Battery selection advise needed please

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flyhop

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Aug 8, 2005
150
Oday 28 Guntersville AL
I have an Oday 28 which we have acquired only this past July. We've had some fun sailing, but there's work to be done to it. The batteries are toast (2 8Ds) and are awaiting to be traded-in. We need new ones, and I need your input. We sail in a freshwater lake in northern AL and go out for daysails in the winter. Our electrical use is limited to a stereo, knotmeter, speedometer for up to 8 hours a day, and navigation lights when we occassionally sail after dark, and of course for starting a Yamaha 9.9 hp outboard. Our intent is to spend summer weekends on the boat (3 days/2 nights). A quick calculation of our possible maximum power usage over a late spring day has us at about 100 aH over a 24 hour period. After a daysail in the winter or on Sunday evening in the summer (after 3 days/2 nights out), the boat is plugged into shore-power, and the SeaRanger 1500 charger is turned on. Being that the charger (and the boat) were used, I can only go by what the user's manual states, and it says "they switch themselves into the charge mode when your batteries...drop below 100%; and they turn themselves to the stand-by mode when the batteries...are restored to a full charge condition." I will assume this to mean some kind of a light or float charge. If I run the math according to Don Casey's book "Sailboat Electrics Simplified" and a brief reference to Nigel Caulder's book, I should never drain my batteries below 50%, so a 200 aH house bank system would seem appropriate. And, if I have two batteries (one house; one starting), they should be the same age/size/etc. My head-scratching is this. Walmart has an Everlast 12-V 115 aH (Group 29) deep-cycle battery offered for around $65; 2 of these (one for house and one for starting) would run me about $130. Local battery guys are showing a Trojan T-105 (6V & 225 aH) for $100, so 2 of them would be about $200 for 225 aH at 12 V; two sets of these would be $400!! Is this overkill for the use I've described above!?! I am totally befuddled (that's my college word for the day). A massive expense to get the best solution with possible overkill or a small expense on something that I'm going to be intermitently running hard in the warmer months. I really don't want the expense of gel/AGM, and I want to be able to spend the whole weekend on the boat without having to recharge. Help me think this through!! Thanks.
 
Dec 2, 2003
4,245
- - Seabeck WA
Great Post!

Thank you for all the info. Your new boat had TWO 8ds! One seems to be twice as much as you need from your description. I would go with the two golfs and call it good. Use it as a start and house. Those will never have trouble starting your outboard. Even when the lights no longer shine. So your names flyhop huh? You know, real names are cool here. This isn't AOL. :) Oh, and $100 bucks each seems high. Mid $70s sound right.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I expect that the little

outboard engine has a pull rope so even if you kill the batteries you cay still start the engine. Most entertainment systems don't draw very much and if you are anchored, you won't need knot or depth,or nav.lights. Probably the battery recommendations are perfectly good. Spend 25 or 30 dollars for a digital volt meter and make provision for wiring a convenient place to check the batteries often.
 
Jan 2, 2005
779
Hunter 35.5 Legend Lake Travis-Austin,TX
flyhop...

shop for your Trojans at a golf cart place or look at Sam's. Fred's right, $70-75 each is max. I just bought 2 myself. I use a group 29 for "start" and the 6vlt. pair for house on my 35.5.
 

flyhop

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Aug 8, 2005
150
Oday 28 Guntersville AL
Honeyman....

Question: Do you have both the 6V-pair and the Group 29 on the same charger?
 

flyhop

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Aug 8, 2005
150
Oday 28 Guntersville AL
Fred....

It's not that I am incognito, but I belong to many bulletin boards so I sometimes forget that I have a real name. The name is Trey, and the boat is Good News.
 
M

Mick

Battery Selection

Flyhop; I have 2 banks (4 batteries) of the Trojan 6v's for house, and a group 27 for starting. They are all charged by the same charger because they are all lead acid, and of the same age. They are separate unless I need the house to help the starter. My charger, however, has 3 outputs, so they are charged as 3 batteries. We do longer cruises here, and spend more days on the hook without charging, and have refridgeration running.
 

flyhop

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Aug 8, 2005
150
Oday 28 Guntersville AL
More input pls...and charger testing?

