Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 07-10-2019, 08:14   #1
Registered User
 
AJ-SeaChange's Avatar

Join Date: Feb 2017
Location: On board our Jeanneau SO 45.1
Boat: 1995 Jeanneau Sun Odyssey 45.1
Posts: 101
Can I add a fourth battery?

Here's the story.



June 2018 - 3 x 95ah 800a Varta 12v batteries were installed.


Noticed a problem in October 2019. Checked batteries, two of them were toast at 10.2v each even after a full day of charge from 600 watts of solar. One of them still shows 12.6v of charge.



Bought 3 x 100ah 800a Varta 12v batteries and replaced all three original batteries. All working fine now.



Here's the question.


Would it be OK to add the June 2018 - 95ah 800a Varta 12v battery into the chain with the 3 new batteries? Does the 5ah difference cause issues?


Thanks in advance. Baz
__________________

AJ-SeaChange is offline   Reply With Quote
Old 07-10-2019, 08:21   #2
Registered User

Join Date: Jan 2017
Posts: 12,440
Re: Can I add a fourth battery?

Yes you can but not ideal.

Every 12V added in parallel means more likely to have balance problems.

More importantly, what was the cause of the previous failure, and was that fixed.

Hypothetically, would buying a whole new set every year be a problem for you?
__________________

john61ct is offline   Reply With Quote
Old 07-10-2019, 08:35   #3
Registered User
 
AJ-SeaChange's Avatar

Join Date: Feb 2017
Location: On board our Jeanneau SO 45.1
Boat: 1995 Jeanneau Sun Odyssey 45.1
Posts: 101
Re: Can I add a fourth battery?

Hi John, the problem was traced and fixed.


Buying a new set every year would not be good.


You say that adding a fourth battery wired in parallel could cause balancing issues, what would be the best way to add more storage capacity?
AJ-SeaChange is offline   Reply With Quote
Old 07-10-2019, 08:36   #4
Registered User
 
S/V Illusion's Avatar

Join Date: Oct 2007
Location: Lakewood Ranch, FLORIDA
Boat: Alden 50, Sarasota, Florida
Posts: 2,228
Re: Can I add a fourth battery?

I’d like to see an 800 amp 12v battery.
S/V Illusion is offline   Reply With Quote
Old 07-10-2019, 08:44   #5
Registered User
 
AJ-SeaChange's Avatar

Join Date: Feb 2017
Location: On board our Jeanneau SO 45.1
Boat: 1995 Jeanneau Sun Odyssey 45.1
Posts: 101
Re: Can I add a fourth battery?

Quote:
Originally Posted by S/V Illusion View Post
Iíd like to see an 800 amp 12v battery.

Nobody mentioned 800amp batteries.


Original post says - 95ah 800a Varta 12v batteries.
Attached Thumbnails
Click image for larger version

Name:	Battery.png
Views:	79
Size:	210.2 KB
ID:	201084  
AJ-SeaChange is offline   Reply With Quote
Old 07-10-2019, 08:58   #6
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 27,498
Can I add a fourth battery?

You can add the fourth battery. Many successfully have a LOT more batteries than four, you do need of course to ensure your neg and pos are at different ends of the bank.
However what is your voltage when you wake up in the morning and how are you determining SOC?

If what is killing your batteries is the gradual walk down of SOC over time and it likely is, adding another battery may not do much.

Not all of them being the same age and capacity is not ideal, but it will work.
Ideal is of course to buy four all new batteries of the same capacity, but as assume you like most have budgetary constraints that get in the way of perfection.
a64pilot is offline   Reply With Quote
Old 07-10-2019, 09:18   #7
Registered User
 
AJ-SeaChange's Avatar

Join Date: Feb 2017
Location: On board our Jeanneau SO 45.1
Boat: 1995 Jeanneau Sun Odyssey 45.1
Posts: 101
Re: Can I add a fourth battery?

We have a Victron BMV 700 battery monitor and I check the voltage on that every morning.


To recharge we have 600 watts of solar. Or if cloudy we run the engine at 1,500prm until we are back to 100% battery capacity.


Thanks for your advice.
AJ-SeaChange is offline   Reply With Quote
Old 07-10-2019, 10:10   #8
Registered User

Join Date: Jan 2017
Posts: 12,440
Re: Can I add a fourth battery?

Quote:
Originally Posted by AJ-SeaChange View Post
You say that adding a fourth battery wired in parallel could cause balancing issues, what would be the best way to add more storage capacity?
Best is to use fewer strings in parallel, each unit being higher Ah capacity, in your case 400Ah cells, 6*2V is best.

3*4V is also possible.

The usual approach, but yes a compromise compared to the above options, is 6V GCs, @200+Ah commonly available, so 2P2S, total two strings gives redundancy, units not too heavy to manage, total well over 450Ah.

Obviously advice for "next time", best to replce the whole bank at once.

Meantime here's wiring guidance on ameliorating those imbalance issues from using too-small 12V units.

http://www.smartgauge.co.uk/batt_con.html
john61ct is offline   Reply With Quote
Old 07-10-2019, 11:14   #9
Registered User

Join Date: Nov 2010
Location: UK, Croatia
Boat: Fountaine Pajot Athena 11.6m Rapa Nui II
Posts: 546
Re: Can I add a fourth battery?

