Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-25-2017, 09:25 PM   #1
Veteran Member
 
Vulcanbike's Avatar
 
City: California, PA
Country: USA
Vessel Name: Jaw Breaker II
Vessel Model: Mainship 390
Join Date: Aug 2013
Posts: 33
New 8D batteries

I'm thinking my 2 8D batteries on my '01 MS 390 are ready for replacement. Cummins 6bta 330 HP. Any suggestions on good quality replacements? Brand/model/price?
__________________
Advertisement

Vulcanbike is offline   Reply With Quote
Old 03-25-2017, 10:29 PM   #2
Guru
 
HopCar's Avatar


 
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 3,982
You will get lot's of answers to your question but I'm going to suggest you use a couple of Group 31 batteries instead of one 8D. At some point those damn things have to be moved and they will destroy your back.

I think Johnson Controls AGM batteries are the best you can buy. Notice I said "you can buy". I can't afford them.
__________________

__________________
Parks Masterson
www.hopkins-carter.com
HopCar is offline   Reply With Quote
Old 03-26-2017, 05:11 AM   #3
Guru
 
motion30's Avatar
 
Join Date: Jan 2010
Posts: 825
Three 6volt golf cart batteries fit in the space of one 8d and are true deep cycle
motion30 is offline   Reply With Quote
Old 03-26-2017, 07:14 AM   #4
Guru
 
djmarchand's Avatar
 
City: Litchfield, Ct/Punta Gorda, Fl
Country: USA
Vessel Model: Atlas Pompano 23- outboard
Join Date: Aug 2012
Posts: 3,849
Let me combine the two foregoing answers. Your boat probably uses one 8D for starting and the other for house loads, but probably on a one,two,all switch so that either can be used for either service.

So select one for starting and replace it with a Group 31. Then replace the other with two 6V golf cart batteries wired in series and designate that for house loads.

You will then have the best battery for the job.

David
djmarchand is offline   Reply With Quote
Old 03-26-2017, 08:04 AM   #5
Guru
 
ranger42c's Avatar
 
City: Maryland
Country: USA
Vessel Model: 42' Sportfish
Join Date: Aug 2013
Posts: 3,830
Quote:
Originally Posted by Vulcanbike View Post
I'm thinking my 2 8D batteries on my '01 MS 390 are ready for replacement.

Maybe comment on how your battery bank are set up? Twin engine boat? Maybe a common Luhrs Group configuration where each engine starting battery also runs approx half the house and one of the bridge loads (electrics on one, electronics on the other)?

If so...

And if you don't want to reconfigure to have separate start and house battery banks...

And if you have some extra space in the battery areas...

3x 12V Group 31 dual purpose batteries will give you more capacity than one 8D (~300 Ah vs. ~245 Ah)... and each individual G31 will weigh less so installation may be easier. These would fit in a space slightly larger than a single 8D.

4x 6V deep cycle golf cart batteries in series/parallel will likely start those engines (check Cummins specs), will give you even more capacity (~440 Ah), each weighs less than an 8D, and these will fit in a space just slightly larger than 3x G31s.

There are taller version of the G31s and the GCs, even more capacity if you have extra height to play with.

And if you have even more horizontal space, 4x G31s or 6x GCs could be even better.

Note increasing battery capacity may in turn want you to increase your charging capacity, depending on how you use the boat, access to shorepower after cycling, etc.

Or... If Dave's right and you have one 8D for start and one for house... what he said! Except 4x GCs instead of two.

-Chris
__________________
South River, Chesapeake Bay
ranger42c is offline   Reply With Quote
Old 03-26-2017, 08:14 AM   #6
Senior Member
 
Rossland's Avatar
 
City: Buffalo
Country: US
Vessel Name: Almost Perfect
Vessel Model: Kadey-Krogen 48
Join Date: Dec 2015
Posts: 161
You have good advise here. Look at the requirements in your engine operators manual. Your engine probably requires a starting battery of 1000MCA rating, and some, but not all group 31 batteries will supply that. Then fill the rest of the available space with house batteries, either group 31 deep cycle, or 6V golf cart in pairs.

Note that there is a big difference between a start battery and a deep cycle house battery.

You will probably want to go with AGM batteries.

A good place to buy batteries is Sam's Club.
Rossland is offline   Reply With Quote
Old 03-26-2017, 10:02 AM   #7
Guru
 
foggysail's Avatar
 
City: Ashland, MA
Country: United States
Vessel Model: 1990 Silverton 40 aftcabin
Join Date: Jul 2016
Posts: 910
8Ds are too heavy for me at my age. When mine failed 6 years ago, I replaced them with a combination of East Penn 6v golf carts. These provide 2 banks of 12v @ 230 amp hours each. Oh-- purchased them from Sam's for about $85 each back then.
foggysail is offline   Reply With Quote
Old 03-26-2017, 10:24 AM   #8
Guru
 
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 7,151
I'm the outlier here. My 8 Ds work quite fine and provide good ballast. This is a trawler forum where ballast is not a bad word.

