On board charger questions.......

[mrcj001]

I have three batteries.....one to start engine only...one is accessory....and one is for the trolling motor.

The accessory battery is connected in series with the troller for 24 volt performance

I want to install a on board charger......do I really need a three bank, or just a two bank....???

I quess the question I`m asking , since I have the two batteries in series, will one bank charge both?

 

[Joe Reeves]

If the batteries are wired in parallel (Pos to Pos... Neg to Neg), it doesn't matter how many batteries are in the circuit... it is still just 12 volts, the amp hours are higher (the battery group would last longer under a load). As such, the charger would charge all batteries... it would just take longer to do so.

 

[interalian]

You cannot charge a 24v battery setup with 12v charging system. Electrically impossible.

You'll have to switch the wiring so all cells are in parallel to charge them off your motor.

 

[icwingman]

I have three batteries.....one to start engine only...one is accessory....and one is for the trolling motor.

The accessory battery is connected in series with the troller for 24 volt performance

I want to install a on board charger......do I really need a three bank, or just a two bank....???

I quess the question I`m asking , since I have the two batteries in series, will one bank charge both?

3 banks soso u don't over it. There expensive I have one cost 295

 

[oldboat1]

Your '76 70 has a 6 amp charger -- thinking maybe you have only the starting battery hooked up to the motor. Might be a little light to charge multiple battery banks anyway, but if the other two batteries are in series as you say, I'm pretty sure a hookup to your motor would fry the rectifier.

I use a small onboard charger to shore charge and maintain two batteries through a Perko switch (set on both batteries). This has worked OK -- chose that over a two bank charger, as I thought using the battery switch would be just as efficient for slow charging and maintenance.

(There is very good electrical/battery info here in the electronics forum -- good system design and setup info. Maybe you know that, but might want to check in there too.)

 

[jimmbo]

Whatever you do, don't try charging them in the boat if the boat is in the water. Unless the AC source is on an isolation transformer

 

[Joe Reeves]

Whatever you do, don't try charging them in the boat if the boat is in the water. Unless the AC source is on an isolation transformer

Yeah.... That'll make your eyes light up huh?

 

[jimmbo]

Yeah.... That'll make your eyes light up huh?

Not for long. But I'm sure a potential Darwin Award Nominee will go ahead and plug in

 

[mrcj001]

No, me no stupid, water electricity dont mix well.

I`m thinking during the winter...not charging the batteries do more harm than good. Plus, it may make my vessel worth more.

I added power steering and power brakes last year.:facepalm:

 

[mrcj001]

I said screw it and bought a 3 bank charger.

Do I need to disconnect the one of the cables in the two battery series when charging??

 

[Faztbullet]

You cannot charge a 24v battery setup with 12v charging system. Electrically impossible.

Yes you can....just attach the leads from charger to the the pos/neg of each battery. I use a 3 bank to charge my 36 volt trolling motor batteries. You only need a 2 bank as motor should keep starting battery charged. How to instructions below as all 2/3/4 banks wire the same.....

http://www.manualsdir.com/manuals/373192/promariner-prosport-smt.html?page=8

 

[bruceb58]

I said screw it and bought a 3 bank charger.

Do I need to disconnect the one of the cables in the two battery series when charging??

No you don't. Each bank is electrically isolated for eachother so they don't combined grounds.

You cannot charge a 24v battery setup with 12v charging system. Electrically impossible.

There are many DC/DC chargers that you can get that do that very thing. So..you never have heard of a DC to DC convertor? Do a Google search...tons of possibilities. Here is just one:https://www.amazon.com/NOCO-G7200-UltraSafe-Battery-Charger/dp/B004LWTHP2

 

[bruceb58]

Whatever you do, don't try charging them in the boat if the boat is in the water. Unless the AC source is on an isolation transformer

LOL...do it all the time on both of my boats.

 

[jimmbo]

Are the outlets you are plugged into on a circuit fed from an Isolation Transformer?

 

[bruceb58]

Are the outlets you are plugged into on a circuit fed from an Isolation Transformer?

Not on my personal dock that's in my backyard.

You do realize I just have a battery charger. I don't have a shore power connection.

 

[interalian]

Quick clarification. I misunderstood the original post and thought the OP was trying to charge a pair of batteries in parallel using the motor. Move along, nothing to see here...

 

[bruceb58]

Quick clarification. I misunderstood the original post and thought the OP was trying to charge a pair of batteries in parallel using the motor. Move along, nothing to see here...

But you still think charging 24V with a 12V system is impossible right?

 

[mrcj001]

No Title

This is how my batteries are wired......do I need to disconnect the jumper cable before charging??

 

[interalian]

But you still think charging 24V with a 12V system is impossible right?

No.

 

[bruceb58]

This is how my batteries are wired......do I need to disconnect the jumper cable before charging??

No. The multi bank charger will have two leads for each battery.