Redoing battery system

[Bumperlt12]

Ok, so last summer I added a second battery to my boat but I don't think I did it properly. I left the old on/off switch and added a 1 2 both switch in a more accesable location. There are two fused wires that go into the old switch, dunno thier purpose. This is where my problem lies. I believe one to be the lead from the alternator, but the other i have no idea. Instead of trying to half *** it I am just going to redo the system.

I am buying everything this weekend and it looks like i'm going to go with 2 costco marine deep cycle, and 1 costco rv/marine cranking. The 2 will be wired in parallel.

For charging I am going to go with a minn kota 2 bank charger:
Amazon.com: MinnKota MK 210D On-Board Battery Charger (2 Banks, 5 amps per bank): Sports & Outdoors

And a minn kota 2 bank DC charger alternator:
Amazon.com: MinnKota MK-2-DC Dual Bank DC Alternator Charger: Sports & Outdoors

I already have the 1 2 BOTH switch.

Is there anything else (besides wire) that I'm going to need to make this system work?

My current system only charges one battery. This obviously is not going to work long term. Does anyone have a wiring diagram that I can follow that incorporates this system? I would like to eliminate the existing switch, or maybe repurpose it to disconnect the 2 deep cycles or something.

 

[Texasmark]

Re: Redoing battery system

I assume you have a bass boat and a 24 volt trolling motor. In reading the files you included it seems you have a pair of dual chargers, one for operation from household current and the other from the engine's alternator. One of each pair would be connected across a single TM battery and being independent circuits allows for them to be in series providing a total of 24 volts for your TM.

It's not good practice to have two separate chargers connected to a battery simultaneously, so if you choose to operate both systems, then yes a disconnect switch is necessary.

The problem I have with your alternator charger is that your alternator will be required to supply makeup power to your starting battery while simultaneously providing makeup power for your TM batteries. The alternator only has so much amperage available, and since losses are in the circuit, continuous usage at full amperage will probably burn up your engine alternator, especially if an OB engine. Course having a automotive engine where alternators are out in free air and usually of high amperage as compared to OB's it is probably OK.

So I assume your question is how to hook up. Your engine alternator is already hooked up to charge your engine starting battery so leave it be. And you don't want your engine battery hooked to a TM battery. No need for it with your dual charger system. Also it simplifies the wiring.

Both TM chargers have dual outputs. Only one wire of each output of each charger needs to be opened when not in use so that you don't have the outputs of 2 chargers hooked up simultaneously. Chargers, especially electronically controlled types get confused when power is fed back into them from another source.....one will always be ahead of the other one in output voltage (potential). I realize the outputs will be forced into being a single voltage (being in parallel) but the electronics internally will be fighting for the output each thinks it ought to have.

So, you have 4 circuits to be switch, 2 at a time to be closed, and 2 to be open. Not familiar with your switch, but a 2 pole double throw switch (DPDT) would do the job.

First the hots (+) of one charger from each type attach to the + terminal of the lower battery (battery 1). The low side of these chargers go to the outer posts of one circuit of the DPDT switch. The center post goes to the battery 1 (-) .

The other charger of each pair is wired the same to battery 2, (the upper 12v battery of the 24v system) through the second set of contacts of the DPDT switch ensuring that the wiring to each side of the switch comes from the corresponding charger.

In short, when the toggle is to the left, the 115 v chargers are hooked in the circuit and when the switch is to the right the alternator chargers are hooked in. That's it. Using a single DPDT switch, you just have to flip 1 switch and accomplish your goal.

I'd give you a diagram but I'm too lazy to be truthful. I'd have to learn to do some things that I haven't done before and I have a full agenda today. This should help.

So check your available switches for DPDT function, amperage rating and go for it. Your 1, 2, dual switch might what you want (never saw one but functionally) in position 1 but it has to be DPDT:

2 separate circuit posts on one side, a separate pair of center posts in the center for each separate circuit, and 2 separate circuit posts on the other side; 6 terminals, 3 for each circuit. Iterating what I said earlier, each 3 terminals of the switch would be one - input from a household charger, one common terminal going to the battery 1 - and one - input from the alternator charger. The other 3 contacts are wired the same from the other halves of the dual chargers for battery 2.

Mark

 

[Bumperlt12]

Re: Redoing battery system

Thank you for the detailed response. The boat is a small cruiser and the deep cycle batteries would be "house" batteries. Minn Kota's chargers had good reviews, thats why I chose that brand, no trolling motor on board.

I would like all batteries to be charging when the motor is running, and when the shore power is hooked up. I am considering buying a portable generator to put on shore and run a chord from it to the shore power receptacle.

Does this change how I should wire everything up?

 

[Georgesalmon]

Re: Redoing battery system

Nope, just make sure your grounding wires are complete and secure from the Gen set to the on board charger.

 

[Silvertip]

Re: Redoing battery system

Dual battery switch wiring has been covered a gazillion times in this thread. Just use the SEARCH feature and keywords DUAL BATTERY SWITCH WIRING to find diagrams.

 

[Bumperlt12]

Re: Redoing battery system

Ok, did a search and it looks like the add a battery by blue sea is what I need to do it properly.

this is the diagram I am going to use:
http://forums.iboats.com/attachment.php?attachmentid=157474&d=1341945229

What if it fails? I guess I wanted a more manual approach?

The large wire shown going to the motor go to the starter, where does the alternator wire connect?

This should be used instead of the minn kota DC alternator yes?

There isn't any reason why I shouldn't use a 2 bank AC charger with this system?

I get it for the most part, Im trying really hard to comprehend this but it isn't clicking.

 

[Bumperlt12]

Re: Redoing battery system

Just read the installation instructions and it shows multiple ways the alternator could be integrated into the system. I'll have to see how Searay wired it up and if I want to keep it as such.

 

[glenn property of pam]

Re: Redoing battery system

look at a dual bank onboard charger that has a automatic transfer built in to it. (i think the dual bank kota has a 10 amp built in). I know 10 amps doesnt sound like much and thats true when you are trying to charge 2 large house batterys which is why you also have a dual switch so you can switch the motor to the house batteries and let the alternator charge them at full power (max output of the alternator).

The alternator is going to be hooked to the common on the a-b-dual switch the same as the starter so the alternator could be connected to the battery side of the starter at the motor. With a dual switch you need to make sure that all battery wiring is the same gauge as the starter wiring


see post #7 http://forums.iboats.com/electrical...tors/need-info-adding-2nd-battery-249593.html then just add a onboard and you are done.

addition: you really need to work out what the old switch did or delete it and the wiring so it doesnt cause a problem between the banks