Trolling Motor charging advice

[Blade]

Hi Raiders, 

After months of contemplating if I should get a trolling motor I made the call that I should and placed my order for a 24v 80lbs motor. (due to arrive mid to late Feb) 

While I wait for the motor to arrive I need to figure out what route to go with regards to charging the batteries. 

As far as I know there are two options. 

1. Shore power to on-board 12amp ProSport dual battery charger 

2. From the outboard to an onboard DC to DC 24v dual battery charger (not sure what Amps are available) 

Some additional context. 

1. I have no choice but to park my boat in the street (the neighbours are not the happiest about it but they tolerate it.) As such I would need to run an extension cable from my house to the boat and leave the cable there over the foot path over night. Are there any rules regarding this I. E. Trip hazard? 

2. My motor is a 2001 2 Stroke 3 cylinder 90hp Mercury, the manual notes the alternator output is 16amp at 4500rpm

3. I have two batteries currently installed, a cranking battery and a dual battery, the cranking battery is getting a bit old now and may need to be replaced in the near future. 

4. I am planning on adding 2 140ah AGM batteries for the trolling motor.

The options I have thought of are: 

1. My ideal set-up would be to have the inboard DC to DC charger, but will the charge be sufficient?

2. I could set up the batteries so that they can be removed and charged in my garage but that is not ideal.

3. I could do a hybrid where I install a DC to DC charger and make the batteries easily removable for when the charge drops below 50% I can then remove and charge them on my existing battery charger (it will take a long time because it is only a few amps and one at a time but hopefully the DC to Dc charger keeps them topped up) 

4. I go with the ProSport shore power charger and see if I can make it so that there is no trip hazard and discuss with the neighbours. 

Another question I have is

If I rewire the boat to have a dedicated cranking battery and wire all other electronics which I don't think draw much (sounder-always on, VHF radio- always on, 12v USB charging port- only used when needed to charge phones, nav lights - all nav lights are led only used for 2-3 hours at a time, live bait tank pump-only runs when the boat is stationary for a long time, bilge pump-only runs when needed but my boat doesn't take on any water so it is only in an emergency) . to the trolling motor batteries, I can do away with one battery which will reduce weight and save space. 

If you made it this far thanks for taking the time to read through my situation. 

Any advice or experience with the above is appreciated. 

Cheers 

[zmk1962]

Hi Blade,

As per my other posts I am deep in the analysis phase regarding a Trolling motor.

Regarding electronics, I had initially considered going down the path you have outlined above regarding the 24V set up... however, in my research I came across the Trollbridge24 product. It eliminates the charging issues (your existing motor 12V charge circuit will do the job) and automatically combines batteries to creates a 24V circuit as required by the trolling motor. You have the option to do this by adding just one additional battery to your existing set up.

My intention is to proceed with the Trollbridge24 when I go ahead with this project.  They have other products as well with variations of how much isolation they provide to the starter battery so browse the site. Here's the link

https://www.yandina.com/troll24info.htm

If you search for Trollbridge there are also several youtube posts.

Cheers Zoran

[kingie chaser]

So there is a 12x24 & a 24.

The 12x24 sounds like it protects the started from over discharge but the 24 doesnt?

 

Using batteries in parallel isnt something that I would want to do normally so wouldnt it just be better as you suggest to have a 3rd battery & run the 3 in parallel but just run an VSR isolator between the starter & the other 2 batteries when running the electric motor but they still charge off the alternator??

 

Just asking 🙂

Edited January 27, 2021 by kingie chaser

[Blade]

I see they have a three battery solution too. That would be ideal for me to have 1 cranking battery and the x 2 deep cycles running in series for the trolling motor. I could then leave the other electronics connected to the cranking battery. 

 

[kingie chaser]

Ah so the 12x24 is the 3 battery option, I missed that bit down the bottom of the page.

So the Tollbridge is the isolator, Im running a bit slow today 😂

 

Thats pretty good value as well!

 

IF I had the coin Id be going Lithium's, about 1/3 the weight of AGM's & 40% more usuable charge & probably 150% more charge/discharge cycles.

