Reply
 
Thread Tools Display Modes
 
Old 02-08-2015, 02:22 PM   #1
Senior Member
 
Bigfish's Avatar
 
City: Salem, Oregon
Country: USA
Vessel Name: My Lady
Vessel Model: Formosa 42 Double Cabin
Join Date: Jan 2013
Posts: 149
New 8D battery or two 6v golf cart batteries??

Unfortunately I think it's time for a new battery for my port engine. The existing one came with the boat when I bought it almost two years ago and it's time. Should I get another 8d or two 6v golf cart batteries. All this bank does is start the port engine and provide power to the windlass.. Any thoughts?? I'm on a super tight budget as I unexpectedly lost my main source of income and I'm living on my social security check alone.. ouch.

Thanks folks
__________________
Advertisement

Bigfish is offline   Reply With Quote
Old 02-08-2015, 03:16 PM   #2
Guru
 
djmarchand's Avatar
 
City: East Greenwich, RI
Country: USA
Vessel Name: Bella
Vessel Model: Mainship Pilot 34
Join Date: Aug 2012
Posts: 2,877
8Ds were meant to start 7 liter DD 671s and bigger and be installed in 18 wheeler tractors mounted low and outside where they can be gotten at with a fork truck, or installed in new boat shops before the superstructure goes on.

Unless you have an engine bigger than 6 liters use a Group 31. I just bought on a Batteries Plus for $150 and it produces 1,000 CCA which is the spec to look at for starting (or MCA which is measure at a higher temperature). It will be less at Costco or Sams Club.

Golf cart batteries are great for house use but not for starting.

David
__________________

djmarchand is offline   Reply With Quote
Old 02-08-2015, 04:56 PM   #3
Guru
 
Edelweiss's Avatar
 
City: PNW
Country: USA
Vessel Model: 1976 Californian Tricabin LRC
Join Date: May 2011
Posts: 1,834
Quote:
Originally Posted by Bigfish View Post
Should I get another 8d or two 6v golf cart batteries. All this bank does is start the port engine and provide power to the windlass..
The 6 volt bats in series is a nice alternative, however they're a few inches taller than the 8D. So if you decide to go that route make sure you have the height clearance.

I didn't have the height clearance, my batteries are located under the engine room floor, so I swapped out my 8D's for 4D LA's and that was a nice compromise, less weight, fits the existing trays. Plus it allowed me room to replace the small generator battery with a 4D which starts the jenny and is a backup to the mains if needed.

Since you're on a budget, look at Pacific Power Batteries. I bought the 4D LA to replace the small automotive generator battery from them a couple of years ago and it's been fine. It was about $200 and they took the smaller old generator bat. for trade.
__________________
Larry B
Careful . . .I Have a Generator and I'm not afraid to use it !
Edelweiss is offline   Reply With Quote
Old 02-08-2015, 06:11 PM   #4
TF Site Team
 
FlyWright's Avatar
 
City: California Delta and SF Bay
Country: Sacramento, CA, USA (boat in Vallejo)
Vessel Name: FlyWright
Vessel Model: Marshall Californian 34 LRC
Join Date: Apr 2008
Posts: 10,175
Bigfish, Check a local industrial and golf cart battery supplier.

Four years ago, I needed to replace my 8D that came with the boat. I found an 8D deep cycle that came out of an industrial application as a standby battery. It was kept in a fully charged state and tested great. I picked it up for $75 and it's only now starting to show one cell with a slightly reduced specific gravity. I thought 4 years for a $75 battery was pretty good.

I just looked into replacing that start 8D deep cycle with a Group 31 start battery. The local battery shop will reduce the price of the 31 with the larger 8D core. I can get a new Group 31 start battery for $75. I bet I can get 5-7 years out of this Group 31 start. The only negative to me is that this Group 31 is a "maintenance free" lead acid. The caps can be removed to add water, but they require a large screwdriver to remove and install the caps. I believe all LA batteries need the electrolyte level checked periodically and there is really no such thing as a true Mx-free LA battery.
__________________
Al

Custom Google Trawler Forum Search
FlyWright is offline   Reply With Quote
Old 02-08-2015, 09:46 PM   #5
Senior Member
 
Datenight's Avatar
 
City: Noank, CT
Country: USA
Vessel Name: Datenight
Join Date: Jan 2008
Posts: 415
Big,

I also replaced an 8D with a group 31 for my Perkins 6-354. Started first time every time.

Rob
__________________
North Pacific 39
Datenight is offline   Reply With Quote
Old 02-08-2015, 09:59 PM   #6
Guru
 
SCOTTEDAVIS's Avatar
 
City: Vero Beach, FL.
Country: US
Vessel Name: FIREFLY
Vessel Model: Pilgrim 40
Join Date: Nov 2012
Posts: 913
Quote:
Originally Posted by djmarchand View Post
8Ds were meant to start 7 liter DD 671s and bigger and be installed in 18 wheeler tractors mounted low and outside where they can be gotten at with a fork truck, or installed in new boat shops before the superstructure goes on.