Anymore input would be appreciated. Further, is there any way to test to see if this battery charger is still performing as advertised? Finally, where to find Trojan T-105s for under $80? Dealers I found on the Trojan website are quoting $100+.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
You will need a digital

volt meter and an accurate amp meter. The amp meter goes inline with the battery charger to measure the input current to the battery the volt meter goes across the battery terminals to measure the battery voltage. With the charger "ON" but not connected to the battery you should read 14.2 volts. When the charger is commected to the battery and the battery needs chargeing the voltage will be a bit lower and the amp meter should show the rated charging current(say 10 amps) as the voltage increases the output current should decrease until you reach about 12.6 volts and almost zero current on the amp meter. All of this presumes that the battery is good. A bad battery just won't "take a charge" and the voltage may come up but once the charger is removed the voltage will steadily drop.
 
C

Chuck

Here's what I did

I owned an O'Day28 for many years and many upgrades and I had (2) group 27 and (1) group 24 batteries. I had an inboard diesel and the Group 24 was for starting and fit behind the fuel tank (factory install). One group 27 (100AH) was beside the fuel tank (factory install) and was paralleled with the other group 27 in the cockpit locker. This gave me a 200AH house battery and ran my TV, DVD and blender for the weekend and some navigational stuff too. A group 27 lead/acid battery can't be more than $65-75 bucks. You need a good, voltage regulated, battery charger though, not an automotive type. One other little thing, I installed a Garmin fish finder for a depth sounder and it displayed the battery voltage too. This way I always knew the condition of my batteries. Best of luck, Chuck
 
Aug 9, 2005
772
Hunter 28.5 Palm Coast, FL
I'd go two type 29 batteries and a selector switch

Plus a Guest battery monitor. Keep life simple.
 

flyhop

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Aug 8, 2005
150
Oday 28 Guntersville AL
Landsend...question please

Could you give a brief description of how many aH you are pulling from your duo-Group29s, and how long inbetween charges are you running them? Thanks.
 
R

Rick Sylvester

How good do you want your anchor to hold?

I know, I know. You're thinking, huh? Well, my philosophy on battery capacity is sorta like anchor holding. I've never heard anybody complain that their anchor holds too good and similarly, I've never heard complaints that someone had too much battery capacity (assuming weight and space demands could be met.) You've gotten some good advice here so I thought I'd chime in with my two cents. First of all, TWO 8 D's? Dang! I think a set of 4 golf carts for a house bank would be ideal. A seperate group 24 or 27 would be fine for a starter battery. The house and starter banks do NOT need to be the same size (if I read your post correctly) but they DO need to be the same type (re: lead-acid, gel, AGM) to match the charger mode. The reason I suggest more capacity than the standard amp/hr formula for your estimated usage dictates is because with an outboard rather than a diesel I assume you don't have a high rate (50-100 amps) means of recharging while at anchor or underway. This would mean that while a 200 amp/hr house bank would be adequate for 95% of your weekending you wouldn't have a lot of options if you wanted to stay out longer or had a problem. I would also recommend that you monitor your batteries periodically by checking the specific gravity of the battery acid using an inexpensive automotive hygrometer. It is by far the most accurate means determining individual cell health and charge state. A voltmeter is good for a quick 'snapshot' of charge state of the entire bank and a monitor such as the Link 10 is even more comprehensive though more expensive (of course.) Unfortunately, neither a voltmeter nor a monitor will tell you which cell in a battery is the culprit should it go bad. If you're not absolutely certain about the charging regimen of your shore charger I would dump it. A top quality multi-mode charger is essential in preserving the health of your sizeable investment in batteries. As always, these are my opinions only. Hope this helps.
 
P

Peter

Get all deep cycles-no starting batt

Your usage siuation is similar to mine. I've got a Cat27, 15HP electric start O/B, used for weekends up to 3 days between shorepower hookups. I've got 2 deep-cycle 24s (about 80AH each; wish they were more like 100). The deepcycle batts start the OB easily; there's nowhere near the draw from an O/B electric starter as there is from a diesel or A4 starter. And there's no need for a dedicated starting battery because you've got the backup rope start. And starting batts are designed to be immediately topped off by the engine's alternator after they start the motor, but you can't depend on the O/B to put out much to charge the batts. Don't sacrifice the deep-cycle feature, which you definitely need, for the high-draw starting feature, which you don't.
 
