Batteries!

C

chandalen

New Member
Aug 7, 2011
367
Alexandra Bay,NY
Boat Info
'83 Sundancer 270, Humminbird 593c
Engines
Twin merc 305, with new SEI 106 drives
I bought a marine maintainer / charger. If I apply the Army line of thinking, as long as the batteries are of same type and same relative initial charge, they can be charged together. The charger 'should' maintain the two batteries as one.
Posts seem hit or miss as to if this is a good idea or a very bad one.

Or would I be better off buying a 1.5a maintainer for each battery?

Thanks
 
techmitch said:
Wow, big no no. There are no two batteries (in the world) alike and they should never be charged together. This is exactly why they make 2, 3, and 4 etc. bank chargers.
Click to expand...

But a standard set up For a boat like mine is a 3-bank charger charging (1) genny battery, (2) port engine/house batteries and (2) starboard engine/helm batteries. Is that not charging two batteries together?
 
How about the 1.5 a trickle maintainers. If I bought one for each battery.. that would be better than charging 2 in parallel?

Going to head to the boat shop today but they seem grossly overpriced a dual bank charger starts around 200. ( have seen much lower online)
 
Most boats are setup to charge multiple batteries at once. ideally they are all the same type and all in the same state of charge and condition. No issue doing that. If that bothers you then a multistage (2-3 bank) charger is the way to go charging one battery on each bank.
 
chandalen said:
How about the 1.5 a trickle maintainers. If I bought one for each battery.. that would be better than charging 2 in parallel?

Going to head to the boat shop today but they seem grossly overpriced a dual bank charger starts around 200. ( have seen much lower online)
Click to expand...

I love my ProMariner. It is a little pricy but woth it to keep the batteries well maintained. Peace of mind on the boat - priceless.
 
tbirdvet said:
Most boats are setup to charge multiple batteries at once. ideally they are all the same type and all in the same state of charge and condition. No issue doing that. If that bothers you then a multistage (2-3 bank) charger is the way to go charging one battery on each bank.
Click to expand...

HUMPH said:
But a standard set up For a boat like mine is a 3-bank charger charging (1) genny battery, (2) port engine/house batteries and (2) starboard engine/helm batteries. Is that not charging two batteries together?
Click to expand...


It doesn't matter what manufacture built/wired the boat, what kind/type the batteries are or who added batteries and reconfigured the charger wiring Without a separate bank (monitored circuit) for each battery the integrity of any battery charged in parallel with any other battery will be severely compromised as far as expected life span and available cranking amps. Think of it this way, you wouldn't test two batteries wired in parallel at the same time would you? Another example is, trying to jump start a car that has an extremely discharged or bad battery with another car that has a good battery and a perfectly good functioning charging system. Guess what? Ain't happin is it. As stated before, there are no two batteries alike.
 
HUMPH said:
But a standard set up For a boat like mine is a 3-bank charger charging (1) genny battery, (2) port engine/house batteries and (2) starboard engine/helm batteries. Is that not charging two batteries together?
Click to expand...

Ken, just because they build/wire them this way doesn't mean it's ideal or even correct for that matter. By the way, love your new sig. pic.
 
If I am reading correctly, it seems like this thread needs some clarification. It seems as though some are referring to a regular battery charger as opposed to a "smart charger". I also think that there is a difference between saying "multiple batteries charged together" and "multiple batteries charged at the same time."

Am I wrong in assuming that a smart charger is essentially a multi-bank charger?
Is it correct to say that with a multi-bank charger you are not charging two batteries in parallel, but charging two batteries separately, wether or not they are wired in parallel?
 
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mwph said:
If I am reading correctly, it seems like this thread needs some clarification. It seems as though some are referring to a regular battery charger as opposed to a "smart charger". I also think that there is a difference between saying "multiple batteries charged together" and "multiple batteries charged at the same time."

Am I wrong in assuming that a smart charger is essentially a multi-bank charger?
Is it correct to say that with a multi-bank charger you are not charging to batteries in parallel, but charging two batteries separately, whether or not they are wired in parallel?
Click to expand...

A smart charger is just that,smart. It continuously monitors battery state of charge and slowly, in stages lowers it's amperage output to the battery until a predetermined level/state of charge (not just a voltage reading) is reached. This is the main reason why they make multi-bank chargers as no two batteries charge at the same rate regardless of their individual state of charge. Furthermore, if two or more batteries are wired in parallel they are not being charged separately. Hope this helps.
 
An interseting thread. Does this apply to alternator charging also? I have single engine with 2 batteries. My battery switch is 1, 2 or both. Should I avoid the "both" position? The batteries are a completely different size and capacity.
 
Mike,

I was just thinking that yesterday and forgot to post. If the batteries are in BOTH the alternator power will charge both at the same time... Is this different than manually jumping the batteries so that 1 smart charger charges them both at the same time? I would lean to its actually better (the smart charger), because at some point both batteries will be fully charged and receiving the trickle charge not a full pulse like the alternator would give.

Fortunately the previous owner bought 3 - 140 batteries last year so all the batt's are the same. He said that he always ran on BOTH, started on 1 or 2 alternating days.

I plan on having '1' as the start battery, and 2 as the out on the water house battery. #3 is all by itself for the port engine only.

As an add on... I did buy a smart battery maintainer 1.5a for the #3 battery.
 
techmitch said:
Wow, big no no. There are no two batteries (in the world) alike and they should never be charged together. This is exactly why they make 2, 3, and 4 etc. bank chargers.
Click to expand...

I've been stewing on this for a few days. I've had an electric golf cart and it had a single bank battery charge. As I understand it, my Camry Hybrid charges the batteries using 1 charging system. So how does this apply to your comment? I would think if the charger has enough beef it could charge multiple batteries at one time.
 
As a relative novice to the world of smart chargers, I often need clarification when discussing or reading about the subject. That being said, I find it interesting that very little reference has been made in this thread as to how the batteries are wired. Maybe it shouldn't be but this is a huge factor in my mind.

In addition, now the position of the battery switch has come into the conversation, again without regard to wiring. Not to mention that the position of the switch has more to to with how the batteries are being used than how they are charged........Correct?
 
I hope no one minds if I jump on this thread with a question. I am currently in the process of replacing my three house batteries, these batteries are hooked up in a series and are charged the same way. The charger is the original, 35 amp, installed by Sea Ray. I also recently purchased a 4 bank charger and want to install it. But my problem is this, how do you charge each battery separately and at the same time use all three as house batteries. It seems to me that to use all three as house batteries they need to be run in a series. Any advise would be appreciated.
 
Thanks for your reply. Regarding your question, I intended to attach each leg to a single battery. I actually have four batteries, the forth one is a dedicated starting battery. I thought the term "bank" when refering to a smart charger meant a single battery. So, if I'm understanding what your saying, in this instance, "bank'" can actually mean one or more batteries run in parralle. In other words, I could have four banks of four batteries each and use one leg of my smart charger for each bank with out any problems. I see you have the same vintage of boat I do, I was wondering if yours still had the original charger or if it has been changed out?
 
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