1 or 2 Bank Charger?

[uscg gunner]

hello,
i am brand new to the site and hope i can find some information. i recently purchased a 2001 bass tracker pro crappie 175 with the 40 hp on it. it has hardly been used, and while giving it a good cleaning i removed the batteries as well. the previous owner did install a single bank charger on the TM battery and i noticed that there is a wire connecting the negative posts on the two batteries...are these wired in parallel from the factory? i dont know if anything has been changed on the boat as far as that goes or not..also, if they are in parallel, do i just run a single bank charger? or do you guys recommend a dual bank? this is my first "real" boat so any help is appreciated. thank you..

 

[johnnybassboat]

Are the positives also connected together? If they are it should be parallel. On my boat the negatives are connected together and so are the positives. I also use a two bank charger from minnkota as it charges both batteries separately,to get best performance from the batteries, and faster charges. Hope this helps

 

[Bugpac]

You need to make a disconnect if they are parallel, a 2 bank charger will charge them, but it wont sense voltage independently. The higher voltage is gonna tell the charger what to do.

 

[earl60446]

Are the positives also connected together? If they are it should be parallel. On my boat the negatives are connected together and so are the positives. I also use a two bank charger from minnkota as it charges both batteries separately,to get best performance from the batteries, and faster charges. Hope this helps

If they are truly hooked in parallel, then 1 bank / charger is the right way to charge it. Probably best to avoid the parallel setup anyway, better to just get 1 big battery. 2 batteries in parallel tend to end up charging and discharging each other.
Tim

 

[uscg gunner]

Thanks guys, im pretty sure the positives are not connected. So has anyone heard of just the negatives being connected ? Did these boats come like this? Or is there a reason for it?

 

[Bugpac]

If the negs are connected, it would make for a quicker swap ti change batterys when first runs low. Swap positives now you have a full charge battery to resume the day.

 

[johnnybassboat]

You need to make a disconnect if they are parallel, a 2 bank charger will charge them, but it wont sense voltage independently. The higher voltage is gonna tell the charger what to do.

I dont know what you have for a charger, but my minnkota will charge both batteries independently even when hooked together. Thats the reason I got this charger. Have never had a problem in the 3 years I have had it and batteries or always checked, specific gravity, load checked and voltage.

 

[Bugpac]

Just curious how it is possible? The charger has to sense the battery voltage. If you had a bad cell the charger would never notice it. Cool if it works for you, i don't run anything parallel.

 

[JMichael]

It can't charge them independently if they are both connected in a parallel setup without some isolator/selector switch or some other means of breaking either the positive or negative portion of the parallel connection.

Out of curiosity, I went to see what Minn Kota had to say about it and this is what I found.

Each output bank is independent and isolated from one another and the AC input. The Minn Kota charger can charge independent batteries or combinations of batteries hooked in series or parallel without disconnecting the batteries from any switches or wires / straps joining the batteries.
See diagram on page 8
CAUTION
-
Due to the high charging current of the Minn Kota charger, it is recommended that each output be connected to only one battery.
Connecting 2 banks to one battery may cause excessive heating in the battery and could cause acid leakage or battery explosion

Next I went to page 8 as instructed but the only instructions and wiring examples they had were showing batteries connected in series and the instructions saying that it wasn't necessary to disconnect the series strap. So I suspect that the use of the word "parallel" in the instructions might have been a typo. Regardless of what else you do, I'd highly recommend you contact Minn Kota about this and get confirmation from their support people as a safety precaution.

 

[johnnybassboat]

Maybe I am wrong, but I read the same thing and also called minnkota tech support. they told me the same thing the book said, maybe they just read me the book lol. All I do know the boat has been set up like this a few years and works as it should. My indicating lights also work independent of one another, if they were seeing the same loads wouldnt they show the same charge rates simultaneously. Mine show different rates at the same time and for different lengths of time. IDK been wrong before #-o

 

[JMichael]

Maybe I am wrong, but I read the same thing and also called minnkota tech support. they told me the same thing the book said, maybe they just read me the book lol. All I do know the boat has been set up like this a few years and works as it should. My indicating lights also work independent of one another, if they were seeing the same loads wouldnt they show the same charge rates simultaneously. Mine show different rates at the same time and for different lengths of time. IDK been wrong before #-o

LoL I know what you mean about them reading the book. I've caught "tech support" for a different company doing that very thing before. #-o And I agree that it would seem that both banks would show the same status so I can't explain that. And I'm thinking we've all been wrong before. :lol:

Between growing up in my dads TV/stereo repair shop, military training and working as an aviation electronics tech, and 10 years of schools and work for a large computer firm, I've had a fair amount of experience with electricity/electronics. I just can't see how it could happen if the 2 batteries are connected by simple copper straps with no switches or other devices to break the connections or restrict current flow between the 2 batteries. But I sure would like to know how it's done if it is indeed working that way. I'm always open to learning new things.