Jun 3, 2004
109
Oday 40 New Bern
electrical power on an O28

My O28 has the saildrive with alternator, but I added two 11 watt solar panels, one per size 27 battery, which are WM deep cycle. More than adequate for instrumentation, stereo, lights, anchor lights, etc. Only need for shore power is the dorm refrigerator and recharging the hand-held VHF. Outboard on a 28-I'm guessing it must have had a saildrive once upon a time. Bill Coxe, O28/40, New London, CT
 

BobW

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Jul 21, 2005
456
Hunter 31 San Pedro, Ca
Dump the charger!

It's so old I couldn't even find anything meaningful about it on Google. Your new batteries will last longer if you buy a modern 3-stage marine charger. If you will only ever day-sail, never anchor out, and your o/b has a backup pull starter, you don't need to worry about most of the capacity calculations. Most of those are based on different requirements, like: I'm halfway to the Marquesas Islands and I can't afford to have no electrical power, and I use my batteries all day, every day so it is imperative that I get the absolute maximum life out of them. My take on your worst-case scenario is that you haul on your pull-starter and motor home with a flashlight as an emergency nav light. And when you get home, you will plug into shore power and fully charge your batteries before you venture out. My recommendation: Sears Group 27 Marine Deep Discharge (2) $65 ea (but you should get about $15 for each 8D) Xantrex TrueCharge 10 amp charger $150 (does everything the 20 amp model does except equalize, costs half as much) If your boat is wired for 2 banks (with the orange switch) use it. If not, don't go to the expense of re-wiring, just parallel them. If you REALLY want peace of mind, go get one of those backup power/jump starter units. I bought one for $65 from West Marine that has its own waterproof case and 12v plug-in. I've never used it, but it's there if I ever need it :) BTW, I have an 8D in my boat ('87 Hunter 31) that's about 8 years old. I know it's about to expire and I'm not looking forward to getting it out of the cabin. Major exercise, for sure! Cheers, Bob s/v X SAIL R 8 1 8D + 2 Gp 27 + Xantrex 20A Truecharge
 

Jim C

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Jun 18, 2004
63
Catalina 30 Tulsa, OK
One note about deep cycles

You mentioned looking at deep cycle batteries at Walmart. One thing worth mentioning is that all batteries are not created equal. If you opt for the lower initial cost you'll probably be replacing the batteries more frequently which would wind up costing more in the long run. Also, as posted earlier you really have to check the water level frequently. Down here where it gets somewhat hot in the summer time can really cook a battery. Jim
 
Jan 2, 2005
779
Hunter 35.5 Legend Lake Travis-Austin,TX
flyhop...

yes, group 29 start and 2 6volt Trojans as house on the same Xantrex TrueCharger 20amp because they are all lead/acid "flooded" batteries. What you really can't mix are flood, gels, or agms in any combination. If you parallel batteries, they should be same type as well...deep cycle to deep cycle or dual purpose to dual purpose. In my case I went with the 2 Trojans for house because I will need to add 2 more when using the boat extended time away from shore power since I have 12vlt. refer. Just not using the boat that way right now. In your case I'd do what I had for my 28.5 Hunter... group 27 start and 2 group 27 deep cycle in parallel, charged by a Xantrex TrueCharger and diligent attention to your 1-2-all-off switch. As far as discount Trojans, check Yellow Pages for Golf Cart dealers or repair shops. Go by the local golf course. May need to drive up to Huntsville.
 
T

Tim

Kinda battery related ?

I sail a Seafarer 30 W/yanmar 2Gm engine , Im in the process of replacing my battery/charger setup this winter , what I have done so far is in the fall I purchased a new Optima red starting battery , and recently purchased a Xantrex truecharge 40a 3 bank charger , I assume I must stay with AGM batteries for the house bank being I already have a red top starting batt ....... Now Im reading in the Ample Power site that it is imperative to fuse the reds directly out of the battery before it connects to anything , for that I intend to use Blue Sea Anl fuse blocks and fuses , is there any need to fuse the charging leads if the charger is connected thru a breaker ? Im also gathering all I can to remove and re wire the 120v as someone in the past used house wiring and metal boxes for the shore power , btw with no fusing to the receptacles , all there is/was is 2 breakers , 1 for the charger, and 1 for the water heater , both home depot variety . Im now measuring up and building power panels for both Ac and Dc, both with Paneltronics breakers for each and all , I do have a question tho on the board to mount the breakers and pilot lights , I understand panel mfgrs use metal , but I want a board thats non metallic , I keep being led back to formica due to its ease of workability and availability , so ......
 
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