Charging 24VDC battery with 12VDC outboard

[whiskywizard]

I want to charge the trolling motor deep cycle batteries when I'm running my main outboard. (The alternator has enough capacity to do this.)

 

A pair of deep cycles wired in series supply 24VDC to the electric trolling motor.

Primary starting battery is a regular cranking battery; 12VDC.

When plugged into shorepower, a 3-bank smart charger charges all 3 batteries.

 

Has anybody tried the Yandina Trollbridge24?

 

Here's a simple schematic. I have simplified it by eliminating the local ground and positive buss bars, fuses, breakers and battery disconnect switches.

Edited March 9, 2012 by whiskywizard

[RSF]

I want charge the trolling motor deep cycle batteries when I'm running my main outboard. (The alternator has enough capacity to do this.)

 

A pair of deep cycles wired in series supply 24VDC to the electric trolling motor.

Primary starting battery is a regular cranking battery; 12VDC.

When plugged into shorepower, a 3-bank smart charger charges all 3 batteries.

 

Has anybody tried the Yandina Trollbridge24?

 

Here's a simple schematic. I have simplified it by eliminating the local ground and positive buss bars, fuses, breakers and battery disconnect switches.

 

 

 

Seems to me, the simplest way might be adding a couple of 3 way battery switches. Outboard to switch 1 and 1 to 2: Start Batt, Deep Cycle 1 and Deep Cycle 2. Effectively selecting each deep cycle individually and bypassing the series hook up which will bring 12 volt charging across the board. You would also have to manually select 12 or 24 volt for both electric trolling, starting and charging.

[Terry]

well I was going to say a step-up converter but that seems to be what that product is

I can't see where it says how many amps it puts out at 24 volts, which is real important

 

the simplest way would be one of those 3 way switches, but half way you would need to switch to the second battery so both batteries are being charged the same amount

[whiskywizard]

I can't see where it says how many amps it puts out at 24 volts, which is real important

 

Current should be exactly halved. The alternator is 40A at ~14.4V, and will step back rather quickly. So the 24V output will be ~20A at 28.8V, and will still get dialled back fast by the 2 series batteries' ability to absorb charge.

 

If I use switces and relays, then the boat is hard for somebody else to operate. For $100, I think I'll go with the Yandina Trollbridge 24.

 

Thanks for the thoughts.

Edited March 14, 2012 by whiskywizard