Depending on brand & how you treat them a 12V AGM will get about 600 cycles while a lithium cam get up to 2000 cycles.

But they are so expensive.

 

 

 

Edited January 27, 2021 by kingie chaser

[zmk1962]

Blade... yes sounds like its possible, but if it was me, I'd want the ability to switch to one of the deep cycles to start the motor if the crank battery died.  It's probably best you draw a sketch of your wiring diagram. Show the 12V positive and negative paths, the trollbridge and the 24V paths, and any other isolation switches you plan to install. That way you'll be able to visualise where the Motor starting circuit will be connected, as well as the electronics circuit.

As an example. I have a 3 battery system on my boat running through 2 isolation switches. I always run with 2 batteries switched online and one battery completely isolated. I rotate between the 3 which one will be offline on any given trip. I start the motor and run all my electronics off the 2 batteries that are online. (I need 2 online as that was the recommendation given by stress free marine for operating my anchor winch - it spreads the high current load across 2 batteries' plates). 

To create a 24V system for the trolling motor, I plan to keep my existing set up as is and add one 12V trolling battery. The trollbridge24 would connect that 12V battery with the Positive and Negative 100A cables that currently feed my anchor winch (these cables are for all effective purposes the terminals of the 12V battery in their diagram).

I will never use the anchor winch and the trolling motor at the same time - they are mutually exclusive.

I have run this past Yandina (trolbridge) and they see no issue. They initially did suggest the 12x24 to always preserve the charge in the starting battery, but that is not a major issue for me as I have a 3rd starting battery kept in total isolation. 

I also monitor the voltage on board (via dash display) and my motor puts out 60A charge at idle if I need to top up the batteries.

Cheers Zoran

PS: KC

41 minutes ago, kingie chaser said:

The 12x24 sounds like it protects the started from over discharge but the 24 doesnt?

That's my understanding as well. Advised if you have just one starter battery, and one Trolling battery.

43 minutes ago, kingie chaser said:

Using batteries in parallel isnt something that I would want to do 

 Re: Batteries in parallel - I need to do that to spread the anchor winch load. This makes the batteries last longer overall as you discharge each battery less BUT the drawback is loss of redundancy, as both batteries are in use and you could drain both. Hence you have to cater for that if its a major concern. I have by having a 3rd isolated battery.

48 minutes ago, kingie chaser said:

wouldnt it just be better as you suggest to have a 3rd battery & run the 3 in parallel but just run an VSR isolator between the starter & the other 2 batteries when running the electric motor but they still charge off the alternator??

Sorry KC can't visualise what you've described. To create 24V you need to run two batteries in series. But for charging purposes you need to have the alternator see each battery as a 12V battery. The trollbridge does that for you, so I'm not sure where I'd fit the VSR with what you describe. Maybe a diagram ?

 

[kingie chaser]

1 minute ago, zmk1962 said:

Sorry KC can't visualise what you've described. To create 24V you need to run two batteries in series. But for charging purposes you need to have the alternator see each battery as a 12V battery. The trollbridge does that for you, so I'm not sure where I'd fit the VSR with what you describe. Maybe a diagram ?

I didnt see the schematic of the 12x24, makes sense now.

[zmk1962]

3 minutes ago, kingie chaser said:

I didnt see the schematic of the 12x24, makes sense now.

Cool 😎 ... the Trollbridge was the very elegant break thru for me ... it simplified the whole 24V dilemma significantly.

Cheers Z

[kingie chaser]

8 minutes ago, zmk1962 said:

Cool 😎 ... the Trollbridge was the very elegant break thru for me ... it simplified the whole 24V dilemma significantly.

Cheers Z

Yes I just read & posted just as yours came up, they look pretty good & great value as well!

 

I would have thought they woulde be a lot more than that.

 

Hope it all works out 

[mob0103]

I installed a prosport 12a charger. very happy with it. easy to use.

[longy509]

The other thing to consider is will you be motoring along with the outboard enough to charge a 24v system or are you just better off charging it when you get home