I use three 8Ds, 2 for engine starts and 1 for genset. and am quite happy with them. There is an already setup space for each and every five years the local yard spends about an hour lifting the main engine starts in and out. The first genset went 8 years with no problem.

Get some prices, question the crowd advice and make your own decision. 8Ds can be very cheap. Sticking with what works has no downside unless you insist on being the strong back rather than using a young buck.
sunchaser is offline   Reply With Quote
Old 03-26-2017, 10:26 AM   #9
Senior Member
 
garrobito's Avatar
 
City: Oakland
Country: US
Vessel Name: Arcangel
Vessel Model: Buewater 40
Join Date: Oct 2016
Posts: 150
If you prefer, replace for 4D batteries.. way less expensive and easy to move around the boat. Group 31 is another good option
garrobito is offline   Reply With Quote
Old 03-26-2017, 10:45 AM   #10
Guru
 
foggysail's Avatar
 
City: Ashland, MA
Country: United States
Vessel Model: 1990 Silverton 40 aftcabin
Join Date: Jul 2016
Posts: 910
Quote:
Originally Posted by sunchaser View Post
I'm the outlier here. My 8 Ds work quite fine and provide good ballast. This is a trawler forum where ballast is not a bad word.

I use three 8Ds, 2 for engine starts and 1 for genset. and am quite happy with them. There is an already setup space for each and every five years the local yard spends about an hour lifting the main engine starts in and out. The first genset went 8 years with no problem.

Get some prices, question the crowd advice and make your own decision. 8Ds can be very cheap. Sticking with what works has no downside unless you insist on being the strong back rather than using a young buck.


My golf carts have the equivalent weight of the replaced 8Ds because it requires 2 of them to provide the service of 1 8D.
foggysail is offline   Reply With Quote
Old 03-26-2017, 10:47 AM   #11
Guru
 
djmarchand's Avatar
 
City: Litchfield, Ct/Punta Gorda, Fl
Country: USA
Vessel Model: Atlas Pompano 23- outboard
Join Date: Aug 2012
Posts: 3,849
Here are the weights of the batteries discussed so far:

Group 31 57 lbs
4D 100 lbs
8D 127 lbs

GC 62 lbs

Any of the first three will start a Cummins 6BTA. Pick your poison.

And as foggysail notes above, two GC batteries weigh the same as one 8D and for house service are true deep cycle batteries, unlike most 8Ds.
David
djmarchand is offline   Reply With Quote
Old 03-26-2017, 10:55 AM   #12
Guru
 
HopCar's Avatar


 
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 3,982
My boat was set up with 2 x 4D from the builder. One was the start and one was the house. I added one group 31 to be the start and combined the 4Ds into a house bank. My engine is a Cummins 6BT5.6.
__________________
Parks Masterson
www.hopkins-carter.com
HopCar is offline   Reply With Quote
Old 03-26-2017, 11:12 AM   #13
Senior Member
 
The Other Gary's Avatar
 
City: Toronto
Country: Canada
Vessel Name: Adios Dinero
Vessel Model: Bayliner 3988 2 x 330 Cummins
Join Date: Sep 2016
Posts: 312
My 3988 came with 3 8D batteries, 1ea. for starting the Cummins and 1 for house. I have since changed to group 31 for starting and GC for house but had problems with the Group 31 overcharging and using too much water vs. the GC. I now have 2 GC for each starting bank and 6 GC for house resulting in no more problems with charging using combiners. And I can lift them.
The Other Gary is offline   Reply With Quote
Old 03-26-2017, 12:19 PM   #14
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: 11,370
My boat started out its life with me with 3 8Ds - 2 house, and 1 for start. I replaced them all in Phase 1 of my electrical mod project and stayed with 1 8D to start both engines and 6 GCs in the other 2 8D boxes for the house. My house bank grew by almost 50% in weight and AH capacity. 7 years later in Phase 2, I replaced the 8D start with a Group 31 start...one battery to start both engines. I figured I'd give it a try and could always add another G31 if needed. It works well with my Perkins 4.236s. Since that start battery is charged by the port alternator, I always start the port engine first.

Quote:
Originally Posted by djmarchand View Post
Here are the weights of the batteries discussed so far:

Group 31 57 lbs
4D 100 lbs
8D 127 lbs

GC 62 lbs

Any of the first three will start a Cummins 6BTA. Pick your poison.

And as foggysail notes above, two GC batteries weigh the same as one 8D and for house service are true deep cycle batteries, unlike most 8Ds.
David
Good info here, David. Sunchaser, if you replace each 8D with 3 GCs, you'd increase your ballast and your AH capacity by almost 50%!

