Kevin

I have a new Motorguide 24 volt trolling motor and need your boat wiring advice.

I hooked up two 12 volt batteries in series, with the boat battery cables going from positive on one battery to the negative of second battery. But, in order to accommodate a 12 volt single battery charger, I need to wire the batteries in parallel.

Will the trolling motor run with the batteries wired in parallel, or does it make a difference?

Thanks,

Jason

Hi Jason,

Nice choice on your trolling motor! It’s nearly unanimous with our readers that Motorguide makes the best.

As for your marine electrical setup:

If the batteries are wired in parallel, the voltage to the trolling motor will only be 12. It will run, but very slow.

You may want to source a different battery charger that is designed for 12/24 battery charging. All of the ones made by the Guest subsidiary of Marinco are designed to connect to 12/24 and in some cases 36/48.

Hope this helps,

Kevin

Kevin,

I recently got a Smart Boat Battery Switch system from your partner marine wiring site.

The Smart Switch seems great and should work really well on my boat. I do a lot of fishing and after running the trolling motor for a long time, often worry about having enough power to start my outboard. Your system seems to be a perfect solution.

But, I have a question:

After boating all day and parking the boat, is it still ok to charge the batteries the same way? In my case, I’ve always used an on board charging system utilizing 110 volt home current. Will that still work?

Thank you,

Josh

Hi Josh,

I’m glad that you like the smart battery switch that we put together. It’s designed to alleviate exactly the concern that you have had about boat battery management.

As for your boat wiring question…

Yes. You can use the charger just like you have in the past. Just as with your alternator charging while underway, the VSR will connect your battery banks as the voltage in your system rises. So when you are ready to head back out, both battery banks should have a full charge.

As for multi-stage chargers, like the Guest line, almost all can be plugged in indefinitely and not overcharge you batteries.

Happy boating,

Kevin

Kevin,

I currently have two batteries on my boat with a battery switch and then another 24 volt trolling motor bank in the front.

In the back one battery is for the main engine only, the other battery is for the electronics and downriggers.

I troll for salmon. I have my kicker motor, a 8 HP Honda 12 amp wired directly to the electronics battery. Many times, I run out of battery power before the end of the day on the electronics battery.

Up front I have a 24 volt trollng motor and two batteries. Can I change my boat wiring so my 12 volt electronics are connecte to this bank (on one of the batteries for 12 volt) and then get a VSR to charge the 24 volt system?

Will this give me more time on the water for electronics and downriggers?

Thanks for your thoughts,

Jason

Hi Jason,

I would consider adding a VSR between your two main boat batteries in the back.

While your main engine alternator is running, it will charge both batteries connected to the battery switch. Then, when your Honda is running and you are not running your electronics, the Honda will charge both your electronics battery and the main engine battery. The batteries will stay paralleled until the voltage drops below 12.7 volts and greatly increase your battery capacity.

When the VSR opens, your electronics battery will drop at the same rate as it did before, but the drain will be starting considerably later.

Happy wiring,

Kevin