Unless you have an engine bigger than 6 liters use a Group 31. I just bought on a Batteries Plus for $150 and it produces 1,000 CCA which is the spec to look at for starting (or MCA which is measure at a higher temperature). It will be less at Costco or Sams Club.

Golf cart batteries are great for house use but not for starting.

David

This ^^^^
SCOTTEDAVIS is offline   Reply With Quote
Old 02-08-2015, 10:46 PM   #7
Guru
 
dhmeissner's Avatar
 
City: Seattle
Country: North America
Vessel Name: The Promise
Vessel Model: Roughwater 35
Join Date: Sep 2012
Posts: 1,325
I'm doing this now, except I'm replacing 2 4d's with 4 6V GC's. My son lifted the 4d' out for me.
__________________
Dave & Suzie - Roughwater 35
http://thepromiserwb1029.org/2012/09...the-promise-2/
dhmeissner is offline   Reply With Quote
Old 02-08-2015, 11:23 PM   #8
Guru
 
City: Venice Louisiana
Country: United States
Join Date: Dec 2013
Posts: 1,097
GC batts are not designed to start an engine. They will do it but for your application a group 31 would be better.
kulas44 is offline   Reply With Quote
Old 02-09-2015, 12:15 AM   #9
Guru
 
Daddyo's Avatar


 
City: Cruising East Coast US
Country: USA
Vessel Name: Grace
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 2,441
I use a group 27 on one of my Lehman 120s. Starts every time with no issue whatsoever. The cart batteries are for the house.
__________________
Mark Bowerman
Brokerage owner and cruiser
Esse Quam Videri
http://graceyachting.com/
Daddyo is offline   Reply With Quote
Old 02-09-2015, 12:20 AM   #10
Senior Member
 
BryanF's Avatar


 
City: Astoria
Country: USA
Vessel Name: Florence A
Vessel Model: 47' Sutton
Join Date: Oct 2014
Posts: 173
You might check out your local semi truck dealers. I used to buy rebuilt batteries Group 31 for about 40 bucks (last year) they tested fine. Worked well the times I used them. And in a couple years if you have to change it out again maybe $$ situation will have changed.
BryanF is offline   Reply With Quote
Old 02-09-2015, 01:16 AM   #11
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Some years ago we replaced the boat's two 8Ds with six 6vdc golf cart batteries. Four of the golf cart batteries replaced one of the 8Ds as our house bank, and gave us roughly double the amount of amp hours. The other two golf cart batteries replaced the other 8D and acts as our start bank, although all six batteries are connected together when a start button is pushed.

Three golf cart batteries fit in a single 8D battery box, so no changes were required to our battery storage or the boat's wiring. The only new wiring required were the short jumpers that connect the golf cart batteries together.

This has been one of the best and most useful changes we've made to our otherwise stock boat.
Marin is offline   Reply With Quote
Old 02-09-2015, 04:02 AM   #12
Veteran Member
 
City: Wherever the boat is
Country: Europe
Vessel Model: 48 foot sailing Yacht
Join Date: Jul 2014
Posts: 92
You have two conflicting requirements. Engine starting and running the windlass.

Have a look at this link. It is written by a very smart guy:
What Is A "Deep Cycle" Battery? Photo Gallery by Compass Marine How To at pbase.com


The windlass current is supplemented by the alternator, but there will be occasions when some cycle capacity is needed. The situation of the anchor failing to set first time. Retrieval and resetting will use some battery capacity. If the engine is then shut down the battery will be sitting at considerably less than 100% SOC.

As a general rule starting batteries have a very poor life if not kept close to 100% SOC. They are designed to start the engine (which uses very few AHrs) and then be rapidly charged back to 100%. Deep cycle batteries are not constructed to deliver the high currents for engine starting, but they still manage this task reasonably well.

There is no perfect answer, but my money would be on the 6v deep cycle batteries having a much better life in your application.
Noelex is offline   Reply With Quote
Old 02-09-2015, 07:46 AM   #13
Guru
 
ranger42c's Avatar
 
City: Maryland
Country: USA
Vessel Model: 42' Sportfish
Join Date: Aug 2013
Posts: 3,157
Quote:
Originally Posted by Bigfish View Post
Should I get another 8d or two 6v golf cart batteries. All this bank does is start the port engine and provide power to the windlass.. Any thoughts??


You can likely find your engine's minimum CCA/MCA requirements in your documentation somewhere, and your starter motor may also be labeled with some minimum MCA/CCA info.

I'd suspect a single Group 31 may actually meet your minimum needs, would be less expensive than either one 8D or 2x6Vs, certainly lighter than an 8D, might free up some usable space...