I would say yes but not ideal as others have said, provided the one remaining battery from the original set is in good health. My concern is that presuming all 3 were in parallel, why would the the one have survived and the other 2 have not. At the least, I would put the survivor on a battery tester and conduct a discharge test.
Rapanui is offline   Reply With Quote
Old 07-10-2019, 11:52   #10
Marine Service Provider
 
witzgall's Avatar

Join Date: Oct 2006
Location: Eastern Shore, MD
Boat: Camper Nicholson 44 Ketch
Posts: 1,913
Re: Can I add a fourth battery?

Given what happened to the bad batteries, it is highly unlikely that the health of the remaining battery did not take a hit. It will quickly draw the health of those new batteries to it's level. Don't do it.

Chris
witzgall is offline   Reply With Quote
Old 07-10-2019, 12:01   #11
Registered User

Join Date: Sep 2019
Posts: 2
Re: Can I add a fourth battery?

Don't use the old battery, you could find yourself replacing all 4 next year. You only mention solar and engine charging, give your batteries a break and go into a marina for the weekend every 6 months at least and let them soak up a full charge and sit at float voltage for at least 48 hours. They will appreciate it.
MoodyS is offline   Reply With Quote
Old 07-10-2019, 12:04   #12
Registered User

Join Date: Dec 2013
Location: Fort William, Highland, Scotland
Boat: Bavaria Cruiser 40
Posts: 814
Images: 16
Re: Can I add a fourth battery?

If you have space for 4x 100a-hr batteries could you instead have 2x 200a-hr batteries? Saves multiple wiring and any potential imbalance issues?

I know Varta do a 140a-hr as I have 2 of them myself and I've found the proMotive 220a-hr online with the SuperHeavyDuty version giving an extra 5a-hr. The AGM version is a 210a-hr. Plus there is also a 260a-hr Deep Cycle AGM in the Professional range.

Maybe these are an option instead of 4x smaller ones.
kas_1611 is offline   Reply With Quote
Old 07-10-2019, 12:42   #13
Registered User

Join Date: Jan 2017
Posts: 12,440
Re: Can I add a fourth battery?

Getting to 100% Full only every six months (!!!) will not do much to help longevity.

Monthly maybe, weekly much better.

If you have both solar, and ICE sources at high amps, no need for marinas, just use ICE powrr to get to 80-85% SoC before a bright solar day starts, and keep consumption down, maintain Absorb V until your endAmps spec is reached.

Ideally, do this most cycles.
john61ct is offline   Reply With Quote
Old 07-10-2019, 12:42   #14
Registered User

Join Date: Jan 2017
Posts: 12,440
Re: Can I add a fourth battery?

This is not three new ones added to one old, but the opposite.

Note I misread the "new" bank of three strings as being July 2019, not 2018, bit more marginal call there.

Just adding one more battery, as long the other three are testing OK, yes the lifetime of that new one will be reduced.
john61ct is offline   Reply With Quote
Old 07-10-2019, 13:31   #15
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 27,498
Can I add a fourth battery?

Yeah, itís one new to add to a newish existing bank.
He has three options.
1. Learn to live with existing capacity.
2. Increase it by adding a battery
3. Replace the whole bank.

Assume 1. Isnít viable, and he doesnít have the funds or maybe just doesnít want to spend the funds to replace the whole bank, that only leaves option 2.
Even if the new battery is drawn health wise to the existing three, which I think it will be, he should still have plenty of life left, even if he only gets one year out of the one battery, itís only 1/4 as much as buying 4 all new batteries.

2 volt cells, 4V batteries (never seen one of those myself) are really sort of unicorns for most people. Yeah they exist, probably wonít fit, and you have to special order them, paying exorbitant shipping rates etc. and if you get a bad one, there isnít another one on the shelf.

Odds are what he has now isnít a deep cycle battery anyway, so buy one more and take some time to decide what is available to buy for next time, and have a plan and maybe save up for it so itís not an unexpected expense.
Primarily take the time to learn about the care and feeding of a LA bank, so that you will be the right kind next time and if you take care of it, you may get more than 5 years out of it.
__________________

a64pilot is offline   Reply With Quote
Reply

Tags
battery

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
FOURTH NATIONAL CLIMATE ASSESSMENT GordMay Off Topic Forum 181 25-11-2018 20:57
Jeanneau 43 DS: Space for a fourth Service Battery? SaltyMetals Electrical: Batteries, Generators & Solar 2 06-03-2018 10:27
Fourth Edition of the Bible Charlie Construction, Maintenance & Refit 0 25-06-2015 14:37
For Sale: The Panama Cruising Guide, Fourth Edition, Eric Bauhaus loved cruising Classifieds Archive 4 09-01-2014 17:56
Heading North On The Fourth IdoraKeeper General Sailing Forum 2 02-07-2013 22:27

Advertise Here


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 01:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×

ShowCase vBulletin Plugins by Drive Thru Online, Inc.