Battery Replacement Questions...

MitchM

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Jan 20, 2005
1,031
Nauticat 321 pilothouse 32 Erie PA
i second all the motions to g et rid of the 4Ds unless you a re going off the grid for very long periods. our boat came with 3 4Ds and we replaced them with 3 Lifeline 31XTs at 135 Ah each. the 31's are much easier to move and a lot cheaper. then 4 Ds. we may eventually go the 6 v golf cart oute to replace the 31 XT's which a after 4 years were shot...
 
Aug 23, 2014
164
Catalina 310 Guntersville, Alabama
Yeah I'm not looking forward to wrestling those 4Ds out of the boat. May get my mother in law to move them.
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
One thing to watch for if you wire your batteries in parallel: Don't wire the hot and ground to the same battery, which is usually physically easier. Connect the hot to one and the ground to the other. That helps balance the current flow through them.

I know Stu and MaineSail both mention that but it bears repeating.
 
Aug 23, 2014
164
Catalina 310 Guntersville, Alabama
One thing to watch for if you wire your batteries in parallel: Don't wire the hot and ground to the same battery, which is usually physically easier. Connect the hot to one and the ground to the other. That helps balance the current flow through them.

I know Stu and MaineSail both mention that but it bears repeating.
Thanks for the reminder. Have decided to go with 4 6v gc2 batteries to get the extra capacity. Will wire these parallel as house bank on switch pos 1. Then switch pos 2 will be a 12 volt starting battery. Now looking for best quality and price...
Also check me here... hook starting battery to alternator only and house bank to charger only... is that correct?
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Also check me here... hook starting battery to alternator only and house bank to charger only... is that correct?
You can wire it that way, but a more flexible setup is to connect both the charger and alternator to the house bank (fused, of course), then connect an ACR between the house and spare bank. Now your battery selector switch determines which bank is being drawn from, and both banks get charged by either the AC charger or alternator.
https://www.bluesea.com/prodcts/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A
Both MaineSail and Stu have lots of info on how to do that, and what the advantages are.
 
Sep 29, 2008
1,944
Catalina 310 #185 Quantico
Thanks rpwillia! I was suffering from overthinking and reading too many posts. Woke up this morning with a fresh coffee and your post. I think I can follow that.
So your picture shows the 4 battery 6 volt as 1 house bank correct? No 5th starting battery? So you only use one of the switch positions on the 1/2/off/both selector?
Where is your charger mounted? Thanks
They are wired as two separate banks, but I normally keep the 1-2-All Switch in all so they are as one battery. I do not have a 5th starting battery. I have a Victron battery monitor and in the years I have had it it has proven to be accurate. Additionally I went all LED where possible and can go for about 3 days without needing to charge the batteries. Since I am a glorified day sailor who spends the occasional weekends and week on the boat on the Potomac River/Chesapeake Bay that battery configuration is sufficient. I placed the new charger where the old one one on the forward bulkhead of the aft port locker so I could re-use all of the factory cabling (the only wire I had to run was for the temp monitor on the battery).

One thing to note is that I used the original factory battery alignment and I understand they should be mounted port to starboard as opposed to forward and aft, but this has worked well for me. I also have a desulfinator circuit on the solar panel on the bank that helps to promote longer battery life.
 
Sep 29, 2008
1,944
Catalina 310 #185 Quantico
Ray, it looks like someone did some surgery on your seat to make it easier to get those batteries in/out! I also noticed that your batteries are not in the optimal orientation http://www.pbase.com/mainecruising/flooded_battery_orientation
You are correct about orientation, but I have never had a problem. Did not have to do any surgery, but since the golf cart batteries are about 1" higher than the 4D's I had to modify how the batteries are secured. So I came up with this so after the batteries were in, I could slide this in, extent the tops extensions and screw them into the holes in the settee bottom like the original board. The electronics you see in the middle are the shunt for the Victron monitor.
 

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Oct 3, 2011
835
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
We still have our 2-4D gel batteries , they are about 7 years old with the Charles charger-original.
If we want to not plug in for three days but run the VHF, fridge, cell phone charger, anchor light, stereo and interior lights (All lights are LEDS) on one battery and leave the second battery for starting, no solar charger, is that reasonable or will we end up with a dead battery? The batteries are still in good shape and still hold a charge for an extended time (No charging for 30 days on the hard with no major battery drain. I am sure somewhere there is a chart to determine drain on batteries. I am a visual person and know at some point we will replace our batteries and like the gel/agm batteries. Maybe We need Rob, Mainsail or Ray to stop by and check it out :clap:.
 