Unless you want to add a bit of safety net for anchoring, in which case a pair of G31s could still be a useful solution.

-Chris
__________________
South River, Chesapeake Bay
ranger42c is offline   Reply With Quote
Old 02-09-2015, 08:00 AM   #14
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,877
Chris is correct with doing the research and I will add follow up with the math.....guesstimate or better measure the average amps used by the windlass and the average time it takes to recover your anchor.

With the engine high idling when pulling the anchor.....most of the time you could probably subtract half the windlaass amps so the drain isn't as drastic.

My "guess" is a group 31 will suffice for your service, I replaced an 8D with one for my 120 Lehman.
psneeld is offline   Reply With Quote
Old 02-09-2015, 08:22 AM   #15
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,518
Starting batts are designed for starting.

They will work as a windlass fill in , esp if mostly used in the AM when some engine operation will follow.

I recently purchased 2 ser 31 to start my RV , price $125 at the DD dealer.

The last 8D cost $150 so is cheaper than 2 ser 31s.

The last price for a Trojan 105 (6V seep cycle) was $88 cash.

All pricing expects a trade in batt.

I would choose a good 8D start batt for your service , and a couple of 6 packs for the dock help on lifting.

The key to any battery is how much lead it has inside.

Find the weights and try to get the proper batt for your service , starting, at the lowest per pound cost.

Never ever use a start batt for deep cycle house service , although many times a set of deep cycles will do fine for warm weather starting.
FF is offline   Reply With Quote
Old 02-09-2015, 09:13 AM   #16
Guru
 
City: gulf coast
Country: pinellas
Join Date: Jun 2014
Posts: 2,198
You don't say what the other battery does but if you are worried about just using a gp31 can you switch the batteries??


Do you have big engines with big CCA requirements?




I would start with the simplest and cheapest solution, a GP 31 with sufficient CCA, keeping in mind that the engine will be sharing the windlass load. If you are not happy with that then add a second in parallel.
bayview is offline   Reply With Quote
Old 02-09-2015, 04:36 PM   #17
Guru
 
Edelweiss's Avatar
 
City: PNW
Country: USA
Vessel Model: 1976 Californian Tricabin LRC
Join Date: May 2011
Posts: 1,834
Quote:
Originally Posted by FF View Post
Starting batts are designed for starting. They will work as a windlass fill in , esp if mostly used in the AM when some engine operation will follow.

I recently purchased 2 ser 31 to start my RV , price $125 at the DD dealer. The last 8D cost $150 so is cheaper than 2 ser 31s.
I would choose a good 8D start batt for your service , and a couple of 6 packs for the dock help on lifting..
I agree. The windless on your starting battery is OK, if your main engine alternator is running when the windless is in use. You don't want the battery to be left sitting half full overnight. Really hard on start batteries and will shorten their life. I would worry about using a start battery that only meets minimum starting requirements. Get air in your injector lines that you can't bleed out, other than by rolling the engine over and you will want that reserve battery capacity. If you're going to go minimum, then you at least have a switch to bring your other batteries into the starting circuit.
__________________
Larry B
Careful . . .I Have a Generator and I'm not afraid to use it !
Edelweiss is offline   Reply With Quote
Old 02-09-2015, 05:14 PM   #18
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 5,729
Quote:
Originally Posted by Edelweiss View Post
... I would worry about using a start battery that only meets minimum starting requirements. Get air in your injector lines that you can't bleed out, other than by rolling the engine over and you will want that reserve battery capacity. If you're going to go minimum, then you at least have a switch to bring your other batteries into the starting circuit.
After we bought Hobo and were re-doing the battery configuration, I asked Norm Dibble, the PNW Ford Lehman guy, now retired, what we should do for the FL SP135. He said that a 4D is suggested but since we were in AK, he recommended an 8D or equivalent due to the routine colder starting temperatures. Just someone else's opinion but it made sense.
Larry M is offline   Reply With Quote
Old 02-09-2015, 05:21 PM   #19
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,877
Quote:
Originally Posted by Larry M View Post
After we bought Hobo and were re-doing the battery configuration, I asked Norm Dibble, the PNW Ford Lehman guy, now retired, what we should do for the FL SP135. He said that a 4D is suggested but since we were in AK, he recommended an 8D or equivalent due to the routine colder starting temperatures. Just someone else's opinion but it made sense.
Cracks me up because when I called American Diesel what battery for my 120....they gave me some designation that could have been a good Group 24 Battery.

I checked the cranking amps required for the 120 starter motor....Around 500 was good enough so I went Group 31 (well something near it) that had 900+ CCA.
psneeld is offline   Reply With Quote
Old 02-09-2015, 07:26 PM   #20
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,564
Battery CCAs seem to have gradually increased for the same battery size. A size that would have been inadequate for starting may not be now. Replacing batteries, I often notice CCAs have risen.
__________________

__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 06:14 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012