Quote:
Originally Posted by The Other Gary View Post
My 3988 came with 3 8D batteries, 1ea. for starting the Cummins and 1 for house. I have since changed to group 31 for starting and GC for house but had problems with the Group 31 overcharging and using too much water vs. the GC. I now have 2 GC for each starting bank and 6 GC for house resulting in no more problems with charging using combiners. And I can lift them.
Good point! I watch for this overcharging of the G31 through my combiner, too. The start G31 is always full when I return to the slip. If I return to the slip and the house is not at or near float (<5A), I leave the combiner switched off until I return. I like this idea of using 2 GCs for the start bank and might consider this as an option for the next start battery change.
FlyWright is offline   Reply With Quote
Old 03-26-2017, 12:47 PM   #15
Guru
 
foggysail's Avatar
 
City: Ashland, MA
Country: United States
Vessel Model: 1990 Silverton 40 aftcabin
Join Date: Jul 2016
Posts: 910
Quote:
Originally Posted by FlyWright View Post


Good info here, David. Sunchaser, if you replace each 8D with 3 GCs, you'd increase your ballast and your AH capacity by almost 50%!

:


NO! It only requires two GCs for one 8D. Remember, you have to connect the GCs in series 6v + 6v = 12v. Of course you could connect two GCs in parallel and series those two with another pair in parallel to have 12v at 460 amp hours.
foggysail is offline   Reply With Quote
Old 03-26-2017, 01:09 PM   #16
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: 11,370
Quote:
Originally Posted by foggysail View Post
NO! It only requires two GCs for one 8D. Remember, you have to connect the GCs in series 6v + 6v = 12v. Of course you could connect two GCs in parallel and series those two with another pair in parallel to have 12v at 460 amp hours.
I probably didn't explain that well. Take 2 8Ds out of the boxes and replace each 8D with 3 GCs. Now connect them in series-parallel and you've got 50% more weight and AH capacity. I did this with my 3 pairs of GCs and went from ~440 to 660AH.
FlyWright is offline   Reply With Quote
Old 03-26-2017, 01:21 PM   #17
Guru
 
foggysail's Avatar
 
City: Ashland, MA
Country: United States
Vessel Model: 1990 Silverton 40 aftcabin
Join Date: Jul 2016
Posts: 910
Quote:
Originally Posted by FlyWright View Post
I probably didn't explain that well. Take 2 8Ds out of the boxes and replace each 8D with 3 GCs. Now connect them in series-parallel and you've got 50% more weight and AH capacity. I did this with my 3 pairs of GCs and went from ~440 to 660AH.

YOu say you replaced one each 8D 12volt battery with three golf carts. Please explain how you wired your three golf carts to make this replacement. I am still confused
foggysail is offline   Reply With Quote
Old 03-26-2017, 01:24 PM   #18
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: 11,370
I wired 6 GC into a 660 AH bank via series-parallel. These 6 batteries fit in the boxes formerly used by 2 8Ds. This makes up my house bank. The third 8D box that formerly held an 8D start battery now only holds a single G31 start battery.
FlyWright is offline   Reply With Quote
Old 03-26-2017, 01:44 PM   #19
Guru
 
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 7,151
Quote:
Originally Posted by FlyWright View Post
I probably didn't explain that well. Take 2 8Ds out of the boxes and replace each 8D with 3 GCs. Now connect them in series-parallel and you've got 50% more weight and AH capacity. I did this with my 3 pairs of GCs and went from ~440 to 660AH.
I do not use 8Ds for house , so no advantage. Also, the cost, associated risk and hassle of redoing something that works is well down my list as compared to other boat projects that take precedence. The beauty of battery discussions is there are so many different ways to do it.
sunchaser is offline   Reply With Quote
Old 03-26-2017, 01:45 PM   #20
Guru
 
foggysail's Avatar
 
City: Ashland, MA
Country: United States
Vessel Model: 1990 Silverton 40 aftcabin
Join Date: Jul 2016
Posts: 910
Quote:
Originally Posted by FlyWright View Post
I wired 6 GC into a 660 AH bank via series-parallel. These 6 batteries fit in the boxes formerly used by 2 8Ds. This makes up my house bank. The third 8D box that formerly held an 8D start battery now only holds a single G31 start battery.

I thought I understood and started to reply. I understand 6 GCs and two 8Ds.

If you truly did as stated, I am still lost. 2 GCs are needed for 1 8D, 4 GCs are needed for 2 8D replacement

Yes, You can wire two GCs in parallel and series those two with another GC for 12v BUT YOU ONLY HAVE 230 AMP HOURS CAPACITY/BANK. If you have this wired as I just described, you are wasting 2 GC batteries. They are doing no good what so ever.

Now of course if you have 3 banks of GCs, that is just fine!!!

Also you could have just one big bank where there are three pairs of GCs connected in parallel for 690 amp hours

Whatever you have, if you're happy with it ..........
__________________

foggysail is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 02:47 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012