145 batteries in series for 245 amps.http://www.dynobattery.com/prod01.htm

 

[Rick Sylvester]

I guess what I don't understand is

if you want a house bank that is optimized for 3 days off the dock why would you build in a capacity (two T-105's) that is guaranteed to be exhausted in a day and a half?Additionally, if you replace your shore charger you'll want to seriously consider the equalization feature. All batteries will sulfate and when (not if) it happens your bank will only be as capable as your weakest (most sulfated) cell. You'll be paying hundreds of dollars to set up an adequate system and it's a false economy to not maintain them properly.

 

[flyhop]

Rick...thanks for the comment

...and that's what I'm asking for. I take it from your comments that draining the batteries down past 50% capacity will do more long-term irreversible damage that even a good charger can't make up for. And I'd be replacing these batteries sooner rather than later.You would recommend 4 golf carts for a total of 450 aH AND a good charger. Do I read that right? Thanks.

 

[Ross]

Have you considered a little

Honda generator? about twenty pounds and a gallon of gas......

 

[JC on Bainbridge]

4 golf cart batt on a 28? Or change usage habit?

That is going to be one heavy boat.I would choose some other alternatives, such as the Honda generator mentioned previously, or solar panel.Or, change your power usage habits. What are you running onboard?For our boat, we hardly use any power during the day when anchored. and when sailing, usually only the depth, speed, and wind. At night, we usually have only 1 or 2 12v light turned on, or a oil lamp instead.

 

[BobW]

It's the stereo that appears to eat the amps

Your log, depth, etc take almost no power.I would suggest that you buy the 2 Gp 27s and the Xantrex, and then see if you can live within that capacity. You can always buy another battery or two.Equalizing is a good thing for lead-acid cells, but you don't HAVE to buy a charger that does it. The Xantrex 10 has a '21 day top-up' feature that provides some of the good stuff of an equalization cycle.If you have the money to spend, you're better off with the Xantrex 20 with the equalization feature.You aren't going to be stressing your batteries all that much. Good deep-cycle batteries are rated for 300 or more complete cycles and you're not going to be doing that.The best thing is that you're not going to go wrong with any of the suggestions here.... kinda makes it hard to decide, eh?Cheers,Bob

 

[flyhop]

Rethinking....hmmmm

I've listed our proposed onboard usage and have now rethought several of them. JC makes some valid points; we've not had this boat long enough to anchor out for 2 nights yet, so don't have an idea on what our real usage would be. The big energy eaters seem to be a stereo (1.25 amps for 12 hours), 2 fans (gets hot in the South.. 0.3 amps for 18 hrs), VHF on receive (1 amp for 12 hours), and guest light in the head (we have kids and they need a little night light... 0.5 amps for 12 hrs). I've got useage expectation down to about 65 aH. At 50% capacity, that's about 130 aH battery per day. So, 2 days/nights with family would be about 250 aH. I guess we don't need to have the VHF on at night, so we should be good on just 2 T-105s, 6V at 225 aH. Any other thoughts?

 

[Tim]

Purchasing a Xantrex

Just a FyI , I just purchased a Xantrex Truecharge 40a , and the best buy I could find was/is sailnet , yes their back and their bending over backwards to win our business , and fast delivery too ......

 

[Rob]

4 T-106, Xantrex 40, Link 10

I just replaced the batteries and charger on my Columbia 8.7 (28'7"). I opted for the golf carts, 4 trojan 106's. As far a weight, this is equal to your current pair of 4D's. The true charge 40 is necessary if your gonna have that much capacity. The smaller chargers will work, but will take much longer and may cause over heating of the batteries. I can't say enough about the link 10. What a marvelous tool. You'll always know the condition of your batteries. Get the 20 if you want to monitor two separate banks.

 

[BobW]

It's all a matter of money management......