SFS

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Aug 18, 2015
2,088
Currently Boatless Okinawa
Alan, you can calculate this for yourself, using the current draw (in amps) for all of the devices you list, the number of hours you run them, and the capacity of your house battery (singular), which is listed in amp-hours. One amp of draw for 2 hours is 2 amp-hours. Construct an energy budget, it should be your starting point:

http://c34.org/bbs/index.php/topic,3976.0.html

This may also help:
Record of Daily Energy Use of 100 ah per day:
http://c34.org/bbs/index.php/topic,6353.msg41471.html#msg41471

As might this:
Largest House Bank 101 (by Nigel Calder)
http://c34.org/bbs/index.php/topic,5807.msg45046.html#msg45046


My guess is that the refrigerator will be a stretch for your hypothetical 3 days on one battery.
 
Aug 23, 2014
164
Catalina 310 Guntersville, Alabama
OK, I've been studying all of this information and now I have a question... the last piece of this puzzle for me is the ACR. I am ready to purchase 4 6v GC2 batteries, 1 12 volt reserve/start battery, and 1 battery charger such as the ProMariner 63120.
With a 3 bank charger like the ProMariner 63120 ProNauticP why do people recommend the ACR?
Seems like I would just connect the house bank (1) and the start/reserve bank (2) to the charger. The alternator would of course charge whichever switch position I select on my 1/B/2/O switch while the engine is running.
Is there anything i am missing here? Thanks.
 
Feb 26, 2004
23,051
Catalina 34 224 Maple Bay, BC, Canada
Is there anything i am missing here?
A number of things:

1. The alternator only has one output and should go to the house bank with a fuse and a service disconnect switch only to be used when working around the engine. This is the preferred method of wiring the AO instead of going through the switch. The switch then becomes a USE only switch,m and NOT a charging source switch.

2. Therefore, the ACR is used to automatically charge the reserve bank.

3. The shorepower charging lead goes ONLY to the house bank, too, and th ACR does its job then also.

This is all covered in the Electrical Systems 101 topic that SFS linked some excerpts to earlier, here:

Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

Also covered in reply #8 on page one. :)
 
Aug 23, 2014
164
Catalina 310 Guntersville, Alabama
Read the electrical 101 info... it helps. You know the old saying "you can lead a horse to electrical knowledge but you can't make him drink the ACR"...
I believe I can do this now thanks to these posts but I still search for the simplest instruction sheet and diagram. I can destroy an anvil without proper supervision.
 
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Oct 3, 2011
835
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
Thanks for the Guidance, I am like SailFysh, I can EASILY Destroy an Anvil and also add hundreds of Dollars in cost to a $10.00 project at the drop of a wrench, just ask my wife. ;)
I WILL Do the energy survey! Thanks
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Read the electrical 101 info... it helps. You know the old saying "you can lead a horse to electrical knowledge but you can't make him drink the ACR"...
I believe I can do this now thanks to these posts but I still search for the simplest instruction sheet and diagram. I can destroy an anvil without proper supervision.
Here's an example of the wiring scheme. It's still a work in progress, but the basic concepts are there. Let me know if you've got any questions about it.

Like Stu said, your switch is now USE only. The ACR deals with charging both banks, and doesn't let a dead bank draw the other one down, which is easy to do with the default wiring by selecting ALL.
 

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Feb 26, 2004
23,051
Catalina 34 224 Maple Bay, BC, Canada
but I still search for the simplest instruction sheet and diagram.
Here's an example of the wiring scheme. It's still a work in progress, but the basic concepts are there.
SailFysh,

Rob's wiring diagram is very similar to the simplified wiring diagram in one of the Electrical System 101 topics that I referenced in my first post on page one of this thread.

It is one of the simplest in terms of how things are connected. Rob's added the + & - distribution bars and fuses.

Quite frankly, I don't know what else we can do for you beyond giving you scores of wiring diagrams that all show the same exact concept in different ways. There are two ends to each wire. They go from point A to point B.

YOU actually have to do the homework and research between your two ears to understand the concepts, which we have freely given to you. Many of us have had to figure this stuff out all on our own, before the internet. Now that you HAVE all this material, you just have to spend the time to figure it out. We're sure you did study during high school and college, right? :):):) You only have to do it one more time.

Many, too many times, we hear, "I don't know nuttin' 'bout 'lekricity..." None of was born an electrician, we studied and we learned. If you feel it is beyond you, then have someone install it for you, with these guides.

But frankly, I have always seen it as a safety issue. If you don't understand enough about it, conceptually, then you'll never know if what someone is installing for you is actually what you want and/or need.

I can understand if you may not be handy with electrician's tools, but that's a whole 'nother issue. You HAVE to figure out what you want before you can get someone to do it for you. Would you just let a contractor redo your kitchen before you and your wife picked out the cabinets, counters, sink and faucets? I doubt it.

Study up. We're here to help with more specific questions once you've invested the time to read the material we've given you. I've seen hundreds of wiring diagrams from many, many skippers, and have helped dozens offline. ALL OF THEM were based on these concepts.
 
Aug 23, 2014
164
Catalina 310 Guntersville, Alabama
Dang fellows... now I guess I have to actually do it. Thanks for all your help. I will report back after the deed is done.