Rob's setup is fantastic. Downside is that it looks like it cost about $1200 (less any discounts available).I am curious about the statement "... and may cause over heating of the batteries."My experience is that heating is caused by MORE current, usually in the charge cycle. Even if you do go with 4 golf-carts (~400ah), a 20 amp charger will work fine. Charging time will be longer, but the extra current will only be used in the bulk phase, from 50% to 80% of capacity:200 amps to 320 ampsSo the bigger charger WILL put these 120 amps into the batteries faster (~4 hours vs. ~8), but once the batteries go into acceptance phase, the charge current will drop below 20 amps and both chargers will perform identically.Since your sailing profile is weekends and daysailing, it doesn't look like you'll be in a big hurry to charge your batteries once you return to the dock.As for the Link 20, I wish I had one but for $500 there are more pressing things my boat needs.Cheers,Bobs/v X SAIL R 8

 

[flyhop]

Continued good information...and solars!!

Bob...I think you got it. Since we're weekend boaters, a charger would have plenty of time to get batteries back to full charge (or reasonably close). Frankly, I'm not sure of the benefit to me to get a Battery Monitor. For all who have remarked on the size of the batteries this boat came with, we bought it with the 2 8Ds already installed. I believe 2 POs ago, he was doing some week-long crusing. For our needs, I'm thinking that 2 T-105s and a good charger is a good start. We'll try it, see how it goes, and full in the knowledge that we can add more if we feel the need. It will no doubt serve to teach us (wife & kids too) about conservation. BTW, I had forgotten to mention that there are two very small solar panels attached (in a lousy position). At best, I am betting they may be capable of 5 aH per day. I don't know how old they are, but I imagine I can hook them to an ammeter and find out.Again, thanks for all of the input and keep ideas coming. This is how I learn best.

 

[rsn48]

Same as Rob, except

My new used older "75" Catalina 27 came equipped with one battery. I want some creaturely comforts and I'm not a racer so extra weight doesn't disturb me. I added a switch to go from shore power to inverted power at all the newly added electrical outlets I have installed, three on each side, each side on its own breaker.I have added four golf cart batteries, two batteries equals 215 amps, which gives me about 100 amps to play with, so a total of 200 amps for a two or three day outing. I am pretty certain I will add another two golf cart batteries to give me another 100 amps.What I am doing is eliminating any item that can be replaced with something non-electrical, not depended on gold cart batteries. For example, I recently purchased a kerosene anchor light which will replace the current electrical light. Because I am in the "North West," heat isn't as much a problem so I will be using one or two kerosene lights in the cabin supplemented by back packing candle lights (I don't like the colour cast of LED's; I'll wait until the technology gets better before I start using many LED's to light my inside cabin.).I have installed a fish finder, chart plotter and radar (JRC 1800) and I will only use it sparingly to more "plot" where I am at the moment, then turn it off (unless of course there is fog). I will use a hand held re-chargeable GPS for more of my crossing.Instead I intend to run a toaster in the morning, probably a total of 20 minutes worth; and a microwave - one of those small jobbies with 700 watts.In the winter, I'll be running my electrical heater at 900 watts for about 8 hours while I am sleeping (around 67 amps of running, including inverter usage).For example, if I needed a night light for the kids, I'd install a portable jobbie running off of batteries. I'd buy some rechargeable batteries and recharger and bring twice as many batteries along as I thought I needed on one trip and use these to light the head at night.I also have one of those portable batteries you can use in an emergency. I have already jump started a couple of boats in the marina with it. I also use it to watch movies on my lap top, on the boat.I also have force ten kerosene heater that I use while I'm awake, and then switch over to electrical heat when I go to bed - Nov thru to April.

 

[BobW]

Electrical heater? Off of batteries?

Waitaminit... 900 watt heater = 75 amps @ 12 volts, but you'll have to run it through an invertor at about 80% efficiency, so figure 90 amps X 8 hours = 720 Amp Hours / 2 for half cycle = 360 Amp Hours for a night of sleeping.I'm afraid you might have neglected to do the 10 to 1 conversion for amperage from 12vdc to 120vac.To accomodate your heater, you'll need about 10 golf cart batteries... for a single night...Several suggestions:1. Replace your Kerosene heater with a diesel heater. They are commonplace on cruising boats.2. Get a marine-quality propane heater.3. Get a Heat Pal 5100 Alcohol heater.4. Get a warm sleeping bag. I have one that zips to my wife's matching bag and she's better than ANY heater ;DAfter all, if you're not nestling up to an iceberg, your boat isn't going to get THAT cold, is it?Cheers,Bobs/v X SAIL R 8

 

[Fred Ficarra]

Wouldn't it be great if

his setup could actually work? Alas, no way.